COMPARISON OF MEASURED ISOTHERMAL AND COMBUSTING CONFINED SWIRLING FLOWS - PERIPHERAL FUEL-INJECTION

A study was conducted on a burner system in which the fuel was injected around the outer periphery of the swirled air jet. This type of burner has advantages in achieving better mixing and rapid combustion. Measurements of the velocity components and static pressure were made in the furnace, of confinement ratio D/d = 2.5, under both combusting and isothermal conditions. In the combusting case, temperatures and species concentrations were also measured. The effect of axial flow acceleration caused by combustion on the observed flow patterns was a weakening or even cancelation of the central reverse-flow zone. For a given swirler, combustion led to a significant increase in the measured axial momentum flux (dynamic component), a small increase in the tangential momentum flux, and thus a reduction in the furnace swirl number S* based on these momentum fluxes. The furnace swirl number was successful in correlating these changes in flow pattern.