Flamelet LES of a turbulent pulverized solid fuel flame using a detailed phenomenological soot model

In this work, large-eddy simulation (LES) is conducted for a turbulent pulverized coal flame with a detailed phenomenological model to characterize the soot evolution and a flamelet model to describe the detailed gas phase kinetics. In particular, a quadrature-based moment method (QBMM) is adopted to describe the soot statistics with the physicochemical processes of soot particle nucleation, condensation, coagulation, chemical surface growth and oxidization being considered. The simulation results are compared to the exfor polycyclic aromatic hydrocarbons (PAHs), laser induced incandescence (LII) for soot, scanning electron microscope (SEM) with the thermophoretic sampling (TS), and the time-resolved LII (TiRe-LII) for spatial soot particle size distribution. The comparisons show that the ignition position and the mean velocity of the coal particles can be accurately predicted with the proposed flamelet/QBMM/LES method, and an overall good agreement is also obtained when comparing against the PAHs-LIF, soot-LII and SEM images. The importance of the contributions of the different physicochemical processes to the soot particle volume growth is quantified by analyzing the corresponding moment source terms. It is found that for the pulverized coal flame studied, the chemical surface growth is the most important contribution to the soot volume growth at different locations along the streamwise direction. Although the nucleation does not make a significant contribution to soot volume growth, it determines the number density of the primary soot particles formed in the main flow region.& COPY; 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

Large-eddy simulation (LES) with a detailed model was used to study a turbulent pulverized coal flame and characterize the soot evolution. A flamelet model was employed to describe the gas phase kinetics, and a quadrature-based moment method (QBMM) was used to describe the soot statistics considering various physicochemical processes. The simulation results were compared to experimental data, and good agreement was observed for various measurements such as PAHs-LIF, soot-LII, and SEM images. The contributions of different physicochemical processes to soot growth were quantified, with chemical surface growth being identified as the most important.