Natural convection gained significant attention of many researchers due its applicability in electronic equipments design [2], fuel cells [1], melting process [3, 4], food processing [5, 6], solidification [7] crystal
growth [9], cooling process [10] solar ponds, [8] etc Natural convection heat transfer and associated transport occurs due to the density difference resulted from temperature gradient in the fluid. As the
sole reason for natural convection is fluid flow due to density difference, this mode is more beneficial compared to forced and mixed convection. A number of approaches were made to investigate natural
convection during simple boundary layer flow to complicated flows inside enclosures [6, 11–18]. Due to the coupling between the momentum and thermal transport properties, internal flow problems lead to complex heat and fluid flow features. In particular, natural convection in complicated cavities involving curved or wavy walls may result in highly complex heat and fluid flow features [19–21]. The
complexity of heat and fluid flow patterns may result in the enhancement of the rate of heat flow in the cavity. This seminar first focus on importance of energy efficiency during convection process and how shape of enclosure is one of the primary factor in the enhancement of natural convection heat transfer. Literature survey on natural convection involving various enclosure shapes is presented. Then presents a detailed analysis of heatlines and entropy generation during natural convection in square enclosure and enclosures with curved (concave and convex) walls. The dimensions of enclosures are fixed in such away that the dimensionless area of the cavity is one and the dimensionless length of the wall is one. Two heating strategies are considered such as (a) Case 1: hot bottom wall, cold side walls in the presence of adiabatic top wall and (b)Case 2: hot left, cold top and bottom walls in the presence of adiabatic right wall. Numerical simulations has been carried out for various Prandtl number,P r = 0.015, P r = 7.2) for different Rayleigh number (103 ≤ Ra ≤ 105). The distributions of isotherms, streamlines, heatlines and entropy generation due to heat transfer and fluid friction are compared for enclosures involving concave and convex walls with the standard square enclosure. The effect of Ra on the total entropy generation, average Bejan number and average Nusselt number is illustrated for considered enclosures involving both the heating strategies. The optimal configuration and optimal heating strategy is chosen based on the less entropy generation rate and larger heat transfer rate.