The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform
Russell L. Detwiler - One of the best experts on this subject based on the ideXlab platform.
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Fracture Permeability Alteration due to Chemical and Mechanical Processes: A Coupled High-Resolution Model
Rock Mechanics and Rock Engineering, 2014Co-Authors: Pasha Ameli, Jean E. Elkhoury, Joseph P. Morris, Russell L. DetwilerAbstract:Reactive fluid-flow experiments in fractures subjected to normal stress suggest the potential for either increased or decreased permeability resulting from fracture-surface dissolution. We present a computational model that couples mechanical deformation and chemical alteration of fractures subjected to constant normal stress and reactive fluid flow. The model explicitly represents micro-scale roughness of the fracture surfaces and calculates elastic deformation of the rough surfaces using a semi-analytical approach that ensures the surfaces remain in static equilibrium. A depth-averaged reactive transport model calculates chemical alteration of the surfaces, which leads to alteration of the Contacting fracture surfaces. The mechanical deformation and chemical alteration calculations are explicitly coupled, which is justified by the disparate timescales required for equilibration of mechanical stresses and reactive transport processes. An idealized analytical representation of dissolution from a single Contacting Asperity shows that under reaction-limited conditions, Contacting asperities can dissolve faster than the open regions of the fracture. Computational simulations in fractures with hundreds of Contacting asperities show that the transition from transport-limited conditions (low flow rates) to reaction-rate-limited conditions (high flow rates) causes a shift from monotonically increasing permeability to a more complicated process in which permeability initially decreases and then increases as Contacting asperities begin to dissolve. These results are qualitatively consistent with a number of experimental observations reported in the literature and suggest the potential importance of the relative magnitude of mass transport and reaction kinetics on the evolution of fracture permeability in fractures subjected to combined normal stress and reactive fluid flow.
Pasha Ameli - One of the best experts on this subject based on the ideXlab platform.
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Fracture Permeability Alteration due to Chemical and Mechanical Processes: A Coupled High-Resolution Model
Rock Mechanics and Rock Engineering, 2014Co-Authors: Pasha Ameli, Jean E. Elkhoury, Joseph P. Morris, Russell L. DetwilerAbstract:Reactive fluid-flow experiments in fractures subjected to normal stress suggest the potential for either increased or decreased permeability resulting from fracture-surface dissolution. We present a computational model that couples mechanical deformation and chemical alteration of fractures subjected to constant normal stress and reactive fluid flow. The model explicitly represents micro-scale roughness of the fracture surfaces and calculates elastic deformation of the rough surfaces using a semi-analytical approach that ensures the surfaces remain in static equilibrium. A depth-averaged reactive transport model calculates chemical alteration of the surfaces, which leads to alteration of the Contacting fracture surfaces. The mechanical deformation and chemical alteration calculations are explicitly coupled, which is justified by the disparate timescales required for equilibration of mechanical stresses and reactive transport processes. An idealized analytical representation of dissolution from a single Contacting Asperity shows that under reaction-limited conditions, Contacting asperities can dissolve faster than the open regions of the fracture. Computational simulations in fractures with hundreds of Contacting asperities show that the transition from transport-limited conditions (low flow rates) to reaction-rate-limited conditions (high flow rates) causes a shift from monotonically increasing permeability to a more complicated process in which permeability initially decreases and then increases as Contacting asperities begin to dissolve. These results are qualitatively consistent with a number of experimental observations reported in the literature and suggest the potential importance of the relative magnitude of mass transport and reaction kinetics on the evolution of fracture permeability in fractures subjected to combined normal stress and reactive fluid flow.
Joseph P. Morris - One of the best experts on this subject based on the ideXlab platform.
