长菱形微针肋热沉的流动与换热特性

加工硅基长菱形微针肋热沉,并对其流动与换热性能进行试验研究和数值模拟。结果表明:在试验雷诺数Re范围内,长菱形针肋的换热系数随Re的增大而增大。雷诺数相同时,热流密度对换热系数的影响较小。热阻随泵功的增加不断降低;在泵功较小时,热阻降低的速度较快;当泵功增大到一定值时,热阻的变化趋于平缓。在一定的泵功下不同热流密度之间的总热阻没有太大的区别。努塞尔数Nu随Re增大而增大。与同样尺寸圆形、菱形针肋相比,长菱形针肋具有较好的换热性能,可以避免针肋尾部涡脱落造成的阻力损耗,同时长菱形针肋尾部延伸拓展了换热面积并扩大了固体导热区,从而提高换热效果。

Flow and heat transfer characteristics for long-diamond shaped micro pin fin

The silicon long-diamond shaped micro pin fin was manufactured, and the flow and heat transfer characteristics of long-diamond shaped micro pin fin were experimentally researched and numerically simulated. The results show that within the range of Re used in experiments, the heat transfer coefficient of the long-diamond shaped micro pin fin increases with the increase of Re. For the same Reynolds number, the heat flux has no effect on heat transfer coefficient. The thermal resistance will decrease with the pump power increasing, and decrease faster when pump power is small. When the pump power increases to a certain value, the thermal resistance will remain unchanged. There is no difference in total thermal resistance for different heat fluxes. Nu increases with the increase of Re. For the diamond shaped circular micro pin fin with the same size, 45° long-diamond micro pin fin has the best heat transfer performance. The long-diamond design can avoid the vortex shedding which causes the pressure loss. Also, the long-diamond design can extend the heat transfer area and improve the conductivity of solid. Therefore it can enhance the heat transfer effect.