General Atomics has some great powerplants to exponentially increase the dielectric discharge on these types of propulsion systems. Just like how the 6' Ionocraft Townsend Brown demo'd at Wright Patterson in the late 40s was rapid prototype engineered with greater discharge, capacitor plates, & layering to increase the Lorentz Forces to create sustainable flight. Pulsed Power applications developed at LANL and Sandia back then allowed for not only Laser Propulsion, but Ion & MHD Propulsion Systems to create extreme acceleration/velocities to "blink" across long distances which to the naked eye looks like FTL. You're welcome.
Use rotating magnets for an AC field and apply synchronised AC to the electrodes. That should minimize electrode erosion. Another way is to keep the magnets stationary and have the electrodes as part of a rotating cylinder. If you could create a closed magnetic path except for the water gap, you can use an AC coil electromagnet.
Look into halbach array magnet configurations. You can double the field strength inside your thruster by arranging the magnets so that the field is contained entirely within the thruster and the external field is cancelled out.
@@EGL24Xx Why not? This looks like the perfect application of halbach arrays to me. The field on the outside is doing nothing to help the thrust. It would be much better to direct the entire field inward.
The force on water is =B*I*L where B is the magnetic flux density, I is the current in the water( between the electrodes), L is the spacing between the electrodes(i.e length of the conducting path), Also current (I=V/R) is voltage(V) by resistance and here the resistance(R) is clearly proportional to the electrode spacing L making R=k*L where k is a proportionality constant. Long story short the force B*I*L becomes B*(V/(k*L))*L that is B*V/k i.e it is independent of the electrode spacing and linear wrt B and V. This should be fine for intuition, but the resistance is also non linear which only complicates things I must also add this, there are two currents now here, one going between the electrodes (I) and the other being the thrust flow itself(i) if you use the same rule for this new current(i) a new force arises opposing the main current (I, between the electrodes), this new force is B*i*c where B again is the magnetic field, i is the flow of water causing thrust and c now is the overall length of the electrode. The direction of this force is ixB that is the cross product of the velocity of charge flow and B(I know it's cXB but that's hard to imagine) and it is opposite to the main current I between the electrodes. This is the back emf in this system where the faster your thrust flow the lesser the current between the electrodes which inturn reduces the thrust force. To put all this mathematically, the thrust force which we saw as F=B*V/k should be replaced by F=B*(V-a*f)/k where 'a' is back emf constant, f is the thrust flow rate showing that flow rate will counter itself
I imagine this intuition probably breaks down as well for very close spacing due to viscous effects of the water over the surface. A minimum electrode spacing when stacking for a more powerfull design could come from that maybe?
A couple of errors in your assumptions, in electrochemistry most of the voltage drop happens at the electrode faces (and it's not usually symmetric), not across the length of the bulk fluid, so only a small part of resistance is proportional to spacing R≅k1+k2·L. Secondly, the way he tested spacing did not use constant magnetic flux density, since he used a single, under-sized magnet for all the tests. A test with constant flux density should show increasing thrust with increased spacing.
I think the electrode spacing test is misleading you here. You are measuring flow velocity, but that is not your actual goal, thrust is. Thust means mass flow, which is proportional to cross section and velocity. If your velocity stays constant, but your cross section increases, it means more thrust. If you are testing with a constant voltage source, more distant electrodes will mean lower current thus lower power. You also likely have a larger flow cross section with more electrode spacing, so combine that with lower power, that means wider spacing should actually be an effective way to improve your thrust/watt.
Noticed this when playing with two hovercrafts of different duct size. Small one less thrust but very powerful small stream, big one less push in a given spot but a much larger area of air so overall more push.
Good work, particularly the parametric testing. The reason the electrode spacing didn't matter was that you did not account for the return path of the magnetic field. The result is a counter magnetic field on the outer fringes closest to the plates creating turbulence and drag. You can see this at timestamp 4:28 on the upper plate on the right. It is even present during the 3cm test at timestamp 4:42. Wider spacing needs a wider magnetic field, at least as wide as the plates are. The second thing is that if you use a magnetic core, such as steel, laminated iron, or ferrite, to complete the return path, your magnetic field in the chamber will be higher still, leading to higher chamber medium velocity. PM me if you need more details. :)
I’d love to chat with you about the second version I’m building. Please shoot me an email (found under the “about” tab), and in the email 📧 indicate that we’ve spoken in comments section.
also if a higher voltage was applied the boundary layer should be considered a plane of high conductivity. If you choose underwater electrodes use a dielectric insulator on any part of the electrode outside the e field including the wiring. And have them taper vertical towards the rear and not parallel but facing away at 1-2 degrees. Also angle the magnet along the horizontal plane 5-8 degrees
This was super interesting, thanks for doing it. I had a scan through the comments and didn't find any of these points: 1) The electrode spacing doesn't change the deltaV, but it might increase the thrust because more volume is being pushed. It would be worth to measure the thrust (hang your device by a string and measure the string angle/displacement). Ultimately thrust force is what you were looking for, so that might be a better metric than DeltaV. 2) Does the current go down with increased electrode spacing? Coupled with point 1, more spacing could be even more efficient (or maybe you did test this and I missed it...) 3) When increasing the voltage, does the current increase linearly or instead have inflection point(s)? I would expect at certain voltages the chemical process (electrolysis) to change as you reach the threshold voltage for new electrolytic reactions. Although you might get less thrust from lower voltage, you might find it more efficient 4) How does the thrust change if there's already an input velocity. I suspect it doesn't (if you can rule out the drag of your vessel).
NICE! May closer spacing doesn't increase current draw because of some factors like bubbles on the metal surface could limit the draw. Good engine though, beside the side effect of electrocuting planktons!
those bubbles are also rather corrosive if i remember my chemistry classes right (NaCl + H2O NaOH + HCl), so would be interesting to see how it holds up after a year or so of runtime.
@@PlasmaChannel use alternating current and electromagnet! And also electrode distance may not affect speed, but it affects total thrust cos the water flow increases.
A laminar flow straightener behind the flow with something to increase the Reynold's number would likely increase efficiency. Break the boundary layer at the electrodes and then columnate the fluid again to get an even thrust across the nozzle. While water is rather sticky it is also viscous enough to react nicely to boundary layer separators especially since it's practically incompressible so there's little spring effect.
@@UnitSe7enThe goal is achieving more thrust and the best performance (more volume and faster speed) , every detail matters. The more tidy axial flow the better. The squared cross section of the device, works in fact, against both goals.
@@UnitSe7en Better to solve these issues *before* scaling up though. Even moving up to the kilograms-force regime would have those effects become nontrivial.
@UnitSe7en, Laminar flow makes a huge difference in aircraft but you're trying to say that it won't in a hydrodynamic environment that is literally 780 times more dense than air??? Think again.
Fun idea! As some other said, I think that smaller opening at the back might decrease the thrust rather than increase it. It does increase velocity of the water coming out but total thrust is dependent on the flow of water as well and the increased velocity most likely doesn't make up for the lost flow. This gets even more a problem if used to power a boat - because the movement forward of the boat will cause the water to also enter the inlet at some speed relative to the unit and get accelerated to even higher speed - which increases the total flow thru the unit by a lot. This will cause that opening to act like a big choke - making the thrust decrease faster with the speed as well. If the channels have the same cross section area thru the whole unit, the water will just enter with some speed and accelerate freely to even higher speed, and continue to produce thrust even when getting up to some speed.
Exactly. This flow design is for compressible fluid like air. Water is not compressible, which makes the scoop and the nozzle an unnecessary hindrance, ultimately reducing the total thrust. If we could increase the output of this thruster by about 10x per watt, it would actually become practical for some uses that I'm not going to talk about here.
Removing the convergent nozzle is right. He doesn't want that at all. But there will be zero difference in static vs. dynamic thrust. Forward movement will not increase thrust in this device.
@@UnitSe7en I never said the thrust would increase by the speed in any case. But, the nozzle will cause the thrust to DECREASE rapidly by the speed. Because the total flow thru the unit increases by the speed (even if the thrust remains constant) - and the higher the flow, the more of a restriction that nozzle will cause. If the nozzle is removed, the water can flow thru freely and allowing the unit to keep producing thrust up to higher speeds.
@@Speeder84XL I was talking about this statement: "because the movement forward of the boat will cause the water to also enter the inlet at some speed relative to the unit and get accelerated to even higher speed - " That is called dynamic thrust.
@@UnitSe7en Yes - but RELATIVE to the unit, the water will move thru it at greater speed. The water will not pass thru the unit at any greater speeds compared to the surrounding water. But if the unit it self is moving, it will from "it's own perspective" behave the same way as if the water was moving towards it and because of that also get accelerated to higher speed than it otherwise would. This will increase the flow thru it. Even if the unit is turned off and just pushed thru the water by some other force - that nozzle will still "steal" energy by creating more resistance in the water. The unit will "scoop up" some of the water, rather than just moving thru it. When the unit is in use, at least that increase in resistance will be subtracted from the thrust.
Try using Pulse Width Modulation (PWM) with a Pulse Repetition Frequency (PRF), it may save on the overall wattage. You may also try and use some low amp high voltage supply. This will allow the water once it's moving to help keep the water flowing even when the voltage is off. Kinda like once you get a tire rolling it doesn't take as much force to keep it going. You may also consider using Idler Plates, they are used in Hydro Gas Generators to keep the water charged while using less electricity. Hope that helps give you some more things to consider and test with. Best Wishes & Blessings. Keith Noneya
@@paulschrum4727 Well sort of. When an electric motor is running it has a term called RLA Running Load Amperage and it's usually quit a big lower than what it takes start it. When a motor 1st starts it has what's called a LRA Lock Rotor Amperage, meaning that's how many amps it takes or draws to initially get the rotor moving. It's one of the primary reasons most home generators can't run a whole household if you have a large AC unit. To figure out how big a generator you'd need you'd have to look at your AC System Tags to find the LRA rating on both the inside and outside units. Add those up and multiply it times the Voltage the system is designed to run on. My old outside unit had an LRA of 110. So multiply that times the volts 220x110 = 24,200 watts. That would be the minimum size generator to start my old AC. You reduce that same system by around 30% adding a soft-start module. So the point I'm trying to make is in order to get the water moving takes a lot of energy, but once it's moving it has a lot of mass and it's not going to stop on a dime like a rolling tire or car or a mass of water. So once it's moving it should only take a pulse now and then to keep it moving at the same flow rate. At least that's my theory.
@@keithnoneya Thanks. This just reminds me of having 1st gear in a car be high torque for getting started, then as speed increases, the gear ratio can be reduced and can keep a car moving at 60 mph with much less power. That's why I asked about the analogy to mechanical power systems.
@@keithnoneya Great explanation and example. This makes sense when thinking about how an old vacuum or power tool may dim the lights in the room when first starting up but then return to standard brightness once the motor is running.
Drag is going to be the limiting factor in this thruster. On top of the thruster drag there will be a vessel drag component as well. So the lengh making faster flow is great for a practical display, but optimizing the design would require that drag be the factor used to determine field strength and voltage inputs. For any given thruster size, it will have a maximum velocity in the water due to it's drag. Practically speaking this would mean that the nozzle used in this video would be a limiting factor of volume because the fluid cannot be compressed. Therefore the nozzle increases drag, and limits volume. I would imagine that a thr
I think this is really cool. A nice upgrade would be a hexagonal configuration and you could run it like a bldc. It could make a water screw improving velocity further
@@KangJangkrik I literally got my last bite. It went pretty well, didn't hurt my tongue or burn it with the fried chicken. Thank you for warning me... lol But I went pretty close from burning my apartment because when I was frying the oil it almost overflew on the red hot element! Fortunately I was quick enough to remove the pot. Never do some frying with a pot and leaving it unattended...
As pointed out by another commenter in another comment thread - a Halbach array doesn't have a uniform linear magnetic field - it would be stronger but would alternately accelerate the water forwards and backwards causing a significant performance penalty at best, or rendering the thruster completely useless at worst.
@@bosstowndynamics5488 You could probably take advantage of that actually. You don't need a uniform magnetic field if you make your electric field also non-uniform, pair that with boundary layer separators and you'd have one funky looking mess of a thruster. You'd probably need somrthing like an evolutionary algorithm to design that thruster for you though. Still, with a 3D printer, it may very well be possible to actually build whatever your fancy genetic algorithm designs. You can buy conductive 3D printer filament.
