Experimental Study of a Small High Speed LH2 Rocket Pump (2nd Report: Fundamental Mechanical Design).

摘要

A small high-speed liquid hydrogen (LH2) pump was designed, fabricated, and tested in order to obtain technical data necessary for the development of upper stage rocket engines, e.g., the LE-5 and orbiter transfer vehicle (OTV) engines. The pump's basic mechanical design is described, as well as its mechanical performance during tests using LH2; both at nominal operating and rapid start/stop conditions. It was confirmed that the same materials employed for liquid oxygen pump components can be used, except for the impeller. An impeller made of titanium alloy (Ti-5Al-2.5Sn) was machined and then diffusion-bonded, and subsequently withstood a high speed operating condition (50,000 rpm) for 350 s. A balance piston configuration was selected for axial thrust control, where the impeller acts as a balance disk. Stress analysis on other components and machine specifications for critical mating parts were also verified as satisfactory. Self-lubricated ball bearings and rotating shaft seals showed adequate performance. Results indicate that smooth operation was achieved, thus confirming the soundness of the pump's mechanical design.