Microfluidic Studies of Fluid-fluid Interaction and Multiphase Flow in Fractures and Channels PDF Download

Author: Negar Nazari
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

View

Book Description
World energy demand increases as global population increases. Seeking new solutions and improving the current energy systems are two attractive options to address the existing problems. Processes of interest include CO$_{2}$ storage security, hydrogen storage, and enhanced oil recovery. Studying fluid behavior at pore scale, improves understanding of fundamental mechanisms and enables mechanistic control of the processes involved. Multiphase and multi-component fluid flow is dictated and controlled by pore-scale phenomena. Understanding fluid-fluid interactions and multiphase flow behavior in complex porous media is the essential component of optimizing the subsurface energy design. Microfluidic devices with representative geometry, and length scales are essential to delineate the fundamental mechanisms dictating the pore-scale fluid behavior of multiphase flow in fractures and channels. Therefore, a primary objective of this research is to develop cutting-edge microfluidic devices. My research improves mechanical and physical characteristics of transport processes in micromodels through development of new microfluidic devices, thorough experimental frameworks, and computer-assisted techniques to process and model the results. First, we designed and fabricated a new microfluidic device to better enable study of foam microstructure and rheology in planar fractures. The workflow included finite element analysis of several designs to enhance the pressure tolerance of the device. The new design illustrated improved ability to sustain large differential pressure compared to previous designs in the literature. Our findings validated the previous microvisual studies mentioned in the literature and revealed that foam apparent viscosity is a strong function of foam quality and water velocity at small qualities and this dependency decreases for greater foam qualities and water velocities. Second, we investigated foam flow behavior in microscale fractures and developed a mechanistic transient foam flow model using the population balance method. Microscale experiments in fractures with apertures of 25 and 88 $\mu m$ were used to validate the model for pressure drop, gas saturation, and bubble texture. Key differences related to modeling foam in fractures are the potential for continuously varying gas-liquid curvature in fractures and the relationship of this curvature to apparent foam viscosity. Incorporation of a local foam flow resistance factor is important to representing flow physics accurately. Third, we designed and fabricated a new microfluidic device with a meter-long channel and a rectangular cross section to study the flow behavior of long gas bubbles in noncircular-cross-section capillaries. Our calculations of channel curvature, Dean number, and centripetal acceleration for this novel symmetric loop design illustrated that this capillary tube on a chip behaves, essentially, as a straight channel for a wide range of velocity, U. We found that the pressure drop experienced by bubbles varies as $Ca^{2/3}$ over the range $10^{-7}

Author: Roberto Mauri
Publisher: Springer Science & Business Media
ISBN: 3709112273
Category : Science
Languages : en
Pages : 181

View

Book Description
Diffuse interface (D.I.) model for muliphase flows.- Phase separation of viscous ternary liquid mixtures.- Dewetting and decomposing films of simple and complex liquids.- Phase-field models. Multiphase flows are typically described assuming that the different phases are separated by a sharp interface, with appropriate boundary conditions. This approach breaks down whenever the lengthscale of the phenomenon that is being studied is comparable with the real interface thickness, as it happens, for example, in the coalescence and breakup of bubbles and drops, the wetting and dewetting of solid surfaces and, in general, im micro-devices. The diffuse interface model resolves these problems by assuming that all quantities can vary continuously, so that interfaces have a non-zero thickness, i.e. they are "diffuse". The contributions in this book review the theory and describe some relevant applications of the diffuse interface model for one-component, two-phase fluids and for liquid binary mixtures, to model multiphase flows in confined geometries.

