Free surface planar liquid jet impingement on a moving surface: interfacial flow and heat transfer characteristics

Understanding heat transfer characteristics of sheet metal is of practical importance in sheet metal rolling operation to ensure strength and quality of final product. We present a numerical study of free surface planar liquid jet impingement on a uniformly heated moving surface. Scale adaptive simulation (SAS) for turbulent flow and volume of fluid (VOF) method was used to capture the liquid-air interface. The computational domain was divided into two parts to carry out 3D simulations, then results of separate domains were superimposed to resolve boundary conditions. A parametric study considered three different jet Reynolds numbers of 4000, 8000 and 12000. Four different surface to jet velocity ratios, u_s/u_j, were considered. We focused on studying interfacial flow characteristics, turbulence intensity variations, and their relation to heat transfer. Splitting the domain into two parts and superimposing results as boundary conditions resulted in a reasonable accuracy and reduced computation cost. We observed that gravity significantly affects interfacial structures at Reynolds number of 4000. As surface velocity increases, the heat removal rate from the impingement surface in the direction of plate motion increases. However, contrasting trends are observed in the reverse direction despite increased turbulence fluctuations with surface velocity.