Numerical investigation of effect of detonation chamber length on back-propagation

The phenomenon of back-propagation of an air-breathing pulse detonation engine (APDE) is numerically investigated. The formation and propagation characteristics of the back-propagation phenomenon are analyzed. The effect of the detonation chamber length on back-propagation is analyzed. The results show that the back pressure can influence the whole inlet. Shortening the length of the detonation chamber has the benefit of reducing the back pressure intensity; a substantial decline of back pressure intensity depends on a significant reduction of the detonation chamber length. However, increasing the detonation chamber length has little effect on back pressure intensity when the chamber is relatively long, but it prolongs the pressure release time. The back pressure will cause the flow to reverse in the inlet. The velocity of the reversed flow increases with increasing chamber length, which is more obvious when the chamber length is relatively short. The hot gas covers a much smaller region than the back pressure. The hot gas will not travel into the inlet when the chamber length is short enough. The distribution of the hot gas will be discontinuous in the region between the upstream chamber and downstream inlet.