Nurmerical Simulation of the Unsteady Cavitation Behavior of an Inducer Blade Cascade

One source of unsteadiness in turbopump inducers consists in a rotating cavitation behavior, characterizedby different cavity shapes on the different blades, which leads to super- or subsynchronous disturbances. Thisphenomenon is simulated for the case of a simple two-dimensional blade cascade corresponding to a typical fourbladeinducer. A numerical model of unsteady cavitating flows was adapted to take into account nonmatchingconnections and periodicity conditions. Single-channel and four-channel computations were performed, and in thelatter case, nonsymetrical unstable flow patterns were obtained. Limits of stability according to the mass flow rateand the cavitation number are presented. Qualitative comparisons with experiments, instability criterion, and themechanisms of instabilities are also investigated.