Mean Concentration Field of a Jet in a Uniform Counter-Flow

Abstract

An experimental investigation of the scaling factors of mean scalar concentration field of jets issuing into a uniform counter-flow stream is presented. The centerline decay and radial spreading of the mean concentration field were measured by using planar laser induced fluorescence. Jet to counter-flow velocity ratios ranging between 4 to19 were investigated for two different jet diameters. The 5% contour of the mean concentration field of the jet was used to define new scaling factors that generate universal forms for the centerline concentration decay. The jet growth rate in the radial direction was found to be divided into two regions where a linear growth was observed and a region characterized by a power law. Empirical expressions are introduced which predict concentration decay in the established flow region in both the axial and radial directions.