LES of turbulent stratified flames under swirling conditions AIP/123-QED Large eddy simulation/probability density function simulations of the Cambridge turbulent stratified flame series under swirling conditions Hasret Turkeri, 1, a) Xinyu Zhao, 2 and Metin Muradoglu 3 1) Tusas Engine Industries (TEI), INC., Eskisehir, 26210, Turkey 2) Department of Mechanical Engineering, University of Connecticut, Storrs CT 06269, USA 3) Department of Mechanical Engineering, Ko¸c University, Rumelifeneri Yolu, Sariyer, 34450, Istanbul, Turkey The large eddy simulations/probability density functions (LES/PDF) methodology is applied to the Cambridge/Sandia turbulent stratified flame series under swirling con- ditions. The methane/air chemistry is represented by a 16-species augmented reduced mechanism, and the in situ adaptive tabulation method is adopted to accelerate the chemistry calculation. Effects of differential diffusion and heat loss through the bluff- body surface are taken into account. The simulations are conducted for premixed (SwB3), moderately and highly stratified (SwB7 and SwB11, respectively) cases un- der swirling conditions. The results from LES/PDF simulations are compared with experimental measurements. The computed mean and r.m.s. profiles of velocity, tem- perature, equivalence ratio and mass fractions of species are in very good agreement with the measurements for all three conditions. Scatter plots and conditional means of species mole fractions and temperature are compared with the experimental data, where overall good consistency with the measurements is achieved. The recirculation zones are five times longer than those obtained under non-swirling conditions. A low-equivalence-ratio high-temperature region near the bluffbody is not captured in the computation, which is attributed to the insufficient entrainment of downstream mixtures into the recirculation zone. The parametric studies show that the differ- ential diffusion has a negligible effect on the mean and r.m.s. results, whereas the heat loss has a considerable effect on the temperature and CO profiles close to the bluffbody. a) Electronic mail: hturkeri@ku.edu.tr, hasretturkeri@gmail.com 1 arXiv:2012.00731v1 [physics.flu-dyn] 1 Dec 2020