低温液体运载火箭输送系统空化特性研究

Study on Cavitation Characteristics in Pressurizing Transmission System for Cryogenic Liquid Launch Vehicle

低温液体运载火箭输送系统空化将导致发动机泵入口压力下降,偏离设计工况,严重时可能引发涡轮泵夹气,为运载火箭飞行可靠性带来灾难性影响。采用数值仿真与地面全尺寸出流试验相结合的方法,系统研究了低温输送系统空化特性及发展规律。结果表明,贮箱压力、飞行过载、液柱高度、推进剂温度、出流口型面等参数均对空化的发生与发展有重要影响,且相互之间耦合效应显著;出流口处存在局部限流环节,是初始空化诱发的位置;当输送管直管段当地静压不足以抑制空化时,空化可能沿输送管向下游传递;合理控制当地静压是抑制空化初生和沿流动发展的有效措施。

The cavitation of pressurizing transmission system for cryogenic liquid launch vehicle will lead to the inlet pressure decreased of the engine pump,which deviates from the design condition,and may lead to the turbine pump clamping in serious cases,which will have a disastrous impact on the flight reliability of the launch vehicle.The cavitation characteristics and development law of cryogenic liquid the pressurizing transmission system are studied systematically by the method of combining numerical simulation with the full-size outflow test on the ground.The results show that the tank pressure,flight overload,liquid column height,propellant temperature,outlet surface and other parameters have important effects on the occurrence and development of cavitation,and the coupling effect among them is significant.There is local flow limiting link at the outlet,which is the initial cavitation in the straight section of the local static pressure is insufficient to suppress cavitation in the straight section of the local conveying pipe cavitation may be transmitted downstream along the conveying pipe.Reasonable control of local static pressure is an effective measure to suppress cavitation initiation and development along the flow.