Quantification and Assessment of Numerical Error in Coupled Computational Fluid Dynamics - Discrete Element Method Simulations of Gas Flow through Granular Solids

Quantification and Assessment of Numerical Error in Coupled Computational Fluid Dynamics - Discrete Element Method Simulations of Gas Flow through Granular Solids

Bibliographic Details
Main Author: Volk, Annette
Language:English
Published: University of Cincinnati / OhioLINK 2018
Subjects:
Mechanical Engineering
Fluidized Bed
CFD-DEM
Particle-Fluid Interaction
Granular Flor
CFDEM project
Fixed-Particle Bed
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543139366302536
id ndltd-OhioLink-oai-etd.ohiolink.edu-ucin1543139366302536
record_format oai_dc
collection NDLTD
language English
sources NDLTD
topic Mechanical Engineering
Fluidized Bed
CFD-DEM
Particle-Fluid Interaction
Granular Flor
CFDEM project
Fixed-Particle Bed
spellingShingle Mechanical Engineering
Fluidized Bed
CFD-DEM
Particle-Fluid Interaction
Granular Flor
CFDEM project
Fixed-Particle Bed
Volk, Annette
Quantification and Assessment of Numerical Error in Coupled Computational Fluid Dynamics - Discrete Element Method Simulations of Gas Flow through Granular Solids
author Volk, Annette
author_facet Volk, Annette
author_sort Volk, Annette
title Quantification and Assessment of Numerical Error in Coupled Computational Fluid Dynamics - Discrete Element Method Simulations of Gas Flow through Granular Solids
title_short Quantification and Assessment of Numerical Error in Coupled Computational Fluid Dynamics - Discrete Element Method Simulations of Gas Flow through Granular Solids
title_full Quantification and Assessment of Numerical Error in Coupled Computational Fluid Dynamics - Discrete Element Method Simulations of Gas Flow through Granular Solids
title_fullStr Quantification and Assessment of Numerical Error in Coupled Computational Fluid Dynamics - Discrete Element Method Simulations of Gas Flow through Granular Solids
title_full_unstemmed Quantification and Assessment of Numerical Error in Coupled Computational Fluid Dynamics - Discrete Element Method Simulations of Gas Flow through Granular Solids
title_sort quantification and assessment of numerical error in coupled computational fluid dynamics - discrete element method simulations of gas flow through granular solids
publisher University of Cincinnati / OhioLINK
publishDate 2018
url http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543139366302536
work_keys_str_mv AT volkannette quantificationandassessmentofnumericalerrorincoupledcomputationalfluiddynamicsdiscreteelementmethodsimulationsofgasflowthroughgranularsolids
_version_ 1719454710072606720
spelling ndltd-OhioLink-oai-etd.ohiolink.edu-ucin15431393663025362021-08-03T07:08:42Z Quantification and Assessment of Numerical Error in Coupled Computational Fluid Dynamics - Discrete Element Method Simulations of Gas Flow through Granular Solids Volk, Annette Mechanical Engineering Fluidized Bed CFD-DEM Particle-Fluid Interaction Granular Flor CFDEM project Fixed-Particle Bed Fluid-solid multiphase interactions are prevalent in many industrial processes. Food processing, pharmaceuticals, petroleum refining, and chemical processing are some of the industries which rely on high-efficiency multiphase processes. While many multiphase processing systems have been developed through prototyping and experimental analysis, recent developments have shown that numerical simulations are effective for design and analysis of multiphase systems. Numerical simulations are able to capture the multi-scale phenomena in fluid-solid interactions, and provide detailed information across a large range of scales.Coupled Computational Fluid Dynamics - Discrete Element Method (CFD-DEM) is a common numerical approach for fluid-solid flows, as CFD-DEM can provide information at the particle scale, while remaining computationally efficient enough to model large experimental systems. However, CFD-DEM simulation results reported in the literature occasionally display large unexplained errors. I theorize that numerical error produced in the coupling procedure between CFD and DEM is responsible for the unexplained error. To evaluate this theory, I question how, and to what extent, the computational mesh cell size affects results from CFD-DEM simulations. My question of `how' contains two parts, (a) how are results quantitatively affected as the cell size is modified, and (b) what is the relationship, fundamentally, between the cell size and the results. For Part (a), I investigate to what extent results are affected by the computational cell size, by systematically modifying cell size for simulations of several common applications of CFD-DEM. Part (b) requires tracing the changes due to cell size through the full CFD-DEM calculation to determine the lattice of effects. I quantify the change in simulation results with computational grid refinement for mono-size particle fixed beds, binary-size particle fixed beds, and binary-size particle fluidized beds. These simulations cover a large range of typical particle mixtures, and range from dense to dilute flow. Results indicate a clear optimal computational cell size range which minimizes numerical error. This optimal cell size range is nearly consistent across the evaluated particle mixtures and system conditions. The quantified changes in simulation results with computational cell size indicate that numerical error magnitude has a non-negligible effect on the simulation solution. I analyze the CFD-DEM coupling models to determine how the numerical error is produced. The coarse-graining procedure, which translates particle-scale information to the fluid-scale, is shown to produce discontinuous fields when the computational grid is sufficiently refined. Drag law models calculate local particle-fluid momentum exchange, based on a non-linear relationship with local porosity. The drag law is shown to magnify the numerical error when discontinuous fields are produced in the coarse-graining procedure.I identify the source-mechanism for the large numerical errors which can be produced by the CFD-DEM coupling procedure. I determine coupling model choices which suppress numerical error production.I report the first grid refinement study applied to CFD-DEM simulations, and quantify numerical error. Grid refinement studies are shown to be a valuable tool for CFD-DEM, and I use the refinement study results to recommend ideal ranges of computational cell size to use in conjunction with ideal modeling choices. 2018 English text University of Cincinnati / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543139366302536 http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543139366302536 unrestricted This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. Specific terms and permissions are available from this document's record in the OhioLINK ETD Center.

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