The effect of cavity leading edge angle on flow field and cavity drag characteristics in a supersonic combustor under the condition with/without chemical reactions was numerically investigated.It is found that low velocity and high temperature recirculation zones form in cavity and upstream boundary layer of wall orifice

respectively

which are induced by a bow shock produced by the normal fuel jet interacting with the supersonic cross flow and expected to facilitate the fuel ignition and enhance the flame stabilization.A shock/boundary layer interaction phenomenon arises from an intense back pressure fluctuation induced by combustion spreading upstream through subsonic region of boundary layer.Decreasing the leading edge angle moves separation point of free shear layer ahead

which strengthens the reattaching shock at angled back wall and consequently increases the total pressure loss

in other words

decreases the total pressure recovery coefficient as well as the drag coefficient.This investigation provides insight into the characteristics of flow field inside supersonic combustor with/without combustion and corresponding mechanism of fuel-air mixing enhancement

which is crucial for optimization of the cavity structure.