本文旨在以實驗量測方式探討在無/具頂板間隙之毫米流道熱沉流過包含純水與奈米流體等兩種不同工作流體的強制對流熱傳特性。實驗所製作的毫米流道熱沉之材料為紅銅，共有12條寬1mm、高3mm、長50mm的流道，熱沉與上蓋形成之單一流道水力直徑分別為1.5mm、1.33mm、1.45mm、1.56mm。毫米流道熱沉底部黏置加熱片以模擬等熱通量加熱邊界條件，強制對流實驗之雷諾數範圍介於329至1280之間。本文使用的奈米流體內含奈米氧化鋁顆粒之質量濃度為0%、5%、10%。純水之熱傳實驗結果顯示：相較於無頂板間隙之熱沉來說，具頂板間隙之熱沉在平均熱對流係數增益最高為15%；且其壓降最大降幅為65%。另一方面，奈米流體之熱傳實驗結果顯示：相較於無頂板間隙之熱沉來說，具頂板間隙之熱沉在平均熱對流係數增益最高為10%；且其壓降最大降幅為60%。綜合評估純水/奈米流體(ω_np=5%、10%)顯示，當通重量濃度為5%之奈米流體時，無/具頂板間隙模組之壁溫相較於通純水來說皆有明顯下降；當重量濃度提高至10%時，各模組在壁溫抑制的效果皆有不同結果。流動特性方面，各模組流阻值皆與雷諾數及重量濃度成正比關係，雷諾數越高時模組之頂板間隙高度提升所導致的流阻值下降更明顯，最低為10(MW/"m" ^"6" )。

The purpose of this paper is to investigate the forced convection heat transfer characteristics of two different working fluids including pure water and nanofluid in the mini-channel heat sink without/with ceiling gap by experimental measurement. The material of the mini-channel heat sink is red copper. There are 12 channels with a width of 1mm, a height of 3mm and a length of 50mm. The single channel has hydraulic diameter of 1.5 mm, 1.33 mm, 1.45 mm, and 1.56 mm, respectively. The heater was placed on the bottom of the mini-channel heat sink to simulate constant heat flux heating boundary conditions, and the Reynolds number of the forced convection experiment ranged from 329 to 1280. The nanofluids used in experiment have a mass concentration of 0%, 5%, and 10%. The experimental results of pure water show that the heat sink with the ceiling gap has a maximum gain of 15% on the average heat convection coefficient compared with the heat sink without ceiling gap. The maximum drop in pressure drop is 65%. On the other hand, The experimental results of nanofluid show that the heat sink with the ceiling gap has a maximum gain of 10% on the average heat convection coefficient compared with the heat sink without the ceiling gap. The maximum drop in pressure drop is 60%.

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