弧后C_(4)F_(7)N/N_(2)混合气体复原过程研究

Research on Recovery Process of C_(4)F_(7)N/N_(2)Gas Mixture at Post Arc

C_(4)F_(7)N/N_(2)混合气体是目前潜在替代SF 6的绝缘介质之一。C_(4)F_(7)N/N_(2)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C_(4)F_(7)N/N_(2)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C_(4)F_(7)N/N_(2)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C_(4)F_(7)N/N_(2)混合气体弧后温度衰减曲线,作为模拟弧后C_(4)F_(7)N/N_(2)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C_(4)F_(7)N/N_(2)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C_(4)F_(7)N和N 2在8~10 ms内完全分解,以C、N、F、CF_(2)C、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,N 2复合至摩尔分数约70%左右,而C_(4)F_(7)N未见复合。

C_(4)F_(7)N/N_(2)gas mixture is one of the potential substitutes for SF 6 insulating medium at present,and the study on decomposition and recovery process of C_(4)F_(7)N/N_(2)gas mixture is of great significance for further understanding of arc extinguishing performance of this mixture.Firstly,the variation of decomposition species concentration of C_(4)F_(7)N/N_(2)gas mixture at 0.3~30 kK thermal equilibrium is simulated.Then the decomposition paths and species of C_(4)F_(7)N/N_(2)gas mixture are established and the forward and reverse rate constants of each reaction are calculated.Finally,the post arc temperature attenuation curve of C_(4)F_(7)N/N_(2)gas mixture under 0.1 MPa is used as the temperature change data in recovery process of C_(4)F_(7)N/N_(2)gas mixture at post arc,and the Chemkin software is used to calculate the recovery process of each decomposition species of C_(4)F_(7)N/N_(2)gas mixture at post arc.The simulation results show that when the post-arc temperature is above 10 kK,C_(4)F_(7)N and N_(2)completely decompose in 8~10 ms,and exist in the form of C,N,F,CF_(2)C,CFCF,NF,CN and other particles and free radicals,and when the post-arc temperature drops to about 2 kK,N_(2)recombines to about 70%mole fraction,while C_(4)F_(7)N does not recombine.