頁籤選單縮合
題名 | Heat and Mass Transfer in the Vertical Twin-parallel-tube Absorber-evaporator Unit=垂直雙圓管吸收--蒸發器之熱質傳分析 |
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作者 | 岑英培; 林恆毅; 周賢福; | 書刊名 | 中國工程學刊 |
卷期 | 24:5 2001.09[民90.09] |
頁次 | 頁581-593 |
分類號 | 446.6 |
關鍵詞 | 表面潤濕; 熱質傳類比關係; 下落液膜; 操作壓力; Surface wetting; Falling film; Analogy between heat and mass transfer; Operation pressure; |
語文 | 英文(English) |
中文摘要 | 本研究建立了一垂直雙圓管吸收﹣蒸發器,以更理想之條件研究於不同操作條件 下,下落液膜之熱質傳效應。為達成吸收液膜均勻下落於吸收器表面,本系統中採用具傾斜 面的環型吸收液分佈器,使圓管表面均勻潤濕。本研究應用了熱質傳間類比關係來分析吸收 過程中吸收液膜表面溫度與濃度變化,進而得到熱傳係數與質傳係數。本研究之結果發現增 加系統操作壓力時, 能提昇吸收液膜出入口濃度差,且在吸收液入口雷諾數低於 200 時, 吸收液出入口濃度差陡然上升,而此一區間便是吸收過程的最佳操作點。由本文的研究可應 用於吸收式空調系統之最佳化操作條件。 |
英文摘要 | A vertical twin-parallel-tube absorber-evaporator unit was built for the present study to investigate the overall heat transfer and mass absorption rates at various operation conditions. In order to establish the optimal surface wetting condition for the thin absorbent film during operation process, an annular-slot type solution distributor with declining surface was adopted for the present system. The main objective of the present study is to perform an experimental investigation of the controlling parameters associated with absorption by falling film, including the operation pressure, the inlet temperature of the cooling water, and the Reynolds number, temperature, and concentration of the inlet absorbent solution. An analogy between heat and mass transfer near the film surface is then applied to calculate the interfacial concentration and temperature of the absorbent film, and thus the heat and mass transfer coefficients of the absorbent film is determined. The present results show that, the higher the inlet Reynolds number of the absorbent solution is, the lower the total heat transfer rate is. Increasing operation pressure will increase the concentration difference of the absorbent solution. The concentration difference of absorbent solution film between inlet and outlet increases sharply as the Reynolds number of the inlet absorbent film decreases below 200. When the Reynolds number of the inlet absorbent film is around 200, optimal absorption-evaporation exists and will provide appropriate conditions for a high efficiency absorption air conditioning system. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。