CROSS-FLOW MIXING OF NONCIRCULAR JETS

An experimental investigation has been conducted of the isothermal mix ing of a turbulent jet injected perpendicular to a uniform crossflow t hrough several different types of sharp-edged orifices. Jet penetratio n and mixing was studied using planar Mie scattering to measure time-a veraged mixture fraction distributions of circular, square, elliptical , and rectangular orifices of equal geometric area injected into a con stant velocity crossflow. Hot-wire anemometry was also used to measure streamwise turbulence intensity distributions at several downstream p lanes. Mixing effectiveness was determined using 1) a spatial unmixedn ess parameter based on the variance of the mean jet concentration dist ributions and 2) by direct comparison of the planar distributions of c oncentration and of turbulence intensity. No significant difference in mixing performance was observed for the six configurations based on c omparison of the mean properties.