稳定燃弧条件下继电器触头蒸发侵蚀特性的研究

Study on Evaporation Erosion of Copper Contacts under Stable Arc

蒸发导致的触头材料侵蚀是触头分断小电流时性能退化和失效主要原因。采用气体动力学与熔池特性仿真相结合的方法研究铜触头在稳态电弧条件下的蒸发物理过程。建立触头内部熔池三维磁流体动力学模型,对熔池内部传热和流动过程进行模拟。利用气体动力学模型获得稳态燃弧条件下蒸发通量与熔池表面温度之间的关系。根据触头表面温度分布以及蒸发通量与温度之间的关系,得到稳态电弧作用下的触头蒸发侵蚀速率。

Contact erosion due to evaporation is the m ain cause fo r the contact perform ance de terioration andfa ilu re under sm all break current. M o lten pool heat transfer and flu id flo w phenom ena in copper contacts werecoupled w ith the gas dynam ics at various locations above the contact to determ ine the evaporation rate under stablearc. The three-dim en sional M H D m odel was set up fo r the m olten pool in the contact. The re la tionsh ip between theevaporation flu x and the surface tem perature o f the m olten pool was obtained w ith gas dynam ics m odel. Theevaporation rate un der stable arc was calcula ted based on the m olten pool surface tem perature d is trib u tio n and there la tionsh ip between the evaporation flu x and the tem perature.