球凹平板冲击冷却性能的数值研究及结构改进

Numerical Investigation on the Impingement Cooling Performance and Structural Improvement of Dimpled Plates

采用SST湍流模型数值研究了球凹平板冲击冷却的流动与换热特性,分析了4种球凹布置形式对带有最大横向流的冲击冷却性能的影响,提出了球凹布置的改进结构。研究表明:球凹结构对气流压力损失的影响很小,展向偏移布置和叉排布置的球凹能够增大通道对称面和下游的湍动能,顺排布置和流向偏移布置的球凹使通道中心处的湍动能降低;展向偏移布置和叉排布置的球凹平板换热效果最好,其次是平板,然后是顺排布置的球凹平板,流向偏移布置的球凹平板换热效果最差;在通道上游,展向偏移布置的球凹表面换热效果优于叉排布置,而通道下游的趋势正好相反。综合展向偏移布置和叉排布置的球凹表面换热优点,布置新的球凹排列方式,改进布置的球凹表面换热效果与预期的效果相吻合;通道底面的换热效果基本不受球凹沿对称面的布置位置的影响。

The flow and heat transfer characteristics of impingement cooling on dimpled plates were numerically investigated using SST turbulence model.The effect of four types of dimple arrangements on the impingement cooling performance with maximum crossflow was analyzed and the structural improvement of dimple plates was performed.The results show that the effect of dimple structure on the pressure loss is small.The turbulent kinetic energy acting on the symmetry wall and downstream of channel can be enhanced by the span-wise shifted arrangement and staggered arrangement;while for in-line arrangement and stream-wise shifted arrangement,the turbulent kinetic energy acting on the channel center is reduced. The heat transfer performance for the span-wise shifted arrangement and staggered arrangement is the best,then followed by flat plate,in-line arrangement and stream-wise shifted arrangement.In the upstream of channel,the Nusselt number on the dimpled surface for span-wise shifted arrangement is larger than that for staggered arrangement,while the trend is reversed in the downstream of channel.Considering the heat transfer enhancement on dimpled surface for span-wise shifted arrangement and staggered arrangement,a new dimple arrangement is performed,and the heat transfer performance of dimpled surface for improved arrangement can achieve the desired results.The heat transfer performance on the channel＇s bottom wall is not significantly dependent on thedimple arrangement along the symmetrical plane.