| Summary: | 碩士 === 元智大學 === 機械工程學系 === 90 === Thermosolutal Convection in a Rectangular Enclosure with Dual Cylinders
Student: Wei-Chun Jeng Adviser: Lin-Wen Wang
Department of Mechanical Engineering
Yuan-Ze University
ABSTRACT
The purpose of present study is to investigate flows pattern, temperature and concentration distributions resulting from buoyancy force due to a combination of temperature and species convection effects in a rectangular enclosure with dual cylinders inside.
In the process of crystal growth, the non-homogeneous phenomenon would become more and more serious. So to know the sufficient understanding of heat and mass transports is indispensable.
In this experiment, the temperature and concentration differences are made between two cylinders and the insulation is kept all over the margin. Cupric Sulphate solution is selected as the working fluid. Two constant temperature baths keep the temperature gradient. Concentration gradient is controlled via electrochemical system. In order to visualize the flow, the shadowgraph technique is used. Electrical measurements will be used to obtain mass transfer rates and to infer a Sherwood number. We can find that in the cooperating case, the interface is shown due to the fluid accumulation after imposing the mass transport. However, in the opposing case, the salt finger is found owing to the difference between the thermal diffusive velocity and mass diffusive velocity.
This study can be divided into two parts:
(1) The enclosure is placed horizontally, and convection is established where one cylinder is inserted right next to the other.
(2) The enclosure is placed vertically, and convection is established where one cylinder is inserted beneath the other.
The range of the parameters in this study are Ar=0.625
Gr,t=2.41 ×105 ~ 7.23 ×105 Gr,m=1.82 ×106
N=-2.52~7.55 Sc=1700~2300 Pr=6.0~7.0
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