Study on pressure wave propagation through cryogenic condensing two-phase flow in liquid rocket propellant feedline

摘要

This paper presents a numerical study on the pressure wave traveling in the condensing flow of the liquid and vapor oxygen in the tank-to-engine propellant feedline of liquid rocket. A computational fluid dynamics (CFD) model is developed based on Eulerian multiphase model, and the coupling of pressure wave and flow condensation is achieved through incorporating user-defined functions (UDF) with interphase mass, heat and momentum exchange models. Experimental validation is undertaken and the predicted pressure profiles by CFD simulation prove to be in good agreement with experimental data. The simulation results indicate that the distance required to condense the oxygen mixture to pure liquid fluctuates with propagation of the pressure wave which experiences attenuation and deceleration with a speed of the order of 1-14 m/s. As the local vapor content reduces, the pressure wave speed increases in an exponential way with an abrupt increase greater than an order of magnitude taking place on transition to the single-phase liquid oxygen, while the amplitude attenuation decreases linearly. The dependence of pressure wave speed and attenuation on frequency satisfy exponential and logarithmic relations, respectively. The wave speed is to a large extent independent of the high frequencies and exhibits a dispersed characteristic at low frequencies.