YES to the magnetic closed circuit, just as is done in dynamic loudspeakers. Significant magnetic field strength is wasted without a closed magnetic circuit between the two outer magnets. Water does NOT close a *magnetic* loop. Also, placing the magnets closer together-perhaps a wider, yet shorter channel for the same volume, will yield a significant increase in magnetic field strength.
It's been a while, but the novel of the Hunt for Red October the RO used ducted turbines deep in the hull. It was called a "caterpillar" because it had many turbines spinning pushing the water. IIRC it did use magnets to move the turbines (instead of prop shafts and motors).
I think you’ll find the exposed electrodes in the water are causing losses. The whole point of the drive is to accelerate charged particles, in the form of ions in the salt solution, using Lorenz force. By having the electrodes exposed you’re allowing ions to loose their charge and escape as gases. You should insulate the electrodes to prevent this, while the losses may be minimal you should still do it to prevent chlorine/hydrogen from being produced which could potentially cause you harm. This may also be the reason why you’re not finding gains in fluid velocity when moving the electrodes closer, as this makes it easier for the ions to move to the electrodes and neutralise, increasing losses. Oh and Lorenz force is governed by electric field flux density, not potential, (I think) so I’d be measuring the effect of current rather than voltage on performance for more direct results. Sorry for the long reply lol, I think the project’s really cool and I’m planning on building one myself at some point!
One design consideration that you're not considering here is the drag of the thruster. It's fine for this test to have a bulky design since the surrounding water is fairly static, but on a boat once it gets going there comes a point where the bulk will definitely be a hindrance. STRICTLY SPEAKING, a MHD could be built with very little drag by lining the boat's hull length-wise with alternating electrode-magnet strips in the pattern +,N,-,S,+,N,-,S,+,N,-,S,+, ... This would mean that the hull of the boat is almost "wrapped" with an EM field where the electric and magnetic field are intersecting almost perpendicularly at every point thus generating a skin layer of thrust along the entire hull. My hypothesis with this is that the thinner the strips (and hence the more +,N,-,S sets per unit length one has along the crossection) the more efficient the energy transfer will be because the field will be more localised around the boat. Also maybe putting some thought into how the wiring is run to the electrodes might help by orienting the magnetic field their current generates to form additively to the fields of the bar magnets rather than have them be wasted EM emissions.
One suggestion - you really need an iron backer to give the magnetic field lines a place to return that aren't the 'wrong' direction through your water.
A pair of halbach arrays with opposite polarities and iron backplanes would give an insanely strong field across the thrust tube. Would sidewalls connecting the backplanes also confine the stray fields? I wonder how well drilling the coils out of a microwave transformer would work as a magnet housing, assuming you could get arrays small enough to fit in the gaps.
@@dustinbrueggemann1875 No, using a halbach array while using a material with good "magnetic conductivity" would be pretty useless. Halbach arrays Increase the field strength on one side and lower it on the other. Plus you want the magnetic field to go all in the same direction, not alternating orientations like your suggestion would entail. What OP suggest is both easier to construct and more efficient.
have you considered a column of ring magnets in the center of an aluminum tube? Forcing the current to run only through the magnetic fields could have an interesting effect.
FANTASTIC! A clear design direction for dramatically increased thrust from an electromagnetics engineer: Widen the port aspect ratio (more distance between electrodes, less distance between magnets), and add a magnetic return path between top and bottom magnets. Reasoning: 1. Low to no loss of thrust from widening the gap between electrodes. 2. HIGH gain of thrust from increase in magnetic field strength easily obtainable by moving magnets closer together and adding a magnetic flux return path from top to bottom magnets. A bit like two custom C-clamps wrapping around each side and clamping against the top and bottom magnets, creating a flux return path. Think of each magnet like a "magnetic battery," and the gaps between magnets as resistors. If you want more current (flux) to flow, you can increase the "voltage" (magnet strength), and/or reduce the path resistance (distance between magnets). A flux return path is like a low-resistance solid conductor in an electrical circuit, so the lower "circuit" resistance means the "current" (flux) goes up. Higher flux, higher thrust of your design. Beautiful work. Thanks for sharing it!
Thanks Alan! Yeah I had never heard of a Halbach array until I posted this video - sounds like that’s an option. One thing I’m curious about though, is the loss of electric field density when electrodes spaced further away, and this less interactive pushing force. I feel like if magnets were halved in distance, and electrodes doubled in spacing, the water flow would be identical, no?
I'm not proposing anything exotic like a Halbach array. You should be able to use all the same magnet and electrode hardware you have now. You can gain a dramatic increase in thrust merely by changing the aspect ratio of your water ports to reduce the distance between magnets, and adding a flux return path between top and bottom magnets. Reasoning: Your testing showed a weak relationship between electrode distance and thrust, yes? So, for example, widening the channel by a factor of 2x will have a very minor cost to thrust. Now halving the distance between the magnets will increase magnetic field strength by 2x. And since there's a strong relationship between magnetic field strength and thrust, you should get more thrust out. Yet the port area is unchanged. Your lowest hanging fruit for increasing magnetic field density is by closing that HUGE air gap between the outer surfaces of top and bottom magnets. This will dramatically reduce magnetic circuit reluctance (akin to electrical circuit resistance). As you already know, be sure all magnets have their poles oriented the same direction, or they'll cancel, like placing batteries in series: you always go + to - to + to - etc., which will have them add, or + to + or - to - will have them subtract.@@PlasmaChannel
Here is some ideas to implement into more research in the design to generate increased thrust in the divice. 1. Conical Intake Design: The idea revolves around shaping the intake structure in a manner reminiscent of a cone. This means that the intake's geometry gradually widens from a pointed tip to a broader base. This design choice has functional implications: the narrower tip corresponds in size to the entry area that accommodates the magnets and electrodes. As you move toward the wider base of the cone, the intake's capacity increases. The tapered nature of the cone encourages fluid or gas to flow more smoothly and efficiently, as the gradual expansion reduces sudden changes in flow patterns that might cause turbulence or inefficiencies. 2. Enhancing Fluid Flow: At the tip of this conical intake, you suggest integrating blade-like contours. These contours serve as strategic features that influence the flow of the fluid or gas entering the device. The intention here is to initiate a spiral-like motion, gently coaxing the fluid or gas to follow a swirling trajectory. This spiral flow pattern carries several benefits. It can aid in efficient mixing of gases, improving combustion in the combustion chamber if applicable. Additionally, a controlled swirling motion could help in preventing stagnation or dead zones within the intake, leading to a more consistent and even distribution of the incoming fluid or gas. 3. Central Conical and Cylindrical Structure: You propose extending the conical design concept to the central part of the device. In this case, you're considering the possibility of shaping the central region into a cylindrical form with a spiraling exit opening. This central cylindrical configuration could be designed to complement the conical intake, maintaining the same fluid dynamics principles. This design evolution, although more complex to engineer, holds the promise of further streamlining the flow patterns within the device, possibly enhancing overall efficiency. 4. Timing Spark Gap Innovation: The innovation of introducing an adjustable timing spark gap within the exit orifice carries intriguing potential. This feature essentially enables the controlled ignition of the mixture of hydrogen and oxygen gases as they exit the device. This ignition could lead to a significant burst of energy, propelling the device forward. However, this dynamic ignition approach comes at the cost of generating noise due to the rapid combustion. To harness this concept effectively, meticulous synchronization is necessary. Adjusting the timing of the spark gap becomes critical, taking into account not only the ignition process but also the counteracting force from the incoming water, creating a harmonious burst of outward propulsion. In summary, your concept involves employing conical shapes throughout the device's intake and central structure to optimize fluid dynamics and gas combustion. Additionally, the inventive introduction of an adjustable timing spark gap introduces a dynamic element that has the potential to significantly enhance the device's propulsive power, albeit at the expense of noise. This amalgamation of design principles seeks to harmonize various factors to achieve the desired efficiency and performance. Cant wait to see more on this.
I'm amazed at the thrust you produced on your first attempt! For efficiency, electrode spacing should be your last parameter to test/adjust. I've seen other comments make this point as well. You didn't have enough energy in the system yet to get a measurable result. I understand why you would want to adjust voltage last, but you can definitely maximize your mag flux first before finding the optimal electrode spacing. Two variables to consider when doing this- one obvious one you are already familiar with is arcing, but the other is volume of energized medium. You will hit a point of diminishing returns as you collapse the volume of fluid that can be accelerated between the electrodes. I think this can be somewhat mitigated if you use a staged approach, perhaps with one wider MHD at entry leading down to many narrow MHDs at exit
Man your channel is more important to me than you know it’s good to see dudes doing good interesting things like this and networking with other interested professionals. Keep playing the game you’re pushing humanity forward
Are you concerned about generating chlorine gas with this electrolysis setup? Or are you using something other than NaCl for the salt in the water? I'd be worried about pushing the voltage up with table salt in the water, that could get dangerous.
At the scale and duration of these tests there shouldn't be much chlorine production. When scaled up to a full-sized boat though you'll definitely be glad you're outdoors.
With copper, iron and aluminum electrodes the anode is chemically degraded by the current and no chlorine is produced. With graphite electrodes they suffer less damage but produce a lot of chlorine vapor.
Electrolysis, top secret navy propulsion systems !!! And separating the molecular bond between hydrogen and oxygen that are also explosive ... Love the Channel
I would redo your test while considering watts in relation to thrust or mass flow. Also consider lover voltage. Voltage below electrolysis doesn’t waste energy on splitting the molecules into ions so it should be more efficient.
@@PlasmaChannel yes I thought about that but what if you make very thin square maybe 5mm x 5mm or even smaller. That way the current should be sufficient, I would assume lover resistance. Very glad your answered my comment btw:)
What if, instead of using direct current perpendicular to a permanent magnetic field, you used a linear sequence of magnets, driven by 3-phase alternating current? (In other words, imagine a string of chasing Christmas lights, but with magnets instead of lights.) The design in the video is like a railgun for water, but this would be more like a coil gun for the water. The reason you're getting the electrolysis is because the current is starting at one electrode and going through the water to the other electrode. Electrolysis happens because electrons are being pulled from their atoms when they jump to the metal electrode. But with a coil gun type design, the only current in the water itself would be eddy currents going in a circle, so there's no electrolysis. All the components carrying electricity would be sealed and water-tight.
@@John73John See the issue here is that the lorentz force only needs the object (water in this case, or a railgun sabot) to be electrically conductive. A coilgun, on the other hand, requires its projectile to be *ferromagnetic*, which water is unfortunately not. Coilguns are definitely better than railguns for moving objects at speed, but only if that object includes materials of a particular kind
@@blak4831Not necessarily. If a strong magnet and any electrically conductive material move past each other quickly, electrical induction will create eddy currents in the material. The eddy currents have their own magnetic field that tends to oppose the relative motion. I did this in my freshmen university physics course using a large horseshoe magnet and pendulum with a thin copper plate at the end -- as the pendulum swings between the poles of the magnet, it will stop quickly even though copper isn't ferromagnetic. Turning it around and putting the magnet on the pendulum and swinging it past the plate causes the plate to experience a force in the same direction as the magnet is moving. The same effect can be achieved as I described above, by using several stationary magnets and sequentially turning them on and off -- it's exactly the same principle as an induction motor except it's linear rather than rotary. Now, this might not be as effective with water as it is with copper because water has a lot more resistance. But it would at least avoid the other problems associated with electrolysis: Your boat generates a cloud of explosive hydrogen gas behind it, if you're doing this in salt water then you're also going to generate highly poisonous chlorine gas, and the formation of unwanted materials on the electrodes.
Hi folks If you want to try this at home, please ensure to do it in a well vented area as it produces flammable hydrogen and also chlorine gas. No reason not to try this though so long as basic safety measures are taken. I'll definitely be trying this myself!
@@the11382 yes, chlorine is more electronegative than oxygen so is the main gas produced by electrolysing salt water, together with hydrogen at the other electrode.
The amount of chlorine produced is very negligible. Chlorine isn’t crazy toxic in low concentrations and since it is in water, it might redissolve to create HCL. Chlorine is very attracted to moisture so it’s unlikely it will create the large of an issue. Hydrogen however will cause problems in small quantities but since this produces probably less than a liter and hour and is completely ventilated it’s kind of a non-issue
"To my local scientific supplier, often mistaken for a home improvement store" 😂 So true! The people at my local store have stopped asking if they can help me find something and started asking what I'm working on today. As they know I'm likely bot using something for what it is being marketed as, lol.
