高压真空断路器用散热器的自然对流换热特性

为提高高压真空断路器的运行安全,以一种新型高压真空断路器为背景,采用计算流体动力学方法研究了不同环境温度下,圆柱形散热器竖直肋片间自然对流换热特性。结果表明:采用扩大计算区域和设置压力边界条件的方法来模拟计算自然对流换热是恰当的。在散热器肋片缝隙的进口处,气体温度较低、流速较小;在肋片缝隙中部,气体温度升高、流速较大;越靠近肋片根部,气体温度越高,但由于粘性阻力大,所以在肋片根部速度较小。在相同的环境温度下,随着肋片温度的逐渐升高,肋片的换热能力也逐渐升高;在相同的肋温情况下,随着环境温度的逐渐升高,肋片的换热能力逐渐下降。所得的肋片缝隙内自然对流的流动换热特性、肋片表面的平均Nu数对高压真空断路器散热器肋片的热力设计和进一步优化设计有重要的意义。

Natural Convective Heat Transfer of Vacuum Circuit Breaker Radiator

With the background of novel high voltage vacuum circuit breaker,the Computational Fluid Dynamics(CFD)method is used to research natural convective heat transfer between vertical fins of cylinder radiator under different ambient temperatures.It is found that,expanding calculation region and setting pressure boundary condition are able to correctly simulate the natural convection heat transfer.Both air temperature and air velocity are low at inlets of fins gap,while those are high at middles of fins gap.The air temperature becomes higher close to the root of fins,while air velocity is lower due to large viscous drag.Under the same atmospheric temperature,the higher radiator fins temperature is,the higher heat transfer performance will be.At the same radiator fins temperature,the higher atmospheric temperature is,the lower heat transfer performance will be.The results are significant to the thermal and optimization design of radiator with vertical fins of novel high voltage vacuum circuit breaker.