摘要
基于流体动力学模型,研究了继电器铜触点材料金属液桥的形成过程。采用包含质量连续方程、动量守恒方程、能量守恒方程和电场方程的数学模型,考虑金属液桥在焦耳热作用下的熔化,通过COMSOL Multiphysics有限元多物理场仿真软件平台的移动网格结合自动重新剖分网格技术,解决了金属液桥与电极结合区域的形变问题。建立了触点间距4μm、初始液桥直径4μm、电流为直流20~50 A的简化二维轴对称金属液桥仿真模型。分析了不同时刻触点金属液桥几何形貌、液桥截面温度分布、液桥电流密度流线分布等关键特征参数的变化规律,同时还对不同电流下的金属液桥熔化时间进行了计算。仿真结果表明:金属液桥的最高温度区域最先出现在液桥中部最细区域;热膨胀应力和表面张力是影响金属液桥形变的主要因素;随着负载电流的增大,金属液桥的熔化时间大幅缩短。
The formation process of the molten bridge of relay copper contacts was studied based on a hydrodynamics model.A series of mathematics models are applied to this study,including mass continuous equation,momentum conservation equation,energy conservation equation and electric field equations.And the melt physics mechanism of molten bridge resulted by joule heats is also considered.According to the above considerations,the deformation occurs in the area where molten bridge and electrodes combine each other and are calculated with the help of moving mesh and automatic re-mesh method in COMSOL Multiphysics code.A simplified symmetric 2D molten bridge model was established with 4μm gap,4μm initial diameter and 10 A^40 A current.The variation of some key characteristic parameters,such as geometrics of molten bridge in different periods,temperature distribution in cross sections and current density distribution,were analyzed.And the meltdown duration of molten bridge under different current is also calculated in the simulation.The results indicate that the hottest area of molten bridge occurs in the central position which is the thinnest part in the whole bridge,and the thermal expansion stress and the surface tension are the most important factors contributing to the deformation.It is also illustrated that the meltdown duration reduces rapidly due to the current increment.
作者
薄凯
周学
翟国富
焦通
BO Kai;ZHOU Xue;ZHAI Guofu;JIAO Tong(School of Electrical Engineering and Automation,Harbin Institute of Technology,Harbin 150001,China;State Grid Liaoning Electric Power Research Institute,Shenyang 110000,China)
出处
《电器与能效管理技术》
2018年第4期6-12,共7页
Electrical & Energy Management Technology
基金
国家自然科学基金项目(51277038
51307030)
关键词
金属液桥
触点
仿真
继电器
molten bridge
contacts
simulation
relays
