EXPERIMENTAL INVESTIGATIONS ON THE EFFECT OF SWIRL AND BLUFF BODY WAKE IN CIRCULAR JETS

摘要

Swirl with bluff body wake in jets finds application in gas turbine engines, turbo machinery etc. to strengthen the recirculation region, improve combustion efficiency, enhance flame stabilization, improve fuel air mixing and blow off limits and lower pollutant formation. This paper discusses the combined effect of swirl and rotating bluff body wake in circular jets. The flow pattern of the swirl jet has been studied in the near vicinity of the jet exit for different inlet high Reynolds numbers (only for which the recirculation effect is beneficial), critical swirl angle (30 degree-similar to what is employed in industrial furnaces and burners), and a constant blockage ratio of the bluff body at eight different axial positions in the recirculation zone. Reynolds stresses, mean axial and tangential velocities, turbulent intensities, turbulent kinetic energy are measured and compared for the bluff body rotating and non-rotating cases. A DANTEC Dynamics make constant temperature anemometer with X-probe has been used to measure mean and turbulence parameters.