Investigation of the Effect of Geometric Parameters on the Natural Convection Heat Transfer of a Non-Newtonian Fluid in a Square Enclosure with two constant Temperature Barriers

This article presents the results of a numerical study on natural convection heat transfer in a square enclosure filled with a non-Newtonian power-law fluid. Two square obstacles with a constant temperature are placed inside the enclosure. The horizontal walls of the enclosure are thermally insulated, and the vertical walls are at a constant temperature . The flow inside the enclosure is assumed to be two-dimensional, laminar, steady-state, and incompressible. The governing equations for the power-law fluid flow are solved numerically with a finite volume approach using a computer program in FORTRAN using the SIMPLE algorithm. To ensure the accuracy of the simulation, the computer code results are compared with the results of other researchers. The influence of pertinent parameters such as the Rayleigh number , the power-law index , the size of obstacles , the distance between obstacles and the obstacles distance from bottom wall of enclosure on the flow and temperature fields and the heat transfer rate of the enclosure is studied. For different power-law indexes, the results show that the average Nusselt number increases as the size of obstacles increases, and that the average Nusselt number decreases as the distance between obstacles decreases. When the obstacles are placed on the vertical walls, as the distance between the obstacles increases, the heat transfer rate decreases for n=1 and n=0.8 and increases for n=1.4. For power-law indexes below unity, a significant increase in the average Nusselt number is observed as the Rayleigh number increases.