Effect of inflow pressure and wall heat transfer on shock-induced combustion/detonation

Abstract

Oblique detonation waves are possible ignition mechanisms for scramjet engines. Results from a numerical study of the effects of changing the inflow pressure on oblique detonation wave structure for supersonic flow of a stoichiometric hydrogen-air mixture over a flat plate followed by a ramp are presented. Viscous effects and finite-rate chemistry are considered. Inflow pressure is varied from 0.1 to 1 atmospheres for Mach 4 inflow over a 30 degree ramp. Also, the effect of wall heat transfer rate is examined by compareing adiabatic wall, and constant temperature wall solutions. A seperation bubble forms at the intersection of the flat plate and the ramp. The bubble size is a maximum for an inflow pressure of 0.5 atm. Increased inflow pressure strengthens and steepens the shock wave. The bubble size is smaller for the adiabatic wall case than it is for the constant wall temperature condition. Oblique detonation waves occur for the higher inflow pressure cases for both wall temperature conditions.