Benchmarking the calculation of electrically insulating properties of complex gas mixtures using a multi-term Boltzmann equation model

The accurate calculation of DC breakdown voltage thresholds solely from elementary electron-neutral interactions in complex gas mixtures using a multi-term Boltzmann equation (BE) kinetic model is demonstrated. SF6:N-2 mixtures in the 100 Td < E/N < 400 Td field regime are explored to benchmark the model's effectiveness. A ten-term BE model is found to yield DC breakdown voltages which, on average, agree within 3% of experimental measurements. A two-term BE model is also applied in order to characterize the error introduced in all calculations by the two-term approximation. These discrepancies are largest in pure N-2 where error is greater than 10% for diffusion coefficients, within 6% for particular vibrational rate coefficients, and within 5% for breakdown voltages. However, this error falls to within 1% for most parameters and breakdown voltages in mixtures with large SF6 content.

Automated summary

This study demonstrates the accurate calculation of DC breakdown voltage thresholds in complex gas mixtures solely based on elementary electron-neutral interactions using a multi-term Boltzmann equation kinetic model. The effectiveness of the model is benchmarked in SF6:N-2 mixtures in the 100 Td < E/N < 400 Td field regime. The results show that a ten-term BE model yields DC breakdown voltages that agree within 3% of experimental measurements on average. A two-term BE model is also used to evaluate the error introduced by the two-term approximation. The largest discrepancies are observed in pure N-2, with errors greater than 10% for diffusion coefficients, within 6% for specific vibrational rate coefficients, and within 5% for breakdown voltages. However, this error decreases to within 1% for most parameters and breakdown voltages in mixtures with high SF6 content.