HYDRAULIC AND MECHANICAL PERFORMANCE OF LE-7 LOX PUMP INDUCER

A liquid oxygen turbopump has been developed for the main engine (LE-7) of the H-II rocket. The LE-7 LOX pump requires an inducer with quite high suction performance and high head, because a low-speed and low-pressure pump is not used ahead of the main pump in the LE-7 engine. The inducer was designed using the customary method, and its hydraulic and mechanical performances were investigated in tests of LE-7 LOX turbopumps. The original combination of an inducer and an inducer housing satisfied the required hydraulic performance criteria. However, this combination was found to result in supersynchronous shaft vibrations due to rotating cavitation which occurred in the inducer. This problem was almost completely solved by a simple modification of the inducer upstream housing. Furthermore, the rotating cavitation of the present inducer was investigated using a new theory of such cavitation.