Large-Eddy Simulation of Premixed Combustion in the Corrugated-Flamelet Regime

© 2015, Published with license by Taylor & Francis Group, LLC © 2015, © I. Langella, N. Swaminathan, F. A. Williams, and J. Furukawa. Large-eddy simulation (LES) is applied to a fuel-lean turbulent propane-air Bunsen flame in the corrugated-flamelet regime. The subgrid-scale (SGS) modeling includes a previously developed treatment of the total enthalpy along with three different SGS velocity, (Formula presented.) , models. In addressing the filtered reaction rate, a presumed probability density function (PDF) approach is employed for the reaction-progress variable, closed by a transport equation for its SGS variance. The statistics obtained using the three (Formula presented.) models are in good agreement with the measurements and do not differ significantly from each other for first-order moments suggesting that commonly used SGS modeling may be adequate to get the mean velocities and reaction progress variable. However, all three SGS velocity models fail to reflect a measured bimodality of the PDF of the radial component of the velocity in the central portion of the flame. This emphasizes a need for further development of (Formula presented.) models required at the reaction rate closure level for practical LES of combustion in the corrugated-flamelet regime