WHAT ELSE CAN A JET ENGINE AFTERBURNER DO?!
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- Опубликовано: 27 июн 2022
- Today we show you our new jet engine design using a new afterburner setup. We start with how you can build it yourself and then run through some demos. We end with a fun show of fog juice (glycerin) running through the turbojet to create huge clouds of smoke.
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/ techingredients
www.techingredients.com/ 
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Exotic speakers, Fancy laser displays, now the mother of all fog machines... If they guy ever opens a night club it's going to be epic!
I suspect the DJ will be restricted to royalty-free classical music
Be great if it's hooked up to a getaway car being chased by a convoy of cops. Dense up the town for days. (Evil laugh😉)
For a minute, there, I thought that Snoop Dogg was in their garage!
Don't forget the fine distillates.
Sponsored by carlsberg
Years ago, one of the first projects I worked on as an aerospace engineer was "Alternative fuels". We took a stock jet engine (as would be found on a light commuter jet) and ran everything from peanut oil to vodka through it. Turns out, the peanut oil ran the engine just fine, but to get it to run on vodka, we had to make modifications to the engine's software. Turns out, peanut oil is more expensive than jet fuel, but it has the added benefit of making the entire test site smell like fried chicken right after start up and shutdown.
Do you got some videos of that would love to see it
@@thorer6778 Unfortunately, I don't have access to videos of it, and if I had video and posted it to youtube, they'd sue me to the point of homelessness.
You can remake it.
I was going through ideas for alternate diesel fuels for cars. Mostly, I was just exploring options. I have a diesel pusher RV, and wanted to know all my fueling options. Ya, peanut oil, or most any food oils you can buy in a grocery store, are more expensive than their road fuel counterparts. It's probably cheaper to get them in industrial quantities, but same can be said about road fuels.
The vodka may not have worked as desired because of the water content in it. The average is 80 proof, or 40% alcohol, 60% water. You can refine it to about 95% alcohol, 5% water, but after that, it starts absorbing it back in from the atmosphere. You may have been better off with strong methyl alcohol. Just don't drink the surplus methyl alcohol jet fuel after work, that stuff will kill you.
@@JWSmythe Something I've heard of people doing is getting _used_ cooking oil from restaurants for free (they'd normally have to pay to get rid of it) then re-refining it to take out anything you don't want going through an engine and using that. It apparently works pretty well, some people even claim to get better engine performance but I think they're probably imagining it.
Neighbors, seeing cloud of fog:
"He's at it again."
"What's he doing this time?"
"I think... I think he's building a thunderstorm."
"Martha, call the fire department! That youngin' across the road has set fire to his workshop again!"
" Yes, Henry," and doesn't bother to call.
Cloudbusting.
Better than the hydrogen explosion... The neighbors are still shaking from that one.
@@nameredacted1242 😂 Nobody in that neighborhood will forget that one.
Maybe, approve his request for reduction of property taxes ?
I've had a pretty awful day filled with 4 separate engineering job rejection emails, but this cheered me right the heck back up. You're the coolest internet uncle around lol
Thanks and good luck.
You need a secondary ignition in Afterburner for a few reasons, Mixture Pressure, Temperature, time of atomization, and the cooling dynamics of the fluid as it makes it's way out of the nozzle. but when the burnfront is behind the ignitable gases moving at that speed with a soft even molecular cushion, you need a nice sharp spark to break that balloon. and that assuming you have some nice pockets at the injectors to stir things up, I find if you ramp up the fuel pressure nice and high with small nozzles it works well. the algorithm gods apparently know what I'm working on right now...whoa .. haha.
You're right about the nozzle size vs pressure to maximize atomization. Pump capability is really the only limitation here.
Like you, I enjoy pushing past the typical barriers. This is why it's important to study how those barriers were established and understanding how the "pros" do it. Then let it rip...😶
@@TechIngredients absolutely! I 100% agree, you have to have fun in life, life is so much fun when you know how to build things and make a lot of noise...lol!.
Also I wanted to mention with the turbo style exducer vs an axial turbine there's usually a spinning pressure zone coming out of that turbo against the walls of the afterburner creating a sorta lean/rich environment in the same space, but there's so many different variations of this I find that each setup requires individual analysis and treatment.
This may be a bit naïve, but would their be any benefit to introducing a stator to vector some of that exhaust gas into a slightly straighter path down your afterburner? I would imagine that the exhaust gasses experience a lot of angular momentum and want to wrap the wall of the pipe. I wonder if a straighter flow over your flame holders would better promote flame stability.
@@aaronschocke2147 I have the same question. As you mentioned, installing a stator should reduce the swirl. It should also reduce the exhaust gas velocity, which, if I understood @Tech Ingredients, is beneficial when igniting the atomized fuel.
Could you pre-heat the after burner fuel (engine cooling?) to ensure auto-ignition in the AB kinda like the regenerative cooling the shuttle uses in it's rocket engine?
“I love my job” was so sincere. I am jealous of your amazing work and the fun you have, at least I can experience it vicariously by watching your videos. I hope you continue this for many years to come!
Other engineering videos: "Don't try this at home."
