Theses and Dissertations at Montana State University (MSU)
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Item An experimental study of drying in porous media in novel 2D micromodels with dual porosity(Montana State University - Bozeman, College of Engineering, 2024) Habib, Md Ahsan; Chairperson, Graduate Committee: Yaofa LiDrying of porous media is pervasive in numerous natural and engineering processes, such as oil recovery, CO 2 storage, and critical zone science. Drying is essentially a multiphase flow process, where the liquid phase evaporates and is displaced/replaced by the gaseous phases, as vapor diffuses out of the porous structure. In terms of pore structure and other physical characteristics like porosity and permeability, many porous matrices exhibit multi-scale heterogeneity. For instance, in critical zone, soil is often viewed as a hierarchical organization: primary particles form aggregates, which in turn form macroaggregates, effectively leading to a dual-porosity medium. Numerous activities, including gases and water transport, are known to be controlled by the resultant multiscale flow dynamics and inter-/intra-aggregate interaction during drying. However, the fundamental physics underlying drying of porous media with dual porosity is not well understood from a fluid mechanics perspective. In this work, a novel 2D microfluidic device fabrication technique has been developed. To study the multi-phase flow of air and water, emphasizing the multi-scale interaction, pore structure, and role of film flows, three distinct types of microfluidic devices have been fabricated, which bear the innovative three-layer glass-silicon- glass architecture, providing precise structural control and excellent optical access from both top and bottom. An innovative dual-magnification imaging technique has been introduced adapted for micro-PIV and epi-fluorescent microscopy which offers insightful information about the flow dynamics at both the micro- and macro-scales concurrently. In this thesis, two distinct types of experiments are outlined, focusing on diffusion-driven drying and flow-through drying, utilizing three diverse micromodels characterized by varying porous structures and distributions. The experimental results have presented the overall drying dynamics observed in different micromodels, each featuring unique porous configurations. The impact of porous geometry and external flow conditions on drying rate and associated pore-scale physics is thoroughly examined. The findings encompass a comprehensive overview of micro-macro pore interactions, as evidenced by separated saturation distribution, displacement rates, and other pertinent flow parameters. The findings have reflected the influence of pore geometry, distribution, hydraulic connectivity, and film flow on the observed effects.Item Experimental characterization of pore-scale capillary pressure and corner film flow in 2D porous micromodels(Montana State University - Bozeman, College of Engineering, 2023) Molla, Razin Sazzad; Chairperson, Graduate Committee: Yaofa LiMultiphase flow in porous media is ubiquitous in natural and engineering processes. A better understanding of the underlying pore-scale physics is crucial to effectively guiding, predicting and improving these applications. Traditional models describe multiphase flows in porous media based on empirical constitutive relations (e.g., capillary pressure vs. saturation), which, however, are known to be hysteretic. It has been theoretically shown that the hysteresis can be mitigated by adding new variables in the functional form. However, experiments are still needed to validate and further develop the theories. In particular, our understanding of capillary pressure characterization and numerous pore-scale mechanisms is still limited. For instance, during capillary pressure measurement, fluid phases become disconnected, making the bulk pressure an inaccurate measure for the actual capillary pressure. In a strongly wetting medium, wetting phase always remains connected by corner films, through which trapped water continues to drain until a capillary equilibrium is reached, but the effects of corner film flow are minimally characterized. In this thesis, two different experiments are presented. In the first experiment, we focused on the capillary pressure characterization and the effect of measurement resolution. Microscopic capillary pressure along with other geometric measures are characterized during drainage and imbibition. By strategically varying the pressure at the boundary, different equilibrium states were achieved and imaged at four different magnifications (i.e., 2, 1.25, 0.5, 0.25 micron/pixel). In the second experiment, we for the first time characterized the corner film flow again during drainage and imbibition condition employing particle image velocimetry. Overall, our results suggest that the calculated macroscale pressure P c and the bulk pressure drop agree reasonably well when only interfaces associated with the connected phases are considered. A spatial resolution of 2 micron/pixel seems to sufficiently resolve the interface, and further increasing the resolution does