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Fracture Permeability Alteration due to Chemical and Mechanical Processes: A Coupled High-Resolution Model
Rock Mechanics and Rock Engineering, 2014Co-Authors: Pasha Ameli, Jean E. Elkhoury, Joseph P. Morris, Russell L. DetwilerAbstract:Reactive fluid-flow experiments in fractures subjected to normal stress suggest the potential for either increased or decreased permeability resulting from fracture-surface dissolution. We present a computational model that couples mechanical deformation and chemical alteration of fractures subjected to constant normal stress and reactive fluid flow. The model explicitly represents micro-scale roughness of the fracture surfaces and calculates elastic deformation of the rough surfaces using a semi-analytical approach that ensures the surfaces remain in static equilibrium. A depth-averaged reactive transport model calculates chemical alteration of the surfaces, which leads to alteration of the Contacting fracture surfaces. The mechanical deformation and chemical alteration calculations are explicitly coupled, which is justified by the disparate timescales required for equilibration of mechanical stresses and reactive transport processes. An idealized analytical representation of dissolution from a single Contacting Asperity shows that under reaction-limited conditions, Contacting asperities can dissolve faster than the open regions of the fracture. Computational simulations in fractures with hundreds of Contacting asperities show that the transition from transport-limited conditions (low flow rates) to reaction-rate-limited conditions (high flow rates) causes a shift from monotonically increasing permeability to a more complicated process in which permeability initially decreases and then increases as Contacting asperities begin to dissolve. These results are qualitatively consistent with a number of experimental observations reported in the literature and suggest the potential importance of the relative magnitude of mass transport and reaction kinetics on the evolution of fracture permeability in fractures subjected to combined normal stress and reactive fluid flow.
Jean E. Elkhoury - One of the best experts on this subject based on the ideXlab platform.
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Fracture Permeability Alteration due to Chemical and Mechanical Processes: A Coupled High-Resolution Model
Rock Mechanics and Rock Engineering, 2014Co-Authors: Pasha Ameli, Jean E. Elkhoury, Joseph P. Morris, Russell L. DetwilerAbstract:Reactive fluid-flow experiments in fractures subjected to normal stress suggest the potential for either increased or decreased permeability resulting from fracture-surface dissolution. We present a computational model that couples mechanical deformation and chemical alteration of fractures subjected to constant normal stress and reactive fluid flow. The model explicitly represents micro-scale roughness of the fracture surfaces and calculates elastic deformation of the rough surfaces using a semi-analytical approach that ensures the surfaces remain in static equilibrium. A depth-averaged reactive transport model calculates chemical alteration of the surfaces, which leads to alteration of the Contacting fracture surfaces. The mechanical deformation and chemical alteration calculations are explicitly coupled, which is justified by the disparate timescales required for equilibration of mechanical stresses and reactive transport processes. An idealized analytical representation of dissolution from a single Contacting Asperity shows that under reaction-limited conditions, Contacting asperities can dissolve faster than the open regions of the fracture. Computational simulations in fractures with hundreds of Contacting asperities show that the transition from transport-limited conditions (low flow rates) to reaction-rate-limited conditions (high flow rates) causes a shift from monotonically increasing permeability to a more complicated process in which permeability initially decreases and then increases as Contacting asperities begin to dissolve. These results are qualitatively consistent with a number of experimental observations reported in the literature and suggest the potential importance of the relative magnitude of mass transport and reaction kinetics on the evolution of fracture permeability in fractures subjected to combined normal stress and reactive fluid flow.
Liming Chang - One of the best experts on this subject based on the ideXlab platform.
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Some insights into Asperity temperatures in mixed-film lubrication
Tribology International, 2001Co-Authors: X. Zhai, Liming ChangAbstract:This paper investigates some fundamental thermal behavior of Asperity contacts in mixed-film lubrication. First, the thermal interaction between the Contacting Asperity and the lubricant is studied. The analysis is based on transient simulations of a mixed-film contact problem under various contact conditions. The results suggest that the solid/fluid thermal interaction can be strong. The lubricant is shown to play an important role in Asperity temperature. It not only generates heat through viscous shearing but also plays a role of cooling by transporting heat out of the thermally intensive Asperity contacts. The interaction can significantly reduce Asperity temperatures especially under high-speed conditions. The interaction also increases the lubricant temperature away from the Asperity contact, thus facilitating thermal coupling among Contacting asperities. Another thermal behavior of mixed-film contact studied is the effect of heat flow in the Asperity contact in the direction perpendicular to the lubricant entrainment. Results suggest that the effect of this thermal side-flow is significant in low-speed contacts and diminishes when the entraining velocity becomes high. Further, the side-flow effect is much weaker in the mixed-film contact than in the dry contact and may be neglected in the modeling of complex mixed lubrication problems.