Wow good to see the end results of those variations of 3D printed Turbines, You are always welcome to Nepal and Kathmandu University for more Research and Hope to be your help again in the future.
Great to get an update of what you've been up to. Looking forward to the archimedes screw fine tuning results and if possible a downloadable file of the final screw design 🙏 Awesome video - thanks for all that you do and share 🙌
The logarithmic spiral types are intended to throw water out to the side, if they're constrained within a tube then all you're doing is increasing the pressure and friction.
@@OpenSourceLowTech Yep. This is also true of airplane propellers. Some of them perform better when they have a shield around them to direct the air and some don't seem to have much of an impact. I think the term for them is "ducted propellers'. In a boat setting, the idea is to grab as much of the surrounding water as possible and throw it backward, OR to move a smaller amount of water very fast. Both of these impart Newton's third law (mass, momentum etc). In a tube like you've got, all the water is inherently 'ducted'. So running the horizonal water grabbing ones in reverse ends up performing poorly.
I think the Lily Impeller might work when constrained given it has more room for the water to be expelled. But ultimately having real world tests like you doing is ideal. These things are so hard to think about and often unintuitive.
After years of casually researching nano-hydro, I keep returning to the conclusion that positive-displacement designs (like the archimedes screw and others) seem preferable due to significantly higher efficiency.
Excellent job! I am a bit surprised that the flow guide didn't help. It should have increased the RPMs of the spindle but probably reduced the torque, Did the flow guide made the tank to empty slower? Could it be the case that cumulative energy is higher while instant power suffers?
With the screw runner the flow guide managed to drop both the rpms and torque. May be just increased friction above vector gains. Going to have to try some other options to get a better idea of what's going on.
In air, gas and water vapour turbines, the directional stator vanes are often used in multi-disk configurations, the stators placed between the discs, to "straighten" the flow before the next disc, and not to rotate it before the disc. By pre-rotating the flow before the turbine you've probably worsened its stall and drag characteristics so it made it less efficient.
Yeah I feel like this is probably the case. I'll aim to try a multistage runner stator stack in some future testing setup, see what if anything that does.
@@OpenSourceLowTech yeah, most designs are calculated with straight incoming flow in mind, the optimal angle of attack is extremely important to maximise the lift, minimize the drag and avoid the stall. So running with the off-spec angle will be worse in most cases
Great work as always! Interesting to see that the Archimedes screw had the best performance, but it makes sense I suppose, and that's great info to know since the Archimedes screws are less considerably less complicated to print or fabricate than the other more complex spiral shapes. I think I can definitely print a screw of that exact size and shape out of recycled #5 PP with my TrashPrinter. There's still a lot it can't do, but it does really well with simple spiral-vase type parts like that, and I've printed turbines with similar sizes and overhangs before. I'll give it a shot once I get the trash printer going again later this summer, and I'll let you know how it goes. If you've got an STL you can send me, lmk, but otherwise I'm sure I can find one online or make one with OpenSCAD. I've got some friends up in Washington with a pond on their property that drains a massive area of steep mountains on their property, and I've been looking into ways to integrate their pond into their off-grid solar power system, as both an energy storage buffer and a way to harvest energy from the huge volume of rain moving through their property in the winter, when they get basically no solar. I would love to test out one of these turbines up there. I figure we can build one to start and get some data on its performance, and if our results are promising, we can calculate how many more we would need to match the natural seasonal flux of the pond, and then build an array of them. Thanks for collecting and sharing this data!
Oh yeah, forgot to include the .STL Is now in the description, but also: drive.google.com/file/d/1LKLKvMf1uGRJezQpzQJxcq62L2xLxtP-/view?usp=sharing Let me know how you get on, and any questions etc.
Have you ever tried 3D printing a adjustable penstock gate that would sit just above the turbine blades? It looks like the circular radio active symbol but there's two that overlap and depending on how much you align the holes in the top plate with the bottom would control the flow rate and head pressure.
@@OpenSourceLowTech True, it's always a fighting balance between adequate head pressure and vectoring the flow at the most efficient angle of attack. I believe your solution lies in in solving that metering and head flow angle though, but that's my opinion. Love your content.
Trimming the shrink wrap after install will change the balance of the wheel. ANY imbalance will be a big loss in efficiency. If you detect vibration during operation, the wheels are off balance, at least the rotating assembly is out of balance. Unfortunately, wear on the rotating parts will change the balance too.