Tech Ingredients: "I'm gonna give you the plans, tell you where to get the parts, and give you some cool ideas. Have fun."❤
At 35:40 Vapers out there, rejoice!! We finally have a new jet powered, after-burning vape mod for your vaping pleasure! 😆 😂 🤣
@@BillAnt fuck yeah I'll make all town have 5 meters of vibisibility and reek heavily of strawberry!!!! :v
though i love that cloud oh my god
dont try this at home sounds like a politically correct way to pathologize uselessness and trust in corporate logos. but... i'm cynical so surely that's not the case. right?
Anyway yeah thank goodness.
@@nicewhenearnedrudemostlyel489 actually its to legally disclaim yourself from liability from that special and way too common class of idiots that are iliterate enough to do something dangerous with no prior knowledge or training in the subject (like the microwave transformer wood burner tutorial followers, do not look up the photos of the aftermath of that) but also literate enough to know that courts exist, that lawyers exist and that some lawyers will pursue any case, and that you can sue people for almost any kind of damage with even the vaguest of cause or liability.
@@nicewhenearnedrudemostlyel489 indeed
Back when I worked as ground-crew on the F-16 fighter-jet, we learned that the afterburner basically doubled the thrust at the cost of _quadrupling_ fuel-consumption.. So if the F-16 were to run on afterburner all the time, it would have enough fuel for ~15 minutes of flight... (That's probably with internal tanks only.)
Yea that's without bags.
The Viper is tiny and doesn't carry that much internally. Still sick AF tho. It amazes me how the F-35 can carry an entire F-16s mass in fuel alone internally. Whew. That a Lotta' gas in a stubby jet. The Panther is pretty cool too, though.
You are quite literally a cooler and more legal Mr. White. 10/10 quality videos
Was trying to form words but I can only salute you 😎
24:18 Stage one exhaust gasses have plenty of CO2 and NOx which are really good at absorbing heat and not giving it to the cold fuel. The way to auto-ignite is to pre-heat the fuel.
Run it through a pipe wrapped around the exaust and pre-heat it(it doubles as protection for the pipe)
I think this is similar to what they do in commercial liquid fuel rocket engines right?
@@bruceschneier6283 It is. In rocket engines they even use the heat to drive the turbopumps and pressurize the fuel. It's really elegant and kinda nuts. These kinds of engines use a system called "expander cycle" and also feature probably the sharpest temperature gradient ever observed, going from being able to boil steel to liquid oxygen in less than an inch
Reminds me of how wide-eyed I was when I found out that huge spiral of tubing wrapped around a hot air balloon’s flame was propane being pre-heated. 😳
I wpuld also suggest a pilot burner inside the combustion chamber instead of the spark plug, a tiny tube with separate fuel and air mix delivered from the atmosphere via venturi intake. The pilot flame needs to be protected from the turbulent atmosphere of the engine with a perforated shield. We found (at our company making industrial burners) that the pilot is a well worth investment because it provides a constant ignition point regardless of the disturbances the main flaim would have due to changing (for example) combustion air temperature.
Remember, with CO2 in the combustion air, just a few Celsius up or down can shut off your flame.
Note: This will however produce NOx and CO so the environment will not like it, but for testing purposes and for proof of concept it will definitely have a huge boost in momentum/inertia performance.
Because a good pilot and a stable flame will allow you to increase the overall speed that you had to reduce initially....
@@ridermak4111 even a simple Coleman lantern or stove uses a preheater, though it's not for cooling, just proper performance.
All I know is I'd be happy as a clam to have neighbors like these guys. I'd be over there all the time checking out what they're up to and offering help where I could.
He would have stopped that long ago.
I love it. The genuine joy on your face when the fog burner was running is heartwarming. Great build. Love the whole thing
I'm still wondering how so many people are considering putting an afterburner on their jet engine. You really shouldn't hesitate.
I'm wondering how do people just casually have loose Jet engines out here.
@@Chris-rg6nm sounds like those "just casually having an electron microscope and Delorean in their garage"
Money problem lol my jet engine sunk me already and then I broke it. Id have to fix it and then build an afterburner
@@Chris-rg6nm Scrap yards are amazing!
@@Chris-rg6nm These are diesel truck and automotive turbochargers converted to jet engines. My first one was made from a "scrapyard" Subaru WRX turbo I got for the price of asking if I could have it. I purchased scrap stainless tubing at the metal scrapyard which included 1"-3" sizes with transition tapers and v bands (probably from a food processing plant) total cost was around $15 by weight. The ignition, oil and fuel pump were from junkyard cars and I got them for free. I started it using air compressor with a blow gun nozzle. I didn't have a TIG welder at the time so I MIG welded everything. It looked like crap but it functioned and made good power. I'm willing to guess I had maybe $100 into my test rig by the time I burnt up the center bearing section and moved on to a really nice gt4202 Diesel truck turbo I purchased on ebay for $250.
Lower oxygen content in the gases after the turbine seem to be a reasonable explaination for an increased temperature for self ignition. Additionally, evaporating the fuel in the afterburner requires energy, which is taken from the turbine exhaust gases. Hence the temperature of those exhaust gases might be decreased significantly, depending on the amount of fuel added. Both effects together might be enough to prevent autoignition...
