Hydrodynamics of polydisperse gas-solid flows: Kinetic theory and multifluid simulation

• DOI: 10.48550/arxiv.2311.09495
• Publication Date: 2024-04-01
• Authors: Bidan Zhao; Kun Shi; Mingming He; Junwu Wang
• Keywords: Fluid Dynamics (physics.flu-dyn); FOS: Physical sciences; Physics - Fluid Dynamics; 02 engineering and technology; 0210 nano-technology

Polydisperse gas-solid flows, which is notoriously difficult to model due to the complex gas-particle and particle-particle interactions, are widely encountered in industry. In this article, a refined kinetic theory for polydisperse flow is developed, which features single-parameter Chapman-Enskog expansion (the Knudsen number) and exact calculation of the integrations related to pair distribution function of particle velocity without any mathematical approximations. The Navier-Stokes order constitutive relations for multifluid modeling of polydisperse gas-solid flow are then obtained analytically, including the solid stress tensor, the solid-solid drag force, the granular heat flux and the energy dissipation rate. Finally, the model is preliminarily validated by comparing to the discrete element simulation data of one-dimensional granular shear flow and by showing that the hydrodynamic characteristics of gas-solid flows in a bubbling fluidized bed containing bidisperse particles can be successfully predicted.