基于耦合场的金属氧化物限压器的温度计算与特性分析

Temperature Calculation and Property Analysis of Metal Oxide Varistor Based on Coupled Fields

为改善金属氧化物限压器(MOV)本体结构的散热能力,利用有限体积法,建立了用于MOV本体冷却结构流场、温度场直接耦合计算的3维分析模型。建立了简化的验证实验模型,计算了其流场、温度场,并通过实验验证了计算结果的准确性。在此基础上,对影响MOV温度特性的主要因素进行了分析。结果表明:在t<300s时段内,对MOV冷却结构起主导作用的是金属导电环的传导散热,加大入口风速对MOV散热效果的影响并不明显,增大冷却通道半径反而消弱了导电环的传导散热能力;在满足约束条件的前提下,增加导电环的厚度,选用热导率大的金属材质,可以得到更好的散热效果;在t>300s时段内,对MOV冷却结构起主导作用的是对流换热,加大入口风速和增大冷却通道半径可明显增强MOV的冷却效果。

In order to improve the heat dissipation ability of metal oxide varistor（MOV）,we established a three-dimensional numerical model of MOV for direct coupling calculation of its flow field and temperature field by using the finite volume method.A simplified practical MOV model was manufactured,and its flow field and temperature field were calculated.The calculation results were verified by comparison of experimentally measured data.Based on the obtained results,the major factors influencing MOV’s temperature characteristics were analyzed.It is found that the heat conduction of metal conductive ring is the leading factor for cooling MOV during the period of t＆lt;300 s,meanwhile,the cooling effects by only increasing inlet wind velocity are not remarkable,and the heat conduction of metal conductive ring will be weakened by increasing the cooling channel’s radius.Under the premise of satisfying the constraint conditions,a better cooling effect can be obtained by increasing thickness of conductive ring and by using metal material with larger thermal conductivity.In the period of t＆gt;300 s,the heat convection plays the leading role in cooling the ventilation structure of MOV,while the cooling effect of MOV can be strengthened obviously by increasing inlet wind velocity and the radius of cooling channel.