not have a significant impact on the results. Additionally, corner film flow was found to be an active transport mechanism. During drainage, trapped water is continuously drained over time via thin film, whereas during imbibition snap-off events are enhanced by wetting films. These observations call for future studies to carefully treat corner film flows when developing new predictive models.Item Design and fabrication of membrane-based pressure sensor for capillary pressure measurement in micromodels(Montana State University - Bozeman, College of Engineering, 2021) Raventhiran, Nishagar; Chairperson, Graduate Committee: Yaofa LiPressure is a fundamental quantity in virtually all problems in fluid dynamics from macro-scale to micro/nano scale flows. Although technologies are well developed for its measurement at the macro-scale, pressure quantification at the microscale is still not trivial. Yet, precise pressure mapping at microscale such as in microfluidics is imperative in a variety of applications, including porous media flows and biomedical engineering. In particular, pore-scale capillary pressure is a defining variable in multiphase flow in porous media and has rarely been directly measured. To that end, this study aims to design and fabricate an on-chip sensor that enables quantification of capillary pressure in microfluidic porous media, called micromodels. The micromodel is fabricated in polydimethylsiloxane (PDMS) using soft lithography with a thin membrane incorporated that deflects with pressure variations in the fluid flow. Employing a microscope coupled with a high-speed camera and the astigmatism particle tracking principle, precise pressure measurement is achieved with an accuracy of ~ 60Pa. This sensor is then applied to characterize the viscous pressure drop in single phase flows, and the capillary pressure in a water-air multiphase in microchannels, and good agreement is obtained between the sensor measurement, theoretical values and measurements employing a commercial pressure transducer. This thesis provides a novel method for in-situ quantification of local pressure and potentially 2D pressure field in microfluidics and thus opens the door to a renewed understanding of pore-scale physics of multiphase flow in porous media.Item Nuclear magnetic resonance studies to characterize phase transitions in porous systems(Montana State University - Bozeman, College of Engineering, 2018) Thrane, Linn Winsnes; Chairperson, Graduate Committee: Sarah L. Codd; Emily A. Berglund, James N. Wilking, David Vodak and Joseph D. Seymour were co-authors of the article, 'NMR relaxometry to characterize drug structural phase in a porous construct' in the journal 'Molecular pharmaceutics' which is contained within this thesis.; Sarah L. Codd and Joseph D. Seymour were co-authors of the article, 'Probing molecular dynamics during hydrate formation by high field NMR relaxometry and diffusometry' submitted to the journal 'Journal of magnetic resonance' which is contained within this thesis.; Ryanne L. Daily, Abby Thane, Catherine M. Kirkland, Evan R. McCarney, Robin Dykstra, Sarah L. Codd and Adrienne J. Phillips were co-authors of the article, 'Detecting microbially induced calcite precipitation in porous systems using low-field nuclear magnetic resonance relaxometry' submitted to the journal 'Environmental science & technology' which is contained within this thesis.Nuclear magnetic resonance (NMR) allows for in-situ non-invasive studies of a wide range of systems at microscopic time and length scales. NMR relaxometry and diffusometry techniques along with magnetic resonance imaging (MRI) are applied to explore and characterize various phase transitions in complex systems. NMR techniques are highly sensitive to the thermodynamic phase of the system as well as restrictions on molecular motion, and the ability to detect and monitor phase transitions non-invasively is of great interest for various industrial applications NMR frequency spectra and 1D T 2 relaxation measurements are used to characterize the presence of an amorphous drug and its liquid-solid phase transition. T 1- T 2 magnetic relaxation correlation experiments monitor the impact of long-time storage at high relative humidity on the drug in a porous silica tablet. The results indicate the ability of non-solid-state NMR to characterize crystalline and amorphous solid structural phases, and the potential for drug quality control by NMR methods. High resolution MRI along with T 1-T 2 magnetic relaxation correlation experiments and pulsed gradient stimulated echo (PGStE) NMR methods are demonstrated to characterize hydrate formation. MRI monitors the spatial heterogeneity of the system as well as local hydrate growth rates. Using T 1-T 2 correlation NMR and spectrally resolved diffusometry, the transition from mobile to restricted dynamics is observed simultaneously for both water and cyclopentane throughout the hydrate formation process. The combination of these MR techniques allows for exploration of the complex molecular dynamics involved in hydrate formation processes. Using a low-field NMR system, microbially induced calcite precipitation (MICP) processes