Cfd Simulation of round Impinging Jet and Comparison with Experimental Data

In this work, fluid dynamics of a turbulent round impinging jet has been studied using Computational Fluid Dynamics (CFD) and the results have been compared with experimental data from the literature. The fluid was water with density of 1000 kg/m 3 and the average velocity of the submerged jet was kept constant at 10.7 m/s while the liquid viscosity varied from 1 cP to 100 cP. Different turbulence models including k-ε, k-ω and Reynolds Stress Model (RSM) have been employed in ANSYS FLUENT and the predicted axial and radial velocity profiles at various distances from the wall are compared with LDV data. It was observed that at locations away from the target wall, predicted velocities are comparable to the measured velocities for all the viscosities. However, near the wall, the deviation between the CFD predictions and experimental measurements become noticeable. The performance of k-ω model and RSM are found to be better than the k-ε model especially for the highest viscous fluid, but no model was found to be superior for all conditions and at all locations. NOMENCLATURE D Nozzle diameter H Standoff distance in submerged geometry um Maximum velocity at jet centerline before impingement; velocity at y = δm V Initial jet velocity x Coordinate parallel to the impingement plane y Coordinate normal to the impingement plane δ Boundary layer thickness δm Distance from wall to the maximum velocity line in the wall-jet region INTRODUCTION Impinging jets have been widely used in industry to enhance the process of heat and mass transfer. Thermal management is vital for electronic equipment and a challenging area for aerospace engineering and many other applications. Gas or liquid impinging jets are used to control the operating temperature of electronic circuits and their components. In aerospace engineering and turbine design, heat transfer and hydrodynamic calculations of jet impinged surfaces is of great importance. Controlling the mass transfer in jet deposition processes and erosion study of slurry jets are other examples of engineering problems which require prediction of the fluid behavior in jet impingement configurations (Arabnejad et al. 2015a; Arabnejad et al. 2015b; Mansouri et al. 2014; Mansouri et al. 2015). In addition to the direct use of a hydrodynamic solution of the impinged jets, heat transfer calculations are possible if velocity of the fluid near the wall is known. Different configurations of impinging jets have been studied in the literature using empirical, numerical or theoretical methods. Donaldson and Snedeker (1971) measured the heat transfer characteristics of a circular impinging jet and introduced a correction term to use the laminar heat transfer coefficient for turbulent flows. Elison and Webb (1994) studied local heat transfer experimentally for a liquid jet impinging a flat surface with uniform heat flux. Womac et al. (1993) conducted experimental investigations of liquid jet impingement cooling of square heat sources in free-surface and