Author: Wonjin Yun
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
My research with the microfluidic Reservoir-on-a-Chip (ROC) platform has produced multiple engineering science contributions toward investigating the fundamental mechanisms that dictate transport through subsurface porous media. Microfluidic devices, better known as micromodels, are devices with a connected porous network that allows the direct visualization of complex fluid flow dynamics occurring under transient conditions. The porous pattern of micromodel in my study is analogous to that of natural reservoir rock (i.e. sandstone or carbonate). The micro-pattern is etched in a crystalline silicon wafer with the DRIE (deep reactive ion etching) technique which offers a large aspect ratio (i.e. pore throat-to-body ratio), with more realistic and well-defined structures. Consequently, investigating fluid flow through representative pore network patterns and material in the micromodels have been greatly beneficial to petroleum, geologic, and environmental engineering field. Micromodel studies are based on the direct observation of the pore-scale fluid structures, the visualization of the flow field, and the characterization of matrix-fluid and fluid-fluid interactions. I implemented various methodologies that enable the real-time monitoring of events occurring in a micromodel by integrating them with high-resolution microscopy and laser-induced fluorescence. My research improves petrochemical and geophysical characteristics of transports in micromodels through the development of new micro-fabrication processes, new experimental frameworks, imaging, and novel image processing algorithms. First, my research addresses greater realism in pore structure and visualization of micromodels for the characterization of single and multiphase flows. I optimized dual-etching fabrication and improved 3D structural realism of carbonate-like flow networks inside the micromodel. I applied the micro-particle image velocimetry (micro-PIV). The micro-PIV provides insights into the fluid dynamics within microfluidic channels and relevant fluid velocities controlled predominantly by changes in pore width and depth. Compared with conventional single-depth micromodels, micro-PIV and fluid desaturation pattern prove that the dual-depth carbonate micromodel is a better representation of pore geometry showing more realistic fluid flow and capillary entry pressures. Second, I demonstrated, for the first time, that micromodels monitored using advanced spectral imaging enables real-time and in-situ quantification of the local viscosity of non-Newtonian viscoelastic polyacrylamide EOR polymers. This, in turn, paves the way to validate computational fluid dynamics models for viscoelastic fluids. Third, novel deep-learning algorithms (convolutional neural networks) were applied to the micromodel images for the automated analysis of surface properties. With proper training of deep-learning architectures on high-quality image datasets, I proved that deep-learning has a great potential to serve as a quick and automated image analysis tool for surface wettability determination with an accuracy larger than 95%. Forth, I established an in-house micro-fabrication procedure using a Direct-Write-Lithography technique for the rapid prototyping of new microfluidic designs. I worked on optimizing the micromodel channel design to make the micromodel more suitable for direct visualization of micro-pore scale mixing dynamics between precipitant and oil phase, which may cause asphaltene aggregation and their agglomerations. Furthermore, confocal microscopy enables the 3D reconstruction of asphaltene agglomerates; it reveals the size and size distribution of asphaltene aggregates as a function of flocculation time.

Author: Santana, Harrson Silva
Publisher: IGI Global
ISBN: 1522571396
Category : Technology & Engineering
Languages : en
Pages : 367

View

Book Description
Microfluidics represent great potential for chemical processes design, development, optimization, and chemical engineering bolsters the project design of industrial processes often found in large chemical plants. Together, microfluidics and chemical engineering can lead to a more complete and comprehensive process. Process Analysis, Design, and Intensification in Microfluidics and Chemical Engineering provides emerging research exploring the theoretical and practical aspects of microfluidics and its application in chemical engineering with the intention of building pathways for new processes and product developments in industrial areas. Featuring coverage on a broad range of topics such as design techniques, hydrodynamics, and numerical modelling, this book is ideally designed for engineers, chemists, microfluidics and chemical engineering companies, academicians, researchers, and students.

Author: Francisco José Galindo-Rosales
Publisher: Springer
ISBN: 3319595938
Category : Technology & Engineering
Languages : en
Pages : 116

View

Book Description
This monograph contains expert knowledge on complex fluid-flows in microfluidic devices. The topical spectrum includes, but is not limited to, aspects such as the analysis, experimental characterization, numerical simulations and numerical optimization. The target audience primarily comprises researchers who intend to embark on activities in microfluidics. The book can also be beneficial as supplementary reading in graduate courses.

Author: Andrew J. Hansen
Publisher:
ISBN: 9781321753509
Category : Microfluidics
Languages : en
Pages : 108