in granular media are explored by means of 1D T 2 relaxation measurements. The 1D T 2 distributions allowed for in-situ monitoring of the mineral precipitation progress and indicates decrease in total pore volume and a significant change in the surface mineralogy of the granular media. The results confirm the potential for detailed characterization of MICP progression in engineering applications. Ultimately, NMR is demonstrated as an effective method for detecting, characterizing, and monitoring several distinct phase transitions at various time- and length-scales.Item The interstitial fluid pressure response during stress-relaxation of articular cartilage due to viscosity and porous media effects: a computational study(Montana State University - Bozeman, College of Engineering, 2018) Paschke, Brandon James; Chairperson, Graduate Committee: Erick JohnsonArticular cartilage is a complex material made of several fluid and solid components. A model that fully describes the responses of cartilage is required to accurately create a cartilage replacement that can be used in cases of injury or disease. Modeling of articular cartilage has proven difficult and currently no constitutive law fully describes its solid and fluid responses. Many of the current models describe the interstitial fluid as inviscid, even though it is known that proteoglycan migration within cartilage causes a viscous response within interstitial fluid. The goal of this research was to create a viscous fluid porous media model that better captures the compressive resistance of cartilage created by migration of interstitial fluid during cartilage compression. Through the creation of this model it was possible to capture the experimental magnitudes of fluid pressure within cartilage during unconfined slow compression simulations. As part of this model, a porous media approximation was used, which demonstrates that small variations in the solid matrix, comprised of collagen fibers, can cause large variations in system response. Magnitudes of mean pressure values, after 150 seconds of compression, for the viscous fluid porous media model bound the values found in experimental testing. Limitations of the fluid model are that system relaxation isn't captured and the slope increase of pressures during compression for experiments don't match those of the fluid model. A main conclusion drawn from the model is that viscosity of interstitial fluid plays a large role in creating compressive resistance within articular cartilage. Another takeaway is that the porous media approximation greatly impacts the magnitude of fluid pressurization, which creates a need to accurately represent the solid matrix within cartilage.Item NMR studies of supercritical CO 2 in carbon sequestration and immiscible two phase flow in porous media(Montana State University - Bozeman, College of Engineering, 2015) Prather, Cody Allen; Chairperson, Graduate Committee: Sarah L. CoddNuclear magnetic resonance (NMR) was used to research mechanisms related to two-phase flow in porous media. Experiments were conducted to further understand; 1) the capillary trapping mechanism that occurs during sequestration of CO 2 in deep underground sandstone reservoirs, 2) the viscous fingering phenomena that occurs when scCO 2 convectively dissolves in brine under reservoir conditions, and 3) flow patterns and fluid mechanisms in immiscible two-phase flow in porous media for the two pressure gradient regimes formed under different capillary numbers. Capillary trapping is a prominent mechanism for initially trapping CO 2 in pore structures of deep underground rock formations during the sequestration process. Because of its significant role in securing CO 2 underground, it is important to characterize and understand the residual saturation and distribution of CO 2 within the pore structure. A setup was developed in which drainage and imbibition of a Berea Sandstone core takes place within an NMR spectrometer under reservoir conditions. NMR results provide comparisons between the different nonwetting fluids used and help characterize the capillary trapping of each nonwetting fluid. In conclusion, scCO 2 is trapped 13% less efficiently than air or CO 2, and the nonwetting fluid is preferentially trapped in larger pores. Viscous fingering is a significant long-term trapping mechanism that further increases storage security by enhancing mass transfer through convective dissolution. A setup was developed in which scCO 2 could dissolve into a water saturated bead pack, under reservoir conditions, within the NMR spectrometer. NMR results track spatial changes in T 2 relaxation time and signal intensity. The results are inconclusive and the phenomena could not be directly observed but results do suggest dissolution is occurring during the experiment. Immiscible two-phase flow in porous media is unpredictable and existent in many industries. Therefore, determining flow patterns and understanding the fluid mechanisms from a capillary number/pressure gradient relationship could prove valuable. A setup was developed in which an immiscible two-phase flow through a bead pack was monitored, for different capillary