Numerical simulation on thermal and mass diffusion of MMH–NTO bipropellant thruster plume flow using global kinetic reaction model

Abstract

Abstract A space propulsion system has a crucial role to perform several mission operations of a spacecraft successfully in an orbit. When a thruster is fired, the exhaust plume gas can have effects on the performance of a spacecraft because the expanded plume gas molecules directly collide with the spacecraft surfaces in the vacuum environment. Thus, the present study investigated more realistic plume flow behaviors using a global kinetic reaction model for an actual combustion process of a fuel and an oxidizer. To achieve this, the 4-step global combustion model of monomethylhydrazine and nitrogen tetroxide was incorporated for the first time in the plume flow analysis to reflect a more practical firing condition of a bipropellant thruster. Then, thermal and mass diffusion predictions of the plume flow were compared with the chemical equilibrium condition to examine the distinct differences between the proposed and conventional approach. For efficient numerical calculations, the Navier–Stokes equations and the DSMC method were combined to deal with a continuum flowfield inside the thruster and a rarefied plume gas flow outside the nozzle together. With the present analysis results, major differences in the thermal and mass behaviors of the plume gases were compared between the two reaction models, and their influences are also discussed.