Enhancement of heat transfer of confined enclosures with free convection using blocks with PSO algorithm

In this paper, optimal shape of cavity with change of hot walls geometry is obtained using PSO algorithm. In this method near domain of hot wall is divided into similar blocks as those can either be solid or fluid. Free convection is dominant in the cavity. Continuity, momentum and energy equations are discretized by finite volume method. These equations are solved by SIMPLER algorithm. PSO algorithm is used for obtaining diffusion parameters near the hot walls. Diffusion coefficients obtained from PSO algorithm (non-dimensional parameters for diffusion terms in momentum and energy equations) are replaced in governing equations such a way that average Nusselt number from cold wall to be maximized. The results are obtained for range of Rayleigh numbers and different boundary conditions. Results show that PSOA is able to obtain size and location of changes in hot walls. These changes can increase heat transfer from cold wall between 13% and 40% for different boundary conditions. If hot and cold walls are near together, millimeter changes are enough for acceptable percent value of increase of heat transfer, but for cases that hot wall is far from cold wall, we must attach medium or large blocks on hot wall or construct new cavities in accordance with optimized shape obtained from PSO algorithm. As told, this method can be applied toconstructed cavities with attachment of rectangular fins.