Study on cryogenic cavitation and its temperature-pressure correlated characteristics of methane pump in rocket engine

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.