Publication

Abstract : Heat transfer from a heated surface is numerically investigated using different types of convection in a lid driven square cavity containing different shapes of heated block. The analysis is done for different range of Reynolds, Prandtl and Grash of Number which serves as the governing parameters. Convection characteristics and flow features produced for each type of convection is compared. Enhancement of heat transfer using surface modification is also tested by introducing random protrusions in the surfaces of the heated block. Heat transfer rate is checked and mixed convection with a parameter combination of Re=100, Pr=100 and Gr=105 is observed to be having high surface heat transfer coefficient or high surface heat flux when compared to other type of convection and parameter combinations. Heat transfer is found to be increasing till Reynolds number (Re) reaches 100; later deterioration is observed when Re approaches 1000. The decline of heat transfer rate is more evidently observed in mixed convection case when Re=1000 for different Prandtl Numbers Pr=1, 50 and 100 and Gr=105 when compared to pure forced convection case (Gr=0) for the same parameter combinations of Re and Pr. Whereas, for the remaining parameter combination of Re=1, 100 and Pr=1, 50, 100, the heat transfer rate of mixed convection (Gr=105) is higher when compared to the heat transfer rate of pure forced convection (Gr=0). After the surface modification of the heated block, there is a valid augmentation observed in the surface heat transfer coefficient and hence in heat transfer rate.