An Advanced Modeling Tool for Prediction and Alleviation of Turbopump Cavitation Instabilities

We propose to develop an advanced modeling tool to predict and to alleviate cavitation related turbopump instabilities. An existing “full cavitation model” developed by the proposing team and used in commercial CFD codes will be used as the starting point. The model will be improved by: a) introducing Eulerian-Lagrangian coupling for bubble dynamics; b) introducing a multi-scale model to study cavitation bubble collapse; c) incorporating thermodynamic effects for cryogenic conditions; d) implementing an innovative instability analysis which couples mixture compressibility and system dynamics; and e) validation of the model against experimental data and those to be carried out at our collaborator of this project, Aerospace Corp. The proposed model is unique in that it addresses the majority of deficiencies in the current modeling approaches, including cavitation damage to blade, acoustic coupling of cavitation bubble with the flow, cavitation instabilities, cryogenic fluids, accurate prediction of cavitation blockage and head fall-off. In Phase I the thermal model and bubble dynamic model will be implemented and tested. Validation studies will be made on NASA’s SSME LH turbo-inducer or LOPO inducer on cavitation blockage and fall-off under normal and cryogenic conditions. The models will be further enhanced for convergence and efficiency, and modularization and implementation strategy in other CFD codes will be carried out during Phase II.