Experimentaland theoretical study of natural convection heat transfer of heated square cylinder placed inside a cooled circular enclosure filled with air

الملخص EN

In this paper, an experimental and theoretical study of natural convection heat transfer in a closed ends annulus region formed by a heated square cylinder placed concentrically in a larger isothermally cooled circular cylinder.

Experiments are carried out for Rayleigh number based on the equivalent annulus gap length ranges from 103 up to 106.

Different aspect ratios, 0.2 up to 0.5, are considered.

The numerical simulation for the problem is carried out by using commercial CFD code (FLUENT 6.3).The average Nusselt number from the experimental results is compared with that obtained from the CFD code.

The fluid flow and heat transfer characteristics for different operating and geometric conditions are illustrated through stream lines and isotherms contours that obtained from the CFD code.

The results showed thatas the aspect ratio increases the heat transfer rateand the average Nusselt number increase.

Also the result showed that as Rayleigh number increases the average Nusselt number increases.