Large Eddy Simulation of a Generic Impinging Jet Configuration

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Abstract

The aim of this work is to generate comprehensive numerical data for multiple impinging jets in cross-flow. Therefore, several Reynolds-averaged Navier-Stokes (RANS) simulations and large eddy simulations (LES) are carried out for an in-row arrangement of nine impinging jets with a jet Reynolds number of ≈10,000. This data should contribute to a better understanding of the heat transport processes being involved. The RANS and LES studies are conducted using the computational fluid dynamics (CFD) solver TRACE (Turbomachinery Research Aerodynamic Computational Environment), which is being developed by the German Aerospace Center (DLR). In the RANS study, grid convergence is verified using the grid convergence index (GCI) method. A sensitivity study indicates that changes in the heat flux have only a minor influence on the overall heat transfer characteristics. However, the effects of changes in mass flow are significant. For the LES, sufficient grid resolution is verified by comparing the filter length scales to the Kolmogorov scales. In terms of statistical convergence, the velocity and turbulent kinetic energy show large sampling errors caused by the limited number of through flows. Concerning global heat transfer, the RANS simulations and LES show only small deviations in Nusselt number well matching with empirical correlations reported in the literature. However, the predicted local Nusselt numbers and velocity fields significantly deviate between RANS simulations and LES. In future studies at DLR, the obtained numerical data will be used for the validation of current numerical design methods and turbulence models for impingement cooling.

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• Large Eddy Simulation of a Generic Impinging Jet Configuration. (deposited 12 Apr 2021 15:54) [Currently Displayed]