Multiphysics coupling investigation of interphase heat transfer in gas-particle coaxial-jet swirling flow via CFD-DEM-CHT

Abstract

The swirling particulate flows with heat transfer are widely encountered in the industry, yet the internal multiphysics coupling characteristics resulting from fluid, particle, and structure interactions are not well-understood. In present employment, a coupled method of computational fluid dynamics-discrete element method and conjugated heat transfer is constructed to provide insights into the thermal analysis in the industrial-scale annular pipe. The heat transfer behaviors between gas-pipe wall, gas-particle, particle-particle and particle-pipe walls are taken into account for the gas-particle coaxial-jet swirling flow. After verifying the mathematical model, the heat and momentum transfer behavior is analyzed, followed by a comprehensive exploration of fluid hydrodynamics, heat transfer characteristics, and particle properties under diverse swirler geometries. The results demonstrate that the presence of the swirler reinforces the forced convection between the jet and the high-temperature pipe wall. The heat exchange performance between the jet and the Wallcp-ann-cas enhances with the increase of vane angle and diameter of the swirler but decreases with the increase of swirler height. The impact of the swirler installing position on the thermophysical field can be neglected. An excessive number of swirler vanes adversely impacts the heat transfer process between the gas phase and pipe walls. The particle temperature increases with decreasing height, while the particle Nusselt number increases and then decreases with the decrease in height.