Ethanol fuel and Jet-engine

Michel Van

ACCESS: Above Top Secret
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13 August 2007
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I have a Question

can you use Ethanol fuel in Jetengine
like J79-GE-11A (F-104 ) or P&W T34-P-9W Turboprops ?

Wat looks maintenance and Lifetime of Jet-engine on Ethanol fuel ?
i believe gas-turbine tank engines can run on pretty much anything liquid and combustible, but i have no idea as to what modifications are involved...

so far Wiki tells me

Ethanol (E100) consumption in an engine is approximately 51% higher than for gasoline since the energy per unit volume of ethanol is 34% lower than for gasoline.[13][14] However, the higher compression ratios in an ethanol-only engine allow for increased power output and better fuel economy than could be obtained with lower compression ratios.
In general, ethanol-only engines are tuned to give slightly better power and torque output to gasoline-powered engines.
However, since the energy content (by volume) of ethanol fuel is less than gasoline, a larger volume of ethanol fuel (151%) would still be required to produce the same amount of energy. The mileage (miles-per-gallon) is therefore usually 20-30% lower than a gasoline-only engine.

but wat do ethanol to Jet Engine ?
like is damaged the engine on long term ?
you have to change your compression to accommodate the fuel (ask someone who knows the flashpoint for ethanol VS JP-8, I'm not one of them) but other than that, it runs the same, essentially. Jets are amazingly simple machines, unlike ICEs (Ok, so maybe studying makes them seem so, but they are by FAR simpler in theory) they really just need some source of heat to work. You can run them on pure hydrogen, as a matter of fact. The concerns involve mixing of the flow and the fuel, and flame propogation speed. If the flame burns faster than the combustor velocity, you're good, as long as the fuel readily atomizes and distributes well into the flow.

To be clear: I wouldn't go putting E85 in the JSF just yet, you most likely have to modify it for a different compression and combustor length/speed.
so engine gona be longer

thanks for info AeroJadeXG
glad to help. (but I never said longer) if the flame speed is lower, longer, if higher, shorter.
You would also have to make the fuel tanks bigger in accordance to what was said above, this is why most ethanol-fuel jet liner concept I've seen are basically akin to an A380 with the entirety of the top deck converted into a massive fuel tank.
mmmm, according to the latest issue of Airliner World, Continental Airlines has just demonstrated a 737-800 with CFM56-7B using a biofuel (not pure ethanol) made by a 50-50 blend of jatropha-derived and algae-derived fuel. It works. In December 2008 Air New Zealand flew a 747-400 with RB211s using a 50-50 blend of Jet A1 and jatopha-derived fuel. So, ethanol is not the best of air fuel due to volume, BUT there are plenty of biofuels alternatives available. For characteristics of the biofuels used in the Continental experimentation, go to the sites of Sapphire Energy (algae) and Terasol Energy (jatropha). Cheer up, folks ! We'll fly forever, till the sun shines !
One note: ethanol is hygroscopic, so you have to be very careful with moisture precipitation or condensation as you change altitude, or when the fuel is stored long-term.

In motorsports, Indycars and some endurance racers use E85, which is 15% gasoline, to help get around this problem (and also provide a visible flame in daylight).
One issue, even with oil based bio-fuels, is compatibility with all the seals used everywhere.
...and that article doesn't even mention "cellulosic" ethanol, for which the EPA has been fining fuel producers millions for not using it in the mandated quantities despite the fact that the stuff for years couldn't be produced outside a laboratory.

Not strictly ethanol, but I recall reading that the Su-25 engines for example can run on a variety of fuel types...including avgas, petrol, and bog standard vehicle diesel.
SASOL, the South African coal to fuel manufacturer, a few years back launched the first 100% synthetic jet fuel via it's coal to liquid (CTL) process.

I have no idea of the long term effects of ethanol, but with the above mentioned in mind, I would imagine it would be easy enough for at least some jet engines to run easily enough off it.
Grey Havoc said:
bobbymike said:
Grey Havoc said:
bobbymike said:

Biofuels need to be created from something, and according to a report released last year by the nonpartisan World Resources Institute, a Washington, DC-based research group, meeting 20 percent of global energy demand using plant-based biofuels by 2050 "would require humanity to at least double the world's annual harvest of plant material in all its forms.... Therefore, the quest for bioenergy at a meaningful scale is both unrealistic and unsustainable."

And throwing yet more good money after bad:

It's diesel, damn it. Not hard to get the correct spelling.

also seeing no relation whatsoever with the thread general topic. Meh.
Just wanted to mention this biodiesel fiasco in order to reinforce just how much of a disaster biofuels in general have been.

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