Micro- and Mesoscopic Models for Flow and Mixing of Suspensions

The mechanistic modeling of flow phenomena in various processes of the chemical industry is still a challenge, especially in case fluid-particle suspensions are involved. In addition, transport of species and thermal energy needs to be considered to make reliable predictions, e.g., on the performance of a chemical reactor.
The present thesis documents Euler-Lagrange (EL) models for the description of momentum, heat, and mass transport in suspensions, as well as selected numerical solutions. The focus is on gas-particle suspensions which are encountered in the energy and pharmaceutical industry. Four goals are followed: The first goal is to establish a simulation platform that enables a time-efficient simulation of EL models. This is achieved by implementing a variety of new software tools, as well improving existing simulators. The newly implemented tools now enable, for example, to account for intra-particle property profiles in EL-based simulations. The second goal is to verify and validate these tools. Specifically, an array of test cases is considered, e.g., heat and mass transfer in packed beds, or particle motion through a T-Junction. These test cases are used to build confidence in the models, as well as to identify weaknesses in numerical schemes used. The third goal is to development new closures for EL models, specifically, for momentum and heat transfer. The results refine previously proposed closures, as well as relax the need for extremely fine computational grids in meso-scale EL-based simulations. The fourth goal is to establish a new set of models that describe particle-particle liquid transfer in wet granular flows. These models enable more rigorous simulations of flow and liquid transport in three-phase systems, e.g., wet fluidized beds.