Modeling and Simulation of Micron Particle Agglomeration in a Turbulent Flow: Impact of Cylindrical Disturbance and Particle Properties.

Abstract

The fly ash generated by coal combustion is one of the main sources of PM2.5, so the particulate matter removal technology of coal-fired boilers is receiving increasing attention. Turbulent agglomeration has emerged as a powerful tool for improving the efficiency of removing fine particulates from environments, sparking interest in its study. Our research meticulously investigated the influence of cylindrical vortex wakes on particle flow, agglomeration patterns, and the dynamics between fluids and particles. By employing a novel hybrid computational approach that integrates the discrete element method (DEM) with large Eddy simulation (LES), we were able to accurately simulate particle-particle interactions. The study focused on understanding how particles with different diameters (2, 5, 10, and 20 μm), densities (2,500, 5,000, 7,500, and 10,000 kg·m^-3), and surface energies (0.01, 0.1, and 1 J·m^-2) behaved within transitioning shear layer flow conditions. Our findings revealed that particles tended to congregate in areas of lower vorticity, with larger and denser particles demonstrating greater agglomeration efficiency due to their resilience against turbulent forces. Conversely, particles of lower density formed smaller agglomerates as their susceptibility to shear forces increased. Additionally, the study discovered that higher surface energies enhance adhesion, leading to the formation of larger agglomerates.