Large Eddy Simulation of a Turbulent Dilute Ethanol Flame Using the Two-Phase Spray Flamelet Generated Manifold Approach.

A recently developed spray Flamelet Generated Manifolds (SFGM) approach has been extended to include turbulence–chemistry interactions for studies of turbulent spray flames based on Eulerian–Lagrangian multiphase Large Eddy Simulation (LES). The Eulerian–Eulerian two-fluid formulation of the SFGM was extended to include the mixture fraction variance to construct a 4-D manifold library. The effect of heat loss due to droplet evaporation was considered in the SFGM tabulation, and the SFGM approach was evaluated using the Sydney ethanol spray flame experimental database. The two-phase interaction was investigated from complete analyses of the continuous- and dispersed-phase dynamics. Comparisons between the numerical results and the experimental data indicate that the SFGM formulated from counterflow spray flames can produce a good agreement with the gaseous flow field and the dispersed-phase statistics. By comparing the results in terms of the temperature field with other existing models, it can be inferred that the discrepancies between the flamelet-based results and the experimental data may not depend on the choice of the flamelet approach but on the modeling of the turbulence/chemistry interaction model. A Beta-function of the normalized progress variable can be an alternative to improve the temperature predictions. Moreover, using a well-designed definition of the progress variable by finding the optimal weights of several appropriate species is another possible path to improve the predictions. [ABSTRACT FROM AUTHOR]