In order to study the action mechanism of air pressure on SF

6

thermal decomposition reaction

a multiphysics simulation model of SF

6

decomposition gas chamber was constructed

and the temperature field and fluid field distribution inside the SF

6

decomposition gas chamber under different pressures were calculated.The influence of air pressure on the over-thermal decomposition of SF

6

was derived from the collision theory.Combined with the experimental data of partial over-ther

mal decomposition of SF

6

under different air pressure

the mechanism of action of air pressure on thermal decomposition of SF

6

was explained.The results show that:with the increase of SF

6

pressure

the volume of the high-temperature region near the heat source increases

and the effective collision times of SF

6

with H

2

O and O

2

molecules in the isothermal region increase

resulting in the significantly accelerated decomposition rate of SF

6

under the dual promotion.The experimental results are mutually confirmed with the simulation calculation and the conclusion derived from the microscopic theory.The over-thermal decomposition rate of SF

6

has obvious positive response to the pressure.The above results can provide theoretical support for DCA to monitor the insulation status of SF

6

gas insulation equipment in the future.