CFD Heat Transfer Predictions of a Single Circular Jet Impinging with Crossflow

Abstract

Jet impingement cooling is used today in a large number of applications ranging from electronic cooling to cooling applications in gas turbines. However, the numerical prediction of impingement is difficult and numerical methods lack inaccuracy for the prediction of heat transfer rates. The aim of the current investigation is to determine the degree of accuracy to which the heat transfer rates of a single circular jet impinging through a well-defined crossflow can be predicted. A commercial CFD package (CFX-5.7.1) with a 3D RANS approach is used for the numerical analysis of the highly turbulent flow field. Computational results are compared to experimental data available from the open literature. Different turbulence models are tested for the configuration of a single jet without crossflow to evaluate a model suited best for the impingement cases. For the crossflow cases, two different nozzle-plate spacings (Z/D = 6 and Z/D = 12) are investigated. Jet Reynolds numbers range from 33,400 to 121,300 while the crossflow velocities investigated correspond to Reynolds numbers ranging from 40,900 to 155,900. The numerical results show a very good agreement with the experimental reference data. The deflection of the jet due to the presence of the crossflow and the corresponding shift of the point of maximum heat transfer rate are captured correctly. Some deviations between the numerical and the experimental results can be observed in the regions around the stagnation point but the effects on averaged heat transfer rates are negligible.