Identification of the initial particle size distribution for coal combustion simulations

Pulverized coal generally features wide particle-size distributions (PSD). How to set an initial PSD in coal combustion simulation remains an open question. To answer this, the Gaussian-quadrature theory was applied to provide a discrete reconstruction of the PSD described by Rosin-Rammler and upper-limit functions. From the perspective of the moments of PSD, a theoretical analysis was conducted for mass, momentum and energy exchange terms between gas and particle phases in pulverized coal jet flame. The analysis presented that the first, the second and the third moment of PSD were the most important to capture the flame ignition behavior. The LES simulations showed that the proposed method with two or more particle sizes could provide complete PSD when predicting the ignition behavior of pulverized coal jet flame.