Effect of Shear-flow Dynamics in Combustion Processes

Experiments were performed to study the effect of shear-flow control on the mixing and combustion process between a low-Mach number, subsonic, ducted air jet with dump and gaseous fuel radially injected through the duct walls. In nonreacting tests using hot-wire anemometry and gas sampling techniques, mixing was enhanced by controlled pressure waves (active shear-flow control) and by controlling the jet's initial shear-flow conditions (passive control) using an elliptical jet-exit cross-section and reducing the initial boundary layer thickness. In combustion tests using thermocouples, the same shear-flow manipulations also resulted in improved mixing when the understanding of the shear-flow dynamics gained from the nonreacting tests was applied to the combustion environment.