管流經過雙極不連續質源之質對流的探討

A STUDY OF DUCT FLOW PASSING IN A CHANNEL WITH DISCRETE MASS SOURCES

徐俊祥(Chun-Hsiang Hsu)

指導教授 ： 王 立 文

元智大學/工程學院/機械工程學系/碩士(1997年)

摘要

本實驗研究是將四個不連續之對稱質源傳遞引入傾斜矩形管道之主流中，來進行質混合對流研究。在此，混合對流係指利用幫浦所造成的強制對流（forced convection），在速度完全發展之後，再與不連續之對稱質源傳遞所形成的自然對流（natural convection）合併之流體運動現象。全實驗可分為三部份進行探討，第一部份為傾斜角度等於零，第二部份為傾斜角度大於零，第三部份為傾斜角度小於零。
實驗使用的工作流體為硫酸銅水溶液（CuSO4+H2SO4+H2O ），不連續之對稱質源傳遞是藉由電化學系統於測試區（test section）之上、下兩銅板加上端電壓，使其成為電極，達成濃度梯度之建立。
本實驗採用雷射光暗影法（shadowgraph）作流場結構觀察及照相記錄，並作質量傳遞率的量測。實驗的無因次參數範圍如下：Ar=1 ，Sc=1700~2400，Re=50~300，Gr,m=1.27×106，θ=-30~30°，L/H=0.5~1（質源長度與矩形管道高度之比），L/Ls=0.33~2（質源長度與間隔長度之比）。
至於質傳遞率量測方面，質傳遞率Sherwood數隨Reynolds數的增加而增加，而且Sherwood值在傾斜角度大於零時，因陰極板對流效應增強而變大，在傾斜角度小於零時Sherwood值因陰極板對流效應減弱而變小，另外增加間隔長度會提高對流效應使Sherwood值增加。

關鍵字

不連續對稱質源 ； 傾斜 ； 混合對流

並列摘要

An experimental investigation of mixed convection mass transfer from four discrete symmetric mass sources flow of a CuSO4＋H2SO4＋H2O solution will be carried in an inclined rectangular channel with an electrochemical system .
The purpose of the present study is to investigate laminar fully developed flow in inclined rectangular channels with four discrete symmetric mass sources . The influence of the mass transfer rate and the separation distance between the sources has been investigated. The experiments would include three parts : (1)inclined angle θ= 0°(2)inclined angle θ> 0° (3)inclined angle θ< 0°.
To visualize the flow , the shadowgraph technique will be used . Electrical measurements will be used to obtain mass transfer rates and to infer a Sherwood number . The ranges of the parameters in the work are Ar=1, Sc=1700~2400, Re=50~300, Gr,m=1.27×106 ,θ=-30°~30°, L/H=0.5~1（mass source length / rectangular channel height ratio）, L/Ls=0.33~2（mass source / space length ratio）.
The mass transfer rate"Sherwood number"increases with increasing Re for a fixed Ra,m and increases with increasing inclined angle for Re and Ra,m. It is found that for increasing space length configuration, the rate of mass transfer increases when the separation distance between the sources is increased.

並列關鍵字

discrete symmetric mass sources ； inclined ； mixed convection

參考文獻

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