5 Why Jet Engines Don't Melt
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- čas přidán 31. 07. 2024
- Why don't the combustors of a jet engine melt in all that fiery heat?
Let's look at a few of them.
Turbofan Blade Draw:
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This draw is open to the entire world.
The winner will not have to pay for shipping.
In order to have a chance to win, you need to do two things:
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AgentJayZ
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V1J 0K9
Entries must be postmarked by April 1 2018
Donations accepted until midnight April 15 2018.
Enter as many times as you want, but please only one entry slip per envelope. - Auta a dopravní prostředky
Why don't jet engines melt? Because they're so COOL!
🙄
😁
"shipped in a padded envelope... nice." -AgentJayZ. you make me laugh every video, brother.
That was a piece of information searching for my lifetime
Sir, may I congratulate you on your great experience of jet engines, your vast practical and theoretical knowledge, and the elegant and accurate vocabulary you use to describe the details of the procedures and the actions involved. When you speak about any working part of the engine, it is as if you are part of it and feeling and experiencing the action yourself. You seem to feel the pains and the glory of all parts of the jet engine which you seem to love so much and you treat them as if they were part of your family. You want them to work, but not suffer. At the moment I am working on a very small jet engine to show my grandson the working principles of the engine. I am using tinned milk containers to make compressors and turbines and combustion chambers and rather than building up pressure with the compressor, I am using the small engine in a vertical manner and so high speed convection currents will help to rotate the turbine which in turn rotates the compressor below it with the flame in between. I found that the combustion chamber part needs to be longer to permit the air to gain a higher velocity due to convection and not the pressure after the compression, which I can never obtain. Even with such a small flame working vertically to get the best convection currents, the combustion chamber has to cooled down and even the first part of the flame has to be in a slow air stream and mixing with other air must be at a later stage. Using convection currents, these are powerful enough to give an idea of the true working principles of a jet engine to anyone. Using this "toyish" engine, I have got it to rotate at about 2500 rpm. I find no difficulty with shaping the compressor blade/ disc and the turbine blade/disc, but the combustion chamber working vertically to obtain high speed convection currents, seem to be the most difficult.
Congratulations for all your videos, you should be invited at Universities to transfer your vast knowledge to students who tend to miss out on the practical side. Prosit.
Thank you for saying those nice things. Feel free to retract them after I regretfully inform you that you have not at all illustrated the true working principles of a jet engine.
If I wasn't honest I would be in the wrong.
Please upload a video of your creation for those of us who are interested in finding out more about it.
I was an AD (jet mechanic) in the USN 89-94 F404-400, TF-30 and J-52... loved working on them
Designing a combustion chamber is an art in itself. And getting it spot on is a miracle. I am looking everywhere to find any guide so I can design one for an experimental 400 foot-pound jet turbine. The other parts can be made on a CNC but not combustion chamber. Thank you for the excellent videos you post. I learnt a lot.
Thankyou for sharing the wealth of experience you have with jet engines that are a modern marvel, keep up the great work 🇬🇧 👍
New to your channel. Love the videos and thank you for your time, patience, and passing on information that no one else is talking about. Cool and interesting to say the least.
Agent JayZ, I've been enjoying your videos for a long time. All of them, the more technical the better. But, like most people, I love the J-79 tests with afterburners. For some reason, I recently stumbled upon videos of the B-58 Hustler, which used four afterburning J-79s, mounted under the wings, airliner style.
FOUR J-79 engines with afterburner per aircraft!! The B-58 set all sorts of speed records in its day, and was known to fly over the USA at supersonic speeds. Sonic booms for everyone! I can only imagine what it might have been like to be on the flightline near one of these during takeoff.
Thanks for all the vids, man. There's a whole generation of people who actually understand turbine engine fundamentals because of your efforts. Keep up the good work!
john90430 I must confess I'm one of those who only started to effectively understand turbine engines after watching some of his videos (even though I still feel more comfortable dealing with piston engines)
john90430 I must confess I'm one of those who only started to effectively understand turbine engines after watching some of his videos (even though I still feel more comfortable dealing with piston engines)
I've always wondered about this topic.
Thanks for your excellent explanation !!!
Sir I just want say thank you very very much, I learn so much from you, so awesome how you actually show the actual things, I want to become a pilot 1 day & I love learning about planes. Once again thank you
Love your Vids man, thanks for sharing your wealth on knowledge with us, your probably the best source on CZcams,
Thank you sir, you just helped me in my modules.
