ISSN Online: 2377-424X
ISBN Print: 0-89116-559-2
International Heat Transfer Conference 8
FLOW PATTERNS OF NATURAL CONVECTION IN ENCLOSURES WITH HORIZONTAL TEMPERATURE AND CONCENTRATION GRADIENTS
摘要
The transport process in the fluid phase during the growth of a crystal has a protound influence on the structure
and quality of the solid phase. In some horizontal growth techniques (e.g., horizontal Bridgman) the fluid phase is
subjected to horizontal temperature and concentration gradients. The main objective of the present work is to obtain basic information on the resultant flows; flow structures are studied in detail under various conditions.
Among actual crystal systems the parameters vary widely. Since it is impossible to cover wide ranges of the parameters in the present experiment, and since the main object of the present study is to obtain basic information on natural convection due to the combined effects of temperature and concentration gradients in enclosures, the parametric ranges studied herein are mainly dictated by the electrochemical system employed herein to impose concentration gradients.
A temperature and a concentration difference are maintained between two vertical end walls. The other walls are kept insulated. The temperature and concentration gradients are imposed in such a way that their effects on the flow are either cooperating or opposing. It is found that in both cases the interaction between the temperature and concentration field may cause secondary cells near two end walls. Shear instability may happen near the hot wall for opposing cases.
Among actual crystal systems the parameters vary widely. Since it is impossible to cover wide ranges of the parameters in the present experiment, and since the main object of the present study is to obtain basic information on natural convection due to the combined effects of temperature and concentration gradients in enclosures, the parametric ranges studied herein are mainly dictated by the electrochemical system employed herein to impose concentration gradients.
A temperature and a concentration difference are maintained between two vertical end walls. The other walls are kept insulated. The temperature and concentration gradients are imposed in such a way that their effects on the flow are either cooperating or opposing. It is found that in both cases the interaction between the temperature and concentration field may cause secondary cells near two end walls. Shear instability may happen near the hot wall for opposing cases.