新一代四机并联火箭发动机喷流热环境数值研究

Numerical Study on Thermal Environment of a New Generation of Four-Parallel Rocket Engine Jet

针对国内首次采用四机并联大推力液氧煤油发动机的新一代运载火箭,采用FLUENT软件研究发动机喷流对火箭底部热环境的影响。结果表明:低空飞行时,喷流的相互作用较弱,返流以亚音速冲击底部中心,返流气体中空气摩尔分数占比在90%以上;高空飞行时,返流以超音速向底板流动,返流气体中高温喷流气体占50%以上,高温的返流导致底部热环境更加严酷。随飞行高度的增加,回流点更靠近箭体,箭体底部的热环境更恶劣,底部最大热流密度点出现在飞行高度约21 km处。

For a new generation of launch vehicle using four-parallel liquid oxygen kerosene engine,FLUENT software is applied to study the influence of the engine jet on the thermal environment of rocket bottom.The study shows that:at low flight height,the jet flow interaction is weak;the backflow impacts the bottom center of the rocket at subsonic speed;and the air mole fraction in the backflow accounts for more than 90%.At high flight height,the backflow flows to the bottom plate at supersonic speed;The high-temperature jet gas in the backflow accounts for more than 50%.With the increase of flight height,the backflow point is closer to the vehicle afterbody,and the thermal environment of the afterbody is more severe.The maximum heat flux point at the bottom occurs at the height of about 21 km.