View

Book Description
As global energy requirements continue to rise, greater demand is being placed on oil producers to maximize production from conventional reservoirs. Conventional oil production techniques leave behind a significant amount of oil due to discontinuities in the oil phase, causing oil trapping. A primary driver of this phenomenon is snap-off. Understanding of how snap-off is affected by straight walled pore-throat geometries is limited. Better understanding of how geometry mediates snap-off is necessary for more accurate and precise simulations of flow through complex porous media. An idealized three dimensional microfluidic device was used to create an approximate replica of simulated pore-throat systems. The platform allows for the studies of the effect of throat aspect ratio upon displacement mechanisms in a water and oil system to be directly investigated. Three dimensional pore-throat geometries were produced with increasing aspect ratio to investigate the Rayleigh-Plateau instability in free standing bridges of nonwetting liquid. The system was designed to be as close to perfectly water-wet as possible while maintaining regions to allow corner flow and wetting phase continuity. This study was performed with the intent of forming an accurate model of how geometry influences snap-off events. It is hypothesized that liquid will become columnated in the throat and will form a free standing bridge between pores. At this point the bridge either remains stable or deteriorates, depending on whether or not the throat aspect ratio exceeds the Rayleigh-Plateau instability criteria. Experimental results indicated fundamental shortcomings in the fabrication medium, which motivated the development of a new high tensile strength silicone for experimental platforms and fabrication intermediates. Mechanical testing was performed on the high tensile strength silicones, verifying anecdotal strength observations. High tensile strength silicone allows for greater flexibility in the fabrication of complex and high aspect ratio structures. Demonstrating the utility of this material, novel triangular channels machined into glass substrates were replicated using the high tensile strength silicone. Triangular channels provide an excellent representation for naturally occurring porous media undergoing multiphase flow by creating superior wetting phase flow and continuity by increasing the relative wetting phase cross-sectional area. Triangular channels also provide superior capillary pressure control inside a microfluidic device for applications sensitive to capillary pressures. Capillary pressure measurements were performed within triangular channels, verifying that they provide an acceptable microfluidic platform for multiphase flow studies with results consistent with those predicted theoretically. The work performed indicates that snap-off is affected by to throat aspect ratios and length, but other factors such as mixed wettability seem to play a crucial role. To fully investigate the phenomena, microfluidic devices with better wettability will be required. The full development and implementation of triangular channels fabricated in glass will provide devices with the improved geometry, optical, and wettability characteristics for multiphase flow studies.

Author: Jean Berthier
Publisher: Elsevier
ISBN: 0815518358
Category : Technology & Engineering
Languages : en
Pages : 463

View

Book Description
After spending over 12 years developing new microsystems for biotechnology – especially concerned with the microfluidic aspects of these devices – Jean Berthier is considered a leading authority in the field. Now, following the success of his book, Microfluidics for Biotechnology, Dr. Berthier returns to explain how new miniaturization techniques have dramatically expanded the area of microfluidic applications and microsystems into microdrops and digital microfluidics. Engineers interested in designing more versatile microsystems and students who seek to learn the fundamentals of microfluidics will all appreciate the wide-range of information found within Microdrops and Digital Microfluidics. The most recent developments in digital microfluidics are described in clear detail, with a specific focus on the computational, theoretical and experimental study of microdrops. Over 500 equations and more than 400 illustrations Authoritative reporting on the latest changes in microfluidic science, where microscopic liquid volumes are handled as "microdrops" and separately from "nanodrops" A methodical examination of how liquid microdrops behave in the complex geometries of modern miniaturized systems and interact with different morphological (micro-fabricated, textured) solid substrates A thorough explanation of how capillary forces act on liquid interfaces in contact with micro-fabricated surfaces Analysis of how droplets can be manipulated, handled, or transported using electric fields (electrowetting), acoustic actuation (surface acoustic waves), or by a carrier liquid (microflow) A fresh perspective on the future of microfluidics

Author: Michael A. Nilsson
Publisher:
ISBN:
Category : Hydrophobic surfaces
Languages : en
Pages : 200

View

Book Description
Multi-phase fluid systems are an important concept in fluid mechanics, seen every day in how fluids interact with solids, gases, and other fluids in many industrial, medical, agricultural, and other regimes. In this thesis, the development of a two-dimensional digital microfluidic device is presented, followed by the development of a two-phase microfluidic diagnostic tool designed to simulate sandstone geometries in oil reservoirs. In both instances, it is possible to take advantage of the physics involved in multiphase flows to affect positive outcomes in both. In order to make an effective droplet-based digital microfluidic device, one must be able to precisely control a number of key processes including droplet positioning, motion, coalescence, mixing, and sorting. For planar or open microfluidic devices, many of these processes have yet to be demonstrated. A suitable platform for an open system is a superhydrophobic surface, as suface characteristics are critical. Great efforts have been spent over the last decade developing hydrophobic surfaces exhibiting very large contact angles with water, and which allow for high droplet mobility. We demonstrate that sanding Teflon can produce superhydrophobic surfaces with advancing contact angles of up to 151° and contact angle hysteresis of less than 4°. We use these surfaces to characterize droplet coalescence, mixing, motion, deflection, positioning, and sorting. This research culminates with the presentation of two digital microfluidic devices: a droplet reactor/analyzer and a droplet sorter. As global energy usage increases, maximizing oil recovery from known reserves becomes a crucial multiphase challenge in order to meet the rising demand. This thesis presents the development of a microfluidic sandstone platform capable of quickly and inexpensively testing the performance of fluids with different rheological properties on the recovery of oil. Specifically, these microfluidic devices are utilized to examine how shear-thinning, shear-thickening, and viscoelastic fluids affect oil recovery. This work begins by looking at oil displacement from a microfluidic sandstone device, then investigates small-scale oil recovery from a single pore, and finally investigates oil displacement from larger scale, more complex microfluidic sandstone devices of varying permeability. The results demonstrate that with careful fluid design, it is possible to outperform current commercial additives using the patent-pending fluid we developed. Furthermore, the resulting microfluidic sandstone devices can reduce the time and cost of developing and testing of current and new enhanced oil recovery fluids.