I also think evaporative cooling of the kerosene might play a role.
That's what I was thinking , cat member the video but that asked a drag car driver why there car had no intercooler he sed the cooling of the air from the fuel evaporating was around 200 degrees .
That's what i thought. TechIngredients, try to measure the ex temp without spark plugs active?
I think I spotted the rocket scientist
I experienced this with an auto ignition coil and butane. Worked fine for slow butane gas, but as you try to increase the fuel delivery rate the expansion of the stored liquid into a gas cooled the fuel to the point the ignition coil couldn't maintain the temperature required for auto ignition.
A fatter element pulling enough power to offset the fuel cooling effect can work, but then it is likely to melt without the cooling from the fuel. This pushes you towards some kind of closed feedback loop maybe based on the resistance of the element in order to vary the voltage and maintain an electrode temperature within operating ranges.
The option I went for in the end was a ~100W ZVS flyback transformer and a spark gap strong enough to melt 2.5 mm steel electrodes. Tungsten electrodes helps with the melting. Then you have to worry about the wind speed "blowing the spark out".
Finally, a person that can explain this so even a dummy like me can understand ! Now I get it......and I'm loving every minute of it ! Thank you
WHEW, you were way beyond my paygrade, but I sat glued to the computer watching this. Thank you, sir, for a MOST INTERESTING education!!!
It's great seeing something being constructed from theory and in the process, overcoming the constraints that a practical, working model presents. Very informative and cool!
My mother always told me growing up to be a physicist or something.
I just became a something.
You got to admire the intellect.....
@@mapo5976 A something is better than a nothing!
I'm despaired when I see all those tiktok and other "social networks" addicted people who can't even answer a simple math or physics question and who have absolutely no curiosity to understand the world around them. Narcissism and superficiality, the keys to this modern society...
Every time you release a video, I'm notified 7 to 10 hours later because of time difference zone, so it's in morning time at work, I impatiently look for a peace time to watch and got drown in extreme pleasure by your nice and easy to understand explanation of each and every science and engineering points.
You are a great teacher, best wishes for you and your family from Iran.
i dont even know how can someone criticize you man, you're the best teacher ever!
I can't believe that I'm watching a video that opens with asking if you happen to have a turbo jet. I love this channel. Great vids. Keep them coming.
I don’t always build turbo jets, but when I do, I always add an afterburner 😆
why dont you always build turbojets ? get a proper hobby then !
Your neighbors must have a great sense of humor.
I wish I was his neighbor!
I wish I was his neighbor
I wish, I was his neighbour.
Especially when the hydrogen/oxygen balloon was touched off. 💥
I wish I had you as a lecturer when I was studying engineering almost 20 years ago.
Neighbours calling fire service, "I think he's finally burnt the place down, there's a lot of smoke." 😆
my first job in the Air Force after turbojet mechanic tech school was in the afterburner shop at Edwards AFB I worked on J85 and J79 afterburners. all this info good
Wow, even KISS would be jealous of that fog machine! Great video, as always.
My favourite moment of this one was watching you walk back through the fog trailing your own wake!
Got to say ..... I Love watching you love your job!
I believe the answer you're looking for is the thermal capacity of the fuel being sprayed into the afterburner. Kerosene has a surprising capacity to absorb heat. So much so that many aircraft are equiped with oil-fuel heat exchangers that use the fuel to cool the hot oil coming from the bearings. Basically, the fuel isn't being heated by the residual gasses fast enough in such a small space before the intended combustion area. If you had a fuel "pre-heater" (basically a length of copper or brass tubing that spirals around or "hugs" a hot part of the combustion chamber before feeding that fuel to the supply manifold) you'd probably have better combustion overall and better chances for autoignition to occur
Auto-ignition: 02 is important, but also consider the temp drop as the fuel is vaporized/atomized
I also suspect the time it takes to get (back?) up to that temperature is too long before it's out of the engine.
My intuition is that air temperature is not distributed equally in the chamber, so may be lower around fuel inlets and it is not able to get auto-ignition one before leaving an afterburner.
But I'm not a rocket 🚀 scientist
also pressure would play a role.
Your commitment to creating this incredibly digestible content is amazing. Thank you for all the time and effort you put in to both the builds and the videos.
Thanks!
Head in the clouds. No thermal camera required , bright orange is self explanatory. . Love the colours of the engine cold parts and the story the holes tell. Made a kiln gas burner with 1" pipe and cut a lip into the 2" exit nozel taper to hold the flame. Works very well. Nice work.
More Jet Engine Stuff Yessssssss! Have you considered making a DIY Turboshaft and/or Turbogenerator?
We had a jet engine t clear ice and snow from the railroad tracks. It was very powerful!
That is literally a cloud generation machine. As in full size clouds up in the sky. Friggin' Amazing !! !
Yes, just like what we see when we look up and watch jets passing overhead on a clear blue day creating clouds that last all day, I think that some say it is just contrails, and others say it is chemtrails.
This guy's a genius, started watching every single one of his video's after I saw the world's best speaker series!