numbers, with NMR techniques. NMR results provide snapshots of the water saturation distribution within the bead pack. The results suggest there's a consistent slug-type flow pattern during the steady state.Item Numerical analysis of two-phase fluid flow and heat transfer in porous media(Montana State University - Bozeman, College of Engineering, 1997) Waite, Matthew WilliamItem Flow and transport studies of porous systems by magnetic resonance microscopy and Lattice Boltzmann simulations(Montana State University - Bozeman, College of Engineering, 2010) Brosten, Tyler Ryan; Chairperson, Graduate Committee: Sarah L. CoddNuclear magnetic resonance experiments and Lattice-Boltzmann simulations are powerful techniques for studying pore scale dynamics in porous media. Several applications of these methods to the study of pore scale hydrodynamics and transport are discussed. Of special interest are concepts relating to pore structure characterization. In the first application it is shown that nuclear magnetic resonance measurements of pre-asymptotic transport dynamics in random open cell foams provide a characteristic structure length scale. These measurements and Lattice-Boltzmann simulations for a model foam structure demonstrate dynamical behavior similar to lower porosity consolidated granular porous media; suggesting a generalized approach to pore structure characterization. Normalizing the data by the characteristic length collapses data for different foam samples and mono-disperse packed beds. The non-equilibrium statistical mechanics theory of pre-asymptotic dispersion is used to model the hydrodynamic dispersive dynamics. In the second application transport of hard sphere colloidal particles under flow through an open cell foam is studied using nuclear magnetic resonance. The temporal dynamics of the colloidal particles and suspending fluid phase are obtained through spectral chemical resolution. The data is interpreted in the broader context of classic hydrodynamic dispersion theory and mechanisms of transport for each phase. In the third application pore scale hydrodynamics of flow over a model porous surface are investigated using three dimensional Lattice-Boltzmann simulations and nuclear magnetic resonance. The Lattice-Boltzmann and nuclear magnetic resonance data are used to interpret classic interfacial hydrodynamic boundary conditions. Finally, in the fourth application a study of magnetic resonance microscopy to novel tape cast porous ceramics is conducted.Item Supercritical fluids, oscillatory flow, and partially saturated porous media by magnetic resonance microscopy(Montana State University - Bozeman, College of Engineering, 2011) Rassi, Erik Michael; Chairperson, Graduate Committee: Sarah L. Codd; Joseph D. Seymour (co-chair)The research presented in this dissertation used Magnetic Resonance (MR) techniques to study fluid dynamics in complex systems. The systems investigated were critical and supercritical fluids, partially saturated porous media, and oscillatory flow. Supercritical fluids (SCF) are useful solvents in green chemistry and oil recovery and are of great current interest in the context of carbon sequestration. Flow in partially saturated porous media and the resultant hydrodynamics are important in fields including but not limited to hydrology, chemical, medical, and the petroleum industry. Lastly, Pulsatile and oscillatory flows are prevalent in many biological, industrial, and natural systems. Displacement propagators were measured at various displacement observation times to quantify the time evolution of dynamics in critical and supercritical fluid flow. In capillary flow, the critical phase transition fluid C2F6 showed increased compressibility compared to the near critical gas and supercritical fluid. These flows exhibit large variations in buoyancy arising from large changes in density due to very small changes in temperature. Ensemble averaged MR measurements were taken to observe the effects on a bead pack partially saturated with air under flowing conditions of water. Air was injected into the bead pack as water flowed simultaneously through the sample. The initial partially saturated state was characterized with MR imaging density maps, free induction decay (FID) experiments, propagators, and velocity maps before the water flow rate was increased. After the maximum flow rate, the MR imaging density maps, FID experiments, propagators, and velocity maps were repeated and compared to the data taken before the maximum flow rate. The work performed here showed that a partially saturated single phase flow had global flow dynamics that returned to characteristic flow statistics once a steady state high flow rate was reached. A system was constructed to provide a controllable and predictable oscillatory flow in order to gain a better understanding of the impact of oscillatory flow on Newtonian and non-Newtonian fluids, specifically water, xanthan gum (XG), polyacrylamide (PAM) colloidal suspensions. The oscillatory flow system coupled with MR measured the velocity distributions and dynamics of the fluid undergoing oscillatory flow at specific points in the oscillation cycle.