Study of the dielectric breakdown properties of CO_2-O_2 mixtures by considering electron detachments from negative ions

摘要

The dielectric breakdown properties of CO_2-O_2 mixtures at different O_2 concentrations and gas pressures were studied in this paper, with electron detachments from negative ions taken into consideration. The influences of the electron detachment on the reduced effective ionization coefficients α_(eff)/N, the critical reduced electric fields (E/N)_(cr), the critical electron temperature T_(cr), the breakdown reduced electric fields (E/N)_(breakdown), and the breakdown electron temperature T_(breakdown) were analyzed for the CO_2-O_2 mixture. Based on the results, it was found that an enhancement in α_(eff)/N and a decrease in (E/N)_(cr) and T_(cr) were caused by the electron detachment, which appeared to be more significant at relatively low E/N and low gas pressures. With the increase in the pd product, both (E/N)_(breakdown) and T_(breakdown) in the CO_2-O_2 mixture decreased first and then tended to be a constant at relatively high pd products.