Numerical Simulation of Cold Flow Field Mixing in Air-breathing Rotating Detonation Engine

Abstract

The mixing characteristic of the fuel is one of the main factors affecting the ignition of the rotating detonation engine and the stable propagation of the detonation wave. In order to investigate the effects of different combustor structures on the cold flow mixing of fuel and oxidant in air-breathing rotating detonation engine,a three-dimensional numerical simulation of the cold flow field was carried out. The density-based implicit format solver was adopted to solve the three-dimensional N-S equations. Based on the air-breathing rotating detonation engine with fuel injected from the small holes, the inflow conditions of air and ethylene remained unchanged, and the effect of area-expansion structure of combustor,cavity structure and blocking ratio on the cold flow mixing was analyzed. The results show that different area-expansion strucures will affect the reflected wave structure formed by the supersonic airflow entering combustor,thereby changing the position of the recirculation vortex and affecting the mixing of air / ethylene. The mixing effect of the double-sided expansion and inner expansion combustor improve may be by adding a cavity on the inside of the combustor when ethylene through the low velocity area of the cavity. After increasing the blocking ratio,the velocity of the main air flow decreases,the influence area of the recirculation vortex in the cavity becomes larger,and the air and ethylene begin to be mixed at the front position of the combustion chamber,and the mixing effect is improved.