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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/69166


    Title: 流動方向對兩相冷媒在板式熱交換器內;Effect of Flow Direction for the Heat Transfer Performance of Refrigerant R-410A Evaporation in Plate Heat Exchanger
    Authors: 林岳宏;Lin,Yueh-Hung
    Contributors: 機械工程學系
    Keywords: 板式熱交換器;逆向流;同向流;蒸發熱傳性能;紅外線熱像;Plate heat exchanger;Counter flow;Parallel flow;R410A evaporation heat transfer performance;Infrared Thermal Image
    Date: 2015-08-31
    Issue Date: 2015-09-23 15:30:35 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 隨著冰水機及熱泵等設備之法定COP日漸提昇且設備體積小型化的需求,板式熱交換器被廣泛應用於冷凍空調系統中。但板式熱交換器蒸發熱傳性能的公開測試資料仍非常缺乏,導致設計者要準確預估板式熱交換器蒸發熱傳性能的難度極高。
    為解決此一問題,本研究以實驗方法進行R410A冷媒對水在板式熱交換器內之蒸發熱傳實驗,探討逆向流與同向流蒸發熱傳性能的差異及不同的冷媒出口過熱度對蒸發熱傳性能的影響,並建立蒸發熱傳性能的預估方法。實驗同時利用紅外線熱像儀觀察板片表面溫度場,分析冷媒的飽和區與過熱區是否與預估的相同,以驗證蒸發熱傳性能預估方式的準確性,作為未來板式熱交換器設計者設計之依據。
    實驗時測試段冷媒入口乾度為0.24,冷媒蒸發溫度為1.1 oC,冷媒出口過熱度為2 oC及5 oC。依實驗結果分別探討蒸發段熱傳性能及整體熱傳性能,同向流之蒸發段熱傳係數比逆向流高,但總體熱傳性能除了受流動方向影響外,也與出口過熱度有關。當冷媒出口過熱度較低時,同向流動之整體熱傳性能與逆向流動沒有差異。當冷媒出口過熱度較高時,同向流動之整體熱傳性能低於逆向流動。
    ;Plate heat exchangers have been popularly used in industrial applications and air-conditioning systems for several decades due to their high effectiveness and compactness. However, owing to its flow complexity, very few test results have been published in the literature for evaporation heat transfer of refrigerant in plate heat exchangers. This article provides an experimental investigation and Infrared Thermal Image observation on the evaporation heat transfer of refrigerant R-410A in plate heat exchanger with various flow arrangement and exit superheat conditions. Parallel flow and counter flow arrangements with 2 oC, 5 oC and 10 oC exit superheat conditions were tested. The refrigerant entered the test section at as vapor quality of 0.24 and evaporated at a saturation temperature of 1.1 oC. The experimental results were analyzed by the evaporation heat transfer coefficient and overall average heat transfer coefficient separately. The evaporation heat transfer coefficient in parallel-flow arrangement is higher than that in the case of counterflow arrangement. However, the average heat transfer coefficients are affected not only by the flow direction, but also by the exit superheat condition. The interaction of these two effects causes there to be almost no difference of the average heat transfer performance between these two flow arrangements for low exit superheat condition. While the refrigerant exit superheat is high, the overall heat transfer performance of the parallel-flow case is lower than that of the counterflow case.
    Appears in Collections:[機械工程研究所] 博碩士論文

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