Thermal sensitivity analysis of a 22 N bipropellant thruster in a spacecraft

Abstract

Transient thermal sensitivities of a 22 N bipropellant thruster in a spacecraft environment are studied in the on-orbit non-firing, firing and soak-back modes. The system has conductive and radiative modes of heat transfer and also for some time heat dissipation on valves. Temperatures of valves of the thruster assembly are analysed for their sensitivities to some of the design parameters, such as conductance between the thruster flange/mounting bracket, thruster flange/combustion chamber and thruster flange/ valve and conductance of the multilayer insulation blanket. Similarly, the influence of optical properties such as absorptance and emittance of the combustion chamber and heat shield are investigated. Studies relating to the heater power on the valves are also conducted. The lumped parameter approach is adopted and the governing equations are solved using a numerical technique. It was demonstrated that flange/ bracket conductance is the controlling parameter of the valve temperature during the sunlit period of the non-firing mode. In the soak-back condition, conductance across the flange and the valve dictates the valve temperature.