This is so cool I hope I can do things like this some day as I am still learning about high voltage and electronics and this channel has been an inspiration for that thank you
I think that a more narrow gaps leads to increased resistance, in the water flow, that cancels out the increased force applied. Maybe testing with different depths of water would show a difference
@@MB-st7be there is less water, but the ratio between frictio inside the water and the friction with the electrodes are higher. I just thought it might be the case, because if you have a smaller flow channel you neef a higher pressure gradient, if you look at poiseuilles equation(which is for a pipe, but i think the same tendencies should be happening for other systems).
@@MB-st7be It's the attraction between the water molecules that means more resistance. It's easier for them to 'stick' to each other and the walls of the thruster when there's less space between electrodes, I think. It's the same physics that generates surface tension.
In the book, the Red October actually has impellers in the two shafts for the caterpillar drive. The pressure pulses, and resulting sounds, are how the sonar crew picked it up. In the book, as the story goes, the US toyed with this sort of system but wasn't able to get past the backpressure issue and abandoned it but the Russians made it work. In the movie it was a "magnetohydrodynamic drive" but again that's different than the book.
Man, when you put that thing in the ocean and traveled. Wow. This renews my hopes of someday building a balsa, rubber band powered, craft for air travel.
This is a fun project. I would like to see it propel a kayak for a long distance. It doesn't seem like it can produce enough thrust for a long enough period of time without making one that's too heavy.
for electrodes, check out those pool chlorine generators. They are designed for this purpose. You gotta take em apart to get the electrodes. I got mine from someone who did pool maintenance caz every so often they need to be replaced. The ones I got were completely jammed with salt. easy for me. trash for him. The electrode is some kinda vanadium oxide on titanium. I use them ALL the time & they surpass everything by lightyears. Second best non-corroding electrode if you have to buy... is ... titanium. Ti is cheap & the least prone to dissolve.
I see stuff on this off and on every so often. Its a really cool concept and on small scale can produce some entertaining results. So far however I've never seen anyone able to scale it up to a usable size. The one attempt I heard about (bear in mind this was a decade or more ago i read about this) got a ship up to 15 knots and maxed out there for a lot of energy. They figured out Magnet tec is not there yet. Electronics and Salt water don't mix well (surprise). And it needed a LOT of power.
"This is also how a railgun works"... I find that explanation the best hit in the entire movie. If you know how a maglev/rail-gun/gauss-gun/etc. works, you know the basics of this MHD propulsion. Thanks for the hint.
This is so amazing. Thank you for sharing this with us. Using this to advance desalination with no moving parts. So many other places this tech could be used.
Great video. Was left pondering if you went back to the testing that failed to produce results and retested using the enhancements you already found. Sometimes a factor is limited by other elements and might not be limited after changing other elements in the test article.
Probably should be measuring volume of flow instead of just velocity of flow. 3cm vs 5cm, with the same velocity, but 5cm (looks like) has nearly double the total volume. Especially if it allows you to put more magnets next to eachother. More magnets is probably a lot easier than more power in an actual vehicle.
This is exactly the problem I saw with his design, you cannot compress that water in this thruster, therefore making a small nozzle is really just a current or throughput limiting component to the thruster. It looks cool, but in reality overall thrust would be most impacted by volume the thruster can move.
ACTUALLY in Hunt For Red October it was not an MHD drive. At least not in the book. It was an impeller design. The film made some remarks pointing towards MHD (Superconductors), though.
@@LeoH3L1 Nooo, not really.. They never use that term, nor actually go into any details. It's only mentioned that it's a new type of magnetic drive. They do not explicitly call it a MHD or really say much else about it at all.
@@UnitSe7en WRONG. It definitely calls it an MHD in several scenes... At the shipyard.... Skip Tyler: I'll be... This... This could be a caterpillar. Jack Ryan: A what? Skip Tyler: Uh, a caterpillar drive. Skip Tyler: Magneto-hydrodynamic propulsion. In the Joint chiefs briefing... Jack Ryan: We believe that these doors, here on the bow and again on the stern, enclose a unique propulsion system... a magneto-hydrodynamic drive, or caterpillar that would enable the sub to run virtually silent. And refers to the design as having magnets in the scene where it is sabotaged... Captain Borodin: What happened? Lieutenant Melekhin: The cryogenic plant! Lieutenant Melekhin: The magnets aren't cooling. Lieutenant Melekhin: Temperature in the caterpillar is 50 degrees above red line and rising.
This is really cool, and I appreciate the care and attention to detail here! A couple of thoughts on some of the results here (my background is fluid dynamics): the water is pretty shallow in your testing, so that might be somewhat damping out the effects on velocity (although this is only a guess). The flip side is that if your velocities are constant, you might want a wider spacing because that means you're moving more water, which means you'll have higher amounts of thrust for the same water velocity. The parametric testing was cool, and I appreciate it! Have you heard of Box-Behnken design of experiments? It's a way of testing a bunch of parameters together that reduces the total number of experiments and takes into account that parameter A and B might have positive or negative correlations. Thanks again for the video!
Umm... The way I remember the story of the Mitsubishi MHD is that the strength didn't really scale well, and despite having massive diesel generators it produced some pitiful amounts of thrust. But it's a nice project :)
What would be really interesting is to know the effectiveness of this kind of propulsion and how it compares to other types like typical propellers or jets.
Always wondered if insulated high voltage AC electrodes combined with superconducting AC magnet coils which are synced to the electrodes alternating voltage would also work and therby get rid of the electrolysis completely.
@@norbertfeurle7905well i believe that you need to have currents going through the water for the effect to work so electrolysis is going to happen no matter what
The distance between the electrodes mostly applies as a function of ion density/saturation. Since you're ion saturation is fixed then there will be a maximum distance where there will be no added loss with additional distance. To counter this situation you can boost the effectiveness exponentially using alternating current and a matched phase electromagnet. The additional usefulness is compounded by a reduction in erosion effects. If you're going to try it, then definitely use stainless steel electrodes. You can also apply the halbach array concept to the electro magnets to increase performance further
An MHD is used in the Oregon Files books by Clive Cussler. They're about a secret off-the-books outfit that operates from a super advanced ship that's disguised as a tramp steamer. It's propelled by an MHD, however, it's far more advanced and powerful than anything in real life, allowing the ship to move incredibly fast for its size.
I love the idea and concept. Just wondering, have you tested the salt water afterwards? Because of the electricity passing through the water, doesn't it become more chlorinated?
It was given the nickname "Caterpillar" because they used several in series which not only applies thrust but were also optimized for the pre-accelerated input flows. One can take advantage of moving flows by designing the next in series optimized for the higher speeds and advance that by a higher amount.
@@PlasmaChannelnooo! Thrust comes from the current in the water pushing the magnets. Water moving backwards inside the duct is a necessary evil but does not in itself add any performance, it only increases friction inside the duct experienced by the hull as drag. Flow inside a closed duct is at a constant velocity, simple conservation of mass. If you are going to use multiple thrusters, rather arrange them in parallel.
@@PlasmaChannelyou are also wasting a good deal if curret from the un-insulated outward facing electrode surfaces. Current sneaks around the outside to the opposite electrode. Had your top and bottom magnets been the epoxy coated type, this current would have been flowing over the magnet resulting in reverse thrust. Since your magnets had condutive platings the current "climbed onto" and flowed through the magnet plating before jumping off the far edge to complete the remaining distance through the water. You can clearly see the resulting electrolysis along the magnet edges. Try to eliminate this external current altogether by insulating the backsides of the electrodes. You can also save on wasted current by trimming the electrodes slightly shorter than the magnets lengthwise. The electrode tips send some current through an arc (curve) extending fore and aft outside the duct wher the magnetic field is much weaker and the thrust is simply not worth the extra amps.
Series thrusters of this type will have zero benefit except using more power. The maximum flow through this thruster is defined by the field. This does not work like a turbine.
If you want to try something, use different shaped exhaust nozzles. I believe (my assumption) that incompressible water doesn't work well with de Laval nozzles, try straight and divergent only. This is something I noticed on jet pumps.
Very cool experiment! One side note: using current instead of voltage as a parameter could give a clearer picture of the effect of varying parameters. For example, making the electrodes longer doesn't increase efficiency, but it does allow more current to flow which is actually what causes the increase in thrust/flow.
It also increases the aspect ratio between opening and electrode area. As water flow the ions are carried with the water, obviously they eventually reach electrode but the path is more in line with the water flow with longer electrodes and a shorter opening
@@cybyrd9615 nice catch! I hadn't taken the flow of the ion medium (water) into account yet. So in theory it should be more efficient with multiple narrow channels as opposed to one wider channel. :)
To quote a saying: 'A sufficiently advanced technology is indistinguishable from magic'. For someone from 300 years ago electricity would be magic. So, quite likely, would be concrete.
@@echomande4395I love that quote. I’m actually a writer and one of my WIP involves a person from pseudo-medieval time period being exposed to modern technology and being utterly horrified, thinking it’s witchcraft
Very nice. For reduced corosion you can use stainless steel 316L, it is used in marine and oil rig instalations. More exotic it is 316L with a coating of titanium. This materials are used in HHO instalations to prevent corosion and contamination of the cells.
Two major concerns that came to my mind: One, your electrodes and magnets were steadily and rapidly dissolving, especially at higher voltages. Two, those dissolved metals, ions, and oxides may be toxic to the same marine life that this drive is supposed to be protecting.
@@kaasmeester5903 No doubt various militaries already experimented or are still experimenting with MHD. It clearly doesn't take much to build an MHD thruster.
Very interesting. Thanks for taking one for the team, and performing this experiment. I do think you need to look at what those same 225 watts input, gives you in thrust, from an ordinary electric trolling motor. Also, you might figure out what fraction of a horsepower (hint... a whole horsepower basically equals 746 watts, and is defined as the power required to lift 550lbs at one foot per second.) I am guessing that your device is operating full throttle at about .01hp. Or about 7.46 watts of output power. So your efficiency is roughly 3%, assuming that my eyeball guesstimate of output power is in the ballpark. I am not too surprised that you achieved a positive result. I am also not surprised that it is incredibly inefficient. Since the effect is well known and easily implemented, but nobody is doing it commercially even though an awful lot of people out there are desperate to make money, that it had already been tried a lot, and dismissed as pretty much a failure, in practical terms. Viable ideas have a habit of being turned into commercial success. Everyone has to be that guy who did it first. Rudolf Diesel. George Westinghouse. Thomas Edison. The Wright Brothers. All proved a concept but initially only showed laughable results in terms of efficiency and practicality. But honestly I don't see this as really becoming a thing. And I can tell you positootly that it is NOT silent. You just aren't listening correctly. One thing you might try, is a very fine matrix instead of discrete magnets and electrodes. Think like nanotubes, bundled together. Maybe the electrodes and magnets etched in the manner of modern integrated circuits of high order, such as microprocessors. Maybe at some point of miniaturization, the induced turbulence or something would begin to cause a diminishing returns effect. Who knows? But one thing is for sure, and that is that you are not giving your viewers any hard data on efficiency. Now you probably have a hundred shade tree redneck physicists buying golf cart batteries and magnets, and butchering boats, and dreaming about clean, silent, swift and efficient passage to their favorite bass fishing holes, and winning tournament after tournament against guys sporting 1200hp pro bassing machines. They are gonna be pretty disappointed. The same guys who saw Wile E. Coyote using a fan blowing into a sail to reach potential roadrunner-catching speed, or who thought that he could hook up a really good motor to a really good generator and make them run each other, with energy left over to tap off and use for other stuff. Well, it's not like you encouraged anyone, but you should level with your viewers about the apparent efficiency of your first iteration of this concept.
I don't think he ever claimed it was efficient in it's current iteration, just an interesting experiment that's potentially worth doing (if for nothing else than to satisfy his own curiosity). Perhaps someday these exotic engines (this and the ionic thruster come to mind) will become viable due to repeated iterations and passionate hobbyist who are willing to put in the work even if it seems unlikely to ever succeed. It's also worth noting that the engine doesn't necessarily have to be more efficient than an outboard motor to have some practical use, if it gets to be powerful and efficient enough and can deliver other advantages like operating in relative silence (compared to other motors) it could still find some commercial (and/or military) success. Never let perfection be the enemy of good.
There you go girls , length matters, and circumference matters, to increase the velocity of the fluid. It's called magnetism. This is a most informative video and interesting new science to me. Thank you for sharing.
