Modelling of Impinging Flow and Heat Transfer in a Confined Narrow Gap

Abstract

In this paper, the flow and heat transfer characteristics of a circular air jet vertically impinging on a flat plate near to the nozzle (H/d = 1∼6, where H is the nozzle-to-target spacing, d the diameter of the jet) are numerical analyzed using the CFD code FLUENT 6.1.18. The relative performance of seven versions of turbulent models, including the standard k–ε model, the renormalization group k–ε model, the realizable k-ε model, the standard k–ω model, the Shear-Stress Transport (SST) k–ω model, the Reynolds Stress (RS) model and the Large Eddy Simulation (LES), for the prediction of this type of flow and heat transfer is investigated by comparing the numerical results with available benchmark experimental data. It is found that Shear-Stress Transport k–ω model and Large Eddy Simulation time-variant model can give better predictions of fluid flow and heat transfer properties; especially, the SST k–ω model is recommended as the best compromise between the computational cost and accuracy. Using SST k-ω model, the effects of jet Reynolds number (Re), jet plate length-to-jet diameter ratio (L/d), target spacing-to-jet diameter ratio (H/d) and jet plate width-to-jet diameter ratio (W/d) on local Nusselt number (Nu) of the target plate are examined. A correlation for the stagnation Nu is presented.