Experimental Study on Rotating Cavitation of Rocket Propellant Pump Inducers

Abstract

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 vibrations 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 shaft vibrations were caused by rotating cavitation in the inducer. A simple modie cation of the inducer upstream housing almost completely extinguished such shaft vibrations. Some characteristics of rotating cavitation have been fairly well elucidated. However, we were not able to fully explain the mechanism of the ine uence of the simple modie cation of the inducer upstream housing on the rotating cavitation. We thus commenced further experimental studies to investigate rotating cavitation in more detail. In the present study, some visual observations of rotating cavitation were conducted using the same inducer test facility as that used in our previous work.