The effect of injection angle on mixing and flame holding in supersonic combustor

Abstract

A numerical study on mixing of hydrogen injected into a supersonic air stream has been performed by solving two-dimensional full Navier-Stokes equations. An explicit Harten-Yee Non-MUSCL Modified-flux-type TVD scheme has been used to solve the system of equations, and a zero-equation algebraic turbulence model to calculate the eddy viscosity coefficient. The main objectives of this study are to increase the mixing efficiency and flame holding capability of a supersonic combustor. The performance of combustor has been investigated by varying the hydrogen injection angle made with the direction of air stream considering anti-clockwise direction as positive. The injector position from left boundary, backward-facing step height and the inlet width of air stream are kept constant. The results show that upstream of injector the mixing is dominated by recirculation and in downstream the mixing is dominated by mass concentration of hydrogen. Upstream recirculation is dominant for injecting angle 60 ° and 90 ° . Incorporating the various effects, perpendicular injection shows the maximum mixing efficiency and its large upstream recirculation region has a good flame holding capability.