극저온 환경용 볼베어링 시험장치 개발 및 터보펌프용 볼베어링 시제품의 성능평가

Abstract

The turbo pump of a liquid rocket engine is composed of three main parts: the oxidizer pump, fuel pump, and turbine. Liquid oxygen (LOX) is the working fluid in the cryogenic environment in the oxidizer pump, but tests are usually performed using liquid nitrogen (LN2), which has a boiling point similar to that of LOX but is comparatively safer and easier to use for the test. In this study, a bearing test rig is developed and its performance is evaluated using a cryogenic ball bearing with LN2 as the working fluid. Verifying the performance of the bearing test rig is crucial for ensuring correct working of the turbo pump unit in the liquid rocket engine. A stable test rig for the bearing in a cryogenic environment makes the bearing technology enhance its reliability. The test results show that the system operates stably and the requirement of performance time of 500 s is met. The test results of temperature, motor speed, and torque are discussed. The developed cryogenic bearing test rig is expected to help in widening knowledge and expanding research on ball bearings in the future.