| Summary: | 碩士 === 中原大學 === 機械工程研究所 === 93 === ABSTRACT
Since the rapid development of notebook computers, there are more and more problems related to high temperature. To find out an efficient method to eliminate heat in a small and limited space is always a direction to research. Also, the research of high performance and miniaturization drives the improvement of traditional heat sink. The old method of using jet to cool may not be applied efficiently. For saving the research cost and time, it is more and more important to use the analysis simulation ability of CFD calculation tool.
The main purpose of this study is to research a porous heat sink and the working fluid flows through straight circular ducts to decrease the temperature of heat sink. Besides, we use two kinds of working fluids; we also discuss the Reynolds number and porosity of heat sink in this paper. The porous heat sink is 60 mm long, 2.4 mm wide and 12 mm high. Constant power of 100-Watt imposed at upper sidewall of the heat sink. Besides, the other walls are adiabatic. The diameter of each duct is 1.5 mm and the wall surface of duct is smooth. We also change diameter of duct to change porosity of heat sink. The CFDRC software package is used for required calculation in temperature field. The flow fields consider only laminar flow.
From this study we can find that the working fluid water is better than air to decrease the temperature of heat sink. For diameter 1.4 mm and 1.5 mm, the best cooling efficiency occurs on the mean temperature of upper wall and lower wall at Reynolds number 500. On the other hand, if we adopt air as the working fluid, the porous heat sink doesn’t have effective ability for cooling when Reynolds number increases.
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