LUMEN LOX Turbopump: Thermal Model Improvements and Water Test Results

Kurzfassung

The DLR LUMEN (Liquid upper stage demonstrator engine) project aims to develop and test a modular bread-board demonstrator to deepen the understanding of the operational behaviour of rocket engine systems. The demonstrator engine includes two separate turbopumps for Liquid Oxygen (LOX) and Liquified Natural Gas (LNG) supply. At the DLR Institute of Space Propulsion, cold gas tests on the LUMEN Oxygen Turbopump (OTP) have been successfully accomplished. The tests were conducted with water as the pumped fluid and pressurized cold nitrogen gas as the turbine drive fluid. These tests verified the operational envelope of the OTP. Additionally, temperatures at different locations in the OTP have been recorded at the operational points. Following up on a preliminary thermal model of the LUMEN OTP, this paper presents improvements of the thermal model on the turbine side. The heat transfer at the turbine stator is obtained by two methods: isothermal wall temperature and conjugate heat transfer method. The model results are compared to the measured temperature at the interface between the bearing unit and the turbine stator during the water test.