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In this study, convective heat transfer by multiple impinging jet arrays in different arrangements is numerically investigated using Computational Fluid Dynamics (CFD). Computational domain consists of multiple jet array either in inline or staggered alignment and a target plate to be cooled by impinging jets. Distance between the jet array and the target plate is kept constant at H=28 mm. Diameter of circular jet nozzles is fixed at D=5 mm for all configurations. Effects of jet Reynolds number (Rej), spacing between circular jets and the alignment of the jet nozzles on aerothermal performance are parametrically investigated in the scope of this study. For staggered and inline alignments of the jet nozzles, Rej ranges from 5000 to 20000 and the ratio of the spacing to the jet diameter (s/D) changes between 2 and 6. CFD calculations are performed using finite volume based ANSYS-Fluent flow solver. Simulations are conducted for incompressible, steady and turbulent flow using k-ω SST turbulence model with ideal gas assumption for density and Sutherland law for viscosity. After intensive mesh convergence and validation tests, appropriate mesh resolution is determined and parametric investigations are performed. The study reveals that most dominant parameter for plate cooling is Rej followed by spacing between jets and finally jet alignment. For all Rej, inline jet nozzle alignment provides 15% higher average heat transfer rate than staggered alignment when s/D is close to the lower limit. However, it is shown that jet alignment does not affect thermal performance when s/D is higher. |
