Heat and flow analysis of laminar natural convection in enclosures with square obstacles

In this study, laminar natural convection heat transfer and ternary fluid flow in the presence of three adiabatic square obstacles differently located in a square cavity is numerically investigated. The analysis focuses on the effects of the location of the obstacles and the Rayleigh number (103 ≤Ra≤ 107) on the heat transfer. The flow is assumed to be steady, laminar and incompressible. Two opposite lateral walls of the cavity are heated and cooled respectively, and the another walls and obstacle surfaces are subjected to adiabatic. Numerical solutions are performed with ANSYS Fluent software using the finite volume method. Spatial discretizations for the gradient, pressure, momentum, and energy are accepted as Green-Gauss node based, Presto, Second order upwind, respectively. The Simple algorithm used a relationship between velocity and pressure corrections to apply mass conservation and to obtain the pressure field is chosen. It is observed that the average Nusselt number is sensitive to the Rayleigh number and the obstacle-location relationship. The streamlines and isotherms corresponding to the different obstacle configurations and Rayleigh number are presented and the flow and heat transfer characteristics are detailed.