本實驗研究探討以R245fa做為工作流體，藉由毛細力及泵驅動之兩組環路熱管傳熱性能。藉由調整加熱功率、冷凝器之冷卻條件以及工作流體流量，分別改變沸騰數(Bo)、冷凝器熱阻(Rth,cond)以及雷諾數(Re)，探討沸騰數、冷凝器熱阻以及雷諾數對兩環路熱管啟動性能、循環壓力、熱力循環特徵、蒸發器與冷凝器紐賽數(Nusselt number)以及環路總熱阻之個別與耦合效應。實驗數據證明，提高汽液循環速率及改善環路壓損特性，提升泵驅動環路熱管之熱傳性能，相較於僅以毛細力驅動之環路熱管，本研究亦探討使用泵驅動環路熱管之熱傳性能提升物理機制。為降低流體阻力，本研究將蒸發器內部之毛細結構以陣列結構取代，並將傳統之管鰭式冷凝器，改用管式冷凝器，探討使用陣列結構之蒸發器與管式冷凝器，對泵驅動環路熱管傳熱性能產生之影響。本研究迴歸各環路熱管之總熱阻實驗數據，推導兩組總熱阻實驗公式，評估環路熱管於各沸騰數、冷凝器熱阻及雷諾數之總熱阻，有助於工程上應用。

The present experimental study investigated the thermal performances of two loop heat pipes (LHP) that were respectively driven by capillary force along and combined capillary and pumping forces with R245fa as working fluid. The start-up performance, loop pressures, thermodynamic cycles, evaporator and condenser Nusselt numbers, and total thermal resistances affected by boiling number (Bo), condenser thermal resistance, and Reynolds number (Re) were examined by adjusting heating power, cooling condition of condenser and flow rate of working fluid. For improving the thermal performance of the pump-driven LHP, the matrix type evaporator and the newly devised condenser were adopted to replace the conventional capillary type evaporator and tube-fin condenser. The comparative thermal performances between the present pump driven LHP and the pump-assisted conventional capillary LHP were studied. Two sets of empirical correlations that evaluated the total thermal resistances of the present pump driven LHP and the pump-assisted conventional capillary LHP were generated to assist the relevant engineering applications.

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