A happy man enjoying his creation. Absolutely love this side of youtube
The fog juice hit is the quickest set up for a Sisters of Mercy show I've ever seen!
That was pretty awesome! 😎 The work and dedication that you have put in to what you do along with being an open source is very admirable! You along with others have been an inspiration to do better. 🤠
Thanks!
@@TechIngredients You are most welcome!
@@TechIngredients Give me my fucking refund
Not only I again learned a bunch, but also wat a great fun to watch. My thanks for the work you and your sons put in it.
The flames look so mesmerizing!
I have to say, you have a way to explain things in a very eloquent and simple manner. I look forward to your video's!
Some of the coolest, well thought out projects on this channel instead of regurgitated content! Thanks guys!
More fascinating explanations and data - as usual very well put together and really super demos. Much kudos and thank you. :)
I love how your assistants shirt is waving in the exhaust winds.
Your channel is so cool. Great job. You make hours of content feel like seconds because i enjoy it so much. Thanks a lot.
22:08 Thank you for including this! I've often found myself telling people to take a break. Step away from their project. Get it out of your head and then take a good long look at what the data is telling you and what your predictions and hopes and dreams were for it were. If they don't agree then stop trying to force the data to fit your prediction. Instead try to under stand why they don't match and decide if it's time to try something else.
It's often easy to stand to the side and see when someone has run straight into a wall and is trying to bash it down rather than go around. But when it's you doing it that darned wall that interferes with your beautiful theory can be hard to accept. Most people will do this at some time. It may be something small and everyday, or it might have you end up spending 30 years and a fortune trying to build a perpetual motion machine or free energy device.
When someone tells you to take a step back and look at something then it's usually not because they want to sabotage your idea but because you have been butting your head at that wall for some time now. Step back and try to look as it as if it was someone else idea. If it was someone else doing that would you think they were following good scientific practice?
Agreed
That is a beautiful jet engine.
With the afterburner, your engine appears to be losing a lot of stability. I think your exhaust/ afterburner section has too much restriction for the compressor you are using. You appear to be touching areas of compressor stall/surge. I think a design implementing less restriction (larger diameter) would work better ! But it sure is one of the nicer jet engines out there :)
Yes, AIT varies with oxygen concentration and other gases at higher partial pressures can interfere. Thanks for being willing to admit it! The exception to this would be self-igniting substances like peroxides and azides. Quality work as usual.
@37:17, after watching the preceding 30 seconds of you smiling while walking through the fog made me say to myself, "i think this guy must really love his job. than you removed any and all doubt in my mind with this clip. I know nothing about jet engines, im a carpenter and wood is my thing, but your love of and manner in which you explain them makes me have a deeper appreciation of them. thxs for sharing.
"I know a fair amount of engineering" the understatement of the century!
The father-son production is so cool, with great camera work, and amazing project ideas.. this channel deserves all of the interaction it receives.
The "Fog juice" reminded me of those mosquito control fog vehicles from the 60s we used to see down in central Florida. I haven't seen one in years but I remember they used to come through the area twice a week. The fog had sort of a creosote-like odor. I think most people then misinterpreted their intended function at the time. I believe they dispersed a residual oil into the environment to starve the mosquito larvae of oxygen in the areas of standing water where they develop. Most people think it was supposed to work like an insecticide and kill them outright but I found that just wasn't the case. In any case very interesting material ... Thank you !
They still have those trucks in St. Louis. I never tried to find out exactly what they were spraying - just assumed it was worse for the mosquitoes than me!
DDT
- Really enjoyed it. I’m an aviation enthusiast, but I didn’t know much about afterburners. Thank you. It is such a variated channel. I love it. Your doing a great job.
TI, add oxygen to the afterburner, monitoring the flow of oxygen. If it ignites without a sparkplug, you can determine the concentration for autoignition.
The flame catchers in the afterburner look to be very close to inducing engine-rich combustion modes. You can see them a bright orange in the camera shot down the afterburner. Could you drill those screw flame catchers out and make them double as a fuel injection stage, which would cool them (and atomize the fuel rather well)?
For a second I wanted to recommend automotive nitrous plates as those sort of match your description, but I think those tend to be made of aluminium so probably aren’t a great idea unless you like your jet exhaust with added chunks 😁
@@ChrisDRimmer extra crunchy
Close to engine-rich isn't engine-rich. If needed, tungsten TIG welding electrodes could handle the heat, but if it's not a problem why overcomplicate it by looking for solutions you don't need? If/when it becomes a problem I'm sure he will solve it.
@@ParadigmUnkn0wn they are clearly much hotter than the surrounding parts, and the engine is likely temperature limited. So updating those parts would likely increase the operating window of the engine.
I am also not convinced that titanium would do any better in that specific use case. Titanium can take a large amount of heat in a oxygen free environment, in a hot oxygen environment like that however it’s heat tolerance is dramatically reduced, and particularly when it is then it can combust.
@@MatthewMenze he said tungsten not titanium.
Love the video, the experiments, the shop, the location, the awesome knowledge.... but! how could you possibly post this without at least some simple thrust comparisons?!?! 😁 Keep them coming...
