Numerical Study on Stagnation Point Heat Transfer by Jet Impingement in a Confined Narrow Gap

Abstract

In this paper, the 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 and d is the diameter of the jet) are numerically analyzed. The relative performance of seven turbulent models for predicting this type of flow and heat transfer is investigated by comparing the numerical results with available benchmark experimental data. It is found that the shear-stress transport (SST) k−ω model and the large Eddy simulation (LES) time-variant model can give better predictions for the performance of fluid flow and heat transfer; especially, the SST k−ω model should be the best compromise between computational cost and accuracy. In addition, using the 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 the local Nusselt number (Nu) of the target plate are examined; a correlation for the stagnation Nu is presented.