Large Eddy Simulation of premixed turbulent combustion using approximate deconvolution and explicit flame filtering

Abstract

Approximate deconvolution and explicit filtering of scalar fields are used to construct a new approach to sub-grid scale modeling in Large Eddy Simulation (LES) of premixed turbulent flames. This modeling is designed to handle any form of chemical description, Arrhenius or tabulated, as soon as the grid resolution is not too coarse. The closure of the unresolved terms relies on the explicit filtering of their exact expressions computed after an approximate deconvolution of the resolved scalars. A specific numerical treatment is needed to capture the deconvoluted peak burning rate over the coarse LES mesh. The method is first tested in the canonical laminar filtered flame context with two strategies for the unresolved fluxes, which are based either on a full approximate deconvolution, or, on the introduction of a corrective factor applied to the resolved diffusive flux. This factor is dynamically determined from the deconvoluted/filtered burning rates to preserve basic filtered flame front properties (propagation speed and thickness). Then, a three-dimensional turbulent Bunsen flame studied experimentally by Chen et al. (1996) [13] is simulated.