I picked up a military surplus fog machine. It tows behind a truck and can single-handedly generate enough smoke screen to cover a international airport (with perfect weather conditions). I used it to fog up a pretty large gorge up in the mountains once.
Thank you so much Main Presenter and team. You have a great job and you bring us so much fun. Another interesting project!
Really interesting to see all the little solutions combined here. I built a mini-turboramjet engine for research in college that only worked (in its turbo bypass mode) inside of this hypersonic wind tunnel they had…but I still have dreams of putting a scaled up version on some crazy homemade jet project someday now that I have my private pilots license.
Your neighbours must be very understanding folks, even those a mile away. 😬🙂
It's a rain maker! California needs you!
Thank you for the lessons. The ease of consuming your information is inspiring.
Great video. I have to say the space you’re living / working looks incredible. As someone who lives in the UK, my little 1 car garage doesn’t quite measure up. Goals!
(Minor note: the pedant in me cannot help but say that that Thrust is not momentum, but is instead the rate of change of momentum since thrust is a force :).
Thanks!
I'll call your pedanticism and raise you.
Momentum relative to the air surrounding the engine assumes that any net velocity differential is the result of acceleration generated by the engine.
@@TechIngredients Ah ha! I suppose that’s technically correct. The best kind of correct.
Apparently it makes the ultimate fog /smoke machine
Such a great teacher. The educational value is a terrific as the projects themselves! I love this channel!
As an HVAC engineer who uses fog makers for air flow visualization I love your gas turbine fog maker. I'd probably get fired for running that inside a building but would it ever work great. It would also set off every smoke detector in the building and the fire trucks would show up.
Constructive feedback for you:
1- I assume you purposely avoided dubbing in a voiceover narration during the loud runs, but I am certain it would've made the video more engaging.
2- I was anxiously waiting for you to explain the difference between optimizing for thrust versus power generation, e.g. in a turbine generator, but I don't think you did; or if you did, I had already zoned out by then.
3- I would've also been much more engaged if you were comparing measured thrusts in your different versions using force transducers.
Still a great show!
for power generation you are just utilizing the thrust differently. instead of a nozzle you would have your vanes that have a shaft that drives your generator rotor.
The auto-ignition issue with the afterburner might be due to a high velocity and low pressure flow of the exhaust gases that are entering into the chamber from the turbine.
Dope, next time I'm building a jet engine I'll keep this in mind
Your presentations are more addictive than *** - (self-censored). Superlatives are insufficient to express my fascination. Thank you so much!
19:00 this was one of the difficulties in SCRAM jets, the geometry needed to have these low pressure slower area's when trying to achieve mach 5+ is obviously very hard.
This dude is an absolute genius. What did you do in your past life?
Oddly enough: olive farmer.
Worked at warehouse 13
seemingly everything technical.
I've casually watched many DIY jet engine videos. But I was glued to this one, for all the 38 minutes.
Thanks!
Check out some of our earlier videos that dive deep into the jet engine builds.
I hope this man lives forever ❤️ love from egypt 🇪🇬
Thanks for the vid!
I noticed you've been having audio issues the last few vids, I'd check all your wires before forking out for a new mic etc. Could easily be a defective wire/connection from how it sounds.
What kind of thrust did you get out of Version 2.0?
The fogger would be an excellent option for people that follow your car too closely!
THE COMPOUND TURBO COMETH. Thank you my hero, and might I say: it feels good to have had the patience.
I love how this video starts off with "Now - if you happen to have a turbojet", like it's commonplace.
The fog juice could be a very good addition for the M1 Abrams. Since they use a jet engine too, the fog juice would add a tactical advantage in the battle field!
It already has a smoke generator
@@shawncooke7991 What i wanted to say is that the smoke generator wouldnt be necessary, since the engine itself could be the smoke generator
@@cdribeiro82 that’s how it works…injects fuel directly into the exhaust
Love the channel, but I hate RUclips Premieres
Now that's some vaping! Great quality content, I love how everything is thoroughly explained!
Amazing !! Watching from Brazil here. Thanks.
Hey Howard, will this turbo finally make my air conditioner cool my entire house? Just kidding. Love the videos. Hate that video. On the other hand, you have enough fans to actually make that happen.
🤣🤣🤣🤣 I had to re-read this, that was epic.
@@MakeItWithCalvin ha thanks
I only did it because they are one of my favorite channels.
@@mannye Tech Grandpa is low key awesome. The dude knows his stuff but is very humble and down-to-earth on camera. I appreciate that!
@@MakeItWithCalvin Absolutely. I discovered his channel a couple/three years ago and it's just brilliant. This guy should have 100 million subs.
Skip to about 35mins in to get to the point, audio is scuffy in the video but the end is good
ah so you're one of those people
Very impressive indeed and as always, beautifully explained. Many thanks.
You do have a lot of fun... thanks for sharing - really interesting 🙂
My hunch for why the jet fuel doesn’t autoignite is heat loss through vaporisation. I’d imagine when you introduce liquid fuel into the exhaust, it rapidly evaporates which could well reject enough heat for long enough that the exhaust gas stream just can’t get the added fuel to auto ignition point before it all escapes out of the nozzle. Perhaps with better atomisation it could work, as the surface area might allow enough heat transfer into the fuel to overcome the cooling, but that seems a difficult target to achieve even for serious engine makers!
