摘要
真空灭弧室阳极热过程对真空断路器的开断能力有重要影响。以往的理论分析多以纯金属为研究对象,未考虑合金对阳极蒸发过程的影响。为研究真空电弧铜铬合金阳极热过程,并研究合金蒸发的影响,在已有的纯铜阳极热过程模型的基础上,提出了针对铜铬合金触头的熔化-凝固过程和蒸发过程的计算方法。研究结果表明:弧后阳极温度衰减有2种模式,模式一是温度平滑下降的模式,对应于小电流扩散态电弧,模式二中温度下降过程有一"水平段",对应于大电流聚集态真空电弧,该"水平段"持续时间与注入阳极热流的幅值正相关;针对不同铬含量的铜铬合金触头,弧后阳极热过程规律为,阳极温度CuCr50>CuCr25>Cu,阳极温度衰减速度CuCr50<CuCr25<Cu,电流过零时刻阳极蒸气压Cr>CuCr75>CuCr50>CuCr25>Cu,在铬的质量分数为25%时完全熔化区的体积最小。
Anode thermal process has a significant impact on the current interruption capacity of vacuum interrupters. Previous modeling and simulation work focused on thermal process of pure metal anodes in vacuum arcs, but they failed to consider the al- loy anodes that influence the evaporation process of anode. To understand the thermal process of CuCr anode in vacuum arcs, the alloy evaporation should be involved. Based on previous thermal models of copper anodes, calculation methods were proposed to simulate melting-solidification process and evaporation process of CuCr anodes. Simulation results show that there are two decay modes for anode surface temperature after current zero. Mode Ⅰ indicates a continuous decline of anode temperature, which is related to diffuse vacuum arcs at low-current. Mode Ⅱ has a ＂horizontal period＂ in the decay process of anode temperature, which corresponds to constricted vacuum arcs at high-current. The duration of the ＂horizontal period＂ is proportional to the heat flux injected into anodes. For CuCr contacts with different Cr proportions, anode thermal process after current zero obeys following rules： anode temperatures CuCr50〉CuCr25〉Cu; decay rates of the anode temperature CuCrSO〈CuCr25〈Cu; vapour pressures of anode surface at current zero Cr〉CuCr75〉CuCr50〉CuCr25〉Cu. When the Cr content is 25%, the complete-molten region volume of CuCr anode is minimum.
出处
《中国科技论文》
CAS
北大核心
2015年第23期2749-2754,2768,共7页
China Sciencepaper
基金
高等学校博士学科点专项科研基金资助项目(20130201110005)
