MSFC cryogenic turbopump bearing tester results and analysis

A full scale High Pressure Oxidizer Turbopump (HPOTP) bearing tester has been developed, and an existing test stand modified, to simulate turbopump operating conditions for Space Shuttle Main Engine HPOTP design. Following a description of test facilities and procedures, design certification and calibration tests, and tests at a moderate axial load, are discussed. Results show that a bearing life of about 4500 seconds is comparable to the life experienced in the engine pump at nominal high power level operating conditions, and that although increased coolant flow increased fluid viscous work and bearing loads, a net decrease in bearing temperature was noted. Increased coolant flow is found to improve bearing cooling for marginal conditions, and bearing temperatures are shown to become more sensitive to coolant flow as shaft speed is increased. For the 6.4 lbs/s test conditions, the heat generated in a bearing pair is determined to be about 67 percent viscous work and 33 percent contact friction.