I don't know jets, but I remain fascinated by the human ingenuity and inventiveness that brought us jet engines, and that's why I find your videos fascinating. I'm reading (Sir) Stanley Hooker's book "Not much of an Engineer" (1985) and it's exciting to see the technology he discusses in the 'flesh' in your videos. Power on!
Also recommended: Herman the German, the autobiography of renowned GE engineer Gerhard Neumann.
I like your channel, taught me A LOT. Thanks. Keep it going you are doing fantastic
Thanks for you're patience and replying to questions that have been answered before, not everyone has the time to watch ALL of you're past videos.
They don't know what they are missing!
Awesome explanation Sir. I didn't know that. Thanks for sharing. Regards from Brazil.
This is excellent, thank you.
Great video. Thanks for the insights.
thought it was the kekistani glag at first lol.. Iv been wondering this too but I figured out a few things on my own from experimenting. still very glad you made this video. thank you.
so funny, how questions keep coming in, that have been ansewered a 1000 times before :D :D :D :D I follow this channel since 2010 and there is no question left to ask about turbine engines ;-)
Thank you for teaching!
thanks bud, always a pleasure.
Thanks again! Great video!
stoichiometric Kerosene/Air mix:
~ 2093°C or 3800°F
Fancy steel alloys melt:
~ 1400°C or 2600°F
... so, that means roughly half of the air flow through the compressor is used for cooling the hot flame down to a usable temperature... and, that half of the compressed air now isn't available for increased power by heating to stoicheometric temperature.
PS: thanks JZ
Two thirds. you might want to watch my latest vid called Heat upon HEAT, and also an old one called cooling air.
Very good explanation. Thanks
Thank You for sharing Your Knowledge
Thanks for the great video :)
Think about this people, for all the air going in the front of the engine only 30% or so is used to burn the fuel, the rest is used for cooling and in the case of a turbofan, thrust. Thanks JayZ for giving us all a lesson in turbine engines. And for the question of flames out the front in a compressor stall, I worked on F-14's with TF-30 engines, they would blow flame almost past the cockpit when in the hush house, can you say BOOM.
I worked at Roll Royce combustion systems Derby UK. 'Film Cooling' is the term for directed air that protects the metal surfaces.
Interesting. I've been challenging myself to design a jet engine for a little while, and while I was close, I had no idea the combustion chambers rely on active cooling to work. And to think I was gonna talk to the guys at Northrop Grumman about this. Thanks, you've spared me a little embarrassment :)
Matt Brody after you're done designing the jet engine, maybe consider designing a new cpu?
.
Love it Agent J!
This was a cool demonstration! It is very interesting how important it is to blanket the ultra high temp. flames with compressed air to keep the surrounding metals from melting in the hot section... I heard that special measures have been taken with the turbine blades (buckets) to keep them from melting as well...
Thank you for helping special olympics. My son is a special person and I help and he participates in the Texas Special Olympics.
This is pure gold ✨️
Hay Jay you give us loads of great info !!!!!!!!
Crack!! We love you!! Keep doing this!!
You might be interested to know that Inconel and Hastelloy alloys have been used in the high heat and corrosive environment of the Molten Salt Nuclear Reactor. The Reactors use a flouride molten salt above 600 degrees to transport and contain the reactants in a convective flow around a reactive barrier of solid graphite. Inconel , even tough it can melt is still tough stuff!
This is cool I'm from Vermont and work at GE Aviation and make jet engine blades.
I just have to say that is the coolest thing, helping out the special olympics like that good for you
Have you entered? There are not as many entries as I expected, so your chances of winning are pretty good!
nice presentation thanks
Very nice channel, and informative .
Thanks man. All kinds of knowledge here. I appreciate you. ,,,,,,,,,,, Jeremy in Alabama.
Cool.
Way to go :-)
Great info, presentation and video.
Good job.
I love your videos. Will look into the raffle. I wanted to know if there has been any progress on the Orenda Iroquois engine you showed a few years ago... cant wait for that one. Also, can you show the accessory drive of a commercial jet engine?
Nice!!!! Never imaginated
Now it all makes sense.
thanks for this video
That was a great a competition with a very worthy cause, I really hate that I missed it.
thank you =]
You have the ultimate snowblower at your disposal ......you need to test an engine during a blizzard...
We've done that a couple times. Videos are up. Your mission, if you choose to accept it, is to find them and enjoy.
