The Study of Mixed Solutal Convection in the Duct Flow Passing Through an Inclined Channel with Multiple Cylinder Sources

• Main Authors: Yu-Chen Kung, 龔育諄
• Other Authors: Lin-Wen Wang
• Format: Others
• Language: en_US
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/68501719278930604172

博士 === 元智大學 === 機械工程學系 === 91 === This doctoral thesis is the research on the mixed solutal convection in the duct flow passing through an inclined channel with multiple cylinder sources. Seldom research can be found on this subject. With the mass transport factor on the channel flow, the flow patterns have become more complex. The fluids from the anode or the cathode are denser or less dense so that they do not match the flow patterns in the pure fluid dynamics. In order to observe the cylinders effects inside the channel, a series of the boundary conditions concerning about the cylinders will be involved. Although the Reynolds numbers in this research are from 50 to 300, the complete natural convection, mixed convection and forced convection are presented in the flow patterns. Besides changing the Reynolds numbers, the gap ratio effects of the cylinders on the inclined channel are also investigated. Some investigations about the mass transfer rate are also clearly found. First, with increasing the Reynolds number, the corresponding Sherwood number is increasing, for the Reynolds number is directly proportional to the Sherwood number. Second, with increasing the height-to-gap ratios (h/l) from 0.88 to 1.5 for the fixed Reynolds number, the corresponding Sherwood number is inversely proportional. It is because the equilateral triangle cylinders arrangement is the best design on the mass transfer. Finally, the Sherwood number is inversely proportional to the electrode area on the cathode. Therefore, the larger the area on the cathode is, the smaller Sherwood number can be. An experimental study of mixed convection with CuSO4+ H2SO4 + H2O solution in the inclined channel is performed. The shadowgraph technique is used to visualize the flow and to determine the nature and effect of solutal driven secondary flows in the inclined channel with the multiple cylinder sources inside. The ranges of the parameters in the present work are Pr=5~7, Ar=1, Sc=1700~2400, Re=50~300, Grm = 1.88×105 (Red=7.94 ~ 47.64, Grm* = 4378), h/l=0.88~1.5, l/H=0.4~0.5, d/H=0.125 and d/G=0.45~0.9, θ=0°~15°.