Author: Patrick Tabeling
Publisher: OUP Oxford
ISBN: 0191524557
Category : Science
Languages : en
Pages : 310

View

Book Description
Microfluidics deals with fluids flowing in miniaturized systems. It is a young discipline, which is expected to substantially expand over the next few years, stimulated by the considerable development of applications in the pharmaceutical, biomedical and chemical engineering domains. The book is an introduction to this discipline. In the first chapter, it presents a short historical background and discusses the main perspectives of the domain, at economical and scientific levels. Then the physics of miniaturization and the fluid mechanics of microflows are discussed. In the following three chapters, dispersion, electrical and thermal phenomena in miniaturized devices are presented. A brief introduction to microfabrication techniques is given in chapter six and the book concludes by providing a few examples of microfluidic systems. The book is written in a simple, direct, pedagogical way. It emphasizes concepts and understanding, rather than technical detail. It offers a cross-disciplinary view of the field embracing biological, chemical, physical and engineering perspectives. By using the book, the reader will have concepts, methods and data to grasp situations which typically arise in microfluidic systems.

Author: Hyundo Lee
Publisher:
ISBN:
Category :
Languages : en
Pages : 174

View

Book Description
Displacement of a fluid by an immiscible fluid occurs in various situations such as oil recovery in underground reservoirs, transport in the human body, and other interconnected network systems and porous media. We are motivated by oil recovery processes in geological porous media that take place at the micrometer scale, and focus in particular on the effects of wettability and geometry of microstructures on immiscible liquid-liquid displacements, that result from interactions in oil-water-rock systems. Microfluidic devices, micromodels, have been proposed as experimental test beds for reproducing flows in oil reservoirs in laboratory environments since they offer fine control over geometry and chemistry, and therefore provide insights into their effects on the process. These microfluidic devices are usually two-dimensional and transparent, with a simplified porous network designed to visualize and study fluid behavior in porous media. In oil reservoir research, the microfluidic test beds reflect underground oil reservoir conditions, for example, porosity, permeability, and wettability. The work in this thesis focuses on simple, additive micromodel fabrication techniques to build robust and reproducible structures in microfluidic channels and on the basic and fundamental understanding of immiscible displacement processes with simplified models and controlled flow conditions. We introduce two simple micromodel fabrication methods that can provide design flexibility with photopatterning, the ability to tailor wetting properties, and the calcium carbonate structure that is the most common constituent of oil reservoirs. We utilize a microscope projection lithography to construct polymeric structures with pre-defined wetting properties using a UV-initiated copolymerization method, and we are also able to make real-rock carbonate micromodels by incorporating calcium carbonate seed particles into microstructures and growing them with a supersaturated calcium carbonate solution. Using the micromodel fabrication methods thus developed, we have systematically explored oil-water immiscible displacement processes in a controlled manner with respect to various geometric and wettability conditions. With the fact that our flow experiment is in a small capillary number regime, we formulate a mathematical model for the oil-water displacement process with photopatterned structures of simple geometry and periodic patterns, and verify our theoretical model by matching it with our experimental observations, and we also conduct oil recovery model studies with encapsulated oil pockets with aqueous surfactant solution flooding. Lastly, based on the experience of calcium carbonate/hydrogel composite structuring and calcium carbonate growth from the structure, we expand our work and develop a method of making drug-laden hydrogel particles. By developing flexible methods to make microfluidic devices for immiscible fluids displacement study and investigation on the displacement process, we have been able to realize that microfluidic research with simplified conditions can enhance fundamental understanding of multiphase flow in natural, complex porous media.