Abstract

Impingement jets are used in different cooling applications where it is required to remove large amounts of heat. Heat transfer in the stagnation point for a single jet impinging on an isothermal plate is investigated with four turbulence models. Two models are RANS (Reynolds Average Navier-Stokes): Transition SST and Transition κ–κl–ω. The other two models are URANS (Unsteady Reynolds Average Navier-Stokes): SAS and DES-SST. This paper explores the best turbulence model for thermal design and cooling purposes. Results are validated with experimental data reported by Gardon & Akfirat. These four turbulence models are available in the commercial CFD software package ANSYS FLUENT 18.1. Special attention is paid to the heat transfer in the impingement region through evaluation of Nusselt number in the stagnation point. Different dimensionless nozzle-to-plate distances are considered in this work (z/b = 14 to z/b = 40), and two different Reynolds numbers are used Re = 11,000 y Re = 22,000. Three turbulence models are within reasonable accuracy (10%) of the experimental data, but some turbulence models have problems with convergence and grid independence, especially the URANS models. Based on these results, the best turbulence model for applications in heating and cooling systems where impingement heat transfer is critical is the Transition κ–κl–ω.

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