Well shit I basically said the same thing as I did not see your comment earlier. 🤣
That's a pretty good theory.
Have you guys tried running gas for the reheat? If introducing something that’s already gas phase doesn’t work that would debunk my hypothesis pretty quickly!
You could achieve a better atomisation through increasing the fuel pressure, like its done in direct injection engines (petrol and diesel). Sometimes upwards of 200 bar or 2900 psi, but these pressures are hard to achieve.(in comertial diesel engines its usually done by a highpressure pump driven by a cam on the camshafts) and he uses the fuel pressure to regulate the amount of fuel deliverd. Cars solve this problem by only activating the injector for a short amount of time (pulsing) to get the right amount of fuel. If you could solve these technical difficulties you could make an autoignition afterburner work. But i dont think this is a resonable thing to build. Its only advantage would be that i could prove or disprove your thesis
If that is the case, a fuel preheater should work. If however the fuel needs to be preheated a lot that would be very hazardous
@Tech Ingredients: Really love your channel brother, another great video (series of videos I hope). When you brought up AgentJayZ I was way ahead of you X-) as any good dude who's geeked out on jet engines should. I have a litany of questions, but I'll just ask: Does not the forcing cone at the beginning of the reheater section negate most of the standard jet thrust achieved by the first stage in your turbo jet? IE if you were measuring the thrust would you not be getting 90% afterburner thrust and a minimal amount of standard jet thrust? Thanks again, I really HOPE you've got some cool sht planned for the 4th of July, and you're planning on filming it!!
Thanks.
Not at all. The cone is located in the duct where the inside diameter has increased so that the open cross sectional area changes little from the area of the exducer of the turbocharger.
I think I enjoyed every moment of this, almost as much as you did.
Your videos keep getting better with every one I watch thanks for all you do and keep up the good work 👍👍👍
Flame grill a steak in under a second?!!😈
I was thinking hot dogs:)
here early to boost engagement cause I love the channel!! we all know premieres are perfectly balanced (?
tea
Pretty sure he’s not on the tea drinking side of the puddle….
@@Relkond oh we know what tea stands for, perfectly balanced with no exploits whatsoever (?
Very excited about the upcoming content expanding on this topic! Excellent work as always guys
I really like your engineering projects and the scientific explanations that you provide. I am a retired electrical engineer myself but I do occasionally dabble in the mechanical engineering side of things.
This dude is in better shape than 90% of twentysomethings these days.
Stupid sexy Flanders!
MP should post his workout routine & diet :)
Impressive ! Have you mesured the thrust and ISP of this jet engine ?
Yes...
@@TechIngredients Tease.
@@TechIngredients So what are the values, if I may ask ?
@@alisioardiona727 I'm betting Howard is doing a video on it .
@@texasslingleadsomtingwong8751 Howard ?
I love the "long" 30+ minute format of these videos. You pack so much quality information into just a few minutes that I feel engaged throughout. I admit that I skipped to the end to see "cloud machine go brrrrrrr," but I intend on watching the entirety over my lunch break in 6 hrs. I run a hackspace and this could be a useful/fun project.
Ooof... I don't think we have the funding/knowledge/time to make this happen after all. It was really cool to watch. We have you playing on our shop TV a lot for inspiration.
you are one smart guy...interesting stuff thanks for the detailed workings of a turbo jet engine
Turbines don't have better compression than diesel engines. It's an apples-to-oranges comparison. In a turbine, the ratio is p1/p2, but in a cylinder engine, it's volume at tdc/bdc. The pressure ratio is higher because the work of compression also raises the temperature. Turbines are more efficient not because of higher compression, but because Brayton cycle is more efficient than Otto, Diesel, or Atkinson cycles.
Also, it's not even generally true that turbines ARE more efficient than diesel engines. They're used for helicopters/jets because of power-to-weight ratio needed for flying, not greater efficiency. Very high efficiency turbines, like the natural gas turbine power plants used on ships for for electric generation, are absolute monsters with multiple compression/intercooling stages, and multiple turbines with re-heat cycles to achieve efficiency levels that beat other options.
I never said they're more efficient than diesel engines (check again). I said they're very efficient and they have a higher compression ratio. With this I explained the relatively low efficiency of the afterburner.
> Turbines don't have better compression than
> diesel engines.
Yes, they do or at least they do in some cases in some cases. The compression ratio of a turbojet depends on the particular turbojet used just as the compression ratio of a diesel depends on the particular diesel used, but a 30:1 compression ratio isn't all that unusual for a turbojet versus a 22:1 compression ratio for a diesel.
> It's an apples-to-oranges comparison.
No, it isn't.
> In a turbine, the ratio is p1/p2, but in a cylinder
> engine, it's volume at tdc/bdc
In both cases, it's the ratio of the air pressure before it was compressed to the air pressure of the air after it was compressed.
> The pressure ratio is higher because the
> work of compression also raises the
> temperature.
When you compress air, it's temperature goes up unless something is done to remove it such as an intercooler in both a turbojet and an Otto cycle engine.
