Testing and Prediction of Heat Exchanger Performance for Liquid Propulsion Engine Based on Simulation Experiment

During performance tests of heat exchangers that use fuel-rich exhaust gas from gas generators operated with kerosene and liquid oxygen, environmental problems may arise owing to gas emissions from incomplete combustion. Moreover, helium is a common yet expensive pressurant gas, and its scarcity may cause supply disruptions. We accurately simulate the operating conditions of a heat exchanger considering existing environmental and economic difficulties. To address environmental concerns, ethanol is used as the fuel in the gas generator instead of kerosene, whereas nitrogen is used as the pressurant gas instead of helium to reduce costs. Theoretical calculations show that the gas temperature after heat exchange has a maximum difference of 2.9% with respect to the experimental values, demonstrating good prediction of the experimental results through simulations. In addition, we obtain the mass flow ratio at which nitrogen and helium, used as pressurant gases, exhibit the same heat transfer performance. The simulation results suggest that performance testing of a heat exchanger can be carried out considering the suggested low-cost and ecofriendly alternatives.