水平方形管中熱質混合對流實驗研究

Experimental Study of Mixed Convection Heat and Mass Tran- sfer in a Horizontal Channel Flow

侯光煦(K. H. Hou)

指導教授 ： 王立文教授

元智大學/工程學院/機械工程學系/碩士(1994年)

摘要

本實驗研究是將質量傳遞及熱量傳遞，個別或者是二者均引入水平矩形管
道之主流中，來進行熱質混合對流研究。在此，混合對流係指利用幫浦所
造成的強制對流在速度完全發展之後，與由質傳、熱傳或熱傳及質傳所形
成的自然對流合併之流體運動現象；所使用的工作溶液為硫酸銅水溶液，
全實驗可分為三部份進行探討。各部份實驗的邊界類型如下：1.質混合對
流：Case(1A)上板陽極、下板陰極（混合）Case(1B)上板陰極、下板陽極
（強制）; 2.熱混合對流：Case(2A)上板冷板、下板熱板（混合) Case(2
B)上板熱板、下板冷板（強制）; 3.熱質混合對流：Case(3A)上板陽極且
為冷板、下板陰極且為熱板(混合)，Case(3B)上板陽極且為熱板、下板陰
極且為冷板（混合），Case(3C)上板陰極且為冷板、下板陽極且為熱板（
混合），Case(3D)上板陰極且為熱板、下板陽極且為冷板。由流場觀察顯
示：Case(1A)之邊界屬於質不穩定，流場為質混合對流的流場型態，而
Case(1B)之邊界屬於質穩定狀態，不會有次流體的產生，其流場屬強制對
流的流場型態。Case(2A)之邊界屬於熱不穩定狀態，會有熱二次流由下板
浮起，其流場屬於熱混合對流之型態，Case(2B)之邊界屬於熱穩定狀態，
不會有熱二次流的發生，其流場屬強制對流的型態。Case(3A)及Case(3B)
之流場分別屬於熱質混合對流不同的流場型態，於本實驗中前者之流場型
隨參數Re及Gr,qb變化，後者則隨參數Re及Gr,qt變化。

關鍵字

混合對流 ； 電化學系統 ； 水平管

並列摘要

An experimental study of mixed convection heat and mass
transfer flow of a sulfate solution in a horizontal
channel is performed with uniform heat flux flexible heat- ers
and an electrochemical system. The purpose of the present study
is to investigate laminar fully developed flow between two
horizontal plates with uniform heat fluxes and concentration
gradients. The exp- eriments would be divided into three
parts:(1)mass transf- er mixed convection (2)heat transfer
mixed convection (3) combined heat and mass transfer mixed
convection. For mass convection, the types of the boundary
of test section are:(a)top plate is anode and bottom plate is
ca- thode (b) top plate is cathode and bottom plate is anode.
For heat convection, the types of the boundary of test
section are: (a) top plate is cold and bottom plate is hot (b)
top plate is hot and bottom plate is cold. The types of
boundary of test section for thermosolutal convection are the
combinations of the cases of heat and mass transf- er
convection. To visualize the flow, the shadowgraph technique
is used. Electrical measurements are used to obtain mass
transfer rates and to infer a Sherwood number. From the flow
visualization, we can find: The flow with the boundary of
type (1a) of test for mass convection belongs to mass
transfer mixed convection , type (2a) belongs to forced
convection. The flow with the boundary of type (2a) of test
for heat convection belongs to heat transfer mixed
convection, type (2b) belongs to forced convection. For
thermosolutal convection, the flow with the boundaries of
types (3a) and (3b) for heat and mass convection are
thermosolutal mixed convection.

並列關鍵字

Mixed Convection ； Electrochemical System ； Horizontal Ch- annel