铜蒸气对CO2电弧等离子体物性参数的影响  

Effect of Cu Vapour on the Physical Property Parameters of CO2 Arc Plasma

作　　者：韩桂全 刘洋 刘庆 卢彦辉 王小华[2] 荣命哲[2] HAN Guiquan1, LIU Yang2, LIU Qing1, LU Yanhui1, WANG Xiaohua2, RONG Mingzhe2(1. State Grid Pinggao Group Co., Ltd., Pingdingshan 467001, China; 2. State Key Laboratory of Electrical Insulation and Power Equipment, Xi＇an Jiaotong University, Xi＇an 710049, Chin)

机构地区：[1]国网平高集团有限公司,平顶山467001 [2]西安交通大学电力设备电气绝缘国家重点实验室,西安710049

出　　处：《高电压技术》2018年第5期1635-1640,共6页High Voltage Engineering

基　　金：国家自然科学基金(51521065);国网平高集团有限公司科技项目~~

摘　　要：CO2气体因其全球变暖潜能值低和低温导热性好等优点而逐渐作为一种SF6替代气体应用于断路器中以充当灭弧介质,触头烧蚀产生的铜蒸气会改变电弧基本特性,影响断路器开断性能。为此,利用最小Gibbs自由能法和Chapman-Enskog理论计算了气压为0.5 MPa、热力学温度区间为2 000-30 000 K时的CO2-Cu混合气体电弧等离子体的物性参数,分析了铜蒸气质量分数对电弧等离子体粒子组分、热力学参数以及输运系数的作用规律。研究结果表明：触头烧蚀引入的铜蒸气会比电弧中的其他非金属粒子更早电离,即使是少量的铜蒸气（质量分数为5%）也会使低温时电弧等离子体的电子数密度增大,进而显著提高电弧等离子体在低温区（热力学温度低于8 000 K）的电导率,最大约提升1个数量级;增大铜蒸气质量分数会在整个热力学温度区间增大电弧等离子体质量密度并减小比定压热容、黏滞系数以及热导率,但对于比焓则在低温区和高温区呈现出相反的作用规律;少量的铜蒸气（质量分数为5%）对热力学参数和除电导率之外的输运系数的改变极其微小,但是大量铜蒸气（质量分数高于25%）会明显改变各个物性参数。这些电弧等离子体物性参数的计算结果对于探究铜蒸气对电弧基本物理性质的影响具有参考价值,并可以为建立考虑触头烧蚀下的电弧磁流体（MHD）模型提供输入参数。Due to the advantages of low potential for global warming and high thermal conductivity at low temperatures, CO2 is regarded as a kind of potential alternatives of SF6 and has been gradually adopted by gas circuit breaker serving as an arc-extinguishing medium. The copper vapor from electrode erosion modifies the fundamental characteristics of the arc and consequently affects the interruption performance of circuit breakers. Thus, utilizing the Gibbs free energy minimization method and Chapman-Enskog theory, we calculated fundamental properties of CO2-Cu arc plasma at a pressure of 0.5 MPa and temperature of 2 000-30 000 K and investigated the effects of copper concentration on species compositions, thermal properties and transport coefficients. It is found that the ionization of copper from electrode erosion occurs earlier than other nonmetallic atoms, which increases the electron number density in the mixture even if the copper concentration is small（5%）, and consequently the electrical conductivity at low temperature（below 8 000 K） is enhanced with a maximum upgrade of about an order of magnitude. Increasing copper concentrations leads to the increase of mass density and decrease specific heat, viscosity and thermal conductivity in the whole temperature range. However, opposite effects of increasing copper concentrations are observed. The influence of copper vapor of a small proportion（5%） is minimal for fundamental plasma properties except for electrical conductivity unless the copper concentration is evaluated up to 25%. These calculated results have reference values for investigating the effects of copper concentrations on physical property parameters of the CO2 arc and can provide input parameters for magnetohydrodynamics（MHD） models for CO2 arc considering electrode erosion.

关 键 词：电弧等离子体 CO2 铜蒸气 平衡态组分 热力学特性 输运系数 

分 类 号：TM501.2[电气工程—电器]