Natural Convection: Analysis of Partially Open Enclosures With an Internal Heated Source

Abstract

A numerical study of the thermal and fluid dynamic behavior of air in partially open two-dimensional enclosures is presented. An analysis is made based on two aspects of the radius, H/W = 1 and 2. The left and right walls are maintained at different constant temperatures, while the upper and bottom walls are thermally insulated. The enclosure has an opening on the right wall and a small heating source located on the bottom or left vertical wall, occupying three different positions. Numerical simulations were performed for several values of Rayleigh number (Ra _e ) in the range between 10³ and 10⁶>, while the intensity of the two effects—the difference in temperature of the vertical walls and the internal heating source (Ra _i )—was evaluated based on the relation R = Ra _i /Ra _e , in the range between 0 and 2,500. Representative results illustrating the effects of relation R on the streamlines and isotherms within the enclosures are reported. In addition, simulation results for the local and average Nusselt numbers on the heated and colded walls of the enclosures are presented and discussed for different values of the parameters R, Ra _e , W _H , and H/W. It is founded that the parameter modifications have significant effects on the average and local Nusselt numbers of the enclosures.