Numerical simulation of cryogenic cavitating flow in LRE oxygen turbopump inducer

Abstract

Turbopump is a critical component of modern liquid rocket engine (LRE), which employs cryogen as propellant. Its working performance is closely relevant to the reliability of LRE. The performance improvement of turbopump is limited by cryogenic cavitation condition. While the cryogenic cavitating flow characteristic is not well understood till now. A novel numerical method for cryogenic cavitation simulation was developed based on a transport-based cavitation model in the present investigation. The real thermodynamic properties of fluids and an additional energy source item which takes the heat transfer during phase change into account were imbedded into the code, and the empirical constants of the cavitation model are unnecessary to alter. It is found that a moderate reduction of released heat by vapor condensation in the energy source item provides better prediction accuracy for temperature distributions, and an optimal reduction proportion has been suggested. The cavitating flow features inside a three-bladed inducer using liquid oxygen as working fluid have been investigated in detail based on the proposed method, thermal effect reduces both the cavitation regions and the vapor volume fraction inside cavities remarkably, producing less blocking effect on the blade flow channels, which delays the head breakdown. Higher temperature shows stronger thermal effect and better cavitation performance. A classical semiempirical theoretical model is introduced to quantitatively predict the influence of thermal effect on cavitation performance. The predicted results are in consistent with the calculated results. The developed numerical model shows favorable universality to act as a reliable tool for cryogenic turbopump design.