Hydrogen-Powered Aircraft Projects

Tu-136
kr_011_b.jpg

http://www.tupolev.ru/Russian/Show.asp?SectionID=82&Page=2
 
Hi,


I never saw like this concept before (four rear mounted engines),what was it ?.


http://www.priceminister.com/offer/buy/122715412/science-vie-n-678-alimentation-legumes-village-solaire-avion-a-hydrogene-revue.html
 

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bigvlada said:
Passengers/cargo in two pods and hydrogen tank in main body?

Without a doubt. A nice variation on the concept, as all the projects previously seen, either from either Lockheed or Boeing, use the pods for fuel, not the main fuselage.
 
Skyblazer said:
Without a doubt. A nice variation on the concept, as all the projects previously seen, either from either Lockheed or Boeing, use the pods for fuel, not the main fuselage.


Yes my friend,


and I think it was very close to Lockheed.
 
There was a discussion a few years back about a safety concept where the passengers were situated in an pod with a parachute inside the main body of the aircraft. It would be easier to implement that idea in this concept. Plus ejection seats for the crew.
 
As a matter of interest; what changes need to be made to the engines & fuel systems to be able to run hydrogen? (Besides the obvious tankage requirements)
 
hosscara said:
As a matter of interest; what changes need to be made to the engines & fuel systems to be able to run hydrogen? (Besides the obvious tankage requirements)


Hi Hosscara,


I think it is not a much bigger changes.
 
:)
In 1937, Von Ohain tested his first gas turbine, the HeS-l, using hydrogen gas as fuel, so that this engine, the Heinkel Strahltriebwerke 1, without any other option, its development could have continued with hydrogen instead of gasoline. But as luck would have it, the story turned out differently, and one could have read later that the He-118 V2, which tested the engine of the He 178, was powered by hydrogen, and that the latter flew for the first time in the summer of 1939 with a hydrogen-powered engine. This is an alternative story that could have happened at Heinkel.
 
It looks like a Rotax motor to me, can anybody confirm that they used a fuell cell?
 
If you refer to H2FLY's HY4 demonstrator aircraft - their website says it uses fuel cell(s?) for power.
 
Reply #17, image 1? Not like any Rotax engine I know of. The orange panels look slightly like valve covers, but no pipes in the right place that might pass for exhausts.
Besides, H2FLY explicitly states the aircraft uses fuel cell power. They ought to know.
We unlock the era of sustainable air travel by developing the first qualified hydrogen-electric powertrain for aviation. In over a decade of researching, refining, and testing, we have developed a radically new, zero-emission solution: Powered by clean hydrogen, which is converted to electric power in our fuel cell´s powertrain, our demonstrator aircraft HY4 proves that zero-emission aviation is within reach.
 
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From Aviation magazine 1981.
 

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“Kerosene [jet fuel] is also extremely dangerous. And hydrogen is no less or more dangerous. It’s just different,” says Jenny Kavanagh, chief strategy officer at Cranfield Aerospace Solutions.

“The flames of the Hindenburg disaster were all about the canopy,” she adds. “The hydrogen was gone before the photographer turned up.”

Kavanagh is among a group of British scientists involved in a government-backed initiative codenamed “Project Napkin”, which has plotted a course to providing Britain with net-zero flights.

The Napkin blueprint, seen by The Telegraph, has been developed by a coalition of industry experts from the likes of Cranfield Aerospace, Rolls-Royce, GKN, and Heathrow airport, as well as academics from University College London and Southampton University.

According to Napkin, hydrogen flights carrying up to 19 passengers between the Scottish islands and the mainland could be a reality between 2025 and 2030. These early flights will be operated by retrofitted planes carrying gaseous hydrogen in tanks beneath their wings.

From 2035, a new fleet of aircraft designed specifically to run on hydrogen could fly the entire domestic schedule from regional airports such as London City, according to the blueprint, which will be unveiled at the UN’s Cop27 climate change conference in Egypt this week.

And by 2040, 90-seater hydrogen-powered jets are scheduled to be in service, meaning the entire UK domestic aviation market will be operated by zero-emissions planes.

The plans pour cold water on electric-powered aircraft playing a central role in “guilt-free flying” - this despite airlines such as easyJet previously identifying electric-powered as the answer to reducing the industry’s carbon footprint.

“Hydrogen aircraft represent a credible solution to reach zero carbon flight and are the natural complement to sustainable aviation fuels,” the blueprint says. “While other solutions were looked at initially, such as electric and hybrid propulsion, the consortium concluded that hydrogen technologies provide the path to zero-carbon emission flight for mainstream commercial services.”

