C4F7N/N2混合气体复原过程研究

Research on Recovery Process of C4F7N/N2 Gas Mixture at Post Arc

摘要:

C4F7N/N2混合气体是目前潜在替代SF6的绝缘介质之一。C4F7N/N2混合气体分解与复原过程的研究，对于深入了解该混合气体的熄弧性能具有重要意义。首先，模拟C4F7N/N2混合气体在0.3～30 kK热平衡条件下分解产物粒子浓度的变化；然后，确立C4F7N/N2混合气体的分解路径及粒子种类并计算出各反应的正、逆向速率常数；最后，引用0.1 MPa下C4F7N/N2混合气体弧后温度衰减曲线，作为模拟弧后C4F7N/N2混合气体复原过程中的温度变化数据，通过Chemkin软件计算弧后C4F7N/N2混合气体各粒子的复原过程。模拟结果表明：弧后温度在10 kK以上时C4F7N和N2在8～10 ms内完全分解，以C、N、F、CF2C、CFCF、NF、CN等粒子和自由基的形式存在；弧后温度降低至2 kK左右，N2复合至摩尔分数约70%左右，而C4F7N未见复合。

Abstract:

C4F7N/N2 gas mixture is one of the potential substitutes for SF6 insulating medium at present, and the study on decomposition and recovery process of C4F7N/N2 gas mixture is of great significance for further understanding of arc extinguishing performance of this mixture. Firstly, the variation of decomposition species concentration of C4F7N/N2 gas mixture at 0.3～30 kK thermal equilibrium is simulated. Then the decomposition paths and species of C4F7N/N2 gas mixture are established and the forward and reverse rate constants of each reaction are calculated. Finally, the post arc temperature attenuation curve of C4F7N/N2 gas mixture under 0.1 MPa is used as the temperature change data in recovery process of C4F7N/N2 gas mixture at post arc, and the Chemkin software is used to calculate the recovery process of each decomposition species of C4F7N/N2 gas mixture at post arc. The simulation results show that when the post-arc temperature is above 10 kK, C4F7N and N2 completely decompose in 8～10 ms, and exist in the form of C, N, F, CF2C, CFCF, NF, CN and other particles and free radicals, and when the post-arc temperature drops to about 2 kK, N2 recombines to about 70% mole fraction, while C4F7N does not recombine.