Numerical Simulation of Natural Convection and Radiation Heat Transfer in Two-Dimensional Enclosure on Hybrid Grids

Natural convection and radiation heat transfer interaction commonly exists in engineering problems, and a numerical method for combined natural convection and radiation heat transfer is very important in practical engineering applications. In this article, the finite-volume method (FVM) for radiation is formulated and implemented in the fluid flow solver GTEA on hybrid grids. For comparison and validation, three test cases, an equilateral triangular enclosure and a square enclosure with/without baffles, are chosen. Then, natural convections in a cavity with/without baffles are simulated with the present FVM to take into account the radiation heat transfer effects. All the results obtained by the presented FVM agree very well with the exact solutions as well as results obtained by the zone method. Natural convection under low gravity is researched with Gr = 0.7 and 700, and the radiation effects on the temperature distribution are also studied with variation conduction-radiation numbers, Nr = 0.06, 0.1, and 0.15. It is found that the solutions are sensitive to the conduction-radiation number but do not change very much with the Grashof number.