微针肋槽道内去离子水换热特性

设计了槽肋比为1:2和2:1的矩形大长宽比微针肋散热器，并实验研究了去离子水在其内的流动换热性能。结果表明:当进口温度为40 ℃、微针肋槽道在雷诺数小于650、最高壁面温度低于77 ℃时，单位面积散热量可达21.32 W/cm2。当雷诺数一定时，同一个槽道壁面温度沿着流动方向不断增加、同一个位置壁面温度随着加热功率的增加而增大，局部努谢尔数沿着流动方向先减小后逐渐增加并趋于定值。当针肋流动换热长度较长时，其入口效应可以忽略，槽道平均努谢尔数随着雷诺数的增大而增大，与加热功率无关；为了更好地表达微针肋槽道内的换热特性，考虑了槽肋比、流动雷诺数等影响，拟合了去离子水在微针肋槽道内的对流换热关系式。

Heat transfer characteristics of mini pin-fin channels

The heat transfer performance of deionized water flowing in the large length/width ratio pin-fin micro channel was experimentally studied with two different ratios of channel to fin. The results show that, when the Reyonolds number is less than 650 and the inlet temperature is fixed at 40 ℃, the channel can achieve a heat dissipation of 21.32 W/cm2 and the maximum wall temperature is below 77 ℃. The thermal properties of the channel can be summarized as follows for a fixed Reyonolds number: the wall temperature increases with the heating power and along with the flow direction; the local Nusselt number decreases along with the flow direction, then increases, and gradually tends to a fixed value. In the case of a long pin-fin channel, the entrance channel effect can be neglected, the average Nusselt number is independent with heating power, and only increases with Reyonolds number. Based on these results, a new correlation is proposed to evaluate heat transfer performance of pin-fins, which considers the Nusselt number as a function of the channel/fin ratio, Reyonolds number and Prandtl number.