Ultra high performance heat sink using minute-tube-fin array of 100% fin efficiency

CPU功耗的不断增加使得热管理成为其设计中的关键因素之一。为了适应高功率密度的要求，提出了一种新型的传热装置--平行管传热装置（PTH）。本研究的目的是了解发生在PTH的物理现象，并显示其可行性。在热传输实验中，首先，二维测试部分由铜制成。工作介质为R-134 a，管内径为0.51 ~ 2 mm，管长为100 mm。以下是参数：集管之间的温差、集管内径和管数（2-12）。管径越小，峰值有效导热系数<ef>越大，最大值为铜的200倍。PTH的k_（max）<ef>比弯曲闭合回路型的k_（max）大10倍以上。其次，采用内径为0.51mm的圆管制作了三维实验段，在内部工质的作用下，其热阻最多可降低80%。工作介质为水和乙醇，管内径为1.0-4.4mm，管数为1-6根。当管数为2-6时，汽液两相均存在上下对流，表明显热和潜热都参与了传热过程。数值分析中采用一维可压缩气液两相流分析。采用CIP方法，再现了气体压差作用下的液塞运动。

The increasing power consumption of the CPUs has made the thermal management one of the critical factors in their design. In order to deal with the high power density, the present investigators proposed a new type of heat transport device, called parallel tube heat transport device (PTH) consisting of several capillary tubes and headers on both ends. The objective of this study is to understand the physical phenomena occurring in the PTH and to show its feasibility.In the heat transport experiments, at first, two-dimensional test sections made of copper were used. The working fluid was R-134a, and the tube inner diameter and tube length were 0.51-2mm and 100mm, respectively. The followings were parameters : temperature difference between the headers, header inner diameter, and number of tubes (2-12). The peak effective thermal conductivity (k_<ef>) was larger for the smaller tube diameter, and the maximum value was 200times larger than that of copper. The PTH gave more than 10times larger k_<ef> than that of the meandering closed loop type. Next, the three-dimensional test section was manufactured using 0.51mm inner-diameter tubes, and its thermal resistance was reduced by 80% at most by the effect of the inside working fluid.In the flow visualization experiments, two-dimensional test sections made of glass were used. The working fluids were water and ethanol, and the tube inner diameter and tube number were 1.0-4.4mm and 1-6, respectively. When the tube number was 2-6, the upward and downward convections of both vapor and liquid were observed, which indicated that heat was transported by both sensible and latent heats.In the numerical analysis, one-dimensional compressible gas-liquid two phase flow analysis was performed. The CIP method was adopted, and the liquid plug motion due to the gas pressure difference was reproduced.