Potentially, tho the masses involved with the plastic runners are super small, and it is in normal use flywheeled by the alternator. Could have unbalanced torque effects tho if one side of the runner is a slightly better profile than the other..
In reply to what you said regarding alternators... a good approach if you have the time is an axial flux machine that you'd build yourself. There's a little bit of stuff in my recent videos about that.
I wonder why you dont use a PMA with a variable resistive load to measure power at the shaft. Perhaps it wouldn't be an improvement over the simple pony brake you have but it seems it might yield smoother results with easier adjustment and nothing to wear out. Perhaps the rpm is too low and such an alternator would need to be too large. I play with wind turbine rotors that way.
The first output testing in Berlin 2020 was essentially exactly that; hoverboard wheel alternator, liquid rheostat variable load. Worked fine and gave full system power numbers. In Nepal tho the main issue was that I just couldn't find a viable option for the alternator. I had intended to use a motorbike alt, but they didn't turn out to be as accessible an option as I'd hoped. Also I kind of just wanted the mechanical output for sake of one less aspect / efficiency gate to potentially complicate the direct comparison of the various runner types. And had used a Prony with the wind turbine testing in Edinburgh (tho with a load cell and ESP32 logger board), so was comfortable enough lashing together a sort of equivalent just using weight scales. Would still love to solve the problem of best alternator options for low resource environments tho..
I wish you could either be in Palestine or in one of the many refugee camps in the region, building water filters and aiding those in need. It's great to see your work on these DIY microhydro projects, though, I love seeing them and they make me hopeful for the future as we'll be facing more and more energy insecurity as the demand climbs and poverty rises.
I've done a bit of work in various refugee camps, mainly in Greece and Uganda, but don't really have the resources to be particularly useful in more active disaster or conflict zones, unfortunately
Presumably for the standard turbine types (Kaplan, Francis, crossflow, etc), but this use case is a bit niche, and fluid dynamics is voodoo.. Will have more of a look tho now that I know the basic efficiencies of each, great if there is.
Did you hear Keppe Motors are releasing the most efficient water pump in the world? 2000L mer Min only 115w. Imagine if it used the most efficient turbine?
Completely uneducated guess here from a fellow kiwi but wouldnt creating laminar flow allow the fluid to impart more energy to the turbine as apposed to creating turbulence with the spin flow guide. If it works it would also have the added benefit of acting as an inline filter. I've used 100mm pvc pipe with endcap -> scotch pad -> straws -> scotch pad -> endcap to generate laminar flow for the kids to play with using a garden hose. Scotch brite pad might reduce the flow too much so a mesh might be better and plastic straws are a little bit controversial so maybe 3d print an insert instead 😂 Anyway love the content and great to see that number 8 wire mentality being spread round the world!
Oh also the issues you have with priming the test systems could be made less so by using a t fitting inline and 3d printing a simple needle / gate / ball style (albeit cylinder shaped) valve to stop flow with a fill port added either to the print or before the t fitting for filling the source tank. If 3d printing is a problem I've seen people use tyre tubes as temporary pipe plug seals with a bike pump.
Laminar flow is probably desirable, but hard to maintain through any length of pipe, even relatively straight. A straw stack would need to be at the intake so that it could be kept clean, as would definitely clog over time even with a coander filter or similar. One of the advantages of this kind of turbine over a pressure type like a Pelton is it's way more forgiving of particulates, not having a jet nozzle to clog. Not sure what you're meaning in the second comment, is about priming the siphon?
@@OpenSourceLowTech yeah, the benifits of the syphon based system is drawing from a depth so you already avoid a lot of potential blockages from surface debris. For a laminar flow stack I was thinking more of incorporating it into the turbine assembly as part of the bushing before the turbine itself but I guess it can defeat the purpose of making this as low cost and access-able as possible when adding additional complexities. If it's found to have considerable efficiency gains then it could be relatively easy to design the turbine and laminar flow stack as one insert so it's easily removed for maintenance and cleaning. The priming comment was about filling via the system itself so it's primed at the same time during filling but is only really considerable for a test rig not in production and might have issues with pump sizes. Probably more trouble than it's worth 😅. I would be really interested to see what the limits are with stacking the turbine heads within your current design (two or more fans stacked together). Kinda see if you're able to extract more energy from the water by increasing the surface area of the turbine. Times like this I wish I could do the math to figure out what the maximum possible energy for syphon given the pipe size and drop etc.
