A new ablation model for ablative pulsed plasma thrusters

摘要

Pulsed plasma thrusters have been widely used all over the world in the past several decades. A new and effective model to calculate the ablated mass bit (the mass ablated from the propellant in each discharge) of ablative pulsed plasma thrusters is presented in this paper. The model is based on the random degradation of molecular chains in polytetrafluoroethylene (PTFE) and statistical methods. New expressions are obtained for the ablated PTFE mass bit as a function of the energy used in PTFE ablation, the ratio of the energy used to successfully break the carbon-carbon bonds to the energy used in PTFE ablation and the ratio of the mass that breaks away from the ablation surface of the PTFE to the total ablation mass. The introduction of statistical methods allows us to define a simplified model that is useful for the prediction of the ablated mass bit and for preliminary design guidance. The obtained theoretical results for the mass bit show very good agreement with the results from experimental studies. The range of the average relative error is approximately - 15.7% to 12.4%. Finally, this new model can be used to evaluate the ablated mass bit, in addition to predicting the lifetime and guiding the design of new ablative pulsed plasma thrusters.