In this paper, a numerical study of the effect of a hot square cylinder placed on a cooled elliptical enclosure of a laminar natural convection was carried out. This problem is solved by using the partial differential equations, which are the stream vorticity formulation for the flow and heat transfer in curvilinear coordinates. An elliptical function is used, which makes the coordinate transformation from the physical domain to the computational domain be set up by an analytical expression. About 48 tests are performed for different ratios of the geometry such as, a /b =1.5,2.,3 , l /b = 0.25,0.5 , and Rayleigh number from 103 to 106, for two position of the major axis of the elliptical enclosure, horizontal (HEE) and vertical (VEE). The results obtained in the form of velocity vectors, streamlines, isotherms, and Nusselt number. The results show that, the increase of the major axis of the enclosure ( a /b ratio) leads to increase the average Nusselt number and decrease the flow strength for all Rayleigh numbers. Moreover, for Ra≤104, there are a little difference in the results of ave Nu for all a / b and l / b ratios, but if Ra increases, the change in the results is clear and large. |