本文主要以實驗方式探討微米相變化流體在矩形熱虹迴路內熱傳特性之研究。實驗迴路模型高度為34.5cm、寬度為34.5cm，迴路材質皆選用不銹鋼（AISI 304，18%Cr，8%Ni）圓管，其外徑為9.5mm 、內徑為8.3mm 。文中考慮迴路加熱段所輸入之熱量及冷卻段外管壁平均溫度對迴路穩態溫度分佈之影響，並同時探討迴路內充填微米相變化流體與純水之間的差異，其相關參數範圍為：加熱段輸入之熱量4~12瓦，冷卻段外管壁之平均溫度10~25度，相變化微粒之質量濃度0~0.15。結果顯示由於過冷效應之影響，導致迴路內微米相變化流體流經冷卻段時無法凝固，其熱傳效果反而比填入純水時為差，當濃度愈大時愈為顯著。另外；將實驗所得之結果與數值模擬相互比較，結果顯示實驗數據與數值模擬之結果相當吻合。

The primary objective of present study is to experimentally heat transfer characteristics of a rectangular thermosyphon loop of phase change material（PCM）suspension. A rectangular loop of 34.5 cm in height and 34.5 cm in width was constructed with a stainless steel（AISI）tube of outer and inner diameters of 9.5 mm and 8.3 mm. Steady state heat transfer experiments of loop were performed for the relevant parameters in the following ranges: the heat input in the heated section q=4~20, the average out surface temperature in the cooled section T=10~25, and the mass fraction of the PCM particles(c=0~0.15). Experimental results obtained show the effectiveness of heat dissipation in the heated section of the circulation loop incorporating the PCM suspension appears inferior to that of pure water(c=0), which may be attributed to occurrence of supercooling of the PCM particles. Corresponding to the experiments, numerical simulations taking the supercooling phenomenon into account were undertaken. Fairly good agreement between the numerical predictions and the experimental data was found for the outer wall temperature distribution along the loop, lending clear evidences of occurrence of supercooling phenomenon in the PCM suspension. The supercooling of PCM particles can thus be detrimental to effectiveness of the suspension as a heat transfer enhancement medium.

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