Cavitation Model for Turbopumps in Liquid Rocket Systems

An innovative model for simulating cavitation in liquid rocket turbopumps using cryogenic working fluids is proposed. The formulation is based on a compressible gas-liquid framework that accurately models the acoustics in a multi-phase mixture. This methodology was successfully applied, in our Phase I effort, to simulate cavitating inducer performance in water. Our Phase II effort will extend this formulation to cavitation in cryogenic fluids which exhibit, relative to water, far more complex physics; cryogenic pumps operate at temperatures closer to the critical temperature of the working fluid making thermodynamic effects important. The model will account for the variation in the properties of the fluid as a function of the local fluid temperature that may vary due to energy requirements of vaporization/condensation. It will be incorporated within the commercially marketed code CRUNCH CFD that has a multi-element unstructured framework and is ideally suited for complex turbomachine configurations. This framework will be used as a design support tool to analyze inducer designs and in particular determine the suction specific speed at which head breakdown occurs. The limited reliability of current design tools in cavitating flow regimes makes this innovation a useful tool for turbomachine designers.