Plenary Talk: Recent Advances in the Multi-Scale Simulation of Mass, Momentum and Heat Transfer in Dense Gas-Particle Flows

Dense gas-particle flows involving mass, momentum and heat transfer are frequently encountered in a variety of large scale industrial processes such as coating, granulation, polymerization and the production of base chemicals and synthetic fuels. In such flows the interactions between the dispersed particles and the continuous gas or liquid phase as well as the complex interactions among these particles govern the prevailing phenomena, i.e. the formation and evolution of heterogeneous flow structures. These structures have a significant impact on the quality of the contact between the phases and consequently strongly affect the overall performance of the process. Substantial additional complexities arise from the presence of non-spherical particles and particles which are partially wet due to the injection of a liquid.

Due to the inherent complexity of dense gas-particle flows a multi-scale modeling approach is used in which both fluid-particle and particle-particle interactions can be properly accounted for. The idea is essentially that fundamental models accounting for the relevant details of both fluid-particle (DNS) and particle-particle (DEM) interaction, are used to quantify the complex phase interactions in terms of closures. These closures are required in continuum models (i.e. the two-fluid model (TFM) or multi-fluid model (MFM)) based on the Kinetic Theory of Granular Flow (KTGF) suited to compute the flow structures on a much larger (industrial) scale. In this presentation recent advances in the multi-scale modelling of dense gas-particle flows will be highlighted with emphasis on coupled mass, momentum and heat transfer. In addition, areas which need substantial further attention will be briefly discussed including the challenges for non-invasive monitoring of such complex flows.