An Experimental and Numerical Investigation of Curved Wall Jet For Locaized cooling

Abstract

The effect of curvature and aspect ratio on wall jet is investigated experimentally and numerically. Measurements on a plane wall and its numerical analysis are performed for correlation. The flow is generated using a rectangular orifice with different aspect ratios varying from 1.0 to 0.4. The jet generated by the orifice is issued tangentially on to different numbers of convex cylindrical and concave cylindrical surfaces. Initial straight portion equals to twenty times the width of the orifice is taken before the jet experiences curvature effects. Each curved surface has a constant radius of curvature i.e., it is a cylindrical surface. Each of the surfaces is vertically placed in front of the orifice The experiments have been conducted to obtain various mean flow parameters like mean velocity profiles both in the longitudinal and spanwise directions, decay of maximum velocity, growth of half width in the longitudinal and spanwise directions. The same parameters are calculated using the numerical investigation. The Reynolds stress transport model is used to estimate all the parameters. Grid independency test is performed for every individual combination of orifice and curved surface. The comprehensive experiments have made to understand the combined effect of curvature and aspect ratio on the plane wall jet flow. The influence of convex and concave cylindrical curved surface on the mean flow characteristics of three-dimensional wall jet, when compared with a plane surface, observed that the most affected parameters are maximum velocity decay and half width growth in the longitudinal direction. The same parameters similarly affected due to the variation of aspect ratio. It is observed that the decay rate is slower on the concave cylindrical surface and faster on the convex cylindrical surface when compared with the decay rate of plane surface. Numerical results show good correlation between the experiments but the regression constants is different. The half width scale is increased over convex cylindrical surfac