> avoid a lot of potential blockages from surface debris. Ideally, but unless it's a pretty deep pool / dam things just tend to get mixed and sucked on to your screen in fairly annoying quantities. Still need to properly test coander filters, but they'll need to be fairly large to handle the volume throughput. > can defeat the purpose of making this as low cost and access-able as possible I'm happy for there to be optional add on efficiency boosters for those with the resources, long as the baseline configuration is as universally accessible as possible. Hence the PC fan runner, tho to be fair that does turn out to do a pretty decent job.. > one insert so it's easily removed for maintenance and cleaning. Maybe, if it's a lot of extra oomph. Bit of a bugger of a process tho, and probably fairly often. > primed at the same time during filling This is more or less what I had going in Berlin, but that required a gate valve on the outlet so the water didn't just drain out. Is an option, if you can find a funnel / cone of exactly the right size to fit the gasket, as I was lucky enough to do. > interested to see what the limits are with stacking the turbine heads Yeah same. Will do some further testing on that front when I'm able. > maximum possible energy for syphon given the pipe size and drop etc. The basic equation for max system power is just flow times drop times gravity. But that gets a lot more complicated when considering pipe friction, turbulence, topology, load management, etc etc etc. I wouldn't even necessarily trust a full CFD sim, pretty much just have to build it well as you can and see what the outcomes are.
@@OpenSourceLowTech Thanks for the replies! I fortunately have all the parts in my garage to build one, joys of being a hoarder. Will definitely be playing with this concept. It's a fairly large rig to lug around for field testing so although it will add some internal turbulence I think I'll try corrugated pipe (collapsible) as for the non critical parts vs PVC lengths. Might be lucky enough to minimise the footprint to the dwc junction and 40-60cm of collapsed corrugated pipe.
I wonder if adding perpendicular grooves on the blades would increase efficiency. Essential creating more water friction/ drag on the rotating impeller = more converted into electrical energy?
Generally you'd benefit from less turbulence and friction not more, but hydrodynamics is voodoo and only way to find out is try every possible iteration in the real world.
That is true (the voodoo). I am going to print out and try your screw impeller. And will play around with some ideas and if anything worthwhile will report back with results.
I didn't see the Basu/shist disk in there. You should try that one, it's shown high efficiency in moving water. Probably means it would be decent as a turbine too.
@@OpenSourceLowTech If you look it up, its the egyptian unusually shaped disk that was made out of shist. Theres a video of a guy using it on ytube in a large paddling pool, with very little input work he could lift the heavy disk and weight on top of it. Theres other videos on redit that show it being used with a drill in a glass of water. It's almost the opposite of an impeller so I think in a tube where the water is coming in from its sides only instead of filling the whole tube it could work better. In order to keep the water flowing to the sides you would obviously need some kind of plug with maybe 3 or 6 fins locked to the edges of the inner tube.
That guide to spin the water was too comlex, too much surface area. If you look at the static blades on a turbine, they are relatively short in terms of the distance the water travels over them. You overdid it, and it needs to be a gradual turn from straight flow to the angle you want the water to be turning at. Plus, quite often the fluid hits the turbine straight, and it's intermediate blades that are used to adjust the fluid angle to hit the second or subsequent sets of moving blades correctly.
This is I think essentially the case, yes. The idea was to double up a flow guide bend with a stator action, but previously when I tried just a bit of carved polystyrene to elbow the flow it didn't really seem to make any difference, so I think maybe the water just doesn't mind taking a corner on its own, but really hates wall friction.. I'll next try a kind of internal vector spinner type thing which may or may not help but should be easier to dial in specific angles, and just a more standard stator stack as you described.