Absolutely fascinating video! The ingenuity and creativity displayed in building and testing the MHD Thruster are truly inspiring. Your exploration of the variables and their effects on thrust is both thorough and thought-provoking. One intriguing observation was the relationship between electrode spacing and thrust, which seemed to follow a sigmoid curve, characterized by an S-shaped pattern bound between two thresholds. This sigmoid curve can often be described by the equation:f(x) = L / (1 + e^(-k * (x - x0))) Given that the other variables-strength of the magnet, voltage, and length of the electrodes-all showed positive correlations with thrust, it would be fascinating to explore potential synergies between these factors. Here's a suggested methodology: 1. Multivariate Analysis: Conduct a series of controlled experiments, systematically varying electrode spacing, magnet strength, voltage, and electrode length. Record the thrust produced for each combination of variables. 2. Statistical Modeling: Use multivariate regression or other statistical modeling techniques to analyze how these variables interact. Look for interactions that might explain the sigmoid curve observed with electrode spacing. 3. Optimization: Based on the statistical model, identify combinations of variables that might maximize thrust or efficiency. Explore whether there are optimal ranges or specific values that align with the sigmoid pattern. This approach could reveal deeper insights into the behavior of the MHD system and uncover synergies that lead to further optimization in the design of MHD thrusters. Keep up the fantastic work, and thank you for sharing your passion and innovation with all of us!
Absolutely pathetic. 20v and 9A is what a small e-scooter would draw. It can pull you uphill. This thing barely moves a hundredth of your weight. ps: I don't see how this can be not absolutely obvious to a sentient physical being.
@redemption7488 Yeah, youtube comments are full of them. Not as bad as all the conspiracy nuts asking about how this can create "anti-gravity" or "free-energy" devices though.
My guess is closer electrode spacing leads to higher E field strength, but proportionately less volume of water between the electrodes to actually be thrusted, so the two things cancel out? Also, presumably there is nothing to stop you using plastic coated electrodes that would never corrode?
@@umutcandemirci4242 Good point, I was thinking it was the random ions in the water that experience thrust, but I guess you actually need to manufacture lots of ions by electrolysis, so you do need current
Fascinating! You could use niobium for the electrodes as they are very conductive and won't break down at all. Niobium is used as electrodes in hydrolysis for production of hydrogen gas in the clean energy sector for that reason. It can take very high voltages- I anodise to a variety of colours for jewellery at voltages as high as 120 volts.
Hi , I have been a sea captain for 45 years and found this very interesting . I don't know if anyone has mentioned that the anode on boats naturally degrades and gets eaten away . This would be a real problem as the more you increase the power the faster the anode and cathode will disappear. if you can overcome the degradation problem it may be viable . Just look at the anode zinc blocks on a standard vessel . Electrolysis will eat away a steel hull very fast if the zinc anodes are of poor quality or are badly connected . Just saying this is a problem . Good luck
When looking at the spacing you only measured velocity and not mass flow. You may find that the wider spacing gives improvements as your percentage losses to wall friction will also be reduced with a larger cross section. Height or depth of the thruster would also be something to optimise again whilst looking at the mass flow.
Verry good explained construction 👍 Can you also end up using a double nested eggshell as an attached end spout or, for example, tea eggs? (Two nested tea eggs with insulating bars, one bowl slightly larger than the other, smaller bowl. The voltage is then applied offset there: The first voltage is at the beginning of the first inner tea egg. The second different voltage is on the outside End of second tee - egg up. To finish, perforate the shell of the outer bowl and put on a small cone. To begin with, however, all you need is an insulated connector to the middle of the tee - egg and an intermediate annular channel between the shells. Inside is used a secondary, better conducting gas for experimentally improved flow.
I've no real idea how any of this works BUT I love my electric prop for my kayak but what I'd love even more would be something more quiet and more efficient. So if this is it - sign me up! :) Can't wait to see you put this on a small boat, subbed!
I cross B is what drives the force. Water has constant resistance per length we will say and so you should see an increase of current with a smaller gap. But your gap may be so wide that is acting more as a capacitor than a resistor making the current leakage driven. If I remember from my course though, mhd is voltage driven. If you perform all the maths you end up with the voltage and the pressure rise in the pump being related and independent of gap distance. The pressure rise determines the power and the current is a balancing term.
The US navy did experiment with MHDs but found that they are still plenty loud at high thrust levels because of all the bubbles formed on the electrodes, and a large slow turning prop is very quiet especially next to all the pump noise for cooling the reactor.
biggest issue I'd see regarding commercialisation is in the "leisure boat" department. some people mostly have their yachts in salt (and brackish) water, others only yacht around fresh water, some switch it up every now and then. Considering that salt water is going to be a lot easier to electrify, the setup of the 'optimal MHD thruster' might be different in salt vs fresh water, leading to wildly different outputs depending on whether the boat is in salt water or fresh water. would love to see this revisited to compare performance in salt vs fresh (vs brackish) water and to see what the differences in optimal setup would be and whether minimal adjustments (that might be made automatically, like toggling fresh vs salt water mode) would be doable.
The ultimate angler's propulsion system. Not unlike electric bikes; adding this to SUP could be next. Way more sophisticated than my mundane ryobo 18 volt powered submersible water pump. But, no saltwater required!
I have come to really like this channels plasma theme. Keep up the great work! You have inspired me to build my first tesla coil. Slayer is going to be my first circuit. Coil is done.
Water doesn't compress I think your outlet and inlet don't need to be so slanted. If you use a ring configuration you may limit vortexes on your corners making your flow more laminar. I would be interested to see if a ring of magnets in the middle of the thruster would allow a stronger field and more propulsion. 2 stages could be tried too. One in front of the other.
Wtg!!! Don't know why, but I knew magnetism was key a lot of scientific revolution when I was growing up...perhaps I was tapping into the Life Scrolls or someone else's tap..but I even felt it was the key to space travel(turns out it gives ship it's own gravitational field), as well as free from fuel/resource necessity which is totally awesome to be APART of the generation/ERA to bring about SO MANY IMPLEMENTED IMPROVEMENTS THAT NOT JUST HELPED MANKIND BUT TURNED AROUND OUR PLACE UPON THE PLANET WHERE WE HELPED IT RATHER THAN HURT IT AND THUS HURT EVERYTHING AND EVERYONE ELSE.
At least with this technology will be used for good intentions to quiet the oceans for marine animals. I'm super glad you mentioned Hunt for Red October cause it's the one movie I learned about such tech, and it's also among my most favorite! It is super nice to see this technology being explored as an option for hydro propellant for ships, that it'll surely make the future look pretty sick! I think Halo 3 was also showing it's use for boats during the first Scarab encounter, I did not see any propellers on the grounded boats except their intake and fixed nozzles. Not sure about it, but that's just my thought!
Excellent demo, Quick suggestion, try Electromagnet - With those 3 parameter, once you have electromagnet - you can increase the power of electromagnet, that will be 4th parameter, higher the power of electromagnet, greater the force, Cheers!
I worked in a magnet shop and we would stack magnets sideways to make the magnetic field reach out further and have a more direct area. For instance stack vertical of north on its side and south on the other then put one in the middle of the 4 facing the opposite of the 2 and in the middle has a further gause
Higher voltage also increases the rate of hydrolysis (lost energy), reducing efficiency. It voltage/current also increases the corrosion rate, so you would likely need to coat in inert material (platinum) for long-term use.
Looking at the shot @10:26, there is a lot of gas being produced at the points where you connect the power lines. I'm no hydro-electric engineer but I would figure a lot of current is flowing around the engine instead of through. So insulating those parts might increase the efficiency by forcing the current to flow through water that is experiencing the strongest magnetic field.
More space for the same velocity means moving more water, more work. You may be capping how much your magnet can push within that area, and it's dumping the excess energy into heat? maybe corrosion? Can probably have some fun with bernoulli's principle.
Grat video! You should consider making your test chamber much longer, so that you don't form circular flow moving from outlet to inlet. The motor geometry (electrode length and spacing...) will become a more significant variable which couples to your other variables depending on the flow interactions. Once the chamber is long enough to produce negligible rotating flow, you won't have to worry about additional uncontrolled variables. 😁
Fun fact: a related thing, the magneto*plasma*dynamic thruster, is actually one of the most efficient spacecraft propulsion methods tested. It's not quite in the top spot, but it has a whole lot more thrust than its competitors in the electric propulsion department, and still easily competes on efficiency, beating out many of the less efficient ones
I would like to suggest to make the electrodes from stainless steel and increase the scale, because some technologies do not work very well in small scales, by the way, the voltage should be increased significantly, let's say to the level of air ionization, but basically you are amazing for doing this! I love your channel and everything you do because if you do something you may fail sometimes but if you try hard enough you will eventually succeed! but if you sit on the couch all the time, then nothing will work 100% , thanks for content!
Scale it up and buy smaller permanent magnets and position them in Halbach array, also integrate a previous ionization stage (electrodes with sharp pointy edges) and test it in salty water, you could put the MHD thrusters in your ionic catamaran.
the direction of charge flow with such a set up will be perpendicular to the magnetic field initially, but once the charged ions are acted on and their path turned, the force the experienced will no longer be in line with the direction of desired flow. not sure if there is enough flow to keep some from turning direction more that 90 degrees, but once they do, they are counteracting your flow perhaps some layering of E field electrodes and B field electromagnets can be frequency controlled to keep the resultant force pointed in the direction of desired flow - also increasing electrode surface area should increase the rate of ion production and thus the charge density of the flow stream - i think... also also, the idea of corroding metal into our waterways is prolly a nonstarter - but neat to play with in small scale
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Let me know your thoughts down below - I'll be revising this to increase output. For the time being, 3D files can be found on my Patreon site!
Bro u r genius 😎
General Atomics has some great powerplants to exponentially increase the dielectric discharge on these types of propulsion systems. Just like how the 6' Ionocraft Townsend Brown demo'd at Wright Patterson in the late 40s was rapid prototype engineered with greater discharge, capacitor plates, & layering to increase the Lorentz Forces to create sustainable flight.
Pulsed Power applications developed at LANL and Sandia back then allowed for not only Laser Propulsion, but Ion & MHD Propulsion Systems to create extreme acceleration/velocities to "blink" across long distances which to the naked eye looks like FTL.
You're welcome.
can you make new star in jar useing tritum atomes
Use rotating magnets for an AC field and apply synchronised AC to the electrodes. That should minimize electrode erosion.
Another way is to keep the magnets stationary and have the electrodes as part of a rotating cylinder.
If you could create a closed magnetic path except for the water gap, you can use an AC coil electromagnet.
where can i get that ruler
Look into halbach array magnet configurations. You can double the field strength inside your thruster by arranging the magnets so that the field is contained entirely within the thruster and the external field is cancelled out.
Oh I get it now it took me a minute to figure it out what u meant, I think that's a very good idea too
I was about to suggest this.
Also would allow for several thrusters next to each other as the magnetic fields would be less noisy.
Yeah sorry, that isn't going to be helpful in this topology
@@EGL24Xx Why not? This looks like the perfect application of halbach arrays to me. The field on the outside is doing nothing to help the thrust. It would be much better to direct the entire field inward.
This! But i also wonder if using graphite electrodes is possible!
The force on water is =B*I*L where B is the magnetic flux density, I is the current in the water( between the electrodes), L is the spacing between the electrodes(i.e length of the conducting path), Also current (I=V/R) is voltage(V) by resistance and here the resistance(R) is clearly proportional to the electrode spacing L making R=k*L where k is a proportionality constant. Long story short the force B*I*L becomes B*(V/(k*L))*L that is B*V/k i.e it is independent of the electrode spacing and linear wrt B and V.
This should be fine for intuition, but the resistance is also non linear which only complicates things
I must also add this, there are two currents now here, one going between the electrodes (I) and the other being the thrust flow itself(i) if you use the same rule for this new current(i) a new force arises opposing the main current (I, between the electrodes), this new force is B*i*c where B again is the magnetic field, i is the flow of water causing thrust and c now is the overall length of the electrode. The direction of this force is ixB that is the cross product of the velocity of charge flow and B(I know it's cXB but that's hard to imagine) and it is opposite to the main current I between the electrodes. This is the back emf in this system where the faster your thrust flow the lesser the current between the electrodes which inturn reduces the thrust force.
To put all this mathematically, the thrust force which we saw as F=B*V/k should be replaced by F=B*(V-a*f)/k where 'a' is back emf constant, f is the thrust flow rate showing that flow rate will counter itself
I imagine this intuition probably breaks down as well for very close spacing due to viscous effects of the water over the surface. A minimum electrode spacing when stacking for a more powerfull design could come from that maybe?
So essentially it is a very short conductor length motor and would need a stack of current to really get it moving.
