After I suggested using a complete J79 compressor for a rig test, with all of the blades/vanes removed after stage 1, I started to have doubts. So, I thought I'd better remind myself of the actual layout of the compressor. On looking at a cross-section, it is plainly obvious that the barely compressed flow from stage 1 will be constricted long before it reaches the mid frame, and I've now realised that I must now screw my designer's head on more firmly. Consequently, I'm now thinking in terms of cutting some large ports in the casing to exhaust the flow, which might need some external support or reinforcement as a result. Or perhaps even more major surgery might be considered, with both the casing and the rotor 'truncated'? However, this would mean numerous new parts having to be designed and made. It could be a great challenge for a designer. I'm not volunteering, but I'll stand on the sidelines to offer support (and constructive criticism, if necessary).
So it’s essentially like the stall of a wing, but with a compressor the energy isn’t transferred to the turbine and gas turbine doesn’t spin the compressor…which experiences a worsening stall…till it stops functioning all together…makes sense … I do want to see if the equations are similar to the equations used in wing theory… I’m trying to build a very small 4 person jet aircraft using mini jet engines from Williams or Franks … although these are centrifugal engines
@@AgentJayZ thanks…that is interesting…a little different from a wing stall but clearly the relationship is there…because when flying as you approach stall…you definitely can…err…tell…😁 yikes…ok, I appreciate you sharing your knowledge…I saw some of your other episodes a few years ago…before I had my private pilot license…makes a difference in understanding.
Good morning, AgentJayZ, and greetings from Austria, where I'm wearing my Jet City tee-shirt today. You mention the Industrial RB211 as having dual fuel capability, but the Industrial Olympus had it years before. As usual, I'm going to be pedantic and explain that the term dual fuel should mean that the unit is capable of changing over from liquid to gas (and vice-versa) at full power, and be capable of continuous running on a mixture. If a shutdown is needed to make the change, then that's a double fuel system. I may have mentioned in the past that I did the original project design proposal for the Industrial RB211 dual fuel burner. That was a real quart-into-a-pint-pot exercise.
I've had yet another thought about a rig test of a bladed disc. There have been suggestions of a small number of composite blades spaced around the row. No, it really needs a full set to be representative. One clever way of detuning a problem blade row is to have blades of different natural frquencies spaced around the row. The first stage of a small turbofan with which I was familiar some years ago had a mixture of 'A' and 'B' blades to do this.
Dual fuel nozzles are the answer. For liquid or gaseous fuel capability, you need two separate fuel management systems. Many LM2500s and RB211s I have seen are configured so. The fuel nozzles are mighty expensive, and are connected to two separate fuel manifolds.
I doubt you could atomize the cryogenic fuel without the nozzles icing up and clogging. Unless you use something like the rocket fuel nozzles where multiple streams converge at enough speed/pressure to atomize fuel through the impact, or some variation.
3 дня назад
Thanks for risking tongue twisters on the weekend for us viewers. It would double (or more than) engineering, manufacturing, supply-chain, inventory, maintenance, and training costs. Standardization (on less) is one key to cost efficiency.
Just designing that combustion chamber looks like a nightmare. I tried designing a small simple one to try and figure out how far beyond my knowledge it is. I think I would need about 3 years to learn how. I'm sticking to electronics, it's easier.
HI Jay, Lovely video. I have the privilege of working in the "oil team" of a big name aerospace company. Your videos are always a treat when trying to understand components outside of just looking at 1D system diagrams. When in this video you talk about the "happy cycle" of the oil, you've skipped a component that I would love you to make a separate video on, the breather or sometimes called air oil separator. I know that different engines have different architectures but I would love if you could share your own expirience with this component! how does it work and look like? is it always necessary? is it always standalone or can it be imbedded into the oil tank? Thanks!
This is so damn interesting! The evaporation of liquid (liquid-gaseous-transition) takes a lot! Of energy. This energy does have to come from somewhere, in the turbine most likely from the compressed burning air. So the evaporation of the fuel must be cooling down the air/fuel mix just before burning. The pressure difference of the gaseous fuel (200 psi to what was it 40?) when exiting the nozzle into the burning chamber also must provide some cooling (expansion is used to make liquid air) but I wondered to which extend? Is the flame fed with a ‚warmer‘ air/fuel mix as when liquid fuel is used? Does this effect turbine efficacy (kJ in fuel fed in vs. power output)? Maybe you guys have not only hit the correct nozzle-hole size in terms of delivering the correct _amount_ of fuel at working throttle, but also to provide the right amount of over-pressure or pressure difference for the correct amount of cooling. Did you experiment with over-pressure and hole size other than starting performance and is this a factor at all? This is so much fun! :) Love your videos an questioning my career choices … and of course: Happy Canada Day!
