A Numerical Study of the Effect of Swirl Number on Premixed Low Swirl Combustion

Low swirl combustion is a novel method to stabilize lean premixed flames. In order to utilize this stabilization method in gas turbines, it is required to gain a better understanding of flow and combustion characteristics of low swirl combustion in different working condition. This paper utilizes large eddy simulation (LES) and a thickened flame model to investigate the characteristics of a low swirl flame under two swirl number conditions. Results from simulation of the low swirl flame show that the lifted flame is stabilized above the burner exit by means of a low velocity zone, rather than the presence of a central recirculation zone. With the increase of swirl number from 0.5 to 0.65, the flame and the central recirculation zone move upstream; however, the stabilization mechanism does not change.