Large-eddy simulation of flow and heat transfer in an impinging slot jet

Abstract

The flow field due to an impinging jet at a moderately high Reynolds number, emanating from a rectangular slot nozzle has been computed using a large eddy simulation (LES) technique. A dynamic subgrid-scale stress model has been used for the small scales of turbulence. Quite a few successful applications of the dynamic subgrid-scale stress model use planar averaging to avoid ill conditioning of the model coefficient. However, a novel localization procedure has been attempted herein to find out the spatially varying model coefficient of the flow. The flow field is characterized by entrainment at the boundaries. Periodic boundary conditions could not be used on all the boundaries. The results reveal the nuances of the vortical structures that are characteristic of jet flows. The stress budget also captures a locally negative turbulence production rate. The calibration of the model has been made through prediction of the normalized axial velocity profile and heat transfer on the impingement plate. The computed results compare favorably with the experimental observations, especially in the stagnation zone.