关键词: 高超音速冲压发动机;燃烧室;支板;湍流;数值仿真

Abstract: In the present paper, the internal flow fields in scramjet combustion chamber with strut and cavities were simulated numerically by using the Favre-Averaged Navier-Stokes equations with the k-ω two-equation turbulence model. The second order TVD scheme is used for the inviscid flux terms of the equations and a central difference is used for the diffusion terms. Furthermore, using the local integral of the nonequlibrium source terms within local fluid time step and the LU factorization technique, an implicit LU-SSOR hybrid arithmetic without computing the inversion of the iteration matrix is established, guaranteeing the high efficiency of the method in simulating nonequlibrium flow fields. During the simulations, the effects of cavity position and length-to-depth ratio on the performance of fuel mixing are studied comparatively. The results show that, the cavity with large ratio of length to depth increases the residual time of fuel in the cavity field, and accordingly improve the fuel/air mixing. Additionally, the cavity behind normal-wall fuel injectors will give more helps in enhancing the fuel/air mixing efficiency than the cavity locating at the downward far from the injectors does.

Key words: Hypersonic ramjet engine;Combustion chamber;Strut~+;Turbulent flow;Numerical simulation