Monte Carlo Simulation of Neutral Xenon Flows in Electric Propulsion Devices

Numerical simulations of neutral xenon flow in three different electric propulsion configurations are presented. Flows through an ion thruster, a plasma contactor, and a Hall thruster are considered. The computations are performed using a Monte Carlo method. The ion thruster configuration chosen for study is the UK-10 engine. Comparisons of the simulations are made with a simple analytical model that has been used in previous computations of backflow from ion thrusters. Both sets of theoretical results are compared with number density measurements. The Monte Carlo simulations provide closer agreement with the experimental data, and the analytical model is found to overpredict density in the backflow plume region. The Monte Carlo simulation of the plasma contractor plume also compares well with experimental measurements. For the Hall thruster, the simulations reveal detailed structures of the fluid flow in the annual anode chamber. Comparison with a measured data point for velocity indicates that the experiment is compromised by a relatively high facility back pressure. Inclusion of the back pressure in the simulation leads to excellent agreement with the datum. (Author)