Bulletin of the American Physical Society
70th Annual Meeting of the APS Division of Fluid Dynamics
Volume 62, Number 14
Sunday–Tuesday, November 19–21, 2017; Denver, Colorado
Session G35: Porous Media Flows: Pore-Scale IIPorous
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Chair: Yaofa Li, University of Notre Dame Room: 301 |
(Author Not Attending)
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G35.00001: Chaotic Fluid Mixing in Crystalline Sphere Arrays Regis Turuban, Daniel Lester, Yves Meheust, Tanguy Le Borgne We study the Lagrangian dynamics of steady 3D Stokes flow over simple cubic (SC) and body-centered cubic (BCC) lattices of close-packed spheres, and uncover the mechanisms governing chaotic mixing. Due to the cusp-shaped sphere contacts, the topology of the skin friction field is fundamentally different to that of continuous (non-granular) media (e.g. open pore networks), with significant implications for fluid mixing. Weak symmetry breaking of the flow orientation with respect to the lattice symmetries imparts a transition from regular to strong chaotic mixing in the BCC lattice, whereas the SC lattice only exhibits weak mixing. Whilst the SC and BCC lattices share the same symmetry point group, these differences are explained in terms of their space groups, and we find that a glide symmetry of the BCC lattice generates chaotic mixing. These insights are used to develop accurate predictions of the Lyapunov exponent distribution over the parameter space of mean flow orientation, and point to a general theory of mixing and dispersion based upon the inherent symmetries of arbitrary crystalline structures. [Preview Abstract] |
Monday, November 20, 2017 10:48AM - 11:01AM |
G35.00002: Multiphase flow towards coupled solid-liquid interactions in 2D heterogeneous porous micromodels: a fluorescent microscopy and micro-PIV measurement at pore scale Yaofa Li, Farzan Kazemifar, Gianluca Blois, Kenneth Christensen Multiphase flow in porous media is relevant to a range of applications in the energy and environmental sectors. Recently, the interest has been renewed by geological storage of CO$_{2}$ within saline aquifers. Central to this goal is predicting the fidelity of candidate sites pre-injection of CO$_{2}$ and its post-injection migration. Moreover, local pressure buildup may cause micro-seismic events, which could prove disastrous, and possibly compromise seal integrity. Evidence shows that the large-scale events are coupled with pore-scale phenomena, necessitating the understanding of pore-scale stress, strain, and flow processes and their representation in large-scale modeling. To this end, the pore-scale flow of water and supercritical CO$_{2}$ is investigated under reservoir-relevant conditions over a range of wettability conditions in 2D heterogeneous micromodels that reflect the complexity of real sandstone. High-speed fluorescent microscopy, complemented by a fast differential pressure transmitter, allows for simultaneous measurement of the flow field within and the instantaneous pressure drop across the micromodels. A flexible micromodel is also designed, to be used in conjunction with the micro-PIV technique, enabling the quantification of coupled solid-liquid interactions. [Preview Abstract] |
Monday, November 20, 2017 11:01AM - 11:14AM |
G35.00003: Pore-scale modeling of phase change in porous media Ruben Juanes, Luis Cueto-Felgueroso, Xiaojing Fu One of the main open challenges in pore-scale modeling is the direct simulation of flows involving multicomponent mixtures with complex phase behavior. Reservoir fluid mixtures are often described through cubic equations of state, which makes diffuse interface, or phase field theories, particularly appealing as a modeling framework. What is still unclear is whether equation-of-state-driven diffuse-interface models can adequately describe processes where surface tension and wetting phenomena play an important role. Here we present a diffuse interface model of single-component, two-phase flow (a van der Waals fluid) in a porous medium under different wetting conditions. We propose a simplified Darcy-Korteweg model that is appropriate to describe flow in a Hele-Shaw cell or a micromodel, with a gap-averaged velocity. We study the ability of the diffuse-interface model to capture capillary pressure and the dynamics of vaporization/condensation fronts, and show that the model reproduces pressure fluctuations that emerge from abrupt interface displacements (Haines jumps) and from the break-up of wetting films. [Preview Abstract] |
Monday, November 20, 2017 11:14AM - 11:27AM |
G35.00004: Flow of emulsion droplets in 3D porous media Chao Huang, Lin Shi, Shima Parsa, David Weitz We study the pore-level behavior of large emulsion droplets in 3D micromodel of porous media using confocal microscopy. We match the index of refraction of the emulsion droplets and the ambient fluid to the porous media. The emulsion droplets are uniform in size and generated using microfluidics. We measure the changes in the fluid velocity as the emulsion droplets flow in the medium using particle image velocimetry. We find that due to the trapping and flow of emulsion the velocities change locally. These changes are particularly beneficial in enhanced oil recovery. [Preview Abstract] |
Monday, November 20, 2017 11:27AM - 11:40AM |
G35.00005: Polymer as permeability modifier in porous media for enhanced oil recovery Shima Parsa, David Weitz We use confocal microscopy to directly visualize the changes in morphology and mobilization of trapped oil ganglia within a 3D micromodel of porous media upon polymer flooding. Enhanced oil recovery is achieved in polymer flooding with large molecular weight at concentrations close or higher than a critical concentration of polymer. We also measure the fluctuations of the velocity of the displacing fluid and show that the velocities change upon polymer flooding in the whole medium. The changes in the fluid velocities are heterogeneous and vary in different pores, hence only providing enough pressure gradient across a few of the trapped oil ganglia and mobilize them. Our measurements show that polymer flooding is an effective method for enhancing oil recovery due to retention of polymer on the solid surfaces and changing the resistances of the available paths to water. [Preview Abstract] |
Monday, November 20, 2017 11:40AM - 11:53AM |
