Mixed convection in lid-driven shallow cavities
Abstract
Experimental and theoretical work was conducted to investigate natural and mixed convection in a rectangular cavity. The cavity was heated (or cooled) from below and cooled (or heated) from above either in the absence or presence of lid motion. Experiments were conducted in a cavity having dimensions of 10 x 1 x 5 in. the x, y, and z-directions, i.e., aspects ration of 1/10 and 1/5 in longitudinal and spanwise directions, respectively. Ethylene-glycol, water and gallium were used as the working fluids. Flow and temperature were visualized using aluminum particles and liquid crystal techniques. Also, the temperature history at different locations in the test cell were recorded and spectral analysis was carried out. Two- and three-dimensional, laminar and turbulent numerical simulations were performed to examine the effect of Rayleigh, Reynolds and Prandtl numbers on the flow structure and heat transfer under both natural and mixed convection conditions in the cavity. The results show that the lid motion has a significant effect on the flow structure and temperature distributions in the cavity. For Gr/Re$\sp2$ O(1) the effect of the lid motion may be to decrease the rate of heat transfer and stabilize the flow. The effect of lid motion is insignificant for Gr/Re$\sp2\gg 1$. The flow remained laminar regardless of the Reynolds number value for a cavity heated from above when Gr/Re$\sp2\ge 1$. Other findings are discussed in the body of the thesis.
Degree
Ph.D.
Advisors
Viskanta, Purdue University.
Subject Area
Mechanical engineering
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