Do we need to account for the velocity of influx of water ?
funny words magic man
A couple of errors in your assumptions, in electrochemistry most of the voltage drop happens at the electrode faces (and it's not usually symmetric), not across the length of the bulk fluid, so only a small part of resistance is proportional to spacing R≅k1+k2·L. Secondly, the way he tested spacing did not use constant magnetic flux density, since he used a single, under-sized magnet for all the tests. A test with constant flux density should show increasing thrust with increased spacing.
I think the electrode spacing test is misleading you here. You are measuring flow velocity, but that is not your actual goal, thrust is. Thust means mass flow, which is proportional to cross section and velocity. If your velocity stays constant, but your cross section increases, it means more thrust. If you are testing with a constant voltage source, more distant electrodes will mean lower current thus lower power. You also likely have a larger flow cross section with more electrode spacing, so combine that with lower power, that means wider spacing should actually be an effective way to improve your thrust/watt.
came here to say this
sick video tho !
Thanks. I was looking for this explanation 👍
Fluid displacement over time.
Thanks, exactly what i wanted to comment. Also, there's another variable that has not been tested at all which is magnet spacing.
Noticed this when playing with two hovercrafts of different duct size. Small one less thrust but very powerful small stream, big one less push in a given spot but a much larger area of air so overall more push.
Good work, particularly the parametric testing. The reason the electrode spacing didn't matter was that you did not account for the return path of the magnetic field. The result is a counter magnetic field on the outer fringes closest to the plates creating turbulence and drag. You can see this at timestamp 4:28 on the upper plate on the right. It is even present during the 3cm test at timestamp 4:42. Wider spacing needs a wider magnetic field, at least as wide as the plates are. The second thing is that if you use a magnetic core, such as steel, laminated iron, or ferrite, to complete the return path, your magnetic field in the chamber will be higher still, leading to higher chamber medium velocity. PM me if you need more details. :)
I’d love to chat with you about the second version I’m building. Please shoot me an email (found under the “about” tab), and in the email 📧 indicate that we’ve spoken in comments section.
also if a higher voltage was applied the boundary layer should be considered a plane of high conductivity. If you choose underwater electrodes use a dielectric insulator on any part of the electrode outside the e field including the wiring. And have them taper vertical towards the rear and not parallel but facing away at 1-2 degrees. Also angle the magnet along the horizontal plane 5-8 degrees
This was super interesting, thanks for doing it. I had a scan through the comments and didn't find any of these points:
1) The electrode spacing doesn't change the deltaV, but it might increase the thrust because more volume is being pushed. It would be worth to measure the thrust (hang your device by a string and measure the string angle/displacement). Ultimately thrust force is what you were looking for, so that might be a better metric than DeltaV.
2) Does the current go down with increased electrode spacing? Coupled with point 1, more spacing could be even more efficient (or maybe you did test this and I missed it...)
3) When increasing the voltage, does the current increase linearly or instead have inflection point(s)? I would expect at certain voltages the chemical process (electrolysis) to change as you reach the threshold voltage for new electrolytic reactions. Although you might get less thrust from lower voltage, you might find it more efficient
4) How does the thrust change if there's already an input velocity. I suspect it doesn't (if you can rule out the drag of your vessel).
NICE! May closer spacing doesn't increase current draw because of some factors like bubbles on the metal surface could limit the draw. Good engine though, beside the side effect of electrocuting planktons!
Please make one of these on your channel!!
those bubbles are also rather corrosive if i remember my chemistry classes right (NaCl + H2O NaOH + HCl), so would be interesting to see how it holds up after a year or so of runtime.
That's a valid point Mehdi. Considering one electrode is essentially covered in bubbles, that's a huge limiting factor.
@@PlasmaChannel use alternating current and electromagnet! And also electrode distance may not affect speed, but it affects total thrust cos the water flow increases.
@@PlasmaChannel what if the metal plates are covered with tape or a thin plastic?
A laminar flow straightener behind the flow with something to increase the Reynold's number would likely increase efficiency. Break the boundary layer at the electrodes and then columnate the fluid again to get an even thrust across the nozzle. While water is rather sticky it is also viscous enough to react nicely to boundary layer separators especially since it's practically incompressible so there's little spring effect.
At these flows, boundary layer drag is insignificant. This will not make a lick of difference. Not a lick.
@@UnitSe7enThe goal is achieving more thrust and the best performance (more volume and faster speed) , every detail matters. The more tidy axial flow the better.
The squared cross section of the device, works in fact, against both goals.
@@UnitSe7en Better to solve these issues *before* scaling up though. Even moving up to the kilograms-force regime would have those effects become nontrivial.
But it doesn't straighten the flow for free
@UnitSe7en,
Laminar flow makes a huge difference in aircraft but you're trying to say that it won't in a hydrodynamic environment that is literally 780 times more dense than air??? Think again.
Fun idea!
As some other said, I think that smaller opening at the back might decrease the thrust rather than increase it. It does increase velocity of the water coming out but total thrust is dependent on the flow of water as well and the increased velocity most likely doesn't make up for the lost flow.
This gets even more a problem if used to power a boat - because the movement forward of the boat will cause the water to also enter the inlet at some speed relative to the unit and get accelerated to even higher speed - which increases the total flow thru the unit by a lot. This will cause that opening to act like a big choke - making the thrust decrease faster with the speed as well.
If the channels have the same cross section area thru the whole unit, the water will just enter with some speed and accelerate freely to even higher speed, and continue to produce thrust even when getting up to some speed.
Exactly. This flow design is for compressible fluid like air. Water is not compressible, which makes the scoop and the nozzle an unnecessary hindrance, ultimately reducing the total thrust. If we could increase the output of this thruster by about 10x per watt, it would actually become practical for some uses that I'm not going to talk about here.
Removing the convergent nozzle is right. He doesn't want that at all. But there will be zero difference in static vs. dynamic thrust. Forward movement will not increase thrust in this device.
@@UnitSe7en I never said the thrust would increase by the speed in any case. But, the nozzle will cause the thrust to DECREASE rapidly by the speed.
Because the total flow thru the unit increases by the speed (even if the thrust remains constant)
- and the higher the flow, the more of a restriction that nozzle will cause.
If the nozzle is removed, the water can flow thru freely and allowing the unit to keep producing thrust up to higher speeds.
@@Speeder84XL I was talking about this statement: "because the movement forward of the boat will cause the water to also enter the inlet at some speed relative to the unit and get accelerated to even higher speed - " That is called dynamic thrust.
@@UnitSe7en Yes - but RELATIVE to the unit, the water will move thru it at greater speed. The water will not pass thru the unit at any greater speeds compared to the surrounding water.
But if the unit it self is moving, it will from "it's own perspective" behave the same way as if the water was moving towards it and because of that also get accelerated to higher speed than it otherwise would.
This will increase the flow thru it.
Even if the unit is turned off and just pushed thru the water by some other force
- that nozzle will still "steal" energy by creating more resistance in the water.
The unit will "scoop up" some of the water, rather than just moving thru it.
When the unit is in use, at least that increase in resistance will be subtracted from the thrust.
Try using Pulse Width Modulation (PWM) with a Pulse Repetition Frequency (PRF), it may save on the overall wattage. You may also try and use some low amp high voltage supply. This will allow the water once it's moving to help keep the water flowing even when the voltage is off. Kinda like once you get a tire rolling it doesn't take as much force to keep it going. You may also consider using Idler Plates, they are used in Hydro Gas Generators to keep the water charged while using less electricity. Hope that helps give you some more things to consider and test with. Best Wishes & Blessings. Keith Noneya
So electric current is analogous to torque in a car would you say? Seems reasonable.
@@paulschrum4727 Well sort of. When an electric motor is running it has a term called RLA Running Load Amperage and it's usually quit a big lower than what it takes start it. When a motor 1st starts it has what's called a LRA Lock Rotor Amperage, meaning that's how many amps it takes or draws to initially get the rotor moving. It's one of the primary reasons most home generators can't run a whole household if you have a large AC unit. To figure out how big a generator you'd need you'd have to look at your AC System Tags to find the LRA rating on both the inside and outside units. Add those up and multiply it times the Voltage the system is designed to run on. My old outside unit had an LRA of 110. So multiply that times the volts 220x110 = 24,200 watts. That would be the minimum size generator to start my old AC. You reduce that same system by around 30% adding a soft-start module. So the point I'm trying to make is in order to get the water moving takes a lot of energy, but once it's moving it has a lot of mass and it's not going to stop on a dime like a rolling tire or car or a mass of water. So once it's moving it should only take a pulse now and then to keep it moving at the same flow rate. At least that's my theory.
@@keithnoneya Thanks. This just reminds me of having 1st gear in a car be high torque for getting started, then as speed increases, the gear ratio can be reduced and can keep a car moving at 60 mph with much less power. That's why I asked about the analogy to mechanical power systems.
@@paulschrum4727 Yep makes perfect sense when put that way too. Best Wishes & Blessings. Keith
@@keithnoneya Great explanation and example. This makes sense when thinking about how an old vacuum or power tool may dim the lights in the room when first starting up but then return to standard brightness once the motor is running.
Drag is going to be the limiting factor in this thruster. On top of the thruster drag there will be a vessel drag component as well. So the lengh making faster flow is great for a practical display, but optimizing the design would require that drag be the factor used to determine field strength and voltage inputs. For any given thruster size, it will have a maximum velocity in the water due to it's drag. Practically speaking this would mean that the nozzle used in this video would be a limiting factor of volume because the fluid cannot be compressed. Therefore the nozzle increases drag, and limits volume. I would imagine that a thr
I think this is really cool. A nice upgrade would be a hexagonal configuration and you could run it like a bldc. It could make a water screw improving velocity further
@@Alfred-Neumanwhat the hell.
@@Alfred-Neumanbeware of bitting your tongue
@@KangJangkrik
I literally got my last bite. It went pretty well, didn't hurt my tongue or burn it with the fried chicken. Thank you for warning me... lol
But I went pretty close from burning my apartment because when I was frying the oil it almost overflew on the red hot element! Fortunately I was quick enough to remove the pot. Never do some frying with a pot and leaving it unattended...
@@epicdaniel508
I apologise if you got hungry because of me. Luckily it's not too hard to cook this, it just takes a bit of time.
@@Alfred-Neuman actually, haven’t eaten anything for 53 hours. Still, weirdest comment I’ve seen in a while
You can significantly increase the magnetic field strength by using a closed magnetic circuit instead of an open one. You can also use Halbach array
As pointed out by another commenter in another comment thread - a Halbach array doesn't have a uniform linear magnetic field - it would be stronger but would alternately accelerate the water forwards and backwards causing a significant performance penalty at best, or rendering the thruster completely useless at worst.
@@bosstowndynamics5488 You could probably take advantage of that actually. You don't need a uniform magnetic field if you make your electric field also non-uniform, pair that with boundary layer separators and you'd have one funky looking mess of a thruster. You'd probably need somrthing like an evolutionary algorithm to design that thruster for you though.
Still, with a 3D printer, it may very well be possible to actually build whatever your fancy genetic algorithm designs. You can buy conductive 3D printer filament.
@@MrRolnicekUnfortunately that would only make it that much more expensive to replace when the galvanic corrosion eats away at the anode.
The water closes the circuit.
YES to the magnetic closed circuit, just as is done in dynamic loudspeakers. Significant magnetic field strength is wasted without a closed magnetic circuit between the two outer magnets. Water does NOT close a *magnetic* loop. Also, placing the magnets closer together-perhaps a wider, yet shorter channel for the same volume, will yield a significant increase in magnetic field strength.
It's been a while, but the novel of the Hunt for Red October the RO used ducted turbines deep in the hull. It was called a "caterpillar" because it had many turbines spinning pushing the water. IIRC it did use magnets to move the turbines (instead of prop shafts and motors).
it causes cavitation bubbles that can easily be heard far away that's why this tech was never adopted on subs.
In the movie it was magnetohydrodynamic drive. No moving parts, almost completely silent. I like the movie version better.
No, it was a magnetohydrodynamic drive, like this. No turbines, no moving parts.
@@stuarthamilton5112On what page is that mentioned?
The original comment is completely correct in reference to the book.
Hunt For Red Oktober specifically mentioned MHD which has no moving parts. No turbines, just electrodes and magnets.
I like how your adds are seamlessly integrated into the video. It's very creative and much less obtrusive
I think you’ll find the exposed electrodes in the water are causing losses. The whole point of the drive is to accelerate charged particles, in the form of ions in the salt solution, using Lorenz force. By having the electrodes exposed you’re allowing ions to loose their charge and escape as gases. You should insulate the electrodes to prevent this, while the losses may be minimal you should still do it to prevent chlorine/hydrogen from being produced which could potentially cause you harm. This may also be the reason why you’re not finding gains in fluid velocity when moving the electrodes closer, as this makes it easier for the ions to move to the electrodes and neutralise, increasing losses. Oh and Lorenz force is governed by electric field flux density, not potential, (I think) so I’d be measuring the effect of current rather than voltage on performance for more direct results.
