A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Massively parallel simulations of chemical dissolution in porous media based on advanced lattice Boltzmann models
https://orcid.org/0000-0003-3656-7028
Civil engineering structures are designed and built to serve for a minimum usage- and life-time. Yet, the state of materials and the resulting structural properties of buildings are subject to change depending on outer conditions and eventually lead to degradation of reliability and safety for the intended loads and usage. The evolution of the properties of building materials and structures may be caused by physical or chemical processes occurring on different spatial and temporal scales. In this thesis the focus is on modeling and simulation of a subset of these processes in cement based materials which are related to the chemical dissolution due to the leaching of calcium. While often the results of such processes are visible on a macroscopic scale after very long times only, its genesis typically has a long history which is only detectable on the pore scale. In order to improve our understanding of such processes on multiple spatio-temporal scales, small scale simulations of multi-species transport and reaction are of vital importance. Due to the geometric complexity of the pore space and the need to consider a representative elementary volume, such simulations require substantial numerical resolutions leading to huge computation times. Thus, an efficient parallelization of such numerical methods is vital to obtain results in acceptable wall-clock time. The goal of this thesis is to improve available approaches based on Lattice Boltzmann methods to reliably and accurately predict the combined effects of mass transport and reaction in porous media. To this end, we will rely on the recently developed cumulant LBM for the momentum equations and the factorized central moment LBM of the second-order accurate approach for describing transport. To include morphology change due to dissolution of the hydrated cement solid phases the volume of fluid method with piecewise linear interface construction algorithm is employed. These developments will be integrated into the LBM research code VirtualFluids. After verification and validation of our developments for simplified problems, results obtained for realistic 3D ct images of hydrated cement pastes are discussed and an outlook to future applications and extensions of the developed methods is given.
Massively parallel simulations of chemical dissolution in porous media based on advanced lattice Boltzmann models
https://orcid.org/0000-0003-3656-7028
Civil engineering structures are designed and built to serve for a minimum usage- and life-time. Yet, the state of materials and the resulting structural properties of buildings are subject to change depending on outer conditions and eventually lead to degradation of reliability and safety for the intended loads and usage. The evolution of the properties of building materials and structures may be caused by physical or chemical processes occurring on different spatial and temporal scales. In this thesis the focus is on modeling and simulation of a subset of these processes in cement based materials which are related to the chemical dissolution due to the leaching of calcium. While often the results of such processes are visible on a macroscopic scale after very long times only, its genesis typically has a long history which is only detectable on the pore scale. In order to improve our understanding of such processes on multiple spatio-temporal scales, small scale simulations of multi-species transport and reaction are of vital importance. Due to the geometric complexity of the pore space and the need to consider a representative elementary volume, such simulations require substantial numerical resolutions leading to huge computation times. Thus, an efficient parallelization of such numerical methods is vital to obtain results in acceptable wall-clock time. The goal of this thesis is to improve available approaches based on Lattice Boltzmann methods to reliably and accurately predict the combined effects of mass transport and reaction in porous media. To this end, we will rely on the recently developed cumulant LBM for the momentum equations and the factorized central moment LBM of the second-order accurate approach for describing transport. To include morphology change due to dissolution of the hydrated cement solid phases the volume of fluid method with piecewise linear interface construction algorithm is employed. These developments will be integrated into the LBM research code VirtualFluids. After verification and validation of our developments for simplified problems, results obtained for realistic 3D ct images of hydrated cement pastes are discussed and an outlook to future applications and extensions of the developed methods is given.
Massively parallel simulations of chemical dissolution in porous media based on advanced lattice Boltzmann models
https://orcid.org/0000-0003-3656-7028
Civil engineering structures are designed and built to serve for a minimum usage- and life-time. Yet, the state of materials and the resulting structural properties of buildings are subject to change depending on outer conditions and eventually lead to degradation of reliability and safety for the intended loads and usage. The evolution of the properties of building materials and structures may be caused by physical or chemical processes occurring on different spatial and temporal scales. In this thesis the focus is on modeling and simulation of a subset of these processes in cement based materials which are related to the chemical dissolution due to the leaching of calcium. While often the results of such processes are visible on a macroscopic scale after very long times only, its genesis typically has a long history which is only detectable on the pore scale. In order to improve our understanding of such processes on multiple spatio-temporal scales, small scale simulations of multi-species transport and reaction are of vital importance. Due to the geometric complexity of the pore space and the need to consider a representative elementary volume, such simulations require substantial numerical resolutions leading to huge computation times. Thus, an efficient parallelization of such numerical methods is vital to obtain results in acceptable wall-clock time. The goal of this thesis is to improve available approaches based on Lattice Boltzmann methods to reliably and accurately predict the combined effects of mass transport and reaction in porous media. To this end, we will rely on the recently developed cumulant LBM for the momentum equations and the factorized central moment LBM of the second-order accurate approach for describing transport. To include morphology change due to dissolution of the hydrated cement solid phases the volume of fluid method with piecewise linear interface construction algorithm is employed. These developments will be integrated into the LBM research code VirtualFluids. After verification and validation of our developments for simplified problems, results obtained for realistic 3D ct images of hydrated cement pastes are discussed and an outlook to future applications and extensions of the developed methods is given.
Massively parallel simulations of chemical dissolution in porous media based on advanced lattice Boltzmann models
Massiv parallele Simulationen der chemischen Auflösung in porösen Medien basierend auf hochentwickelten Lattice Boltzmann Modellen
Alihussein, Hussein (author) / Universitätsbibliothek Braunschweig (host institution) / Krafczyk, Manfred (tutor) / Geier, Martin (tutor)
2020
Miscellaneous
Electronic Resource
English
| UB Braunschweig | 2020