20 Jun 07
This is what the 21st century is all about:
Jet engines that do not use aviation fuel, but liquid hydrogen which also cools the engine which happens to be a superconducting electric motor doing the same thing a regular jet does, compress air and shoot it out the back but without burning anything. Much more efficient than present day jet engines. Here is the link:
http://www.sciencedaily.com/releases/2007/06/070619183236.htm
20 Jun 07
1 edit
Originally posted by sonhousewhat are the cost comparisons between liquid hydrogen and diesel?
This is what the 21st century is all about:
Jet engines that do not use aviation fuel, but liquid hydrogen which also cools the engine which happens to be a superconducting electric motor doing the same thing a regular jet does, compress air and shoot it out the back but without burning anything. Much more efficient than present day jet engines. Here is the link:
http://www.sciencedaily.com/releases/2007/06/070619183236.htm
EDIT: and is this likely to takeoff in the commercial sector?
😉
20 Jun 07
Originally posted by rmackenNot sure how much it is now but it would go the way of all things when it would be ramped up to industrial volumes, the price would come way down. BTW liquid H2 has 4 times the energy of aviation fuel, pound for pound so that would figure in also. I think what they are talking about is using LH to feed fuel cells to produce multimegawatts onboard the aircraft. I am sure area 51 and the skunk works know all about it too, eh. Military implications are obvious. Its a lot quiter for one thing. How bout this for a variation: Using a system like this but carry a supply of liquid oxygen also and use the jet system to get above the atmosphe then ignite a liquid H2/O2 rocket to get to space. I bet that has not escaped notice either.
what are the cost comparisons between liquid hydrogen and diesel?
EDIT: and is this likely to takeoff in the commercial sector?
😉
20 Jun 07
Originally posted by PonderableNASA has dealt with Liquid Hydrogen for decades, there have been no hydrogen explosions except the shuttle in '86 and that was an O ring problem with active flame hitting the tank. The tanks around today are very strong and in an aircraft is much safer in the air because it would take a collision to make it explode and if that happened, everyone would be dead hydrogen or no. The cost will go down as consumption goes up, it always does. The advantages include no greenhouse gas emission (partly untrue, only if the energy required to make the hydrogen comes from renewables and not just a coal or oil fired plant, you havet to look at the total energy budget, not just what the aircraft do), much more efficient propulsion, meaning more cargo weight, or longer range aircraft or faster or some combination thereof. It ultimately might mean cheaper access to space by using such a system to get through the atmosphere without consuming oxygen then switching to H2/O2 rockets to go the rest of the way.
at which temperaturtes does Hydrogen liquify.
cold cost double approximatly every tenn degrees downwards!
And there is a safety issue: if there is a leakage you get an explosive mixture with air.
That would mean more payload to space or faster craft to the outer solar system or cheaper satellite launches.
20 Jun 07
Originally posted by sonhouseAll talk of the liquid H, have there been any investigations into producing their energy source from Uranium or Plutonium? The aircraft would be alot bigger due to having a led lined reactor but could then have more passengers to make this up. There is also a greater risk of terrorism as there is the radiation element (not to mention the risk to the passengers) On the upside to this, the fuel source continuous but would need highly qualified nuclear engineers/ pilots.
NASA has dealt with Liquid Hydrogen for decades, there have been no hydrogen explosions except the shuttle in '86 and that was an O ring problem with active flame hitting the tank. The tanks around today are very strong and in an aircraft is much safer in the air because it would take a collision to make it explode and if that happened, everyone would be de ...[text shortened]... more payload to space or faster craft to the outer solar system or cheaper satellite launches.
Just a thought!
21 Jun 07
Originally posted by rmackenThe idea was pursued in the 1960's but reactors are just too heavy and like you say, have significant downsides. We have enough problem getting rid of the spent fuel as it is, it would be hell if there were 100,000 commercial aircraft flying with nuclear material onboard.
All talk of the liquid H, have there been any investigations into producing their energy source from Uranium or Plutonium? The aircraft would be alot bigger due to having a led lined reactor but could then have more passengers to make this up. There is also a greater risk of terrorism as there is the radiation element (not to mention the risk to the passenge ...[text shortened]... source continuous but would need highly qualified nuclear engineers/ pilots.
Just a thought!
Don't forget, its not just the fuel that needs storage, the material of the reactor itself gets highly radioactive and that is yet something else we need to deal with it. All in all, not worth the trouble, especially now that we see the possibility for H2 planes that only produce water as the effluent and superconducting motors.
I am wondering how big the fuel cells will have to be to convert that H2 into electricity, I am thinking maybe it needs to be like 10 megawatts, 13,000 horsepower, or so, to run a big jet. Thats a lot of fuel cell!