After problems with You Tube channel, in the past , I thought that you've given up filming and fell off the radar (turns out that you've gone above the radar -I mean Nepal...). Btw , I was under impression that in Nepal wind power would be more interesting , but I could be wrong.... Now , since you are back (on YT , I mean) , I have some questions , regarding the turbines you've built (in the past and recently) . Since you utilized height difference of about 4 meters and more , between intake and outlet of the pipe , would it be possible and/or beneficial (in terms of energy production) to put more than one turbine along the length of the pipe , using some "T" fittings at angle of 45° , let say , one meter apart ? Second question: would the "screw" design benefit from making the screw longer , using the more mass of the water (more available torque ?) and how we can determine the best pitch of the screw and whether is uniform pitch better (more efficient) , or ever changing one (for a particular length of screw and water velocity). Third one : did you ever compared , or calculated , what would produce more power (with exact same generator used) - the siphon turbine version , or (for an example) pressure powered Turgo turbine (given the same intake height nad same diameter of pipe , of course , with injector at the end for a Turgo turbine version) ? All the best !
> I thought that you've given up filming Took about a year, but they finally fixed the channel in 2022. Since then I've just been lazy / distracted. > more than one turbine along the length of the pipe Short answer not really. They'll all steal momentum and power from each other, so you'll multiple your costs but not your output. > making the screw longer Quite possibly. There'll be a sweet spot somewhere for all the various settings, could potentially CFD it, but probably best just print and test a bunch of variations. >the siphon turbine version , or pressure powered Turgo Turgos and Peltons are a lot more efficient, but need at least 20m head to function well. So if you have that much drop, use them. Less; mine should do better.
Good work, but you dont need to reinvent the wheel. The engineering and science of water flow as a energy source is well know, we've been using it for centuries. Impellers, syphons, etc are well understood and tested, use the research of others. I've been using ram pumps to lift water, the technology is 150 years old, and as good as it gets.
Wow good to see the end results of those variations of 3D printed Turbines, You are always welcome to Nepal and Kathmandu University for more Research and Hope to be your help again in the future.
Thanks!
Great to get an update of what you've been up to. Looking forward to the archimedes screw fine tuning results and if possible a downloadable file of the final screw design 🙏
Awesome video - thanks for all that you do and share 🙌
Cheers!
The logarithmic spiral types are intended to throw water out to the side, if they're constrained within a tube then all you're doing is increasing the pressure and friction.
It's likely something like that, yes. I'm finding that good propellers don't necessarily make good impellers.
@@OpenSourceLowTech Yep. This is also true of airplane propellers. Some of them perform better when they have a shield around them to direct the air and some don't seem to have much of an impact. I think the term for them is "ducted propellers'.
In a boat setting, the idea is to grab as much of the surrounding water as possible and throw it backward, OR to move a smaller amount of water very fast. Both of these impart Newton's third law (mass, momentum etc).
In a tube like you've got, all the water is inherently 'ducted'. So running the horizonal water grabbing ones in reverse ends up performing poorly.
I think the Lily Impeller might work when constrained given it has more room for the water to be expelled. But ultimately having real world tests like you doing is ideal. These things are so hard to think about and often unintuitive.
After years of casually researching nano-hydro, I keep returning to the conclusion that positive-displacement designs (like the archimedes screw and others) seem preferable due to significantly higher efficiency.
Are you working with Chris evens? hes just been awared an OBE.
Excellent job! I am a bit surprised that the flow guide didn't help. It should have increased the RPMs of the spindle but probably reduced the torque, Did the flow guide made the tank to empty slower? Could it be the case that cumulative energy is higher while instant power suffers?
With the screw runner the flow guide managed to drop both the rpms and torque. May be just increased friction above vector gains. Going to have to try some other options to get a better idea of what's going on.
In air, gas and water vapour turbines, the directional stator vanes are often used in multi-disk configurations, the stators placed between the discs, to "straighten" the flow before the next disc, and not to rotate it before the disc.
By pre-rotating the flow before the turbine you've probably worsened its stall and drag characteristics so it made it less efficient.
Yeah I feel like this is probably the case.
I'll aim to try a multistage runner stator stack in some future testing setup, see what if anything that does.
@@OpenSourceLowTech yeah, most designs are calculated with straight incoming flow in mind, the optimal angle of attack is extremely important to maximise the lift, minimize the drag and avoid the stall. So running with the off-spec angle will be worse in most cases
Love your channel - great work.
Thanks!