Been to Glace Bay, and to NL. Trailer Park Boys is hilarious, but Maritimers are the nicest, most honest people on Earth. They are Canada's treasure for the world.
Just imagine how much effort and power is WASTED moving natural gas to a pumping centers and larger pipelines to a power center, and then pumping electricity back over high voltage back into the grid then back. If gen stations were modular, hey, yes, the size of a shipping container, and placed on natural gas distribution sited next to grid, I wonder how much that could actually save. Jayzeuschristmas.
Well, since we're dreaming of a decentralized future power grid, replace or augment all of your generating stations with wind turbines. Despite the naysayers, if will be that way soon. In the great oil nation of Texas, I have seen installations of thousands of megawatt class wind turbines. Gigawatts baby. To all those saying "the wind doesn't always blow", they don't understand decentalization. Bless their hearts.
@@AgentJayZ Yeah I know wind is all the rave, you must have your brain strapped to the wingtips to think its so... great. Solar, off grid systems in texas actually work great, I myself am using this daily, and it would be a perfect source for power, expecially when its engineered properly and economically, not in a "pseudopsychopatically beneficial" way. It takes, lightweight, efficient, and easy.
The issue of using compressed or cryogenic gas as a fuel is an interesting one. Wheeled vehicles have been doing this for a while, and I had the fun of being part of a "dual fuel" diesel engine project that could run on natural gas (mostly). As noted, you need some sort of pressure vessel to store compressed gas, and this quickly gets large and heavy. Not a big problem for a truck or bus, but it's not going to be easily fit into an aircraft. Cryogenic fuel is another whole bag of problems... just ask the folks building rocket engines. The change to a new fuel is something that the aviation industry has been researching for some time, and I think their best answer so far is to just synthesize a liquid fuel from hydrogen and carbon dioxide. As always, thanks for the video!
Toyota has played round with a liquid hydrogen direct injected race car, the tank is 150liters to store 10kg of fuel, the fuel pump only last few tanks worth of fuel because it can't be lubricated and has to work at -253'C. I see that there is some companies working on running jet engine in airplanes on ammonia, which to me sounds insane
Is there a sensor to measure combustion temperature in addition to EGT ? I did a quick check and found that propane has a higher combustion temperature-range vs jet fuel. I hope the engine can be operated in a manner that there wont be heating significantly higher than it is for jet fuel. Is the initial testing with one 3D-printed turbine blade, or several ? Cant wait to see this.
To all of the people saying his answers are harsh (including other videos) yes, they are. That's kinda the point. JayZ is teaching jet engine components and jet operations. If you've ever talked to an aircraft mechanic, you'd know JayZ is one of the nicest 😅
Hello AgentJayZ. In a next video in this series, could you tell us which exact 3D-printing method is used? And maybe show the machine while printing? Very interesting. I am familiar with plastic 3D-printing, not metal, but I know there do exist several metal printing methods: (1) the worst: metal-filled plastic filament you can run through a good home-printer (with hardened gear and nozzle). After printing, the model is cured in an oven to burn off the plastic, melting the metal pieces together. Sometimes another metal is added to the mix, e.g. like copper or tin to fill the voids left by the burned plastic. But these models do shrink and deform, so it is good enough for art, but not suitable for aviation purposes. (2) Sintering: melting metal powder together with a laser, then adding another layer of powder, melting it together with the laser, etc., layer by layer. This could work, but the resulting model is still porous. Here too, another metal with lower melting-temp could be added in post-processing to seep into the voids. And (3) a machine that deposits liquid droplets of metal onto the model. This works very much like an inkjet printer, but then jetting liquid metal instead of ink, obviously. This is way more solid than sintering. But as far as I know, all methods produce quite high stresses in the model, due to uneven local cooling. Just like in plastic 3D-printing. Because molten hot material is laid upon cold solid material, and then it cools down and solidifies and wants to shrink and warp, but it can not. If you warm-up plastic 3D-printed models to around glass transition temperature (where they start to get softer), they do warp horribly. So I am not sure what 3D-printed blades are going to do in an "oven" like a jet engine? Under high centrifugal load and high wind load? Maybe you could construct a sort of "sand box" around those discs, to capture any blade parts that break off? So they do not rip everything and everyone to pieces? We can't have you cut in half, because you need to make more videos. :-) A sandbox can not be done for an airplane engine, but for a stationary industrial engine where weight is not an issue, like in your test cells, it might be possible? Anyway, I appreciate these new series, very interesting indeed. Can't wait to see the outcome of the tests.
As explained here, I'm just here to witness and document testing. I'm not the engineers, and they have sent us these blades they've produced. I'll try to get some more info.
