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Armadillo Aerospace News: Flameholders
We had a couple more things to cut-and-try on the vehicle engines to see if we could get them to behave better, but I decided to step back and think about the problem a little more.
Our working theory about the operation of our mixed-monoprop engines is that the “cold pack” decomposes some of the 50% peroxide and vaporizes the methonal, which gives a somewhat combustible atmosphere that can be ignited by the glow plug and stabilized behind the perforated metal plate. With a stable flame in the open space between the cold pack and the hot pack, the remaining liquid (water and undecomposed hydrogen peroxide) will be vaporized and heated enough that when it enters the “hot pack” it decomposed and further combusts without progressively quenching the pack as all of our early attempts would do, even if we had preheated the pack to very high temperatures. When the hot pack has been preheated enough, it radiates quite a bit of heat back up to the perforated metal flameholder, helping to stabilize the flame. Once it gets fully established, the engine runs very stably, but the problem for us has been getting the engine up to its operating steady state. Read More

posted by Sigurd @ 2/22/2004 12:43:00 AM