The simulation and modeling of settling and clustering behavior of polydisperse gas-solid flows with application to pyroclastic density currents

Abstract

Gas-solid flows are present in many industrial and natural systems, including fluidized beds, energy systems, and pyroclastic density currents (PDCs). Predicting these flows remains challenging due to complex interactions between particles and the carrier fluid, particularly in polydisperse systems where particle sizes vary significantly. These challenges are especially important for PDCs, whose large temporal and spatial scales require coarse-grained multiphase flow solvers with closure models to represent unresolved particle-scale physics. This work investigates the settling and clustering dynamics of polydisperse gas-solid flows relevant to PDCs using high-fidelity Euler-Lagrange simulations and develops models and correlations for coarse-grained solvers.