Earlier story:
 
hosscara said:
As a matter of interest; what changes need to be made to the engines & fuel systems to be able to run hydrogen? (Besides the obvious tankage requirements)


Hi Hosscara,


I think it is not a much bigger changes.
To gas turbines, nothing but the fuel metering system, although if the engine uses sensors to measure turbine inlet temperature, they may need replacement as there would no longer be strong thermal radiation from microscopic burning carbon particles. Piston engines may need more internal modifications.
 
hosscara said:
As a matter of interest; what changes need to be made to the engines & fuel systems to be able to run hydrogen? (Besides the obvious tankage requirements)


Hi Hosscara,


I think it is not a much bigger changes.
To gas turbines, nothing but the fuel metering system, although if the engine uses sensors to measure turbine inlet temperature, they may need replacement as there would no longer be strong thermal radiation from microscopic burning carbon particles. Piston engines may need more internal modifications.
I also seem to remember something about "hydrogen embrittlement" of various metals from far-off chemistry classes.
 
hosscara said:
As a matter of interest; what changes need to be made to the engines & fuel systems to be able to run hydrogen? (Besides the obvious tankage requirements)


Hi Hosscara,


I think it is not a much bigger changes.
To gas turbines, nothing but the fuel metering system, although if the engine uses sensors to measure turbine inlet temperature, they may need replacement as there would no longer be strong thermal radiation from microscopic burning carbon particles. Piston engines may need more internal modifications.
I also seem to remember something about "hydrogen embrittlement" of various metals from far-off chemistry classes.
It's more a problem at low temperatures (see https://demaco-cryogenics.com/blog/hydrogen-embrittlement/); it can also be minimized by choice of materials, possibly including the ceramic coating that it is common in gas turbine engines.
 
For combustion engines and gas turbines some development work needs to be done, but there is no real job stopper. I know there is an experimental hydrogene conversion of a gas turbine here in Aachen which emitts even lower NOx emissions than standart turbines.

About combustion engines; quite promising results have been published by Keyou (https://www.keyou.de/#news) which are converting Truck engines to Hydrogen for Deutz. The efficiency is allready high (44 %) and the power output is sacceptable. The best solution for liquid hydrogen would be direct injection systems, these are under development but this really isn"t easy (extreme cold temperatures, no lubrication, temperature changes, leaks etc.).
 
I don't know about gas turbines, but I do know about gas boilers. There it is mainly a question of adapting the fuel/air injection system and the ignition for the different densities and ignition energies of H2. Also, the combustion speed of H2 is a lot higher than methane, so you'd need a higher injection pressure to stop the flame from moving up the fuel line (bad juju). Hydrogen flames are invisible, so you'd also need to develop an IR-based system for flame detection.
None of these things are particularily difficult.
But then, a gas boiler, like a gas turbine is essentially a one-way system: you inject the gas at one end, you burn it, and it comes out at the other end (hopefully having done useful in the meantime). If you want it to power a cycle of a piston engine, I can image you need to take more factors into account.
 
The flames can't move up the fuel line, simply because there is no oxygen. You don't need to monitor the flames, you just ignite the mixture and let it burn, just like in any other engine.

Several companies already tested direct injected hydrogen engines (BMW, MAN, Hörbiger), it is not undoable, but takes a lot more effort than port fuel injection.

BTW, current traditional aero engines are in my view well suited for hydrogen conversions. I would suggest a turbo charging system which is suitable for high pressure ratios in combination with a lean burn concept (Lambda > 1.8) and port fuel injection. The thermal load (good for air cooling) would be very low due to lean burn and the fast burn helps to cope with the huge cylinder diameters.
 
I also seem to remember something about "hydrogen embrittlement" of various metals from far-off chemistry classes.
It's more a problem at low temperatures (see https://demaco-cryogenics.com/blog/hydrogen-embrittlement/); it can also be minimized by choice of materials, possibly including the ceramic coating that it is common in gas turbine engines.
Precisely. I was thinking about fuel tanks, pumps, and piping where the fuel remains in liquid form before reaching the engine. Such things can be fixed, but not easily or cheaply.
 
Many standart stainless stell alloys are suitable for hydrogen ans show no embritlement, so this isn"t a big issue for the fuel supply.
 
The biggest problem with hydrogen is where do you get it from? Hydrolysis consumes more energy than it produces in the hydrogen fuel.
That is the whole problem of the hydrogen story. Once you have to make your own fuel (and not have biological/geological processes provide it for free), the second law or thermodynamics really starts to bite.
 
The biggest problem with hydrogen is where do you get it from? Hydrolysis consumes more energy than it produces in the hydrogen fuel.
All fuels do; it's just that the energy costs for production of coal, crude oil, and biofuels are included in their costs. The questions are, first, are the inefficiencies low enough to make hydrogen economically viable, and, second, are the net environmental damages less than directly using fossil fuels.

For ground-based transport, the answer to the first is "probably not," as battery power is viable for most road vehicles and electrified railways -- even transcontinental lines -- are very well-proven technology.
 
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