大电流真空电弧阳极熔蚀过程的热力学仿真研究

发布时间：2018-08-16 14:59

【摘要】：在大电流真空电弧开断过程中,阳极现象对于能否成功开断具有重要影响。当电弧电流超过阈值时,阳极表面温度将超过材料熔点,从而在阳极局部形成熔池。阳极熔池中的液态金属蒸发出的金属蒸汽及喷溅出的液滴将极大的提高弧后击穿的概率,并可能造成开断失败。该文建立了大电流真空燃弧过程中阳极熔池的流体流动和传热模型,着重研究真空大电流电弧对于阳极表面的熔蚀、变形以及相应的温度分布的变化。模型考虑了从电弧等离子体到阳极表面的传热以及表面材料在热流作用下的相变过程,将磁流体仿真结果获得的热流密度和压力分布作为阳极熔池流动和传热的仿真的边界条件,并采用有限体积法仿真获得阳极表面破坏过程以及温度分布的变化规律。仿真结果给出了不同电流下的温度分布和由电弧引起的阳极表面破坏情况,发现考虑熔池中液态金属流动和变形的仿真模型所获得的表面温度分布更加均匀,解释了实验中触头表面温度的均匀分布现象,证明液态金属的流动是影响温度分布的重要因素。所获得模型更为准确地描述了大电流真空电弧作用下的阳极现象,为评估真空断路器的开断能力提供了理论依据。
[Abstract]:In the process of high current vacuum arc breaking, anode phenomenon plays an important role in successfully breaking. When the arc current exceeds the threshold value, the surface temperature of the anode will exceed the melting point of the material. Metal vapor vaporized by liquid metal and droplets spattered in the anode pool will greatly increase the probability of back-arc breakdown and may result in failure of breaking. In this paper, the fluid flow and heat transfer model of anodic molten pool during high current vacuum arc burning is established. The corrosion, deformation and temperature distribution of the anode surface caused by vacuum high current arc are studied. The heat transfer from the arc plasma to the anode surface and the phase transition process of the surface material under the heat flux are considered in the model. The heat flux and pressure distribution obtained from the magnetofluid simulation results are taken as the boundary conditions for the simulation of the flow and heat transfer in the anode molten pool. The failure process of the anode surface and the variation of the temperature distribution are obtained by the finite volume method. The simulation results show that the temperature distribution and the anodic surface damage caused by the arc are obtained under different currents. It is found that the surface temperature distribution obtained by the simulation model considering the flow and deformation of liquid metal in the molten pool is more uniform. The uniform distribution of contact surface temperature is explained in the experiment. It is proved that the flow of liquid metal is an important factor affecting the temperature distribution. The obtained model more accurately describes the anode phenomenon under the action of high current vacuum arc and provides a theoretical basis for evaluating the breaking capacity of vacuum circuit breaker.
【作者单位】：电力设备电气绝缘国家重点实验室(西安交通大学);
【基金】：国家重点基础研究发展规划项目(973计划)(2015CB 251002) 国家自然科学基金(51407135,51323012) 高等学校博士学科点专项科研基金(20130201110005)~~
【分类号】：TM501.2

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