In the case of the turbojet, the rise in temperature due to compression does *NOT* change the fact that the engine is basically an open tube and so the pressure from the last compressor stage must be greater than the pressure from that point onwards or else the gas would flow back out the front of the engine ... which doesn't happen.
> Turbines are more efficient not because
> of higher compression, but because Brayton
> cycle is more efficient than Otto, Diesel, or
> Atkinson cycles.
I'm pretty sure that you are mistaken and/or have a pretty weird definition of "efficiency".
For both a Brayton cycle (turbojet) and Otto cycle engine, the thermal efficiency depends pretty much on just pressure ratio.
A Diesel cycle engine is a bit harder to describe, but for a given pressure ratio, a Diesel cycle engine is LESS efficient than an Otto cycle engine, but this is made up for by operating a Diesel cycle engine at a higher pressure ratio than an Otto cycle engine.
But presumably we're not strictly talking about thermal efficiency but rather total efficiency where the effects of propulsive efficiency also takes part.
(Thermal efficiency is the ratio of mechanical work produced in the system to the heat energy in the fuel and oxidizer, whereas the propulsive efficiency is the useful work done by the engine, (on whatever it's attached to, versus the mechanical work produced in the system.
And these two efficiencies are multiplied together to come up with the "total efficiency" (n[o] = n[t] * n[p]) ).
And when propulsive efficiency is considered, then it quickly becomes obvious that a Brayton cycle (turbojet) engine sucks in comparison to Otto (or Diesel) cycle engine until the aircraft speed reaches say about Mach 0.8.
This is because the thrust of the heated air coming out of the turbojet (which is being directly used to push the aircraft forward) is so much faster than the speed of the air that the aircraft is moving through.
(In the ideal case, the speed of the air coming out of the engine moves at the same speed as the aircraft at which point there is ZERO thrust.)
Otto cycle (and Diesel cycle engines if they were used), OTOH, generate thrust by turning a propeller which moves a much larger mass of air at a slower speed that more closely approximates the speed of the aircraft up until about Mach 0.8 at which point the thrust from the propellor drops off due to shockwaves forming over the blades.
So if you're planning on flying relatively close to the speed of sound or beyond, a turbojet beats an Otto cycle (or Diesel cycle) engine in terms of total efficiency, but otherwise it doesn't.
@@lewiscole5193 The compression ratio of a piston engine is defined by the volume of the cylinder when the piston is at the lowest point, bottom dead center (BDC) divided by the volume when the piston is at the highest point, top dead center (TDC). so, if the cylinder is 400 cc at the bottom of the stroke, and 20 cc at the top, then it has a 20:1 compression ratio. But, during compression, the gas also heats up a lot. In a diesel, so much the fuel will spontaneously ignite when injected. So, in addition to being 1/20th the volume, it's also over 2x the temperature. So with the compression ratio is 20:1, the actual pressure might be 45:1. Diesel engine compression can easily be 500 psi, from less than 14.7, probably more like 12 psi since you can't ever a full 1 atm into the cylinder that fast. No one ever talks about the pressure ratio of piston engines, because it changes from second to second based on atmospheric pressure, temperature, engine temperature, etc. Compression ratios for cars are always just the physical volumetric property of the cylinders, which is fixed, and is not based on pressure.
But for a turbine, the pressure ratio is the ratio of the pressure at the exit of the compressor divided by inlet pressure. That's what I mean by saying it's an Apples-to-Oranges comparison. Properly, we should not even call them the same thing, with turbines more properly having a pressure ratio vs piston engines having a compression ratio. But they are called the same thing, so people, even intelligent and knowledgeable people, can get tripped up. I just think it's important to note that difference, especially because making a direct comparison like that can lead people to mistaken conclusions about efficiency etc.
You are correct in noting that most of the efficiency difference isn't due to the cycles, as they'd all be pretty close if we could run them "ideally" instead of realistically, which means it's more due to the pressures we can achieve in the engines in practice that limits efficiency. Which is why it's all the more important to not confuse turbine pressure ratios to cylinder engine compression ratios. Juxtaposing turbine and diesel compression ratios makes it seem like they can be compared, but it's no more valid than saying something like "top fuel drag racers have 500 cubic inch displacement engines, but our turbine as a 600 cubic inches volume". It's a totally different measurement that doesn't allow for any meaningful comparison.
By "efficiency", I'm meaning more usable power for the same fuel. Which is really just thermal efficiency. Piston engines of all flavors leave quite a bit on the table vs a turbine in that they can only expand the gas back to the same volume it started, which means there's always a significant amount of pressure left when the exhaust valve opens that doesn't get used. With a turbine, they just keep adding stages until there's not enough pressure left to make it worth it. That's why piston engines (virtually all diesels) use turbochargers to improve efficiency, because there's a lot of energy left in the exhaust you can still get. Piston engines can run higher pressures and temperatures than all but the largest most efficient turbines, though, since they have closed volumes with better compression, and are exposed alternately to high temperature combustion and cool intake gas, unlike the turbine which has continuous exhaust gas flowing over it, and would melt if the mix was stoichiometric.
