Mixing characteristics of a ducted elliptical jet

Abstract

Mixing between elliptical ducted air jets discharged at a sudden expansion and nitrogen, which was radially injected through the larger duct walls, was experimentally studied using hot-wire anemometry and gas sampling techniques. Mixing for this flowfield, which simulates a combustor with fuel addition through the side walls, increased considerably when the air jet was produced by an elliptical, rather than a circular, cross section. Elliptical jets discharging from orifices provide better mixing than jets discharging from elliptical and circular pipes. Additional mixing enhancement was achieved when the elliptical jets were acoustically forced by excited resonant pressure waves of the duct. The mean and turbulent velocity measurements provide insight into the mechanism of the observed mixing enhancement for this simulated boundary-layer combustion process.