Thermal Analysis for Propellant Stream in Thruster'sInjection Tube During Start Process

Abstract

According to the leading design features of the monopropellant attitude-control thruster and the cryogenic condition in space, the coupling heat-transfer physical model and a set of mathematical equations are put forward to calculate the temperature variation of the injection tube and three other components of the thruster, which are the aggregate organ, the bracket, and the injection plate. The wall temperature of the injection tube is taken as the thermal boundary conditions for the propellant stream temperature drop calculation. The temperature calculation of the propellant stream flowing inside the injection tube during the start process in a typical 10 N thruster has been performed, and two simulation experiments are carried out on the same type thruster in the vacuum cryogenic chamber. The results of the calculation agree well with the experiments. The validated calculation model can be used to judge whether the propellant stream freezes or not in the injection tube during the start process after the thruster has been exposed to the cryogenic space for a long time. In addition, four factors that affect the front temperature of the propellant stream at the injection tube exit during the propellant filled process are studied, and according to the calculation results, three correlation relationships are deduced, respectively.