An Experimental and Computational Study of a Swirl-Stabilized Premixed Flame

An unconfined strongly swirled flow is investigated for different Reynolds numbers using particle image velocimetry (PIV) and large eddy simulation (LES) with a thickened-flame (TF) model. Both reacting and nonreacting flow results are presented. In the LES-TF approach, the flame front is resolved on the computational grid through artificial thickening and the individual species transport equations are directly solved with the reaction rates specified using Arrhenius chemistry. Good agreement is found when comparing predictions with the experimental data. Also the predicted root mean square (rms) fluctuations exhibit a double-peak profile with one peak in the burnt and the other in the unburnt region. The measured and predicted heat release distributions are in qualitative agreement with each other and exhibit the highest values along the inner edge of the shear layer. The precessing vortex core (PVC) is clearly observed in both the nonreacting and reacting cases. However, it appears more axially elongated for the reacting cases and the oscillations in the PVC are damped with reactions.