@@AgentJayZ sir you have a deal....blow some snow...
If you had a chance to design a new engine what would you change from the ones currently in use today?
Your humour kills me lol
Cool to see the four flags together.
Lotta flags. Can't fit all of them in one shot.
03:12 - 03:30
Reminds me why i love this guy and this channel :-D
cool idea!
They are made of unmeltium.
I think the explanation at 6:39 is why you get a hot start unless you let the speed reach ~15% before applying fuel so that adequate airflow prevents the flame from touching.
Carlos Pulpo similar thought came to my mind too :)
Nice channel!
Can't wait to see the raffle selection.
OMG can't believe i only just saw this video! will you do a draw again?
Have you ever happened to work on any forein jet engine? USSR or Chinese jets? If yes whats your opinion(design, quality, tolerances, etc) thanks man I love your vids.
Hi AgentJayZ,
I'm Marco Lopes (as in envelopes) and I've watched your show for some time. My favorite playlist is on the AI-25. And yes, I know how you got the tension member coupling cap off. I work in IT (Datacenters) and have an M.S. in physics, so I know how turbojets work pretty well. My question is more on your industry. Have there ever been directives or updates (given out by manufacturers or regulatory agencies) where a maintenance schedule is adjusted for turbojet engines with long service histories, i.e. J-79 or Orenda Type 14? I'm thinking about the thrust bearing service interval. Thanks for your channel.
Hi JayZ. I thoroughly enjoy your programmes, ty for making them. What makes a low-smoke fuel nozzle low smoke? I'm guessing it must mix the reactants more efficiently or at a higher temperature but have no training or experience in jet engines so wondered if you knew. As a knock on question is the low-smoke property what was being sought when these nozzles were designed or is being smokeless a secondary bonus of just trying to make a more efficient engine? Many thx.
Totally agree about the detonation thing. Get fed up of hearing people talk about explosions or detonation, when they mean Combustion!!
Question, what the movement in the shaft , as they use journal bearing or roller bearing ?
Never been a huge jet fan, but love these videos. Always thought I was born too late and wished I was a radial tech in the 40,s. Qualified for anything the military had asked for jets in 1983 was told there was a year waiting list. Should have waited. I could be where you are.
I think dumping entry tickets in a jet blast is the greatest idea ever
Fun with flags, Dr Sheldon Cooper :D
love the things you teach us jay. a question, please.
why soviet jets make so much smoke?
because they are inefficient crap, the whole internet debate that they are more powerful is an utter bs
They run Rich. Aka Too much Fuel being fed into the Combustion Chamber
2/3 of the compressor gas flow is used for combuster & turbine cooling , how much energy as percentage of output is used
in cooling roles ??
Hey, Agent Jay Z, do you still have your Orenda iroquois in your shop ?
Watching a video on F-86 when they entered service in Korea it was mentioned engine had a 60 hour service life. Thought it would be the cans but not sure. Maybe bearing surfaces?
good video. could you show us the amount of snow you have ?
Hello Sir,
The amount of knowlegde you have, I think that now you should be making your own engines. Have you ever had designed any? wish to work with you as a researcher.
As far as I'm aware, he isn't an engineer, so designing one would be out of his field of knowledge. Rebuilding engines though? Yeah he can obviously do that.
Hey how's the ORENDA IROQUOIS COMING??
Hi ! I just discovered your collection of videos. Being a pilot, i find them highly interesting. Thank you so much for the job, keep it up. I also have a question relating to the fan blade you showed at the end of this video. I have a few of them that I would like to clean up and put on stands. Any trick on how to make them shiny ? Thanks a million !! Seb
Depending on how beat up they are, and how shiny you want:
Wet sanding by hand with 320, 400, 600 grit sandpaper (about an hour or more on these steps).
Cleaning with soap and water until a white cloth stays white.
Metal polish, with hand rubbing.
Loads of elbow grease required if you want that mirror finish.
AgentJayZ Thanks a lot. Did you ever try it yourself ? Seb
Great stuff Jay, and thanks for your support of the Special Olympics.
Could you comment on the air/flame/heat flow at the flame holders in the afterburner? Why don't they melt, where is the actual flame, how are they cooled?
Thanks much, I love your stuff.
The burning happens just downstream of the flame holder, so it's not in the flame, but it does glow red hot, as you can see in many of my test run videos.
