Simulation of rarefied gas flow inside the satellite air intake in ultra-low Earth orbit

Abstract

The key problem for the long-term operation of the satellite in ultra-low Earth orbits (ULEO) and its safety is to provide the propulsion system with a sufficient amount of working fluid. Gas from the atmosphere can be used as the working fluid, for which the satellite is equipped with an air intake. In this paper, the problem of rarefied gas flow in such an air intake in ultra-low Earth orbit (140 km) was solved. Using the method of event-driven molecular dynamics (EDMD), we studied how the narrowing of the effective aerodynamic cross-section after the air intake (in the ionization chamber) can affect the compression ratio and the flow field. It was shown that the flow field in the air intake depends significantly on the geometry of the subsequent sections of the device, therefore it is incorrect to model the flow in the air intake separately from the rest of the internal tract of the propulsion system, as it was done in the literature earlier.