Numerical Investigations on the Effect of Isothermal Multi-Jets in Air Curtains with LES Approach

Abstract

This work focuses on the analysis of the turbulent intensity of the flow field resulting from planar jets applied in air curtains systems, which are used in various industry sectors. The air curtains allow realizing cellular containment. Hence, the main objective is to improve the quality of confinement’s separation by air curtains. In order to achieve this target, the jet flow must be as laminar as possible. Numerical LES investigations are carried out in this study. A jet impingement against a flat and a smooth surface without recirculation has been used for this assessment. The WALE (Wall Adapting Local Eddy) structure models the subgrid-scale tensor. First, the configuration of air curtain with a single jet and then with a twin-jet are investigated. Result comparisons to available experimental measurements have been performed and good agreements have been noticed. The study is then extended for the first time to air curtain configurations with more than two planar jets. The configuration of the triple jet indicates a lower turbulence level than the single jet and the twin-jet ones. This improves the confinement’s separation quality. However, increasing the number of jets highlights a limit because the turbulence decrease will be not significant beyond a certain number of jets taking into account the operating conditions. In this study, an effective process shows that, the four jets configuration is considered as the better compromise under the considered operating conditions.