Great work as always! Interesting to see that the Archimedes screw had the best performance, but it makes sense I suppose, and that's great info to know since the Archimedes screws are less considerably less complicated to print or fabricate than the other more complex spiral shapes. I think I can definitely print a screw of that exact size and shape out of recycled #5 PP with my TrashPrinter. There's still a lot it can't do, but it does really well with simple spiral-vase type parts like that, and I've printed turbines with similar sizes and overhangs before. I'll give it a shot once I get the trash printer going again later this summer, and I'll let you know how it goes. If you've got an STL you can send me, lmk, but otherwise I'm sure I can find one online or make one with OpenSCAD.
I've got some friends up in Washington with a pond on their property that drains a massive area of steep mountains on their property, and I've been looking into ways to integrate their pond into their off-grid solar power system, as both an energy storage buffer and a way to harvest energy from the huge volume of rain moving through their property in the winter, when they get basically no solar. I would love to test out one of these turbines up there. I figure we can build one to start and get some data on its performance, and if our results are promising, we can calculate how many more we would need to match the natural seasonal flux of the pond, and then build an array of them.
Thanks for collecting and sharing this data!
Oh yeah, forgot to include the .STL
Is now in the description, but also: drive.google.com/file/d/1LKLKvMf1uGRJezQpzQJxcq62L2xLxtP-/view?usp=sharing
Let me know how you get on, and any questions etc.
Amazing work!
Cheers
Have you ever tried 3D printing a adjustable penstock gate that would sit just above the turbine blades? It looks like the circular radio active symbol but there's two that overlap and depending on how much you align the holes in the top plate with the bottom would control the flow rate and head pressure.
Doable, but the use case with these tends to be that you always want as much power as you can possibly get out the thing.
@@OpenSourceLowTech True, it's always a fighting balance between adequate head pressure and vectoring the flow at the most efficient angle of attack. I believe your solution lies in in solving that metering and head flow angle though, but that's my opinion. Love your content.
Trimming the shrink wrap after install will change the balance of the wheel. ANY imbalance will be a big loss in efficiency. If you detect vibration during operation, the wheels are off balance, at least the rotating assembly is out of balance. Unfortunately, wear on the rotating parts will change the balance too.
Potentially, tho the masses involved with the plastic runners are super small, and it is in normal use flywheeled by the alternator.
Could have unbalanced torque effects tho if one side of the runner is a slightly better profile than the other..
Just found you, channel looks brillant. Subbed.
Thanks and welcome
In reply to what you said regarding alternators... a good approach if you have the time is an axial flux machine that you'd build yourself. There's a little bit of stuff in my recent videos about that.
Yes, but they're a bit of work..
I wonder why you dont use a PMA with a variable resistive load to measure power at the shaft. Perhaps it wouldn't be an improvement over the simple pony brake you have but it seems it might yield smoother results with easier adjustment and nothing to wear out. Perhaps the rpm is too low and such an alternator would need to be too large. I play with wind turbine rotors that way.
(BTW, neat video/fun stuff)
The first output testing in Berlin 2020 was essentially exactly that; hoverboard wheel alternator, liquid rheostat variable load. Worked fine and gave full system power numbers.
In Nepal tho the main issue was that I just couldn't find a viable option for the alternator. I had intended to use a motorbike alt, but they didn't turn out to be as accessible an option as I'd hoped. Also I kind of just wanted the mechanical output for sake of one less aspect / efficiency gate to potentially complicate the direct comparison of the various runner types. And had used a Prony with the wind turbine testing in Edinburgh (tho with a load cell and ESP32 logger board), so was comfortable enough lashing together a sort of equivalent just using weight scales.
Would still love to solve the problem of best alternator options for low resource environments tho..
I wish you could either be in Palestine or in one of the many refugee camps in the region, building water filters and aiding those in need. It's great to see your work on these DIY microhydro projects, though, I love seeing them and they make me hopeful for the future as we'll be facing more and more energy insecurity as the demand climbs and poverty rises.
I've done a bit of work in various refugee camps, mainly in Greece and Uganda, but don't really have the resources to be particularly useful in more active disaster or conflict zones, unfortunately
Should be a well developed formula for turbine blade shape based on speed and viscosity of fluid. Most of it is avoiding cavatation damage.
Presumably for the standard turbine types (Kaplan, Francis, crossflow, etc), but this use case is a bit niche, and fluid dynamics is voodoo..
Will have more of a look tho now that I know the basic efficiencies of each, great if there is.