@@Timestamp_Guy
[Part 1]
> The compression ratio of a piston engine is
> defined by the volume of the cylinder when the
> piston is at the lowest point, bottom dead center
> (BDC) divided by the volume when the piston is
> at the highest point, top dead center (TDC).
> < snip a lot of further exposition >
If you take a cylinder of air and compress by reducing the volume of the cylinder, the air inside the cylinder will heat up.
When thinking about heat engines in theoretical terms, it is often times convenient to think in terms of the compression and/or expansion taking place so slowly that the temperature rise can be entirely ignored.
This is referred to as "isothermal" (i.e. "same temperature") compression/expansion.
And when the volume of a cylinder is reduced by half isothermally, the pressure of the air inside the cylinder will double.
IOW, the compression ratio (i.e. the ratio of the compressed pressure to the reference pressure) is THE SAME as the volumetric ratio before and after the volume changed.
So what does any of this have to do with anything?
Well, in the case of a theoretical consideration of one type of engine cycle versus another, the fact that the air heats up when compressed is a non-issue as presumably the same assumptions with regard to isothermal compression/expansion were made.
And by making a very sweeping statement about the efficiency of a Brayton cycle versus an Otto or Diesel cycle, you are clearly suggesting that your assessment is (or some point was) based on what happens theoretically, say by looking at some generalized PV diagrams.
To then talk about how real world compressive heating somehow screws things up seems not at all consistent.
Of course, in "real" heat engines, compressed air heats up.
But the important thing is that compressed air heats up the same regardless of the method of compression, be it by reducing the volume of a cylinder or turning the dynamic pressure of a stream of air into static pressure by reducing its velocity in a centrifugal compressor.
So if you want to say that the "compression ratio" for an Otto cycle or Diesel cycle engine isn't really what everyone thinks it is due to compressive heating which somehow doesn't occur in a Brayton cycle engine, then may I not so humbly suggest that you need to demonstrate (1) that no comparable compressive heating doesn't occur in a real world Brayton cycle engine and (2) that I should care even if it is.
Until you can do something about point (1), it is you who is making an apples-to-oranges comparison by assuming something that occurs for an Otto cycle or Diesel cycle engine doesn't occur for a Brayton cycle engine.
WRT point (2), if real world engines are what we are talking about, then presumably real world movement of air into and out of the cylinder during the compression stroke matters (i.e. we're talking about the DYNAMIC compression ratio rather than the STATIC compression ratio involving just the volume ratio) and so there's a lot more than just compressive heating that comes into the picture such as when/how long the valves are open.
But let's get back to this video, shall we?
IMHO, @Tech Ingredients effectively covered his ass WRT any of this when he mentioned during his piston explanation that he was playing a bit fast and loose with the Ideal Gas Law.
That statement IMHO basically obviates your bitch about a comparison between an Otto cycle or Diesel cycle engine and a Brayton cycle engine that HE DID NOT MAKE.
> You are correct in noting that most of the
> efficiency difference isn't due to the cycles,
> as they'd all be pretty close if we could run
> them "ideally" instead of realistically, which
> means it's more due to the pressures we
> can achieve in the engines in practice that
> limits efficiency.
There's that word again ... "efficiency".
> Which is why it's all the more important to
> not confuse turbine pressure ratios to cylinder
> engine compression ratios.
Which again implies that you think they are different.
> Juxtaposing turbine and diesel compression ratios
> makes it seem like they can be compared, [...]
They can be.
From the abstract to John Shaw's paper entitled "Comparing Carnot, Stirling, Otto, Brayton and Diesel Cycles" which can be found on the Internet:
Comparing the efficiencies of the Carnot, Stirling,
Otto, Brayton and Diesel cycles can be a frustrating experience
for the student. The efficiency of Carnot and Stirling cycles
depends only on the ratio of the temperature extremes whereas
the efficiency of Otto and Brayton cycles depends only on the
compression ratio. The efficiency of a Diesel cycle is generally
expressed in terms of the temperatures at the four turning points
of the cycle or the volumes at these turning points. How does
one actually compare the efficiencies of these thermodynamic
cycles? To compare the cycles, an expression for the efficiency
of the Diesel cycle will be obtained in terms of the *compression
ratio* [emphasis added is mine] and the ratio of the temperature
extremes of the cycle. It is found that for a fixed temperature ratio
that the efficiency increases with compression ratio for the Otto,
Brayton and Diesel cycles until their efficiency is the same as that
of the corresponding Carnot cycle. This occurs at the point where
the heat input to the cycles is zero. For a fixed compression ratio
the efficiency increases with temperature ratio for the Carnot
and Stirling cycles but decreases for the Diesel cycle. This is
an important factor in understanding how a Diesel cycle can be
made to be more efficient than an Otto cycle.
I would like to see more videos on turbine technology. Maybe a video on different fuels like hydrogen, common pump gas, oxyacetylene, 50%< alcohol... Etc!
The last demonstration reminded me of "I am the great and powerful OZ....Pay no attention to that man behind the curtain" hahahah...You rock!
You explain so well. You awe us with your knowledge. Thank you. Love from Pakistan.