Numerical Simulation of the Jet Impingement Cooling of a Circular Cylinder

A numerical investigation was carried out on circular jet impingement heat transfer from a constant temperature circular cylinder to understand the major parameters which influence the fluid flow and heat transfer characteristics. In this study, air was considered as the working fluid. The flow was considered to be three-dimensional, incompressible, and turbulent. To select a suitable turbulence model for the parametric study, numerical simulations were carried out with standard k-E, standard k-, RNG k-E, Realizable k-E, and SST k- turbulence models for modeling Reynolds stress terms. Simulations were also carried out using four low Reynolds number models. The results obtained using these models were compared with the available experimental results of jet impingement heat transfer from circular cylinder. It was identified that the RNG k-E model predicts heat transfer characteristics better compared to all other turbulence models considered in this study. Using this turbulence model, a parametric study was carried out for the Reynolds number (Re-d), defined based on the diameter of the nozzle ranging from 10,000 to 50,000. The ratio of distance between the nozzle exit and the cylinder surface to the diameter of the jet (h/d) was varied from 4 to 16 and the ratio of nozzle diameter to cylinder diameter (d/D) varied from 0.11 to 0.25. For a fixed Re-d and d/D, the stagnation point Nusselt number increases as h/d decreases. The stagnation point Nusselt number decreases as d/D increases for a fixed value of Re-d and h/d. The effects of change in h/d and d/D are significant only near the stagnation region.