Re: Pulse Combustion
Posted by: Jim Crank
Date: January 01, 2005 03:31PM
<HTML>Happy New Year Peter,
The best information I can give you is that you search out a copy of the book: "Pulsating Combustion, The Collected Works of F. H. Reynst", Pergamon Press, 1961. A very rare book, and it took me years to find a copy; but absolutely priceless. The only book I ever heard of dealing with the subject. Goes into dozens of uses for it, stationary boilers, locomotives, marine, coal dust burning, all that sort of stuff. All the math and many design parameters and intake valveless designs are thoroughly examined.
There are, or were, many papers on the subject, so look on web sites for: Argus pulse jet engines, pulse jet engines, V-1 pulse jet, pulsating combustion, etc.. I have a large file on the subject.
Graeme is right, the noise is fantastic in a single tube version. However, Reynst does go into push-pull versions that self cancel the pressure waves.
I still have my Dyna-Jet engine from my model airplane days. We got thrown off the field every time we flew the plane. The racket was deafening.
The heat release is, according to the book and some papers I have on the subject, up to 7.5 MBTU per cubic foot.
Starting one is often very tricky, and hard to throttle, if you wanted varying rates of output.
The valve mechanism is also very tricky, reed valves, aero valveless intakes, rotating butterfly valves. and such all have been tried.
The U.S. Navy spent a lot of time working with this engine for pilotless drones after WW-2 and the O.N.R. published some papers.
Also look for insect foggers and movie studio stage foggers, they also used this engine. Big ones too. I still have a 4" dia reed valve/fuel nozzle assembly from one of these.
Try to contact Jim Tangeman, old time SACA member. When I was trying this idea he got interested too and built some steam generators using this.
Finally abandoned the idea because of the necessary length of the assembly and some nasty operating problems; but any Hemholz (Sp?) type resonator will also work in addition to one long tube. It is a matter of designing a resonating chamber, long organ pipe types and also chamber types, think of large police whistles, same idea.
Have fun and wear ear plugs!!