The partially stirred reactor model for combustion closure in large eddy simulations: Physical principles, sub-models for the cell reacting fraction, and open challenges

For their ability to account for finite-rate chemistry, reactor-based models are well suited Turbulence–Chemistry Interactions (TCI) Sub-Grid Scale (SGS) closures Large Eddy Simulations (LES). The SGS closure in the Partially Stirred Reactor (PaSR) model relies on determination of reacting fraction each computational cell, whose definition is based estimates characteristic mixing and chemical time scales. Direct Numerical (DNS) turbulent combustion can supply key information TCI development, validation, comparison models. In particular, a priori testing allows direct validation assumptions. present work, an assessment PaSR conducted. Its reconstruct thermo-chemical quantities interest investigated along with Sub-grid extracted from DNS investigate role cell fraction. Various definitions then proposed estimate timescale model. Modeled source terms heat release rates compared against filtered data two-dimensional, spatially developing, nonpremixed jet flame detailed kinetics. results demonstrate importance accounting fine structures context A new formulation provides improved overall predictions. Several issues raised discussion, representing realistic prospects further developments as LES.