The harsh and complex working environment such as low temperature, high pressure and high speed in the turbopump brings great challenges to the working performance, operation stability and structural safety of the turbine pump device. In this research, the cryogenic cavitation of methane pump in liquid oxygen-methane rocket engine is studied by the combination of experiment and high-performance computing cluster numerical simulation. The unsteady flow calculation of the methane pump is carried out to reveal the cavitation and its temperature-pressure correlated characteristics of the methane pump in different operation conditions. A cryogenic cavitation model considering the thermal effect of cryogenic medium is established and the cryogenic cavitation simulation of methane pump is carried out. The hydraulic and cavitation performance experiments of methane pump are also performed. It is demonstrated that: 1) The volume fraction and cycle of cavitation in pump will decrease exponentially with the increase of inlet pressure. The cavitation cycle under low inlet pressure (0.146 MPa) is five times of that under high inlet pressure (0.3 MPa). 2) The decrease of inlet pressure will lead to the decrease of Strouhal number, which will weaken the unsteady cavitation effect of methane pump and enhance the influence of fluid inertia effect on cavitation. 3) Cavitation in inducer is mainly dominated by the backflow vortex cavitation (BVC) and the blade cavitation (BC) under lower inlet pressure condition, while the backflow vortex cavitation (BVC) and the tip vortex (TVC) cavitation are the main contribution in higher inlet pressure conditions. Through the study of cryogenic cavitation under harsh pump working conditions is benefit to reveal the cavitation mechanism of methane pump, and provide theoretical basis and technical support for the improvement design of turbopump.

中文翻译：

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火箭发动机甲烷泵低温空化及其温度-压力相关特性研究


涡轮泵内低温、高压、高速等恶劣复杂的工作环境，给涡轮泵装置的工作性能、运行稳定性和结构安全带来了极大的挑战。本研究采用实验与高性能计算集群数值模拟相结合的方式，研究了液氧-甲烷火箭发动机中甲烷泵的低温空化。通过对甲烷泵进行非定常流量计算，揭示了不同工况下甲烷泵的空化及其温度-压力相关特性。建立了考虑低温介质热效应的低温空化模型，并进行了甲烷泵的低温空化模拟。还进行了甲烷泵的水力和气蚀性能实验。结果表明：1） 泵中空化的体积分数和周期将随着入口压力的增加呈指数下降。低入口压力 （0.146 MPa） 下的空化循环是高入口压力 （0.3 MPa） 下的 5 倍。2）入口压力的降低会导致Strouhal数的减小，从而减弱甲烷泵的非定常空化效应，增强流体惯性效应对空化的影响。3） 诱导轮中的空化主要以较低入口压力条件下的回流涡流空化 （BVC） 和叶片空化 （BC） 为主，而在较高入口压力条件下，回流涡流空化 （BVC） 和尖端涡流 （TVC） 空化是主要贡献。 通过对恶劣泵工况下的低温空化研究，有利于揭示甲烷泵的空化机理，为涡轮泵的改进设计提供理论依据和技术支持。