Computer Simulations of Exothermic Propellants in a Microlaser Ablation Plasma Thruster

摘要

Interest in development of micro- and nanosatellites has led to the design of the microlaser ablation plasma thruster. Previous work succeeded in constructing a working computational model of the microthruster's operation via MACH2, a two-dimensional magnetohydrodynamic code; however, this model was limited to simulating only nonenergetic solid propellant ablation in the microthruster. Recent experimental investigations have demonstrated that use of an exothermic (energetic) propellant can significantly improve performance of the microthruster and allow for higher-thrust modes of operation. The present work details new simulations of exothermic glycidyl azide subdetonation and full detonation processes; the results indicate a successful capability to match the detonation characteristics of the glycidyl azide and its ablative behavior. Particularly, the threshold for the onset of detonation in the fuel is explored and matches within approximately 14% of theoretical calculations of threshold pressure. This demonstrates the possibility to explore the selection of fuel for the microlaser ablation plasma thruster via computational investigations. Glycidyl azide polymer subdetonation simulations indicate a 74% improvement in impulse bit over the previous nonenergetic propellant. A confined ablation setup is also explored for detonation, which demonstrates a vast improvement to performance while suppressing the propagation of shocks.