稀薄气体环境对逆向喷流的减阻和防热效果的影响  

Influence of rarefied gas environment on the drag and heat reduction effect of opposing jet

作　　者：张智勇 张艳[1] Zhang Zhiyong;Zhang Yan(School of Mechanical Engineering, Southeast University, Nanjing 211189, China)

机构地区：[1]东南大学机械工程学院,南京211189

出　　处：《东南大学学报（自然科学版）》2022年第3期594-601,共8页Journal of Southeast University：Natural Science Edition

摘　　要：为研究在稀薄气体环境下逆向喷流的有效性,对使用逆向喷流的超声速钝头体在稀薄气体环境中飞行的流场结构及减阻和防热效果进行了计算.首先使用直接模拟蒙特卡罗方法计算全局克努森数为0.01、0.03及0.05时的流场结构,分析不同克努森数时逆向喷流的减阻和防热效果;然后研究了稀薄气体环境下,总压比、气体种类、喷流速度及气体温度等参数对逆向喷流效果的影响.结果表明:随着全局克努森数的增大,马赫盘和剪切层的厚度增加,回流区域减小,使逆向喷流的减阻和防热效果降低;增大总压比能增加逆向喷流的效果,但过大的总压比不仅会导致飞行器的阻力增大,而且会降低飞行器表面热流密度的减小效率,因此应避免使用过大的总压比;改变喷流的其他参数,如喷流气体种类、喷流速度以及喷流气体温度,可以改善逆向喷流在稀薄气体环境中的减阻和防热的效果.In order to investigate the effectiveness of the opposing jet in rarefied gas conditions,the flow field structure and the drag and heat reduction effect of supersonic blunt body with opposing jet in rarefied gas conditions were calculated.Firstly,the pressure and heat flux with the global Knudsen number of 0.01,0.03,and 0.05 were calculated by the direct simulation Monte Carlo(DSMC)method to analyze the drag and heat reduction effects of the opposing jet.Besides,the influence of some parameters such as the total pressure ratio,gas type,ejected flow velocity and temperature on the opposing jet in rarefied gas conditions were studied.The results show that as the global Knudsen number increases,the size of the Mach disk and the shear layer thickness increase and the area covered by the recirculation region decreases,which decrease the drag and heat reduction effect.Moreover,increasing pressure ratio can effectively improve the effect of the opposing jet.However,an excessively large pressure ratio will cause the increase in the drag coefficient and the decrease in the heat reduction efficiency.Therefore,the pressure ratio should be maintained within a proper range.Furthermore,by changing the parameters of the ejected gas,such as the gas type,jet velocity and temperature,the drag and heat reduction effect of the opposing jet in the rarefied gas condition can be improved.

关 键 词：热防护系统 克努森数 阻力系数 热流密度 钝头体 

分 类 号：V411.8[航空宇航科学与技术—航空宇航推进理论与工程]