The euler turbine and pump equation(s) is a useful tool, but it doesn't give detailed blade shapes beyond incoming and outgoing pitch/angles.
Hy and thanks to show your work
In my opinion you are in the way to create a vortex, like Victor Schauberguer
Did you hear Keppe Motors are releasing the most efficient water pump in the world? 2000L mer Min only 115w. Imagine if it used the most efficient turbine?
Completely uneducated guess here from a fellow kiwi but wouldnt creating laminar flow allow the fluid to impart more energy to the turbine as apposed to creating turbulence with the spin flow guide.
If it works it would also have the added benefit of acting as an inline filter.
I've used 100mm pvc pipe with endcap -> scotch pad -> straws -> scotch pad -> endcap to generate laminar flow for the kids to play with using a garden hose.
Scotch brite pad might reduce the flow too much so a mesh might be better and plastic straws are a little bit controversial so maybe 3d print an insert instead 😂
Anyway love the content and great to see that number 8 wire mentality being spread round the world!
Oh also the issues you have with priming the test systems could be made less so by using a t fitting inline and 3d printing a simple needle / gate / ball style (albeit cylinder shaped) valve to stop flow with a fill port added either to the print or before the t fitting for filling the source tank. If 3d printing is a problem I've seen people use tyre tubes as temporary pipe plug seals with a bike pump.
Laminar flow is probably desirable, but hard to maintain through any length of pipe, even relatively straight. A straw stack would need to be at the intake so that it could be kept clean, as would definitely clog over time even with a coander filter or similar. One of the advantages of this kind of turbine over a pressure type like a Pelton is it's way more forgiving of particulates, not having a jet nozzle to clog.
Not sure what you're meaning in the second comment, is about priming the siphon?
@@OpenSourceLowTech yeah, the benifits of the syphon based system is drawing from a depth so you already avoid a lot of potential blockages from surface debris.
For a laminar flow stack I was thinking more of incorporating it into the turbine assembly as part of the bushing before the turbine itself but I guess it can defeat the purpose of making this as low cost and access-able as possible when adding additional complexities. If it's found to have considerable efficiency gains then it could be relatively easy to design the turbine and laminar flow stack as one insert so it's easily removed for maintenance and cleaning.
The priming comment was about filling via the system itself so it's primed at the same time during filling but is only really considerable for a test rig not in production and might have issues with pump sizes. Probably more trouble than it's worth 😅.
I would be really interested to see what the limits are with stacking the turbine heads within your current design (two or more fans stacked together). Kinda see if you're able to extract more energy from the water by increasing the surface area of the turbine. Times like this I wish I could do the math to figure out what the maximum possible energy for syphon given the pipe size and drop etc.
> avoid a lot of potential blockages from surface debris.
Ideally, but unless it's a pretty deep pool / dam things just tend to get mixed and sucked on to your screen in fairly annoying quantities. Still need to properly test coander filters, but they'll need to be fairly large to handle the volume throughput.
> can defeat the purpose of making this as low cost and access-able as possible
I'm happy for there to be optional add on efficiency boosters for those with the resources, long as the baseline configuration is as universally accessible as possible. Hence the PC fan runner, tho to be fair that does turn out to do a pretty decent job..
> one insert so it's easily removed for maintenance and cleaning.
Maybe, if it's a lot of extra oomph. Bit of a bugger of a process tho, and probably fairly often.
> primed at the same time during filling
This is more or less what I had going in Berlin, but that required a gate valve on the outlet so the water didn't just drain out. Is an option, if you can find a funnel / cone of exactly the right size to fit the gasket, as I was lucky enough to do.
> interested to see what the limits are with stacking the turbine heads
Yeah same. Will do some further testing on that front when I'm able.
> maximum possible energy for syphon given the pipe size and drop etc.
The basic equation for max system power is just flow times drop times gravity.
But that gets a lot more complicated when considering pipe friction, turbulence, topology, load management, etc etc etc. I wouldn't even necessarily trust a full CFD sim, pretty much just have to build it well as you can and see what the outcomes are.
@@OpenSourceLowTech Thanks for the replies! I fortunately have all the parts in my garage to build one, joys of being a hoarder.
Will definitely be playing with this concept.
It's a fairly large rig to lug around for field testing so although it will add some internal turbulence I think I'll try corrugated pipe (collapsible) as for the non critical parts vs PVC lengths.
