Evaluation of the Dynamic Transfer Matrix of Cavitating Inducers by Means of a Simplified “Lumped-Parameter” Model

Abstract

The paper will present an analytical model for the evaluation of the pressure and flow rate oscillations in a given axial inducer test facility. The proposed reduced order model is based on several simplifying assumptions and takes into account the facility design and the dynamic properties of the tested inducer. The model has been used for evaluating the dynamic performance of a prototype of the LE-7 engine liquid oxygen (LOX) inducer, in tests carried out under given external flow rate excitations. The main results of these calculations will be shown, including the expected oscillations under a wide range of operational conditions and the influence of facility design. Calculations showed that the only way to obtain the two linearly independent test conditions, necessary for evaluating the inducer transfer matrix, is by changing the facility suction line: Any other changes in the facility design would result ineffective. Some other important design indications provided by the analytical model will be presented in the paper.