Sorry for the long reply lol, I think the project’s really cool and I’m planning on building one myself at some point!
One design consideration that you're not considering here is the drag of the thruster. It's fine for this test to have a bulky design since the surrounding water is fairly static, but on a boat once it gets going there comes a point where the bulk will definitely be a hindrance.
STRICTLY SPEAKING, a MHD could be built with very little drag by lining the boat's hull length-wise with alternating electrode-magnet strips in the pattern +,N,-,S,+,N,-,S,+,N,-,S,+, ... This would mean that the hull of the boat is almost "wrapped" with an EM field where the electric and magnetic field are intersecting almost perpendicularly at every point thus generating a skin layer of thrust along the entire hull. My hypothesis with this is that the thinner the strips (and hence the more +,N,-,S sets per unit length one has along the crossection) the more efficient the energy transfer will be because the field will be more localised around the boat. Also maybe putting some thought into how the wiring is run to the electrodes might help by orienting the magnetic field their current generates to form additively to the fields of the bar magnets rather than have them be wasted EM emissions.
I would design it so that internally it resembles the chamber of a hydrojet drive.
Hydrogen generated by electrolysis should be collected and used later somehow 🧐
@@TANOCA17 with salt water you don't guarantee that hydrogen is getting preferentially discharged. It might not be as straightforward to collect.
@@SeanOHanlon wouldn't that need to pull the water against gravity tho?
A magnet shaped like a doughnut 🍩
One suggestion - you really need an iron backer to give the magnetic field lines a place to return that aren't the 'wrong' direction through your water.
That, and also to reduce the reluctance therefore increasing the magnetic field.
A pair of halbach arrays with opposite polarities and iron backplanes would give an insanely strong field across the thrust tube. Would sidewalls connecting the backplanes also confine the stray fields? I wonder how well drilling the coils out of a microwave transformer would work as a magnet housing, assuming you could get arrays small enough to fit in the gaps.
@@dustinbrueggemann1875 No, using a halbach array while using a material with good "magnetic conductivity" would be pretty useless. Halbach arrays Increase the field strength on one side and lower it on the other. Plus you want the magnetic field to go all in the same direction, not alternating orientations like your suggestion would entail. What OP suggest is both easier to construct and more efficient.
have you considered a column of ring magnets in the center of an aluminum tube? Forcing the current to run only through the magnetic fields could have an interesting effect.
FANTASTIC! A clear design direction for dramatically increased thrust from an electromagnetics engineer: Widen the port aspect ratio (more distance between electrodes, less distance between magnets), and add a magnetic return path between top and bottom magnets.
Reasoning: 1. Low to no loss of thrust from widening the gap between electrodes. 2. HIGH gain of thrust from increase in magnetic field strength easily obtainable by moving magnets closer together and adding a magnetic flux return path from top to bottom magnets. A bit like two custom C-clamps wrapping around each side and clamping against the top and bottom magnets, creating a flux return path.
Think of each magnet like a "magnetic battery," and the gaps between magnets as resistors. If you want more current (flux) to flow, you can increase the "voltage" (magnet strength), and/or reduce the path resistance (distance between magnets). A flux return path is like a low-resistance solid conductor in an electrical circuit, so the lower "circuit" resistance means the "current" (flux) goes up. Higher flux, higher thrust of your design.
Beautiful work. Thanks for sharing it!
Thanks Alan! Yeah I had never heard of a Halbach array until I posted this video - sounds like that’s an option. One thing I’m curious about though, is the loss of electric field density when electrodes spaced further away, and this less interactive pushing force. I feel like if magnets were halved in distance, and electrodes doubled in spacing, the water flow would be identical, no?
I'm not proposing anything exotic like a Halbach array. You should be able to use all the same magnet and electrode hardware you have now. You can gain a dramatic increase in thrust merely by changing the aspect ratio of your water ports to reduce the distance between magnets, and adding a flux return path between top and bottom magnets.
Reasoning: Your testing showed a weak relationship between electrode distance and thrust, yes? So, for example, widening the channel by a factor of 2x will have a very minor cost to thrust. Now halving the distance between the magnets will increase magnetic field strength by 2x. And since there's a strong relationship between magnetic field strength and thrust, you should get more thrust out. Yet the port area is unchanged.
Your lowest hanging fruit for increasing magnetic field density is by closing that HUGE air gap between the outer surfaces of top and bottom magnets. This will dramatically reduce magnetic circuit reluctance (akin to electrical circuit resistance).
As you already know, be sure all magnets have their poles oriented the same direction, or they'll cancel, like placing batteries in series: you always go + to - to + to - etc., which will have them add, or + to + or - to - will have them subtract.@@PlasmaChannel
Here is some ideas to implement into more research in the design to generate increased thrust in the divice.
1. Conical Intake Design: The idea revolves around shaping the intake structure in a manner reminiscent of a cone. This means that the intake's geometry gradually widens from a pointed tip to a broader base. This design choice has functional implications: the narrower tip corresponds in size to the entry area that accommodates the magnets and electrodes. As you move toward the wider base of the cone, the intake's capacity increases. The tapered nature of the cone encourages fluid or gas to flow more smoothly and efficiently, as the gradual expansion reduces sudden changes in flow patterns that might cause turbulence or inefficiencies.
2. Enhancing Fluid Flow: At the tip of this conical intake, you suggest integrating blade-like contours. These contours serve as strategic features that influence the flow of the fluid or gas entering the device. The intention here is to initiate a spiral-like motion, gently coaxing the fluid or gas to follow a swirling trajectory. This spiral flow pattern carries several benefits. It can aid in efficient mixing of gases, improving combustion in the combustion chamber if applicable. Additionally, a controlled swirling motion could help in preventing stagnation or dead zones within the intake, leading to a more consistent and even distribution of the incoming fluid or gas.
3. Central Conical and Cylindrical Structure: You propose extending the conical design concept to the central part of the device. In this case, you're considering the possibility of shaping the central region into a cylindrical form with a spiraling exit opening. This central cylindrical configuration could be designed to complement the conical intake, maintaining the same fluid dynamics principles. This design evolution, although more complex to engineer, holds the promise of further streamlining the flow patterns within the device, possibly enhancing overall efficiency.
4. Timing Spark Gap Innovation: The innovation of introducing an adjustable timing spark gap within the exit orifice carries intriguing potential. This feature essentially enables the controlled ignition of the mixture of hydrogen and oxygen gases as they exit the device. This ignition could lead to a significant burst of energy, propelling the device forward. However, this dynamic ignition approach comes at the cost of generating noise due to the rapid combustion. To harness this concept effectively, meticulous synchronization is necessary. Adjusting the timing of the spark gap becomes critical, taking into account not only the ignition process but also the counteracting force from the incoming water, creating a harmonious burst of outward propulsion.
In summary, your concept involves employing conical shapes throughout the device's intake and central structure to optimize fluid dynamics and gas combustion. Additionally, the inventive introduction of an adjustable timing spark gap introduces a dynamic element that has the potential to significantly enhance the device's propulsive power, albeit at the expense of noise. This amalgamation of design principles seeks to harmonize various factors to achieve the desired efficiency and performance. Cant wait to see more on this.
I'm amazed at the thrust you produced on your first attempt! For efficiency, electrode spacing should be your last parameter to test/adjust. I've seen other comments make this point as well. You didn't have enough energy in the system yet to get a measurable result. I understand why you would want to adjust voltage last, but you can definitely maximize your mag flux first before finding the optimal electrode spacing. Two variables to consider when doing this- one obvious one you are already familiar with is arcing, but the other is volume of energized medium. You will hit a point of diminishing returns as you collapse the volume of fluid that can be accelerated between the electrodes. I think this can be somewhat mitigated if you use a staged approach, perhaps with one wider MHD at entry leading down to many narrow MHDs at exit
Man your channel is more important to me than you know it’s good to see dudes doing good interesting things like this and networking with other interested professionals. Keep playing the game you’re pushing humanity forward
Are you concerned about generating chlorine gas with this electrolysis setup? Or are you using something other than NaCl for the salt in the water? I'd be worried about pushing the voltage up with table salt in the water, that could get dangerous.
At the scale and duration of these tests there shouldn't be much chlorine production. When scaled up to a full-sized boat though you'll definitely be glad you're outdoors.
With copper, iron and aluminum electrodes the anode is chemically degraded by the current and no chlorine is produced.
With graphite electrodes they suffer less damage but produce a lot of chlorine vapor.
Lol.
Don't forget about the sodium hydroxide from the reaction. It's a corrosive alkali.
The marine animals don't like the noise, but the chlorine won't be any good either
Electrolysis, top secret navy propulsion systems !!! And separating the molecular bond between hydrogen and oxygen that are also explosive ... Love the Channel
Excellent job at communicating a complex process and theory into something easily understood. Way to go!!!
I would redo your test while considering watts in relation to thrust or mass flow. Also consider lover voltage. Voltage below electrolysis doesn’t waste energy on splitting the molecules into ions so it should be more efficient.
1.3 volts would be a very, very low power level
@@PlasmaChannel yes I thought about that but what if you make very thin square maybe 5mm x 5mm or even smaller. That way the current should be sufficient, I would assume lover resistance. Very glad your answered my comment btw:)
What if, instead of using direct current perpendicular to a permanent magnetic field, you used a linear sequence of magnets, driven by 3-phase alternating current? (In other words, imagine a string of chasing Christmas lights, but with magnets instead of lights.) The design in the video is like a railgun for water, but this would be more like a coil gun for the water.
The reason you're getting the electrolysis is because the current is starting at one electrode and going through the water to the other electrode. Electrolysis happens because electrons are being pulled from their atoms when they jump to the metal electrode. But with a coil gun type design, the only current in the water itself would be eddy currents going in a circle, so there's no electrolysis. All the components carrying electricity would be sealed and water-tight.
@@John73John See the issue here is that the lorentz force only needs the object (water in this case, or a railgun sabot) to be electrically conductive. A coilgun, on the other hand, requires its projectile to be *ferromagnetic*, which water is unfortunately not. Coilguns are definitely better than railguns for moving objects at speed, but only if that object includes materials of a particular kind
@@blak4831Not necessarily. If a strong magnet and any electrically conductive material move past each other quickly, electrical induction will create eddy currents in the material. The eddy currents have their own magnetic field that tends to oppose the relative motion. I did this in my freshmen university physics course using a large horseshoe magnet and pendulum with a thin copper plate at the end -- as the pendulum swings between the poles of the magnet, it will stop quickly even though copper isn't ferromagnetic. Turning it around and putting the magnet on the pendulum and swinging it past the plate causes the plate to experience a force in the same direction as the magnet is moving.
The same effect can be achieved as I described above, by using several stationary magnets and sequentially turning them on and off -- it's exactly the same principle as an induction motor except it's linear rather than rotary.
Now, this might not be as effective with water as it is with copper because water has a lot more resistance. But it would at least avoid the other problems associated with electrolysis: Your boat generates a cloud of explosive hydrogen gas behind it, if you're doing this in salt water then you're also going to generate highly poisonous chlorine gas, and the formation of unwanted materials on the electrodes.
Hi folks
If you want to try this at home, please ensure to do it in a well vented area as it produces flammable hydrogen and also chlorine gas.
No reason not to try this though so long as basic safety measures are taken. I'll definitely be trying this myself!
Chlorine? Didn't know salt is split apart this easily. I guess you get sodium hydroxide left in the solution, which can cause chemical burns.
@@the11382 yes, chlorine is more electronegative than oxygen so is the main gas produced by electrolysing salt water, together with hydrogen at the other electrode.
The amount of chlorine produced is very negligible. Chlorine isn’t crazy toxic in low concentrations and since it is in water, it might redissolve to create HCL. Chlorine is very attracted to moisture so it’s unlikely it will create the large of an issue. Hydrogen however will cause problems in small quantities but since this produces probably less than a liter and hour and is completely ventilated it’s kind of a non-issue
While probably save at those voltage levels might not be the best idea to stick your finger in there either.
@@MJTVideosAh, yes, HCl. Nothing dangerous at all about that chemical. 🙄
"To my local scientific supplier, often mistaken for a home improvement store" 😂
So true!
The people at my local store have stopped asking if they can help me find something and started asking what I'm working on today. As they know I'm likely bot using something for what it is being marketed as, lol.
