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Pulse detonation?
http://www.popsci.com/popsci/aviatio...3272-1,00.html
Is pulse detonation applicable for rocket technology? Considering "loud" isn't really that big an issue for a rocket. And considering rockets carry their own fuel and oxidizer, it would seem that pulse detonation technology would be something that would be easier to use and develop instead of trying to make into an advance jet engine first. Arthur Hansen P.S. Thanks, Slashdot.org for noticing this neat article! |
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Pulse detonation?
Arthur Hansen wrote:
http://www.popsci.com/popsci/aviatio...3272-1,00.html Is pulse detonation applicable for rocket technology? Considering "loud" isn't really that big an issue for a rocket. And considering rockets carry their own fuel and oxidizer, it would seem that pulse detonation technology would be something that would be easier to use and develop instead of trying to make into an advance jet engine first. Arthur Hansen P.S. Thanks, Slashdot.org for noticing this neat article! One goes to the trouble of trying to develop pulse detonation engines precisely *because* they're airbreathers. If your application doesn't require airbreathing over a wide Mach nuber range, you use rockets. |
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Pulse detonation?
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Pulse detonation?
(Iain McClatchie) wrote in message . com...
(Arthur Hansen) wrote in message om... http://www.popsci.com/popsci/aviatio...3272-1,00.html Is pulse detonation applicable for rocket technology? Considering "loud" isn't really that big an issue for a rocket. And considering rockets carry their own fuel and oxidizer, it would seem that pulse detonation technology would be something that would be easier to use and develop instead of trying to make into an advance jet engine first. Arthur Hansen P.S. Thanks, Slashdot.org for noticing this neat article! The article is enthusiastic but not informative. Here's a basic question: why would a pulse detonation engine be any more efficient than a fanjet? The basic premise is that "exploding" fuel is more energetic and efficient than just burning it, isn't it? I can imagine that the detonation wave compresses the unburned fuel- air to much higher pressures before burning than the compressor in a turbojet core would. And I know that burning at higher compression is good because when you expand the gas back down to ambient pressure you recover more of the heat added as work and less ends up as residual exhaust temperature. It seems that PD technology seems to hold higher fuel efficiencies by more perfectly combusting fuel and oxidizer because of very highly defined pulsed explosions. Ergo, more efficient thrusters. IIRC, aren't they hoping for a 500% increase in fuel efficiency? But how do you get the detonation wave to accelerate lots of unburned air out the back of the tube? Puffs of fuel detonated between long stretches of unburned air? [This would have the advantage of a variable "bypass" ratio -- just change the ratio of puff to unburned air.] I'm not sure there is "un-burned" air at that point, but I could be very wrong. I'm just an enthusiast, after all. Arthur Hansen |
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Pulse detonation?
In article ,
Arthur Hansen wrote: Is pulse detonation applicable for rocket technology? In principle, yes. It offers very high combustion pressures without needing high-pressure pumps. In practices, maybe someday. The fact that it's been coming "real soon now" for going on fifty years is not encouraging. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
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Pulse detonation?
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Pulse detonation?
(Greg) writes:
good explanation snipped Why is it constant volume?.The shock wave travels from the closed end of the tube to the open end. After the shock-wave the pressure rises a lot, this higher pressure is pushing on the closed face of the tube producing thrust. Now the detonation wave travels faster than the One small thing -- of course, pushing on the closed face of the tube isn't what causes thrust. -- Joseph J. Pfeiffer, Jr., Ph.D. Phone -- (505) 646-1605 Department of Computer Science FAX -- (505) 646-1002 New Mexico State University http://www.cs.nmsu.edu/~pfeiffer Southwestern NM Regional Science and Engr Fair: http://www.nmsu.edu/~scifair |
#9
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Pulse detonation?
In article GIv0b.8326$cj1.7746@fed1read06, Fox2 wrote:
Sounds like 1940's German V1 engine. There are similarities but it's not really that close. The *detonation* part is new, and is a major source of difficulties. Combustion in the V-1's pulsejet was ordinary burning, not detonation. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
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Pulse detonation?
Joe Pfeiffer wrote in message
One small thing -- of course, pushing on the closed face of the tube isn't what causes thrust. Indeed this is exactly what produces the thrust. In normal rockets also. If you sum (integrate) all the pressure forces on a thrust chamber walls and nozzle walls, you will find a net force in the excepted direction. This is how thrust of a engine is often calculated (checked) with CFD codes (including viscus losses i think). Of course this is the same as working out the average exhaust velocity and using conservation of momentum. But this dose not tell us where the thrust is transmitted to the engine structure. ie all the trust is not on the nozzle, so there is no need to make the nozzle that strong. In fact a very large portion of the net thrust comes from the injector plate. |
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