BACKFLOW FROM INDUCER AND ITS DYNAMICS

摘要

The present paper summarizes recent studies on the dynamics of backflow vortex structure associated with cavitaion instabilities in turbopump inducers. First, the cause of cavitation instabilities is discussed. Various methods for the suppression of cavitation instabilities are then reviewed to illustrate the importance of backflow vortex cavitation on instabilities. The characteristics of backflow vortices are described based on experimental observations. Calculations based on the k-ε turbulence model are used for clarifying the mechanisms of inlet backflow and its response to flow rate fluctuations. Backflow vortex structure is simulated by LES calculations on a simplified geometry. Cavity volume is estimated from the volume of the regions with the pressure lower than the vapour pressure and its response to flow rate fluctuation is clarified. From the results obtained, the effects of backflow vortex cavitation on cavitation instabilities are discussed.