My chemist also has a special shelf for rocket propulsion ingredients, but I don't think he knows that.
All this is fascinating and all, but what has me in awe is the sheer believe that he will not drill into his tempered glass table 😲
So much stuff on youtube is one offs, watching the iterative design adds so much.
This is so cool I hope I can do things like this some day as I am still learning about high voltage and electronics and this channel has been an inspiration for that thank you
I think that a more narrow gaps leads to increased resistance, in the water flow, that cancels out the increased force applied. Maybe testing with different depths of water would show a difference
But smaller gap means less water which should mean less resistance not more?
@@MB-st7beno
@@MB-st7be there is less water, but the ratio between frictio inside the water and the friction with the electrodes are higher. I just thought it might be the case, because if you have a smaller flow channel you neef a higher pressure gradient, if you look at poiseuilles equation(which is for a pipe, but i think the same tendencies should be happening for other systems).
@@MB-st7be It's the attraction between the water molecules that means more resistance. It's easier for them to 'stick' to each other and the walls of the thruster when there's less space between electrodes, I think.
It's the same physics that generates surface tension.
@@MB-st7be I think it's more along the lines of larger diameter cable reducing resistance
It would be interesting to see how an electromagnet could be used to vary the thrust.
In the book, the Red October actually has impellers in the two shafts for the caterpillar drive. The pressure pulses, and resulting sounds, are how the sonar crew picked it up. In the book, as the story goes, the US toyed with this sort of system but wasn't able to get past the backpressure issue and abandoned it but the Russians made it work. In the movie it was a "magnetohydrodynamic drive" but again that's different than the book.
Man, when you put that thing in the ocean and traveled. Wow.
This renews my hopes of someday building a balsa, rubber band powered, craft for air travel.
This is a fun project. I would like to see it propel a kayak for a long distance. It doesn't seem like it can produce enough thrust for a long enough period of time without making one that's too heavy.
for electrodes, check out those pool chlorine generators. They are designed for this purpose. You gotta take em apart to get the electrodes. I got mine from someone who did pool maintenance caz every so often they need to be replaced. The ones I got were completely jammed with salt. easy for me. trash for him. The electrode is some kinda vanadium oxide on titanium. I use them ALL the time & they surpass everything by lightyears. Second best non-corroding electrode if you have to buy... is ... titanium. Ti is cheap & the least prone to dissolve.
Thank you, i'll definitely look into this! Fascinating.
I see stuff on this off and on every so often. Its a really cool concept and on small scale can produce some entertaining results. So far however I've never seen anyone able to scale it up to a usable size. The one attempt I heard about (bear in mind this was a decade or more ago i read about this) got a ship up to 15 knots and maxed out there for a lot of energy. They figured out Magnet tec is not there yet. Electronics and Salt water don't mix well (surprise). And it needed a LOT of power.
You forgot the raw chlorine gas the electrodes produce. Not only
leaving a telltale trail in the ocean but essentially rotting away your own vessel.
"This is also how a railgun works"... I find that explanation the best hit in the entire movie. If you know how a maglev/rail-gun/gauss-gun/etc. works, you know the basics of this MHD propulsion. Thanks for the hint.
This is so amazing. Thank you for sharing this with us. Using this to advance desalination with no moving parts. So many other places this tech could be used.
Great video. Was left pondering if you went back to the testing that failed to produce results and retested using the enhancements you already found. Sometimes a factor is limited by other elements and might not be limited after changing other elements in the test article.
Probably should be measuring volume of flow instead of just velocity of flow. 3cm vs 5cm, with the same velocity, but 5cm (looks like) has nearly double the total volume.
Especially if it allows you to put more magnets next to eachother. More magnets is probably a lot easier than more power in an actual vehicle.
This is exactly the problem I saw with his design, you cannot compress that water in this thruster, therefore making a small nozzle is really just a current or throughput limiting component to the thruster. It looks cool, but in reality overall thrust would be most impacted by volume the thruster can move.
ACTUALLY in Hunt For Red October it was not an MHD drive. At least not in the book. It was an impeller design. The film made some remarks pointing towards MHD (Superconductors), though.
It made more than just remarks, it outright said it was an MHD several times.
@@LeoH3L1 Maybe I should watch that movie once more... why not? ;)
@@LeoH3L1 Nooo, not really.. They never use that term, nor actually go into any details. It's only mentioned that it's a new type of magnetic drive. They do not explicitly call it a MHD or really say much else about it at all.
@@jackmclane1826 The movie is actually considered to be a masterpiece, so there's no downside to watching it a second time.
@@UnitSe7en WRONG.
It definitely calls it an MHD in several scenes...
At the shipyard....
Skip Tyler: I'll be... This... This could be a caterpillar.
Jack Ryan: A what?
Skip Tyler: Uh, a caterpillar drive.
Skip Tyler: Magneto-hydrodynamic propulsion.
In the Joint chiefs briefing...
Jack Ryan: We believe that these doors,
here on the bow and again on the stern,
enclose a unique propulsion system...
a magneto-hydrodynamic drive,
or caterpillar that would enable the sub
to run virtually silent.
And refers to the design as having magnets in the scene where it is sabotaged...
Captain Borodin: What happened?
Lieutenant Melekhin: The cryogenic plant!
Lieutenant Melekhin: The magnets aren't cooling.
Lieutenant Melekhin: Temperature in
the caterpillar is 50 degrees above red line
and rising.
I cheer for you, regardless of outcome, you did this well with a great approach. Be proud.
This is really cool, and I appreciate the care and attention to detail here! A couple of thoughts on some of the results here (my background is fluid dynamics): the water is pretty shallow in your testing, so that might be somewhat damping out the effects on velocity (although this is only a guess). The flip side is that if your velocities are constant, you might want a wider spacing because that means you're moving more water, which means you'll have higher amounts of thrust for the same water velocity.
The parametric testing was cool, and I appreciate it! Have you heard of Box-Behnken design of experiments? It's a way of testing a bunch of parameters together that reduces the total number of experiments and takes into account that parameter A and B might have positive or negative correlations.
Thanks again for the video!
Umm... The way I remember the story of the Mitsubishi MHD is that the strength didn't really scale well, and despite having massive diesel generators it produced some pitiful amounts of thrust. But it's a nice project :)
What would be really interesting is to know the effectiveness of this kind of propulsion and how it compares to other types like typical propellers or jets.
It's terrible, there's a reason you don't see it on any actual boats
The comparison would be terrible , still I love the concept.
The efficiency is quite low. Worse is that you’re effectively electrolysing salt, creating corrosive chlorine gas at one of the terminals.
Always wondered if insulated high voltage AC electrodes combined with superconducting AC magnet coils which are synced to the electrodes alternating voltage would also work and therby get rid of the electrolysis completely.
@@norbertfeurle7905well i believe that you need to have currents going through the water for the effect to work so electrolysis is going to happen no matter what
The distance between the electrodes mostly applies as a function of ion density/saturation. Since you're ion saturation is fixed then there will be a maximum distance where there will be no added loss with additional distance.
To counter this situation you can boost the effectiveness exponentially using alternating current and a matched phase electromagnet. The additional usefulness is compounded by a reduction in erosion effects. If you're going to try it, then definitely use stainless steel electrodes. You can also apply the halbach array concept to the electro magnets to increase performance further
How awesome!
We are definitely getting into a magnet era. Our world will be so different in 30 years from now. 😊
An MHD is used in the Oregon Files books by Clive Cussler. They're about a secret off-the-books outfit that operates from a super advanced ship that's disguised as a tramp steamer. It's propelled by an MHD, however, it's far more advanced and powerful than anything in real life, allowing the ship to move incredibly fast for its size.
I love the idea and concept. Just wondering, have you tested the salt water afterwards? Because of the electricity passing through the water, doesn't it become more chlorinated?
Simple question that has to considered during development. environmentally safe?
It was given the nickname "Caterpillar" because they used several in series which not only applies thrust but were also optimized for the pre-accelerated input flows. One can take advantage of moving flows by designing the next in series optimized for the higher speeds and advance that by a higher amount.
Now we're talking adaptive engineering. love it, and that is my plan for V2!
@@PlasmaChannelnooo! Thrust comes from the current in the water pushing the magnets. Water moving backwards inside the duct is a necessary evil but does not in itself add any performance, it only increases friction inside the duct experienced by the hull as drag. Flow inside a closed duct is at a constant velocity, simple conservation of mass. If you are going to use multiple thrusters, rather arrange them in parallel.
@@PlasmaChannelyou are also wasting a good deal if curret from the un-insulated outward facing electrode surfaces. Current sneaks around the outside to the opposite electrode. Had your top and bottom magnets been the epoxy coated type, this current would have been flowing over the magnet resulting in reverse thrust. Since your magnets had condutive platings the current "climbed onto" and flowed through the magnet plating before jumping off the far edge to complete the remaining distance through the water. You can clearly see the resulting electrolysis along the magnet edges. Try to eliminate this external current altogether by insulating the backsides of the electrodes. You can also save on wasted current by trimming the electrodes slightly shorter than the magnets lengthwise. The electrode tips send some current through an arc (curve) extending fore and aft outside the duct wher the magnetic field is much weaker and the thrust is simply not worth the extra amps.
Series thrusters of this type will have zero benefit except using more power. The maximum flow through this thruster is defined by the field. This does not work like a turbine.
@@williamfraser Finally, someone else who understands.
If you want to try something, use different shaped exhaust nozzles. I believe (my assumption) that incompressible water doesn't work well with de Laval nozzles, try straight and divergent only. This is something I noticed on jet pumps.
Very cool experiment!
One side note: using current instead of voltage as a parameter could give a clearer picture of the effect of varying parameters. For example, making the electrodes longer doesn't increase efficiency, but it does allow more current to flow which is actually what causes the increase in thrust/flow.
It also increases the aspect ratio between opening and electrode area. As water flow the ions are carried with the water, obviously they eventually reach electrode but the path is more in line with the water flow with longer electrodes and a shorter opening
@@cybyrd9615 nice catch! I hadn't taken the flow of the ion medium (water) into account yet. So in theory it should be more efficient with multiple narrow channels as opposed to one wider channel. :)
Cool.
Now put a pair of these on the boat you were playing around with before
Can you imagine what our ancestors 300 years ago would of thought about today's technology? Salem Witch trials 2.0
would've, not "would of"
To quote a saying: 'A sufficiently advanced technology is indistinguishable from magic'. For someone from 300 years ago electricity would be magic. So, quite likely, would be concrete.
@@echomande4395I love that quote. I’m actually a writer and one of my WIP involves a person from pseudo-medieval time period being exposed to modern technology and being utterly horrified, thinking it’s witchcraft
Hey! It'd be cool if you included how the thrust compares to other devices of similar class and their counterparts at the end.
Hey Jay! can you give us any updates on the nuclear fusor you made? :)
Love your channel man!
Very nice.
For reduced corosion you can use stainless steel 316L, it is used in marine and oil rig instalations.
More exotic it is 316L with a coating of titanium.
This materials are used in HHO instalations to prevent corosion and contamination of the cells.
Two major concerns that came to my mind: One, your electrodes and magnets were steadily and rapidly dissolving, especially at higher voltages. Two, those dissolved metals, ions, and oxides may be toxic to the same marine life that this drive is supposed to be protecting.
What about the sodium hydroxide?
Might have one-off military applications. Silent marine drones for Ukraine perhaps.
@@kaasmeester5903 No doubt various militaries already experimented or are still experimenting with MHD. It clearly doesn't take much to build an MHD thruster.
Is thrust scaling linearly with voltage? Might be interesting to try the stun gun modules to get that insane spike.
Better annoy animals with noise than electrocuting them to death.
Very interesting. Thanks for taking one for the team, and performing this experiment.
I do think you need to look at what those same 225 watts input, gives you in thrust, from an ordinary electric trolling motor. Also, you might figure out what fraction of a horsepower (hint... a whole horsepower basically equals 746 watts, and is defined as the power required to lift 550lbs at one foot per second.) I am guessing that your device is operating full throttle at about .01hp. Or about 7.46 watts of output power. So your efficiency is roughly 3%, assuming that my eyeball guesstimate of output power is in the ballpark. I am not too surprised that you achieved a positive result. I am also not surprised that it is incredibly inefficient. Since the effect is well known and easily implemented, but nobody is doing it commercially even though an awful lot of people out there are desperate to make money, that it had already been tried a lot, and dismissed as pretty much a failure, in practical terms. Viable ideas have a habit of being turned into commercial success. Everyone has to be that guy who did it first. Rudolf Diesel. George Westinghouse. Thomas Edison. The Wright Brothers. All proved a concept but initially only showed laughable results in terms of efficiency and practicality. But honestly I don't see this as really becoming a thing. And I can tell you positootly that it is NOT silent. You just aren't listening correctly.
