Numerical simulation of nonequilibrium plasma flow in 10 kW hydrogen arcjets

A thermal and chemical nonequilibrium modeling study is performed to investigate the plasma flow and heat transfer processes in 10 kW arcjets. In this modeling, the heavy particle and electron energy equations are introduced to examine the thermal nonequilibrium characteristics, while the equations of hydrogen atom and ion species equations combined with the a global continuity equation and the suitable chemical reactions, are introduced to examine the chemical nonequilibrium characteristics of plasma flow within the arcjet nozzle. The transport properties used in this paper are recalculated according to the conditions at each point in the plasma. The Roe scheme is employed to solve the governing equations. The predicted arcjet performance agrees well with the referred experimental results. The modeling results show that the differences between the temperatures of electron and heavy particles temperatures along the interior surface of thruster nozzle are significantly larger than those along the axis of thruster, which means that there is the thermal nonequilibrium in the regions near the interior wall of nozzle. Furthermore, based on the analysis of computed hydrogen species profiles and their evolutions within the arcjet thruster, it is found that deviations from chemical equilibrium occurs downstream of the thruster nozzle.