Numerical research on local heat transfer distribution of liquid sodium turbulent flow in an annulus

Local heat transfer distribution of liquid sodium turbulent flow in an annulus has been investigated numerically. The high Reynolds number k-ε model and boundary condition of wall function method were applied. The numerical results are in good agreement with some experimental results in open literature. Heat transfer distributions of liquid sodium and water were compared under the same geometry, flow and heating conditions. Meanwhile, influencing factors, including the turbulence, heating and geometry, were studied. Comparing results of different turbulence conditions, the Nusselt number increases with the Reynolds number increase, and the turbulence was mainly influenced on the entrance of the annulus. By analyzing heat transfer distributions under different inlet temperature and heat flux conditions respectively, it can be concluded that this two factors have little influence on the Nusselt number. The gap size and the curvature were considered as the main geometry factors influencing on heat transfer. When the gap size of the annulus increases from 5 to 15 mm, the Nusselt number will increase. While with the same gap size, as the curvature of the annulus changes, the Nusselt number changes very little.