Simulation of a Hall Effect Thruster Using Krypton Propellant

The multifluid computational framework Hall2De is updated to perform simulations of Hall thrusters operating with krypton propellant. The implementation is validated by comparison to past experimental measurements obtained for the NASA-300M thruster that operated with both xenon and krypton. For xenon, the computed thrust matches experimental values to within 6%, whereas for krypton the difference is only 1.8%. From simulations at the same thruster power level, the krypton propellant specific impulse is 15% higher than that for xenon, and the thrust is only 17% lower than that for xenon. These results are consistent with a simple theoretical calculation and experimental values. Next, the unshielded H6 thruster, which has not yet operated experimentally with krypton propellant, is also simulated for both gases at the same power level. The flow rate for krypton is reduced by 28% to maintain the 6 kW power level used for xenon propellant. The performance trends observed are consistent with the NASA-300M thruster simulations. Although the singly charged ion current fraction for xenon is 11% lower than that for krypton, for the doubly and triply charged species the trend is reversed. This behavior is expected when considering the relative differences in cross sections between the various ionization processes.