Experimental and numerical study on heat transfer with impinging circular jet on a convex hemispherical surface

In this paper, the experimental and numerical study has been carried out to investigate the water jet impingement on a convex hemispherical surface. The pressure and skin friction coefficient distributions on the impingement surface were analyzed numerically. A great deal of attention was paid to analyze the effects of the jet impingement exit velocity and the nozzle-to-surface distance on the heat transfer characteristics. A comparison of the heat transfer coefficient was performed between the jet impingement on the convex surface and the flat plate. The results show that the Nusselt number for the convex surface is higher than that for the flat surface. The local Nusselt number is decreased monotonically from its maximum value at the stagnation point for lower Reynolds numbers. A secondary maxima occurs for higher Reynolds numbers. The experiment and simulation were performed with the following parameters: the jet impingement Reynolds number of Re = 1947-19478, and the nozzle-to-surface distance of L/D = 2.5-25.