G35.00006: Pore-scale investigations into the stability of residual CO$_{\mathrm{2\thinspace }}$ Charlotte Garing, Jacques A de Chalendar, Marco Voltolini, Jonathan B Ajo-Franklin, Sally M Benson After brine imbibition following CO$_{\mathrm{2}}$ injection, substantial volumes of supercritical CO$_{\mathrm{2}}$ (scCO$_{\mathrm{2}})$ may be disconnected from the plume and trapped in the pores. Whereas conventional multi-phase flow models assume that the residually trapped non-wetting phase is permanently immobilized, multiple physiochemical mechanisms exist which could potentially invalidate this assumption. One mechanism is CO$_{\mathrm{2}}$ transfer driven by differences in capillary pressure between disconnected neighbor ganglia, called Ostwald Ripening.work presents two experiments. In the first experiment Ostwald ripening was assessed by calculating pore-scale capillary pressure distribution in sandstones using a multi-scale synchrotron-based X-ray microtomographic (micro-CT) dataset of residually trapped air after a simple gravity-driven imbibition experiment. In the second experiment a scCO$_{\mathrm{2}}$-brine drainage-imbibition cycle was performed in a sandstone with reservoir conditions coupled with time-resolved synchrotron micro-CT imaging after imbibition stops. [Preview Abstract] |
Monday, November 20, 2017 11:53AM - 12:06PM |
G35.00007: Surfactant variations in porous media localize capillary instabilities during Haines jumps Yaniv Edery, David Weitz, Steffen Berg We use confocal microscopy to measure velocity and interfacial tension between a trapped wetting phase with surfactant and a flowing, invading non-wetting phase in a porous medium. We relate interfacial tension variations to surfactant concentration and show that these variations localize the destabilization of capillary forces and lead to rapid local invasion of the non-wetting fluid resulting in a Haines jump. These spatial variations in surfactant concentration are caused by velocity variations at the fluid-fluid, and lead to localization of the Haines jumps even in otherwise very uniform pore structure and pressure conditions. Our results provide new insight into the nature of Haines jumps, one of the most ubiquitous and important instabilities \newline in flow in porous media. [Preview Abstract] |
Monday, November 20, 2017 12:06PM - 12:19PM |
G35.00008: Investigation of pore-scale flow physics in porous media burners Sadaf Sobhani, Priyanka Muhunthan, Emeric Boigne, Danyal Mohaddes, Matthias Ihme Porous media burners (PMBs) operate on the principle that the solid porous matrix serves as a means of internally recirculating heat from the combustion products upstream to the reactants, enabling a reduction of the lean-flammability limit, higher power dynamic range, and lower NOx and CO emissions as compared to conventional systems. Accurate predictions of the flow features and properties such as pressure loss in reticulated ceramic foams is an important step in the characterization and optimization of combustion in porous media. In this work, an integrated framework is proposed from obtaining the porous sample to performing a computational fluid dynamics simulation, including X-ray microtomography scanning, digital topology rendering, and volume meshing. Three-dimensional numerical simulations of the flow in the complex geometries of porous foams are obtained by solution of the Navier-Stokes equations using an unstructured, finite-volume solver. This capability enables the investigation of pore-scale flow physics in a wide range of porous materials used in PMBs. In this talk, results obtained at pore-scale Reynolds numbers of order 10 to 100 in a Silicone Carbide foam are presented to demonstrate this capability. [Preview Abstract] |
Monday, November 20, 2017 12:19PM - 12:32PM |
G35.00009: Experimental Investigation of Flame Stability in Porous Media Burners Danyal Mohaddes, Sadaf Sobhani, Emeric Boigne, Priyanka Muhunthan, Matthias Ihme Porous media burners (PMBs) facilitate the stabilization of a flame inside the pores of a solid porous material, and have benefits when compared to traditional burners in terms of emissions reduction and operating envelope extension. PMBs can potentially find application in a wide variety of domains, including household and industrial heating, internal combustion engines, and gas turbine engine combustors. The current study aims to motivate the use of PMBs in such applications on a thermodynamic basis, and subsequently compares the performance of two PMB designs. To this end, an experiment was devised and conducted to determine the stable operating conditions of a continuously varying and a discontinuously varying pore diameter profile PMB. In addition to investigating the stability regime of each design, pressure drop and axial temperatures were measured and compared at different operating conditions. The collected experimental data will be used both to inform computational studies of combustion within porous media and to aid in future optimizations of the design of PMBs. [Preview Abstract] |
Monday, November 20, 2017 12:32PM - 12:45PM |
G35.00010: Pore-scale and topology analysis of flame stabilization inside inert porous media using X-ray microtomography Emeric Boigne, Priyanka Muhunthan, Danyal Mohaddes Khorassani, Sadaf Sobhani, Dula Parkinson, Harold Barnard, Matthias Ihme Synchrotron X-ray microtomography is used to perform gas-phase thermometry of a premixed flame burning within an inert porous media. Using a two-zone porous media burner, the flame is stabilized inside of a reticulated porous ceramic made of silicon carbide. The flame structure is visualized using a mixture of Kr/O$_2$/N$_2$/CH$_4$, where radio-dense Krypton is added to enhance the gas phase attenuation. Spatial resolution below 10 microns allows for the spatial characterization of the gas-phase temperature field at the pore scale. Taking advantage of the high photon count from the synchrotron source, effects of the combustion process on the thermal degradation of the solid ceramic are examined in detail. X-ray microtomography are also used to extract the topology of the entire porous media burners. Relevance of the ceramic geometric parameters for the combustion process are discussed. Analysis of different porosities and pore diameter profiles as well as different burner designs are correlated with the experimental performance of these burners. [Preview Abstract] |
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