不同气压对SF6热分解反应的作用机制研究

Study on the Mechanism of Different Air Pressure on Thermal Decomposition of SF6

文中为了研究气压对SF6热分解反应的作用机制,构建了SF6分解气室的多物理场仿真模型,计算了不同气压下SF6分解气室内部的温度场和流体场分布;在微观角度上基于碰撞理论推导得到了气压对SF6过热分解反应的影响特性;并结合不同气压下SF6局部过热分解实验数据,阐释了气压对SF6热分解反应的作用机制。研究结果表明:随着SF6气压的升高,热源附近高温区域的体积增大,同时等温域内SF6与H2O和O2分子有效碰撞次数增加,在双重促进作用下致使SF6过热分解速率明显加快。实验结果与仿真计算以及微观理论推导得出的结论相互印证,SF6气体的过热分解速率对气压有明显正响应的效果。以上的研究结果可以为将来采用DCA对SF6气体绝缘装备进行绝缘状态监测提供理论支撑。

In order to study the action mechanism of air pressure on SF6 thermal decomposition reaction,a multiphysics simulation model of SF6 decomposition gas chamber was constructed,and the temperature field and fluid field distribution inside the SF6 decomposition gas chamber under different pressures were calculated.The influence of air pressure on the over-thermal decomposition of SF6 was derived from the collision theory.Combined with the experimental data of partial over-thermal decomposition of SF6 under different air pressure,the mechanism of action of air pressure on thermal decomposition of SF6 was explained.The results show that:with the increase of SF6 pressure,the volume of the high-temperature region near the heat source increases,and the effective collision times of SF6 with H2O and O2 molecules in the isothermal region increase,resulting in the significantly accelerated decomposition rate of SF6 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 SF6 has obvious positive response to the pressure.The above results can provide theoretical support for DCA to monitor the insulation status of SF6 gas insulation equipment in the future.