本研究採取實驗方式，就以相變化材料奈米膠囊與純水調配而成之奈米相變化膠囊懸浮液取代純水，探討其分別流經具平行/漸擴流道兩個毫米熱沉時所呈現強制對流熱傳遞特性，並進一步評比兩毫米熱沉所呈現熱散逸功效。實驗所使用之平行及漸擴流道兩毫米熱沉均具八條入口寬度1.0mm、高度1.5 mm及長度50mm之單位流道，其間差別僅在於單位流道水平寬度自進口端起分別為固定不變與線性遞增，因而出口端流道其水平寬度分別為1.0mm 與2.2mm。本實驗所探討相關參數範圍為；奈米相變化膠囊懸浮液內含膠囊質量分率與相變化材料質量分率分別為nepcm =1%、2%、5%與pcm = 0.63%、1.8%、3.8%；體積流率 Qf =50~420 cm3 /min(雷諾數Ref = 112-940)，毫米流道熱沉之加熱功率 qh = 10~30 W，進口懸浮液溫度 Tin =33.5~34.3 ℃。由本文所得強制對流熱傳遞實驗結果分析顯示，以奈米相變化膠囊懸浮液取代純水做為工作流體之平行或漸擴流道熱沉，於固定加熱通量下兩者所呈現熱傳遞增益情形均取決於懸浮液進口溫度、內含相變化材料質量分率、及其體積流率之適宜組合。此外，將奈米相變化膠囊懸浮液流經兩毫米流道熱沉所致熱傳遞增益量與其伴隨壓降上升量列入整體考量所得之熱溢散增益指數(FOM)及性能係數(COP)之結果顯示，由於漸擴流道熱沉其所產生壓降上升量較低，而具較高之熱溢散增益指數(FOM)及性能係數(COP)。

In the present study, the force convection heat characteristics of a cross-section designed two mini-channel heat sinks with parallel and laterally divergent cross-sections, respectively, were studied experimentally to explore their cooling efficacies of using water-based suspensions of nano-phase change material (nano-PCM) capsules. The parallel and divergent mini-channel heat sinks used in experiments were fabricated using oxygen-free copper, constructed of eight rectangular channels of 50 mm in length and 1.5 mm in height with width, respectively, fixed at 1.0 mm and axially increased from 1.0mm at the inlet to 2.2 mm at the exit of each channel. Forced convective cooling experiments have been performed for the parallel and divergent minichannel heat sinks, respectively, with the relevant variables in the following ranges: the volumetric flow rate, = 50~420 cm3 /min; the heating power dissipated by the heat sinks, qh = 10~30 W; the inlet temperature of water-based suspensions, Tin = 33.5~34.3C; and the mass fractions of the nano-PCM capsules dispersed and the phase change materials contained in the water-based suspensions, nepcm = 1%、2%、5% ,pcm = 0.63%、1.8%、3.8%, respectively. The resulting ranges of dimensionless parameters pertinent to the present experiments are: the Reynolds number, Ref = 112-940; the Peclet number, Pef = 554-5221; the modified Stefan number, = 0.18-0.516; and the inlet subcooling parameter, = 0.01825-0.0334 The experimental results obtained clearly demonstrate promising efficacy of using the water-based suspensions nano-PCM capsules formulated to replace pure water as the forced convective cooling fluid in both the parallel and divergent minichannel heat sinks. Meanwhile, the cooling performances of the two minichannel heat sinks was compared in terms of their figure of merit (FOM) and coefficient of performance (COP) by taking the accompanied pressure drop penalty of using the water-based suspensions of nano-PCM capsules into account. The heat sink with divergent minichannels appears outperform significantly that with parallel minichannels.

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