Computational study of thermal and fluid mixing behaviour of a dual jet flow using LES approach

Abstract

The primary goal of any thermal system which demands efficient cooling is to improve heat transmission. For a turbulent jet, this condition becomes far more significant. The present work has employed large-eddy simulation (LES) for an offset ratio of 2.0 to investigate the transfer in heat and flow characteristics of a dual jet. An isothermal boundary wall condition is considered for a Reynolds number of 7500. The present findings are evaluated by comparing with the published experimental and numerical studies on wall jets. A comparative analysis here exhibits the profiles of Reynolds normal stresses, Reynolds shear stresses, turbulence kinetic energy, Nusselt number and turbulent heat fluxes. A comprehensive investigation of the mixing and flow properties of the dual jet is presented by using the Q-criterion of the iso-surface for mean velocity, pressure and vorticity. The present outcomes show that an efficient thermal transmission from the wall occurs in the recirculation region. The magnitudes of the profiles of Reynolds normal stresses, Reynolds shear stresses, r.m.s. temperature and turbulent heat fluxes are observed to be low in the combined region. Roller-like structure formation and near-wall eddies are noticed which spread in the combined region indicating large heat loss due to the turbulent flow.