Numerical investigation of cavitation characteristics of a liquid oxygen turbo pump

Liquid oxygen turbo pump is a key part of a liquid rocket engine, and is used for supplying liquid oxygen to combustion chamber. Cavitation may seriously compromise the pump from working properly; it can cause hydraulic instability and decline in efficiency. Cavitation flow is a multiphase flow in which propellant gets vaporized and is not able to keep its liquid state in some regions of the flow. Numerical investigation of cavitation flow in turbo pump can help in determining an approach to prevent the turbo pump from cavitation. Numerical simulations for a two-phase flow described by the Zwart-Gerber-Belamri model are performed to investigate the liquid volume fraction and vortex structure in the cavitation flow. Based on the numerical simulations of nascent cavitation flow and developed cavitation flow, detailed patterns of cavitation flow in turbo pump are obtained. Cavitation regions grow in the inducer and impeller and expand to the suction chamber as cavitation develops. Angles of attack on both the inducer blades and impeller blades change with the increase in cavitation, and increase in cavitation leads to separation and swirl in some flow regions around the blades. A vortex analysis method is proposed to determine the characteristics of the cavitation flow. Analysis of vortex volume fraction indicates that the vortex structure due to cavitation is of low-intensity but is very different from that in flow without cavitation.