Might be lucky enough to minimise the footprint to the dwc junction and 40-60cm of collapsed corrugated pipe.
I wonder if adding perpendicular grooves on the blades would increase efficiency. Essential creating more water friction/ drag on the rotating impeller = more converted into electrical energy?
Generally you'd benefit from less turbulence and friction not more, but hydrodynamics is voodoo and only way to find out is try every possible iteration in the real world.
That is true (the voodoo). I am going to print out and try your screw impeller. And will play around with some ideas and if anything worthwhile will report back with results.
Nice one, please do.
I didn't see the Basu/shist disk in there. You should try that one, it's shown high efficiency in moving water. Probably means it would be decent as a turbine too.
The which?
@@OpenSourceLowTech If you look it up, its the egyptian unusually shaped disk that was made out of shist. Theres a video of a guy using it on ytube in a large paddling pool, with very little input work he could lift the heavy disk and weight on top of it. Theres other videos on redit that show it being used with a drill in a glass of water.
It's almost the opposite of an impeller so I think in a tube where the water is coming in from its sides only instead of filling the whole tube it could work better.
In order to keep the water flowing to the sides you would obviously need some kind of plug with maybe 3 or 6 fins locked to the edges of the inner tube.
@@OpenSourceLowTech Oh, its the sabu disk, sorry, that was a typo.
Its good
That guide to spin the water was too comlex, too much surface area. If you look at the static blades on a turbine, they are relatively short in terms of the distance the water travels over them. You overdid it, and it needs to be a gradual turn from straight flow to the angle you want the water to be turning at. Plus, quite often the fluid hits the turbine straight, and it's intermediate blades that are used to adjust the fluid angle to hit the second or subsequent sets of moving blades correctly.
This is I think essentially the case, yes.
The idea was to double up a flow guide bend with a stator action, but previously when I tried just a bit of carved polystyrene to elbow the flow it didn't really seem to make any difference, so I think maybe the water just doesn't mind taking a corner on its own, but really hates wall friction..
I'll next try a kind of internal vector spinner type thing which may or may not help but should be easier to dial in specific angles, and just a more standard stator stack as you described.
After problems with You Tube channel, in the past , I thought that you've given up filming and fell off the radar (turns out that you've gone above the radar -I mean Nepal...). Btw , I was under impression that in Nepal wind power would be more interesting , but I could be wrong.... Now , since you are back (on YT , I mean) , I have some questions , regarding the turbines you've built (in the past and recently) . Since you utilized height difference of about 4 meters and more , between intake and outlet of the pipe , would it be possible and/or beneficial (in terms of energy production) to put more than one turbine along the length of the pipe , using some "T" fittings at angle of 45° , let say , one meter apart ? Second question: would the "screw" design benefit from making the screw longer , using the more mass of the water (more available torque ?) and how we can determine the best pitch of the screw and whether is uniform pitch better (more efficient) , or ever changing one (for a particular length of screw and water velocity). Third one : did you ever compared , or calculated , what would produce more power (with exact same generator used) - the siphon turbine version , or (for an example) pressure powered Turgo turbine (given the same intake height nad same diameter of pipe , of course , with injector at the end for a Turgo turbine version) ?
All the best !
> I thought that you've given up filming
Took about a year, but they finally fixed the channel in 2022. Since then I've just been lazy / distracted.
> more than one turbine along the length of the pipe
Short answer not really. They'll all steal momentum and power from each other, so you'll multiple your costs but not your output.
> making the screw longer
Quite possibly. There'll be a sweet spot somewhere for all the various settings, could potentially CFD it, but probably best just print and test a bunch of variations.
>the siphon turbine version , or pressure powered Turgo
Turgos and Peltons are a lot more efficient, but need at least 20m head to function well. So if you have that much drop, use them. Less; mine should do better.
Good work, but you dont need to reinvent the wheel. The engineering and science of water flow as a energy source is well know, we've been using it for centuries. Impellers, syphons, etc are well understood and tested, use the research of others. I've been using ram pumps to lift water, the technology is 150 years old, and as good as it gets.
Always easiest if someone's already done it, but low head medium power low cost hydro is unfortunately not currently a well catered to niche..
The “Michelin” wheel company R&D expenses are 756 million € per year.