I really enjoy your videos. The functional and theoretical detail of turbine engines is very interesting even tho I will never actually need the information.
Great video as always. Nice to see a master at work. As I am not a turbine mechanic and have always had an interest in turbine engines and currently working in the fuel industry, roughly what size of propane supply lines to the pump would be needed for the propane based on the engine in the video? If it is liquid propane coming to the engine, where does the liquid to gas change take place? If its possible could you also touch on Natural gas a little more as many of the electricity producers use that method. Is there is any differences with NG other than the orifice sizing? Just trying to educate myself. Many thanks.
Propane pump is a liquid pump upstream of the vaporizer, which is upstream of a control valve, which leads into a 2 inch ID line, which connects to a 1.5 inch ID manifold, which has 3/4 inch ID lines going directly to fuel nozzles. Exact same setup is used for natural gas, except no pump and no vaporizer needed. Natural gas in pipelines is at roughly 900psi.
I work on small industrial gas turbine generators (300KW) we've on a couple occasions injected liquid fuel into the combustors (not intentionally)...it doesn't work well though...she's heading for the moon! overspeed, then BOOM! game over!!
Propane is a liquid at 200psi and room temperature, maybe it wouldn't be too difficult to run on liquid propane. After all fork lift trucks run on liquid propane from a tank with a syphon tube. Not saying I have the means to try it or anything, just a thought.
Fork trucks are not really running on liquid propane. You can store more fuel as a liquid than as gas giving you greater time between cylinder swaps. Your delivery system does it's best to create a gas-like state in the combustion chamber by spraying a fine mist that then vaporizes in the combustion chamber.
Actually, forklifts do not spray liquid into the engine. The propane is sent through a small vaporizer, just like in my truck. The vapor is then sent through the engine. In BBQ tanks, the necessary flow is so small, the propane vapor that forms in the tank is used.
@@AgentJayZ I was just trying to say (and failing) that liquid delivery from a pressurized tank to a target is possible with out anything fancy so long as the delivery pressure is high enough. ( cryogenic temperatures don't need to be maintained). The burst disk on a normal propane tank is set to 28 Bar, so, somewhere between 200psi and 28Bar at room temperature the propane will be liquid.
@@AgentJayZ 🤣 well it's better than the tank rupturing. When I lived in England i worked at a university and had to do the BOC pressurised gas safety course. they showed a video of a 50Kg propane tank in a fire on the back of a truck. When the burst disk released there was a jet of flame but if they had got the fire out it would have been fine.
You know you've found a niche when you didn't ask a question but still get that instructor/student fear shock of 'Oh god, please don't call my name!' 😁
I never like to use the word suction anymore But I wonder whether using the word vacuum intake would be scientifically correct, Interestingly there is nothing on Google thesaurus check for suction but vacuum does reference the Hoover I know it is late for you and hope you read this messages tomorrow goodnight my friend
realizing we're still a way from aviation...are you allowed to comment on grain structure and how they go about 'forging' the blades? As shown narrow neck, potential different quick airfoil just seems 'wow'!
I'm just a guest commenter. I have met these guys. They are materials engineers, and have previous experience making internal engine parts for top fuel cars. Yeah, so let's all go a bit easier on our armchair worries.
Coming from a performance boat background, I'll give an opinion, inaccurate as it may be. With that said, my money is on the carbon blades being vacuum infused construction, with cure time controlled via vaiable heatl.
4 дня назад
Injecting cryogenic methane into a combustor would be a recipe for thermal stress and fatigue. Perhaps like a Saturn rocket nozzle, I would try cooling the tailpipe areas with cryogenic methane with a heat exchanger before injecting somewhat warmed methane into the combustor. This could have the benefit of allowing cheaper and lighter materials to be used in the normally inconel- and titanium-dominated areas. Note: Jet A has a specific energy of ~46 MJ/kg, while cryogenic methane is ~55 MJ/kg.
Gotta go all the way to liquid hydrogen (142 MJ/kg), so it looks good on paper and can convince investors. Someone will surely make money from this development... Don't explain the difference between high heating value and low heating value either, that'll just confuse them.
If you do it like an expander cycle engine then maybe you can even run the fuel pumps and accessories without drawing power from the main shaft. Might make it more difficult to start the engine in the first place... oh, well...
@@AgentJayZ Nope, you mentioned 200PSI and 220PSI in different parts of the video but no temperature. That brings me on to my second question. Do you have any issues with propane condensing in the supply pipes before startup? Maybe that could be a contributing factor to the startup issues you had when initially developing gas nozzles.
It seems I have already lost my patreon I live in my overdraft I wonder is it possible to pay in advance rather than resetting it every month I can afford it I believe this is well worth it Goodnight sir
