The effect of nozzle geometry on turbulent impinging air jet heat transfer

In this study, influence of nozzle geometry with confined impinging jet heat transfer is numerically investigated. Nozzle geometry is changed by changing thickness of confinement plate and using straight, chamfered outlet and chamfered inlet geometries. Confinement plate thickness is defined as 10, 15 and 20 mm in this investigation. Due to nonconicity on the straight nozzle variant, angle is defined as 0°. But in chamfered outlet and chamfered inlet models, chamfer angle is defined as 15°, 30° and 45°. Also, three different jet to impingement surface distance (H/D= 2.6, 4.0, 6.0) effect is investigated with the other parameters which are mentioned before. The flow is assumed as incompressible, two dimensional and turbulent air flow. SST k-ω is used as the turbulence model. Conservation equations and turbulence model equations are solved by using ANSYS R14.5 CFX software. For each model, influence of confinement plate thickness, chamfer angle and jet to impingement surface distance (H/D) on the heat transfer are investigated. In order to evaluate the results, local heat transfer curves are compared with each other. Also, averaged Nu numbers are calculated, compared and evaluated. Keywords: Impinging air jet, turbulent heat transfer, computational fluid dynamics, nozzle geometry. 2018, xxv + 336 pages