Quasi-one-dimensional numerical simulation of magnetoplasmadynamic thrusters

Magnetoplasmadynamic (MPD) thrusters are a promising method of propulsion for a variety of space missions. This research develops and analyzes a numerical simulation of a quasi-one-dimensional model of a MPD thruster. A finite-difference scheme is used to integrate the governing equations. These equations allow for separate heavy species and electron temperatures and a variable nonequilibrium ionization fraction, and they can be expanded to allow for velocity slip between neutrals and ions. The model includes source terms used to represent collisional energy transfer between species, viscosity, and ambipolar diffusion, electron heat conduction, and the effects of velocity slip. Solutions to the governing equations were found for a range of cases and geometries, including different source terms in order to determine their effect on the thruster flow. These results show that thermal equilibrium is not a valid assumption in a typical MPD thruster, that viscosity and velocity slip can greatly influence heavy species temperature, and that viscosity and area variation play a significant role in determining thruster performance. Finally, good agreement is found with experimental thrust measurements, but not with operating voltage measurements.