Numerical Study of Compressible Mixing Layers in Hyshot II Supersonic Combustor

Abstract

The compressible mixing layers inside a supersonic combustion chamber (HyShot II combustor) are numerically studied in this paper by using the DLR TAU code. The TAU code is firstly verified by calculating supersonic mixing layers downstream of a splitter plate. Studies of numerical settings show, that the AUSMDV upwind scheme plus dual time stepping with small physical time step is stable and efficient for the calculation of unsteady supersonic mixing layers. With the aid of this numerical experience, the DES calculation of the HyShot II combustor is subsequently carried out. Different from most previous studies, overexpanded and under-expanded flow states occur simultaneously at the exit of the current jet porthole. The shock system near the injector is a combination of detached normal shock and a small three-dimensional barrel shock ended with a Mach disk. Further insight into the flow physics is conducted by visualizing instantaneous coherent structures. A new understanding of the key flow physics in the low-momentum flux-ratio jet in supersonic crossflow is schematically provided, which is helpful to future design of injection systems for scramjet applications.