Low Reynolds Number Effects on Jets from Round, Square and Elliptical Orifices

Abstract

An experimental study was undertaken to investigate low Reynolds number effects on mixing characteristics and turbulent transport phenomena in the near and intermediate regions of free orifice jets. The cross-sections examined were round, square and ellipse of aspect ratio 3. For each orifice cross-section, detailed velocity measurements were obtained at the following 4 Reynolds number based on the equivalent diameter and maximum velocity: 2500, 4300, 8500 and 17000. A high resolution particle image velocimetry was used to conduct measurements in the symmetry planes that extend from the exit to 15 equivalent diameters. Preliminary results show that an axis-switching happens at 2.7 equivalent diameters in the case of ellipse nozzle which leads to a higher spread rate compared to square and round ones. Also increase in Reynolds number decreases the jet widths.