Numerical analysis on ablating boundary layers of pulsed plasma thruster based on Knudsen model

In order to accurately describe the essential relationship between ablation processes and inflow conditions for pulsed plasma thruster (PPT), the characters of ablating boundary and internal reflux mechanism were simulated numerically by Knudsen analytical model using bimodal velocity distribution function. For the deficiencies of K-B model in actual PPT ablation, the method adding the energy due to internal degrees while applying the conservation of energy flux was used on the basis of chemical kinetics simulation of vapor composition. Effects of thermochemical reaction on the thermodynamic state around ablating boundary layers, as well as the internal flow were deeply analyzed and Knudsen analytical model was formed to adapt to the PPT ablation. The boundary relation of hydrodynamic non-equilibrium layer was then established on momentum. Combined with the electric and configuration parameters of the parallel-plate PPT, numerical examples were given for the analysis of the influence of boundary layer and state conditions on the "late-time" ablating rate. It is valuable for theoretically studying the coupled character of ablation and plasma flow in PPT.