Swirling jets with and without combustion

Strongly swirled, unconfined jets were quantified using a laser Doppler velocimeter measurement system with a unique, in-house single-particle processor under isothermal and combustion conditions. A drastic alteration of mean flow profiles was recognized as a result of combustion. Deviations of the swirl velocity from a solid-body rotation in the flame zone were probably due to unstabilizing effects caused by the viscous forces which outweighed the centrifugal forces. Turbulence levels were higher in the reacting flow with a scatter of the measured data than in the isothermal jet. It may be deduced that time-dependent variations of the density as well as the flame location, caused by interaction of chemical reaction/turbulence, produced the scattered data and hence the flame-generated turbulence. The experimental data indicate that the turbulence local equilibrium model may be accepted in the reacting strongly swirled jet.