PULSE COMBUSTION AND WAVE ROTORS FOR HIGH-SPEED PROPULSION ENGINES

A wave rotor is an example of a non-steady flow device that can be used to create a low-cost, low-weight combustion engine with superior performance suitable for acceleration of a vehicle to hypersonic speeds. Pressure-gain combustion using a wave rotor can avoid some of the difficulties with other non-steady devices. This paper examines the relative merits of a wave rotor utilizing pulse combustion or pulse detonation to produce thrust. The combustion and flow processes are simulated using a 1-d wave rotor code, and estimates of thrust, specific impulse, and rotor dimensions are obtained for hydrogen/air operation at subsonic cruise conditions in an idealized engine. Given similar limitations on combustion cyclic frequency and rotor size, a detonation wave rotor can produce about three times the thrust and about twice the fuel-specific impulse of a deflagration wave rotor. If detonation initiation limits the frequency or requires oxygen enrichment, the disparity in thrust and propellantspecific impulse could disappear, and the deflagration wave rotor may remain a serious candidate for highspeed flight applications.