绝缘气体输运参数计算对于其绝缘灭弧性能和其他宏观物性研究具有重要意义.首先基于最小吉布斯自由能方法,获得了 CF3SO2F 混合气体在 300～30 000 K 温度下的粒子组分.在粒子组分的基础上,采用Chapman-Enskog方法求解Boltzmann方程,计算了0.01～1 MPa压强范围内CF3SO2F混合气体的输运系数(电导率、热导率和黏滞系数),重点考察了气压、混合比例和缓冲气体类别对 CF3SO2F 混合气体输运参数的影响.结果表明:增大气压会抑制气体解离和电离反应,延缓升温过程对输运系数的影响;增大CF3SO2F混合比例则会直接影响体系主要粒子的相对含量,进而使解离和电离反应的温度发生变化,导致低温区的电导率和中高温区的黏滞系数增大,中高温区的热导率减小;与前两者相比,气体混合类别对输运参数影响较小.此外,相比SF6,CF3SO2F混合气体具有更大的热导率和更小的黏滞系数,能够更有效地将焦耳热传递到电弧外从而避免弧后击穿.该研究不仅为CF3SO2F混合气体用于高压电气设备提供一定的指导,也为进一步评估其绝缘和灭弧能力及绝缘气体配置优化提供了必要的数据支撑.
Arc Plasma Transport Parameter Calculation and Related Influencing Factor Analysis for CF3SO2F Gas Mixture as New Eco-friendly Insulating Medium
The transport parameter calculation of insulating gas is of great significance for the study of its insulation and arc extinguishing performance and other macroscopic physical properties.Firstly,the particle composition of CF3SO2F gas mixture under 300～30 000 K was obtained by means of the Gibbs free energy minimization method.On the basis of the particle composition,the Chapman-Enskog method was adopted to solve the Boltzmann equation to obtain the transport coefficients(such as electrical conductivity,thermal conductivity,and viscosity coefficient)of CF3SO2F gas mixture under the pressure range of 0.01～1 MPa.Meanwhile,we mainly focused on the effects of air pressure,mixing ra-tio and buffer gas type on the transport parameters of CF3SO2F gas mixture.The results show that increasing the pressure will suppress the gas dissociation and ionization reactions and delay the effect of temperature ramping process on the transport coefficients.While,increasing the CF3SO2F ratio can directly affect the relative content of the main particles in the system,which will lead to temperature variations for the dissociation and ionization reactions and will further increase the electrical conductivity within the low-temperature region and the viscosity coefficient within the medium-to-high temperature region,anddecrease the thermal conductivity within the medium-to-high temperature region.However,in contrast to the former two factors,the gas mixture category exhibits an inapparent influence on the transport parameters.Additionally,CF3SO2F gas mixture shows larger thermal conductivity and smaller viscosity coefficient than SF6,which will transfer Joule heat outside the arc more effectively and avoid post-arc breakdown.The research not only offers guid-ance for the utilization of CF3SO2F gas mixture in high-voltage electrical equipment,but also provides necessary data for further evaluation of its insulation and arc extinguishing capability,as well as optimization of insulating gas configuration.
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