高展弦比之密閉區內由垂直溫度梯度與水平濃度梯度引起的熱質自然對流

Experimental Study of Thermosolutal Convection in High Aspect Ratio Rectangular Enclosures with Vertical Temperature and Horizontal Concentration Gradients

玉立文(L. W. Wang) ； 盧明初(M. C. Lu) ； 鄧榮峰(Z. F. Deng) ； 林政宏(J. H. Lin) ； 王士榮(S. L. Wang)

《中國航空太空學會學刊》 30卷3期 (1998/09) Pp. 203-210

https://doi.org/10.6124/TAASRC.199809_30(3).04

摘要

本研究目的是以實驗方法探討由上熱下冷的垂直溫度梯度與水平濃度梯度所引起的熱質自然對流現象，另對於不同之高展弦比密閉盒內工作流體所展現的流場型態及其溫度、濃度的衡的有形亦是研究的對象。
實驗裝置是由銅板及壓克力板，構成各種不同展弦比之矩形盒。工作流體爲硫酸鋼水溶液。溫度梯度自上下兩個不同溫度的恆溫水槽來維持，濃度梯度是由電化學方法造成，即利用電解方式在兩鋼板附近形成不同濃度的邊界屑。對於盒內流場現象採用雷射光暗影法(shadowgraphy)或加入質點(particles)的質點光幕法來觀察流場。爲瞭解流場結構，對流場的溫度與濃度分佈亦作量測。最後，對於質傳遞率Sh值在固定的Gr,t(上標 *)，探討Sh與Gr,m(上標 *)的關係。本研究的參數範團如后：
Ar=4~8, Pr=7~8, Sc=1800~2100, N=0.5~21, Gr,m=1.06×10^7~6.34×10^8及Gr,t=4.54×10^6~1.22×10^8。

並列摘要

Experimental Study of Thermosolutal Convection in High Aspect Ratio Rectangular Enclosures with Vertical Temperature and Horizontal Concentration Gradients
The purpose of this study is to investigate the transport phenomena of thermosolutal convection in high aspect ratio rectangular enclosures with vertical temperature and horizontal concentration gradients.
Flow visualization has been accomplished using the particle tracer and shadowgraph technique. Both the temperature and concentration distrbutions at different time the quantitatively measured. The concentration distribution of cupric ions in the solution is determined by measuring the attenuation of light through the test cell with a 35mW He-Ne laser as the light source, According to Beer's law the concentration of a solution is proportional to an absorbency, which is defined as the logarithm of the ratio of input and output light intensities. Finally, the relations between the dimensionless mass transfer rate Sh and Gr, t(superscript *), Gr, m(superscript *) are discussed. The ranges of the dimensionless parameters studied in the present work are:
Ar=4~8, Pr=7~8, Sc=1800~2100, N=0.5~21, Gr, m=1.06×l0^~6.34×10 and Gr, t=4.45×10^6~1.22×10^8.