3D flow visualization and geometry optimization of cavity based scramjet combustors using k-ω model

Abstract

In this paper numerical studies have been carried out to examine the intrinsic flow features of cavity based scramjet combustors with backward facing step and forward ramp using 3D, density-based, implicit, SST k-omega turbulence model. The preliminary results show a wide variety of flow features resulting from the interactions between the injector flows, shock waves, boundary layers, and cavity flows. In all the cases the C2H6-CO2-H2O fuel is injected at three different jet angles for the optimization of the jet orientation. Through the 3D numerical simulation we have corroborated that an optimized cavity is a good choice to stabilize the flame in the scramjet combustor as it generates a benign recirculation zone in the scramjet combustor. We comprehended that the cavity based scramjet combustors have a bearing on the source of disturbance for the transverse jet oscillation, fuel/air mixing enhancement, and flame-holding improvement. We concluded that the cavity shaped combustor with backward facing step and 45° forward ramp having an injector location of 1.6 times of its hydraulic diameter from the inlet facilitating at an angle of injection of 45° opposing the inlet flow is a good choice to getting relatively higher temperature at the exit.