Multiscale Eulerian CFD of Chemical Processes: A Review

Abstract

This review covers the scope of multiscale computational fluid dynamics (CFD), laying the framework for studying hydrodynamics with and without chemical reactions in single and multiple phases regarded as continuum fluids. The molecular, coarse-grained particle, and meso-scale dynamics at the individual scale are excluded in this review. Scoping single-scale Eulerian CFD approaches, the necessity of multiscale CFD is highlighted. First, the Eulerian CFD theory, including the governing and turbulence equations, is described for single and multiple phases. The Reynolds-averaged Navier–Stokes (RANS)-based turbulence model such as the standard k-ε equation is briefly presented, which is commonly used for industrial flow conditions. Following the general CFD theories based on the first-principle laws, a multiscale CFD strategy interacting between micro- and macroscale domains is introduced. Next, the applications of single-scale CFD are presented for chemical and biological processes such as gas distributors, combustors, gas storage tanks, bioreactors, fuel cells, random- and structured-packing columns, gas-liquid bubble columns, and gas-solid and gas-liquid-solid fluidized beds. Several multiscale simulations coupled with Eulerian CFD are reported, focusing on the coupling strategy between two scales. Finally, challenges to multiscale CFD simulations are discussed. The need for experimental validation of CFD results is also presented to lay the groundwork for digital twins supported by CFD. This review culminates in conclusions and perspectives of multiscale CFD.

Computational and Experimental Analysis of Axial Flow Cyclone Used for Intake Air Filtration in Internal Combustion Engines

“…Computer simulation packages, based on specially created codes (CFD) [48] are helpful tools that are successfully used during the design and optimization of devices operation used in energy production [49][50][51], chemical engineering [52,53], process engineering [54,55] and environmental protection processes [56]. The versatility of application, the possibility of quick modification of the size and geometry of the designed device, as well as the wide possibilities of simulating single and multiphase flows, make them useful for the analysis and design optimization of axial-flow cyclones.…”

Modeling of gas–liquid flow in a rotating packed bed using an Eulerian multi‐fluid approach

“…On the contrary, the usage of Eulerian multi‐fluid methods could be a promising approach for simulation of gas–liquid flow and mass transfer in pilot‐scale or large‐scale chemical reactors due to the lower requirement of computational grid and shorter calculation time 24 . Currently, Eulerian multi‐fluid approach has been widely used in studying the liquid dispersion, 25 hydrodynamic behaviors, 26–31 and CO 2 absorption 32–34 in conventional packed beds or trickle beds. Eulerian two‐fluid model with a porous media model 35–37 and Eulerian three‐fluid model 38 are commonly used in these CFD studies.…”

Numerical and Experimental Analysis of Flow Pattern, Pressure Drop and Collection Efficiency in a Cyclone with a Square Inlet and Different Dimensions of a Vortex Finder

“…The helpful tools that can be successfully used during design and optimizing the operation of device and equipment, applied in energy production processes [31][32][33], chemical engineering [34][35][36], process engineering [37][38][39] and environmental protection processes [40][41][42] are computer simulation packages, based on specially created codes of Computational Fluid Dynamics (CFD) [43,44]. Their advantages such as the universality of application, ability to quickly modify size and geometry of designed device and also broad possibility of simulations single and multiphase flows, make them useful for analysis, re-scaling and design optimization of dust separators, including cyclones.…”