www.pulse-jets.com

Here is a untested idea for a deflagration to low velocity detonation engine.
For now I am considering low velocity detonation in the neighborhood of 0.45-0.60 of the CJ detonation velocity.
Some references show low velocity detonation to be in the range of 500-1000m/s

Ignition is presumed to occur at the far right of the CC.
Basically as the flame front moves from right to left in the CC, it encounters both blockage geometry and pressure piling to transition.

Not sure if a fuel supplied ejector would pickup enough energy to facilitate a longer detonation volume but may be worth a try.

Hey Joe

What kind of blockage geometry does the pdf describe precisely? Also, thanks for sharing!

Thanks,
I was thinking of using a stainless coiled fuel line in a Shchelkin Spiral, but think it may cool the transition area which would be unacceptable. There are many reports of various geometry that allow for short Length / Diameter ratios. Would probably need to utilize something along those lines.

It would be difficult to predict how the pressure piling would change the geometry needed. The design is somewhat backwards of what is typically tested, many designers tend to use the exit of the Pulse Jet tail for the primary exit for the detonation wave.


I haven't see anything like this, though it may be out there somewhere. Considering the size of the engine that would be needed and fuel requirements, running this engine could be unpleasant.

May be a good practice for someone who thinks their CFD program is up to snuff. Lots of fun accounting for resonant volume, inertial pumping, deflagration to detonation transition while pressure piling into various blockage geometry.(just joking, this thing would be a nightmare in CFD)

metiz, thank you also for sharing your work, there are few that do these days.