I worked for a Pratt & Whitney vendor, and was trained in GTAW at Pratt, to go back and weld Flaps and Seals. Rowboats, Adams and Eves. I also did some Electron Beam welding, connecting the machined ends to the honeycomb portions.
I started out in resistance welding, assembling Turkey Feathers for the braze ovens.
And in cooling down the combustion chamber and flame, the cooling air heats up and expands, and in expanding is able to do work. M
Ok Jay, I have a mother question that may be rudimentary to you but new to me. During a compressor stall/surge, does the flame front from the combusters move forward into the compressor blades? Is this what can cause the damage to the compressor blades? Does the flame front ever move forward of the combusters? Please let me know if there is a video I should watch that would explain this better. Once again cheers from the Yukon. Keep up the good work
Here's a quote from a Boeing training video on the subject of engine surge, as near as I can remember it: "Usually, there are flames visible from both ends of the engine." In the video, there are a couple of shots of the intake of a 'Dependable Engine' with visible flame projecting forwards through the fan. Frequently, this is propelled rearwards by the fan and down the by-pass duct. I actually saw this happen on a Russian aircraft at the Farnborough Air Show some years ago.
You might like to check out a clip on CZcams of a birdstrike event at Manchester Airport (UK). The right-hand engine of a B.757 ingests a bird on take-off and suffers multiple surges, with flames and smoke pulsating from the engine efflux, before it is shut down. The engine has a full-length cowling, so it is not possible positively to identify that any flame is coming down the by-pass duct, but it certainly looks that way to me.
In this case, the engine surged because the compressor blades and vanes were damaged by the passage of the sliced-up remains of the bird and their aerodynamic efficiency was degraded. However, undamaged compressors can surge for various reasons, but brief exposure to a surge event should not result in damage to a properly designed compressor. In particular, the very brief exposure to the flame should not cause any damage whatsoever to the blading.
All engine manufacturers will have design rules for dealing with surge, which dictate the need for adequate axial clearances between blades and vanes. During a surge event, the blading will experience extreme deflections, because of the rapid change(s) in pressure and flow reversal. The degree of dynamic deflection will typically be so great that, if it was imposed statically, the aerofoils would be permanently deformed. However, if you want an explanation of this phenomenon, which is well known, you will need a specialist in materials science.
When looking at the air right as it exits the compressor, about what percent of it is working air? Also, the percentages used to feed the flame, cool the blades, etc.?
Very nice explanation by the way.
Check my channel search bar: cooling air.
I want a jet engine to effectively swirl My coffee... spoons are overrated, and dangerous. Someone could gouge your eyes out
they went to fort ticonderoga...... *_WAIT A SECOND_*
you _could_ kill someone with a pencil... but you don't, why, because its too impractical and schools let you use them, there could be mass murderers at a school and would have a full supply of "weaponry". never thought of that now did ya? thats why im the edgyest kid at my highschool.
Ignore the stupid responses here. I like your videos. Love turbines, some of the concepts are simple, but that’s cool too.
My son might be there with you some day
Maybe the guy that mentioned detonation was referring instead to a compressor surge/stall. Makes a heck of a bang at full throttle. The ITT rises and damage can be done depending on the cause. Still not a detonation but can sure spill the pilots coffee and ruin the passengers day when the pilot ends up having to go back to the airport for inspection/ repair.
Maybe, but the point is, we do not use vague and inaccurate terms in this occupation.
Get it right, or get it wrong...
Canadians are awesome mechanics
Even the RC turbine engine I have cost $4000.00. Putting out 45lbs thrust @ 110,000rpm idles @ 33,000rpm. I can only imagine what the big boys cost! 😆
My little engine schooling explained it burns. Just real really fast.
Hello
I am in Montreal right now
Can I get an appointment to visit the workshop....
Bcz I am a jet engine lover
Ft. St. John, BC.
Hi AgentJayZ, great video as always, could you explain a little more about the smoke less fuel injectors? how are they different? only the injector makes the difference or there is also a special smoke less cobustion casing?
In one of the combustor liner videos i mention in this video, I compare the shapes or the original "standard" liners and the newer "lo-smoke" liners.
Hi Agent Jay Z!
Awesome video, thank you!
Speaking of heat, metals expand under heat, so a few questions on the topic:
1.Do jet engines account for that and how?
2. Are there parts that are you have to assemble with some freedom of movement or some such?
3. In your testing, do you have to run engines long enough to experience thermal expansion?
Thanks a bunch!
