液氧文氏管汽蚀特性计算流体力学研究

CFD study on cavitation of liquid oxygen in Venturi

文氏管用于精确控制液氢/液氧推进液体火箭发动机的燃料流量。考虑汽蚀过程热效应并假设气相与液相间热平衡,利用计算流体力学方法对液氧文氏管的汽蚀特性进行分析。首先给出了基于多相均匀流模型的雷诺平均Navier-Stoker方程组(RANS)及完全汽蚀模型的数值模型。然后通过对液氮水翼汽蚀过程的计算,得到压力、温度等分布并与美国NASA实验数据做对比,验证了数值模型的准确性。最后详细分析了液氧文氏管的汽蚀特性,给出了文氏管壁面压力、温度及汽蚀强度的分布,考察了进出口压比对汽蚀特性的影响,分析了低温流体维持汽蚀过程的机理。本文计算结果可用于指导液氧汽蚀文氏管的设计。

To accurately control the flow rate of liquid hydrogen and oxygen in liquid-fuel rocket engine, Venturi is commonly used. A CFD study on cavitation of liquid oxygen in Venturi was conducted, taking into consideration the thermal effect on the assumption about liquid-vapor thermal balance. The numerical model comprised homogeneous multiphase model on the basis of Reynolds-averaged Navier-Stokes equations and the full cavitation model. Computational results about the pressure and temperature distributions along the cavitating hydrofoil were then compared to the experimental data of NASA to validate the model. Detailed analysis on cavitation characteristics included the pressure, temperature and cavitation intensity profile along the hydrofoil wall, the impact of inlet-outlet pressure ratio on cavitation and the mechanism of maintaining cavitation in cryogenic fluids. The numerical results of this paper can be used to guide liquid-oxygen-Venturi design.