结构尺寸对固体燃料冲压发动机燃速影响的仿真研究

为研究结构尺寸对固体燃料冲压发动机燃速的影响规律,采用3阶单调迎风(MUSCL)重构方法,AUSMPW+通量分裂格式,k-w SST湍流模型,7组分3反应有限速率化学反应模型以及2阶矩湍流燃烧模型,编制了二维轴对称湍流燃烧仿真程序,研究入口直径、药柱直径、喷喉直径以及相似结构尺寸对燃速的影响规律。仿真结果表明:入口直径以及药柱直径影响较大,相似结构尺寸的影响相对较小,喷喉直径几乎没有影响;固体燃料冲压发动机结构尺寸影响燃速的主要机理是湍流黏性的变化以及火焰面位置的变化;突扩比对燃速起着关键的作用,燃速与突扩比近似呈线性关系。

Numerical Investigation on Effect of Solid Fuel Ramjet Geometry on Solid Fuel Regression Rate

In order to investigate the influence of solid fuel ramjet geometry on regression rate of solid fuel, a 2D axisymmetric turbulent flow and combustion program is developed. The Navier-Stokes governing equations are solved by using MUSCL reconstruction method and AUSMPW+ flux splitting technique, k-w SST turbulence model, 7 species/3 reaction kinetics finite rate model and second-order moment turbulence-chemistry model. The effects of inlet diameter, grain diameter, nozzle throat diameter and geometrical similarity on regression rate are studied. The simulation results show that the inlet diameter and grain diameter affect the regression rate mostly, while geometrical similarity and nozzle throat diameter have less effect on it. The variation of regression rate is caused by the variation of turbulent viscosity and flame position directly; port-to-inlet-diameter ratio has the most important influence on regression rate, and the regression rate has a linear relation with port-inlet-diameter ratio.