Invited Paper PS1-ThA8
Computational Modeling of DC and Pulsed Microplasmas-Based Space Propulsion Devices

Thursday, October 21, 2010, 4:20 pm, Room Aztec

Very small microplasma-based propulsion is gaining importance as a viable propulsion concept for small satellites that weigh less than 100 kg. These devices involve complex multiple physical phenomena associated with high-density plasma discharge in small volumes and coupling of plasma phenomena with high-speed viscous dominated flows. Specific requirements of minimal wall erosion and wall heat transfer are also driving oscillatory dielectric-barrier microdischarge designs, which introduced additional physics complexity associated pulsed microplasmas. We present computational modeling studies of microplasma propulsion devices. The model describes the plasma dynamics, gas-phase chemical kinetics, neutral dynamics, and coupling of plasma phenomena with high-speed flow for both DC and pulsed mode microdischarges. Unique computational challenges associated with this problem are described and solutions to these challenges as addressed in our model are presented. Results show the dominant mechanism for thruster performance improvement is the gas heating in the microplasma. The gas heating is primarily a result of near-wall ion Joule heating in the case of DC discharges and is also accompanied by significant wall heat loss. The use of dielectric-barrier microdischarge configuration accompanied by oscillatory excitation is shown to mitigate wall heat loss while sustaining off-wall gas heating.