Yakov
yes, yes, yes. Maybe have a look at Twin Shaft Turbine Engine Bearings
Thanks a lot!
That combustor works a lot like an oil furnace.
Would love to win that fan blade...very cool.
That's really interesting. I wonder though -- how does the cooling work in rocket engine thrust chambers and nozzle walls? There's no air stream there that keeps the exhaust gases off the walls, afaik there's just yet-unburned liquid fuel that streams through pipes in the nozzle walls to cool it. So how is this enough to keep the wall from melting, even though (I assume) the gas touches the wall directly. Is it just cooler that jet engine exhaust gas?
I don't work on rocket engines, but I have done some reading. It's much like what you said. Rocket fuel is vaporized around a liner to create an insulating layer that keeps the actual flame from touching the chamber walls. The liner was very difficult to develop, and is extremely expensive to make.
Wannabe rocket scientist here. Rocket engine bells/nozzles can be coated in ablative materials that 'burn' away, protecting the bell itself (Like a heat shield).
Or, cryogenic fuel can be pumped through channels in the nozzle and back into the combustion chamber for nozzle cooling. The Shuttle engines actually worked like this.
The combustion chambers themselves are more complicated. I believe they are made of extreme temperature resistant materials and use a blanket of excess fuel or oxidizer surrounding the combustion area for protection. Don't quote me on that though, I might be wrong.
There are several ways too cool the bell of a rocket engine, many are listed here by others who responded to the question. For a detailed examination of rocket engines from someone who is as knowledgeable as Agent Jay Z is on jet engines, check out Scott Manly and his CZcams channel. He does a great job teaching one about how rocket engines work, just as Jay does with jet engines.
Same principle you have with flame containment as the magnetic bottle containing the antimatter for the enterprise
You mention no flame touching metal. What happens during a "torch" on startup where there is flame running through the turbines? Is that definitely causing damage or since the turbine is rotating it has time to cool off since the flame is probably only at a certain point along the circumference of the combustor?
There is insufficient oxygen exposure, or an incomplete burn of the fuel, which means the flame temperature is insufficient to cause damage over a short term.
As discussed before in videos about hot starts, it's all about exposure time.
The temps involved at starting are definitely enough to destroy the engine... if they are experience for more than a few seconds.
It's exactly like your hand and a flame.
Put your hand fully into a fire, for one quarter of a second... everything is exciting and fine.
Put your hand fully into a fire, for one quarter of a minute... uh, oh... I think we wrecked it.
very cool video, just subbed. me likey likey
OBTW, have you ever had a TF-41 apart, and if so how does it compare to the Spey? The whackopaedia is a bit vague on the topic... Great video, keep up the superb work!
I'll leave this to AgentJayZ for the moment. I was busy designing the Industrial RB211, while my colleague Keith O** was busy designing the Marine Spey, which is really a TF41 with a cropped fan.
This is from memory, plus a little bit of research.
The HP system of the TF41 was basically that of the Spey Mk 555 (aka Spey Junior), which powered the Fokker F28. This had an 11-stage HP compressor, as compared to the 12 stages of other marks.
The 5-stage LP compressor, sometimes described as an LP/IP compressor, was all new for the TF41, with the flow split for the by-pass after the third stage. Unique to the TF41, relative to other marks of Spey, was the fact that the LP compressor had no inlet guide vanes. The LPC first stage rotor was in front of the LPC front bearing housing, which was carried by structural first-stage stator vanes.
PS I'm not at all sure about the 11-stage HP compressor. Maybe I'm getting confused with the Spey Mk 807, which I worked on at R-R Bristol. Perhaps AgentJayZ can confirm, or otherwise, as he's seen a few Industrial and Marine Speys recently. As I said before, they are essentially TF41s with the first three stages of the LPC 'cropped' to delete the by-pass flow.
PPS Wikipedia states that the TF41 had an 11-stage HPC, so my fading memory is probably correct.
Why is there a fin on the fan blade?
I'm taking a guess, to stop pressure building up and channel the air
Nope ..... er, no, I'm a Brit and we've been here several times before on this channel. It's called a mid-span shroud in N America, or a clapper, if you work at R-R Derby, or a snubber, if you work at R-R Bristol. It has no aerodynamic function: it is essentially a friction damping and vibration modifying device for the blade aerofoil. It works by coming into contact with the mid-span shrouds of the blades on either side of it, effectively forming a ring.