Hybrid (Particle-Fluid) Modeling of Pulsed Plasma Thruster Plumes

摘要: Integration of a pulsed plasma thruster (PPT) onboard spacecraft requires the evaluation potential plume/spacecraftinteractionsthatcanbedetermined through plumemodelingand characterization.APPTplume model, numerical results, and comparisons with experiments are presented. The physical characteristics PPT plumesare reviewed e rst, theoutstanding modeling issuesrelated to theunsteady,partially ionized, collisional plume model is axisymmetric based on hybrid particle ‐euid approach. Neutrals ions modeled combination direct simulation Monte Carlo hybridparticle-in-cell method. Electronsaremodeled asa masslesse uid momentum equation that includeselectric elds, pressure gradients, contributions from neutrals. nontime-counter methodology isusedforneutral ‐neutral,elasticion ‐neutral,and charge-exchangecollisions. Ion ‐electron collisionsaremodeled use collision force eld. Electric elds obtained charge conservation under assumption quasi neutrality. Thecodeincorporates subcycling forthetimeintegration unsteady injection.SimulationsareperformedusingPPTconditionsrepresentativeofa NASAJohn H.GlennResearch Center atLewisFieldlaboratory-modelPPToperatingatdischargeenergiesof 5,20,and40J.Theresultsdemonstratethe expansion neutral ion components plasmoid during pulse, thegeneration low-energy high-energy neutrals due charge-exchange reactions, generation backe ow. Numerical predictions compared electron density data show good quantitative agreement. Backe ow presented for three discharge energy levels considered.