关键词: 当量比分配；双十字支板；部分预混火焰面模型；正癸烷

Abstract: Numerical simulations were performed to investigate the effects of equivalence ratio distribution on the combustion performance of a liquid kerosene fueled dual-staged scramjet combustor. High enthalpy vitiated inflow at a total temperature of 1231K was supplied using a hydrogen-combustion heater. The Mach number at combustor inlet was 2.0. The fuel was injected into the combustor using crossed dual-strut. The global equivalence ratio was held constant to be 0.8，and three injection distribution schemes were conducted. The two-equation k-ω SST turbulence model was adopted to simulate the turbulence. The discrete phase model was utilized to predict the breakup，atomization，evaporation，and the coupling with the continuous phase of the liquid kerosene. The partial-premixed steady flame model was applied to consider the turbulence-combustion interaction. The n-decane was selected as the surrogate fuel of kerosene. Its skeletal mechanism included 40 species and 141 steps. The calculated wall pressure profiles in three fuel distribution schemes agreed well with the experimental values，illustrating that the present numerical method can provide a relatively accurate description of the supersonic combustion process of high molecular hydrocarbon fuels.Further analysis on the reacting flow field demonstrated that two reaction regions occurred in the combustor: the upstream reaction region was anchored at the trailing edge of the upstream strut，and the downstream one at the trailing edge of the downstream strut. With the upstream equivalence ratio increased from 0.1 to 0.3，the upstream reaction region was gradually transferred from its symmetric structure located in the vertical middle of the flow path to an asymmetric structure inclined towards the corner of the bottom and side walls; while the downstream one was contracted. The original location of the pre-combustion shock train propagated upstream. The flow entering into the upstream reaction region was gradually transferred from supersonic to subsonic，while that entering into the downstream reaction region from subsonic to supersonic. The exit total pressure recovery coefficient monotonically increased from 37.6% to 41.1%，while the net thrust was monotonically decreased from 366.4N to 331.8N. However，there was no monotonic correlation between the exit combustion efficiency with the upstream equivalence ratio.

Key words: Equivalence ratio distribution；Crossed dual-strut；Partial-premixed steady flame model；n-decane