EXPERIMENTAL-STUDY ON ROTATING CAVITATION OF ROCKET PROPELLANT PUMP INDUCERS

Research on rotating cavitation progressed during the development of a liquid oxygen (LOX) turbopump for the LE-7 engine of the H-II rocket. In some ranges of cavitation numbers, supersynchronous shaft vibratio ns were observed in the LE-7 LOX main pump inducer, From a comparison with the results of our previous studies it was concluded that such sh aft vibrations were caused by rotating cavitation in the inducer, A si mple modification of the inducer upstream housing almost completely ex tinguished such shaft vibrations. Some characteristics of rotating cav itation have been fairly well elucidated. However, we were not able to fully explain the mechanism of the influence of the simple modificati on of the inducer upstream housing on the rotating cavitation, We thus commenced further experimental studies to investigate rotating cavita tion in more detail, In the present study, some visual observations of rotating cavitation were conducted using the same inducer test facili ty as that used in our previous work.