关键词: 冲压喷气发动机;超音速燃烧;二相流;湍流;数值仿真

Abstract: A kerosene-fueled scramjet with 3D cavity was numerically investigated.The main characteristic of this kind of cavity is its special designed slots opened in the upstream of the cavity.The simulations include two typical cases of flying mach number,which are 4 and 6,respectively.One-staged injection is used in the first case while two-staged injection is used in the latter. The mathematical methods include particle stochastic trajectory model for two phase flow, SST k-ω model for turbulence, and C₁₂H₂₃’s 17 species and 30 step reactions model for kerosene’s multi-step chemistry.The side wall’s numerical results　for static pressure were calibrated with experimental values　and　it which shows a good agreement, except an error of 23% occurs in the cavity part of M₀=6 case. The general flow analysis shows particle collision and secondary atomization caused by the asymmetry injection and combustion exist in that case but it was ignored by present numerical model because of huge computational cost.Further analysis shows: （1） M₀=6 case has a high combustion efficiency by staged fuel injection,while M₀=4 case has a low combustion efficiency by low fuel injection pressure.（2） The supersonic state of primary flow above the cavity gives much higher turbulence intensity than subsonic state, which is helpful for mixing.

Key words: Ramjet engine;Supersonic combustion;Two phase flow, Turbulent flow;Numerical simulation