One-Dimensional Analysis of Cavitation Surge Considering the Acoustic Effect of the Inlet Line in a Rocket Engine Turbopump : 2nd Report, Effect of a Phase Lag/Lead of Unsteady Cavitation Characteristics and POGO Suppression Device(Fluids Engineering)

Abstract

We investigated the effect of a phase lag/lead of unsteady cavitation characteristics on cavitation surge using a one-dimensional analytical model and applying the acoustic effect of the inlet pipe. The phase lag/lead of cavitation compliance was found to strongly affect the instability of cavitation surge, even though that of the mass flow gain factor does not so. An actual liquid rocket propulsion system is usually equipping a POGO suppression device (PSD). We thus modified the analytical model to consider the effect of the PSD. The frequency of cavitation surge was found to basically become the Helmholtz frequency, defined by the cavitation compliance and the length of pipeline between the PSD and the turbopump. And when the frequency of cavitation surge matches one of the acoustic resonance frequency of inlet pipeline, the cavitation surge is strongly excited.