Combined forced and natural convection heat transfer in a deep lid-driven cavity flow

Abstract In this study, we describe the combined forced and natural convection (also known as mixed-convection) heat transfer process within a recirculating flow in an insulated lid-driven cavity of rectangular cross section (150 mm × 450 mm) and depth varying between 150 mm and 600 mm. The forced convection is induced by a moving lid, which shears the surface layer of the fluid in the cavity, thereby setting up a recirculating flow, while the natural convection flow is induced by heating the lower boundary and cooling the upper one. By appropriately varying the lid speed, the vertical temperature differential, and the depth, we obtained Gr Re 2 ratios for these flows from 0.1 to 1000. Flow visualization using liquid crystals and heat flux measurements at specific locations over the lower boundary provided an insight into the nature of the heat transfer process under different flow and temperature conditions. The mean heat flux values over the entire lower boundary were analyzed to produce Nusselt number and Stanton number correlations which should be useful for design applications.