激光光船周围连续/稀薄混合流场的数值模拟

当火箭模式激光推进器在高空稀薄大气中飞行时,需要在激光聚焦区附近喷射稠密气体工质,从而利用激光聚焦击穿气体工质形成等离子体,为光船提供推力。为了分析该光船的推力产生过程,采用连续流体力学计算方法(CFD)和直接数值模拟蒙特卡洛方法(DSMC)耦合的混合算法,数值模拟飞行高度为80 km飞行马赫数为5的激光光船周围高温连续气体和稀薄环境大气耦合的非定常混合流场,并得到推力随时间的演化曲线。结果表明,稀薄效应明显增加了激波厚度,高温效应延迟了推力的产生,并导致冲量耦合系数和比冲的降低。

Numerical simulation of continuum/rarefied flow around laser lightcraft

For a rocket mode laser thruster flying at higher altitude with rarefied atmosphere,a dense gas is injected into the focused region to generate high temperature plasma by laser beam focusing in order to propel the lightcraft.In order to analyze the thrust evolution,a hybrid method that combines continuum fluid models with the direct simulation Monte Carlo(DSMC) method is used to simulate the unsteady high temperature continuum flow coupled with the rarefied ambient around the lightcraft at 80 km and Mach 5.As a result,the rarefaction effect increases the shock thickness obviously.The high temperature effect delays the thrust production,and reduces the impulse coupling coefficient and the specific impulse.