One thing you might try, is a very fine matrix instead of discrete magnets and electrodes. Think like nanotubes, bundled together. Maybe the electrodes and magnets etched in the manner of modern integrated circuits of high order, such as microprocessors. Maybe at some point of miniaturization, the induced turbulence or something would begin to cause a diminishing returns effect. Who knows? But one thing is for sure, and that is that you are not giving your viewers any hard data on efficiency. Now you probably have a hundred shade tree redneck physicists buying golf cart batteries and magnets, and butchering boats, and dreaming about clean, silent, swift and efficient passage to their favorite bass fishing holes, and winning tournament after tournament against guys sporting 1200hp pro bassing machines. They are gonna be pretty disappointed. The same guys who saw Wile E. Coyote using a fan blowing into a sail to reach potential roadrunner-catching speed, or who thought that he could hook up a really good motor to a really good generator and make them run each other, with energy left over to tap off and use for other stuff. Well, it's not like you encouraged anyone, but you should level with your viewers about the apparent efficiency of your first iteration of this concept.
I don't think he ever claimed it was efficient in it's current iteration, just an interesting experiment that's potentially worth doing (if for nothing else than to satisfy his own curiosity). Perhaps someday these exotic engines (this and the ionic thruster come to mind) will become viable due to repeated iterations and passionate hobbyist who are willing to put in the work even if it seems unlikely to ever succeed. It's also worth noting that the engine doesn't necessarily have to be more efficient than an outboard motor to have some practical use, if it gets to be powerful and efficient enough and can deliver other advantages like operating in relative silence (compared to other motors) it could still find some commercial (and/or military) success. Never let perfection be the enemy of good.
There you go girls , length matters, and circumference matters, to increase the velocity of the fluid. It's called magnetism.
This is a most informative video and interesting new science to me. Thank you for sharing.
Absolutely fascinating video! The ingenuity and creativity displayed in building and testing the MHD Thruster are truly inspiring. Your exploration of the variables and their effects on thrust is both thorough and thought-provoking.
One intriguing observation was the relationship between electrode spacing and thrust, which seemed to follow a sigmoid curve, characterized by an S-shaped pattern bound between two thresholds. This sigmoid curve can often be described by the equation:f(x) = L / (1 + e^(-k * (x - x0)))
Given that the other variables-strength of the magnet, voltage, and length of the electrodes-all showed positive correlations with thrust, it would be fascinating to explore potential synergies between these factors. Here's a suggested methodology:
1. Multivariate Analysis: Conduct a series of controlled experiments, systematically varying electrode spacing, magnet strength, voltage, and electrode length. Record the thrust produced for each combination of variables.
2. Statistical Modeling: Use multivariate regression or other statistical modeling techniques to analyze how these variables interact. Look for interactions that might explain the sigmoid curve observed with electrode spacing.
3. Optimization: Based on the statistical model, identify combinations of variables that might maximize thrust or efficiency. Explore whether there are optimal ranges or specific values that align with the sigmoid pattern.
This approach could reveal deeper insights into the behavior of the MHD system and uncover synergies that lead to further optimization in the design of MHD thrusters.
Keep up the fantastic work, and thank you for sharing your passion and innovation with all of us!
What is the thrust per Watt ratio of this compared to an electric motor in energy used?
Absolutely pathetic. 20v and 9A is what a small e-scooter would draw. It can pull you uphill. This thing barely moves a hundredth of your weight.
ps: I don't see how this can be not absolutely obvious to a sentient physical being.
Could you increase thrust with/by laminar flow???
Either before it gets between the two metal parts or after...
@redemption7488 Yeah, youtube comments are full of them. Not as bad as all the conspiracy nuts asking about how this can create "anti-gravity" or "free-energy" devices though.
My guess is closer electrode spacing leads to higher E field strength, but proportionately less volume of water between the electrodes to actually be thrusted, so the two things cancel out?
Also, presumably there is nothing to stop you using plastic coated electrodes that would never corrode?
Wouldn't covering them with plastic stop the current?
I think in chemistry they use carbon electrodes which dont oxidise and dont react but do conduct
@@umutcandemirci4242 Good point, I was thinking it was the random ions in the water that experience thrust, but I guess you actually need to manufacture lots of ions by electrolysis, so you do need current
Fascinating! You could use niobium for the electrodes as they are very conductive and won't break down at all. Niobium is used as electrodes in hydrolysis for production of hydrogen gas in the clean energy sector for that reason. It can take very high voltages- I anodise to a variety of colours for jewellery at voltages as high as 120 volts.
Hi , I have been a sea captain for 45 years and found this very interesting . I don't know if anyone has mentioned that the anode on boats naturally degrades and gets eaten away . This would be a real problem as the more you increase the power the faster the anode and cathode will disappear. if you can overcome the degradation problem it may be viable . Just look at the anode zinc blocks on a standard vessel . Electrolysis will eat away a steel hull very fast if the zinc anodes are of poor quality or are badly connected . Just saying this is a problem . Good luck
When looking at the spacing you only measured velocity and not mass flow.
You may find that the wider spacing gives improvements as your percentage losses to wall friction will also be reduced with a larger cross section.
Height or depth of the thruster would also be something to optimise again whilst looking at the mass flow.
I don't know how it is I worked with plasma systems for 4 years and only stumbled across this channel last night... but yeah subscribed.
Your "bias" is pride in quality !!
Thank you for your contributions.
Your videos remind me of what TKOR was in its prime, but with more advanced topics. Didn't know I needed that itch scratched in years
Awesome creative effort. Humans at their best creatively. Will save a lot of marine life if it ever goes to scale.
Verry good explained construction 👍
Can you also end up using a double nested eggshell as an attached end spout or, for example, tea eggs? (Two nested tea eggs with insulating bars, one bowl slightly larger than the other, smaller bowl. The voltage is then applied offset there: The first voltage is at the beginning of the first inner tea egg. The second different voltage is on the outside End of second tee - egg up. To finish, perforate the shell of the outer bowl and put on a small cone. To begin with, however, all you need is an insulated connector to the middle of the tee - egg and an intermediate annular channel between the shells. Inside is used a secondary, better conducting gas for experimentally improved flow.
This was very cool and interesting. I had never heard of this concept before this. Thanks for sharing this experiment.
I've no real idea how any of this works BUT I love my electric prop for my kayak but what I'd love even more would be something more quiet and more efficient. So if this is it - sign me up! :) Can't wait to see you put this on a small boat, subbed!
I cross B is what drives the force. Water has constant resistance per length we will say and so you should see an increase of current with a smaller gap. But your gap may be so wide that is acting more as a capacitor than a resistor making the current leakage driven. If I remember from my course though, mhd is voltage driven. If you perform all the maths you end up with the voltage and the pressure rise in the pump being related and independent of gap distance. The pressure rise determines the power and the current is a balancing term.
The US navy did experiment with MHDs but found that they are still plenty loud at high thrust levels because of all the bubbles formed on the electrodes, and a large slow turning prop is very quiet especially next to all the pump noise for cooling the reactor.
biggest issue I'd see regarding commercialisation is in the "leisure boat" department. some people mostly have their yachts in salt (and brackish) water, others only yacht around fresh water, some switch it up every now and then.
Considering that salt water is going to be a lot easier to electrify, the setup of the 'optimal MHD thruster' might be different in salt vs fresh water, leading to wildly different outputs depending on whether the boat is in salt water or fresh water. would love to see this revisited to compare performance in salt vs fresh (vs brackish) water and to see what the differences in optimal setup would be and whether minimal adjustments (that might be made automatically, like toggling fresh vs salt water mode) would be doable.
The ultimate angler's propulsion system. Not unlike electric bikes; adding this to SUP could be next. Way more sophisticated than my mundane ryobo 18 volt powered submersible water pump. But, no saltwater required!
That is a very cool effect! I am glad it came out so well.
I have come to really like this channels plasma theme. Keep up the great work! You have inspired me to build my first tesla coil. Slayer is going to be my first circuit. Coil is done.
Water doesn't compress I think your outlet and inlet don't need to be so slanted. If you use a ring configuration you may limit vortexes on your corners making your flow more laminar. I would be interested to see if a ring of magnets in the middle of the thruster would allow a stronger field and more propulsion.
2 stages could be tried too. One in front of the other.
Wtg!!! Don't know why, but I knew magnetism was key a lot of scientific revolution when I was growing up...perhaps I was tapping into the Life Scrolls or someone else's tap..but I even felt it was the key to space travel(turns out it gives ship it's own gravitational field), as well as free from fuel/resource necessity which is totally awesome to be APART of the generation/ERA to bring about SO MANY IMPLEMENTED IMPROVEMENTS THAT NOT JUST HELPED MANKIND BUT TURNED AROUND OUR PLACE UPON THE PLANET WHERE WE HELPED IT RATHER THAN HURT IT AND THUS HURT EVERYTHING AND EVERYONE ELSE.
You have the smoothest segue into sponsored content of anyone.
At least with this technology will be used for good intentions to quiet the oceans for marine animals. I'm super glad you mentioned Hunt for Red October cause it's the one movie I learned about such tech, and it's also among my most favorite!
It is super nice to see this technology being explored as an option for hydro propellant for ships, that it'll surely make the future look pretty sick! I think Halo 3 was also showing it's use for boats during the first Scarab encounter, I did not see any propellers on the grounded boats except their intake and fixed nozzles. Not sure about it, but that's just my thought!
Excellent demo, Quick suggestion, try Electromagnet - With those 3 parameter, once you have electromagnet - you can increase the power of electromagnet, that will be 4th parameter, higher the power of electromagnet, greater the force, Cheers!
I worked in a magnet shop and we would stack magnets sideways to make the magnetic field reach out further and have a more direct area. For instance stack vertical of north on its side and south on the other then put one in the middle of the 4 facing the opposite of the 2 and in the middle has a further gause
Higher voltage also increases the rate of hydrolysis (lost energy), reducing efficiency. It voltage/current also increases the corrosion rate, so you would likely need to coat in inert material (platinum) for long-term use.
Looking at the shot @10:26, there is a lot of gas being produced at the points where you connect the power lines. I'm no hydro-electric engineer but I would figure a lot of current is flowing around the engine instead of through. So insulating those parts might increase the efficiency by forcing the current to flow through water that is experiencing the strongest magnetic field.
More space for the same velocity means moving more water, more work. You may be capping how much your magnet can push within that area, and it's dumping the excess energy into heat? maybe corrosion? Can probably have some fun with bernoulli's principle.
Grat video! You should consider making your test chamber much longer, so that you don't form circular flow moving from outlet to inlet. The motor geometry (electrode length and spacing...) will become a more significant variable which couples to your other variables depending on the flow interactions. Once the chamber is long enough to produce negligible rotating flow, you won't have to worry about additional uncontrolled variables. 😁
Fun fact: a related thing, the magneto*plasma*dynamic thruster, is actually one of the most efficient spacecraft propulsion methods tested. It's not quite in the top spot, but it has a whole lot more thrust than its competitors in the electric propulsion department, and still easily competes on efficiency, beating out many of the less efficient ones
I worked on MHD projectiles in the 80's, it is a pretty cool technology.
I would like to suggest to make the electrodes from stainless steel and increase the scale, because some technologies do not work very well in small scales, by the way, the voltage should be increased significantly, let's say to the level of air ionization, but basically you are amazing for doing this! I love your channel and everything you do because if you do something you may fail sometimes but if you try hard enough you will eventually succeed! but if you sit on the couch all the time, then nothing will work 100% , thanks for content!
Scale it up and buy smaller permanent magnets and position them in Halbach array, also integrate a previous ionization stage (electrodes with sharp pointy edges) and test it in salty water, you could put the MHD thrusters in your ionic catamaran.
the direction of charge flow with such a set up will be perpendicular to the magnetic field initially, but once the charged ions are acted on and their path turned, the force the experienced will no longer be in line with the direction of desired flow. not sure if there is enough flow to keep some from turning direction more that 90 degrees, but once they do, they are counteracting your flow perhaps some layering of E field electrodes and B field electromagnets can be frequency controlled to keep the resultant force pointed in the direction of desired flow - also increasing electrode surface area should increase the rate of ion production and thus the charge density of the flow stream - i think... also also, the idea of corroding metal into our waterways is prolly a nonstarter - but neat to play with in small scale