Design and Implementation of a Coupled CFD-DEM Framework for Modeling Heat Transfer in Gas–Solid Systems

Thermal transport in solid–gas multiphase systems remains a major challenge because the particle-level dynamics of granular materials are often not accurately captured by continuum solvers used for fluid flows. In this study, a coupled Computational Fluid Dynamics–Discrete Element Method (CFD–DEM) simulation is performed, in which granular particles are tracked using a Lagrangian formulation while the gas phase is maintained in an Eulerian framework. The open-source CPL Library is employed to exchange transport variables between the solvers. In the coupled setup, the fluid-phase momentum and energy equations are computed by the CFD solver, with source terms and flow properties updated using data provided by the DEM solver. Simultaneously, particle-scale force and energy equations are resolved by the DEM solver, while flow-field information is incorporated from the CFD solver. This coupled framework enables the investigation of heat transport in solid–gas multiphase systems and clarifies its distinction from conventional single-phase flow behavior.