吸气式电推进系统进气道结构对进气性能的影响

Influence of air-intake structure in air-breathing electric propulsion system on intake performance

吸气式电推进系统能收集高空稀薄气体作为推进剂,延长卫星的工作寿命,其关键性技术之一是进气道的结构设计。采用直接模拟蒙特卡罗(DSMC)法,数值研究了进气道长纵比、进气道出口锥角和栅格结构及其几何尺寸参数对进气道进气性能的影响规律。结果表明:提高进气道长纵比,能提高进气道的压缩比和收集效率,当长纵比为7时,压缩比和收集效率达到最大值,分别为200和0.65;增大进气道出口锥角,进气道的压缩比和收集效率呈现先增大后减小的变化趋势,出口锥角的理论最优值为70°;栅格结构能有效防止已捕获粒子从进口逸出,从而提高进气道的压缩比和收集效率,改变栅格板厚度对进气道的压缩比和收集效率影响不大,而增加栅格板的长度和层数,进气道的压缩比随之提高,但收集效率降低。

An air-breathing electric propulsion system can collect the rarefied gas as propellant and extend the operating life of the satellite.One of the key technologies of this system is the design on the air-intake structure.In this paper,using the Direct Simulation Monte Carlo(DSMC)method,the effects of the aspect ratio,the cone angle of the air-intake,gird structure and its geometric parameters on the intake performance were examined numerically.The results show that increasing the aspect ratio of air-intake leads to the enhancement of the compression ratio and collection efficiency of air-intake.When the aspect ratio is 7,the maximum of compression ratio and collection efficiency are obtained and they are 200 and 0.65 respectively.With the increase of cone angle of air-intake at exit,both the compression ratio and collection efficiency of air-intake increase first and then decrease.The theoretical optimal value of the cone angle at exit is 70°.The grid structure improves the compression ratio and collection efficiency of the air-intake by effectively preventing the captured particles from escaping from the inlet of air-intake.Changing the thickness of grid plate has little effect on compression ratio and collection efficiency of air-intake.With the length of grid plate and the layer number of grid plate increasing,the compression ratio of air-intake increases,while the collection efficiency decreases.