| Budget Amount *help |
¥13,200,000 (Direct Cost: ¥13,200,000)
Fiscal Year 2005: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2004: ¥10,300,000 (Direct Cost: ¥10,300,000)
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| Research Abstract |
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.
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