本文模擬奈米流體作為微渠道散熱器(MCHS)之冷卻流體，奈米流體分別使用單相法與兩相法模擬，並以數值方法分析其性能。在層流的情況下，與參考文獻的實驗數據作數值預測值的確認，接著再進一步延伸應用至紊流場。紊流流場的模擬，以標準 雙方程式模式配合牆函數來求解。網格設計則採用正交非均勻的交錯式網格。考慮的參數為：粒子體積濃度，體積流率，雷諾數。
數值計算結果顯示，使用兩相法的計算值較單相法準確。奈米流體的熱傳性能隨著粒子體積濃度的增加而增強。在層流情況下，奈米流體的熱阻比水的熱阻小，並隨著體積濃度與體積流率的提高而下降；在紊流情況下，奈米流體的熱阻則隨著粒子體積濃度與體積流率的提高而有輕微的增加。另一方面，討論奈米流體冷卻MCHS與水冷卻MCHS的壓降值，在層流情況下，奈米流體壓降有些微的增加；但在紊流情況下，壓降則是相當顯著地增加。

In this study, microchannel heat sink (MCHS) performance using nanofluids as coolant is analyzed numerically and nanofluids are modeled using the single phase approach and the two phase approach. The numerical predictions are validated with available experimental data in the literature in the laminar flow, then extend to turbulent flow. The turbulent governing equations are solved with the standard turbulence model. An orthogonal non-uniform staggered grid is used for the establishment of mesh grids. The parameters studied include the particle volume fraction, the volumetric flow rate , Reynolds number.
The numerical computations indicate that the results of the two phase approach are more accurate than the single phase approach. The heat transfer performance enhances by increasing the particle volume fraction. In the laminar flow, the thermal resistance of nanofluids is smaller than that of water, and which reduces as the particle volume fraction and the volumetric flow rate increases. In turbulent case, a slight increase in the thermal resistance of nanofluids with increasing of the particle volume fraction and the volumetric flow rate. In addition, the pressure drop of both nanofluid-cooled MCHS and pure water-cooled MCHS is discussed. For laminar case, it seems slight increase in pressure drop for nanofluid-cooled MCHS. But in turbulent flow, the pressure drop increases quite significantly.

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