A Hybrid Large Eddy Simulation/Filtered Mass Density Function for the Calculation of Strongly Radiating Turbulent Flames

Due to the complex nonlinear coupling of turbulent flow, finite-rate combustion chemistry and thermal radiation from combustion products and soot, modeling, and/or simulation of practical combustors, or even laboratory flames undergoing strong soot formation, remain elusive. Methods based on the determination of the probability density function of the joint thermochemical scalar variables offer a promising approach for handling turbulence-chemistry-radiation interactions in flames. Over the past decade, the development and application of the filtered mass density function (FMDF) approach in the context of large eddy simulations (LES) of turbulent flames have gained considerable ground. The work described here represents the first application of the LES/FMDF approach to flames involving soot formation and luminous radiation. The initial focus here is on the use of a flamelet soot model in an idealized strongly radiating turbulent jet flame, which serves to detail the formulation, highlight the importance of turbulence-radiation interactions, and pave the way for the inclusion of a soot transport and finite-rate kinetics model allowing for quantitative comparisons to laboratory scale sooting flames in the near future.