Near Surface Characterization of an Impinging Elliptic Jet Array

Abstract

In this study naturally occurring large-scale structures and some turbulence characteristics within an impinging jet array are investigated. The dynamics of a three-by-three elliptic jet array are analyzed relative to the flow structures within the array. With applications to electronic component cooling, low Reynolds number conditions, Re = 300 to 1500, are presented. Two jet aspect ratios are used, 2 and 3, with identical jet hydraulic diameters and jet-to-jet space. The effects of impinging distance are studied in the range of one to six jet hydraulic diameters. Flow visualization and PIV are used for the identification of structures and quantitative analysis. These results are used to evaluate the integrated surface layer vorticity, Γ*, which is shown to depend on the jet aspect ratio and impingement distance. Also, a transport coefficient is presented, based on a turbulence velocity and length scales. This coefficient is shown to experience a maximum value versus impingement distance that coincides with the location of axis switching.