Evolution of the soot particle size distribution in turbulent nonpremixed bluff body flames using the Bivariate Multi-Moment Sectional Method

To address current and emerging soot particle size regulations, understanding the evolution of the soot particle size distribution (PSD) is a critical need. Traditionally, sectional methods have been utilized to simulate the evolution of the PSD in turbulent reacting flows utilizing Large Eddy Simulation (LES) but suffer from simultaneous shortcomings of excessive computational cost and physical inaccuracy due to their limitation to a single size coordinate incapable of accounting for the aggregate structure of soot. The Multi-Moment Sectional Method (MMSM) tackles the former shortcoming by considering two moments per section and a locally linear reconstruction of the size distribution within a section but fewer sections so fewer overall unknowns. In this work, the Bivariate MMSM (BMMSM) extends MMSM to consider a joint description of soot aggregate morphology in volume and surface area and overcome the latter shortcoming. BMMSM is first validated in one-dimensional laminar flames and then implemented in LES and applied to simulation of a series of turbulent nonpremixed bluff body flames. The evolution of the PSD is analyzed in the different regions of the flame.