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Wang YD, Kearney LM, Blunt MJ, Sun C, Tang K, Mostaghimi P, Armstrong RT. In situ characterization of heterogeneous surface wetting in porous materials. Adv Colloid Interface Sci 2024; 326:103122. [PMID: 38513432 DOI: 10.1016/j.cis.2024.103122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 02/28/2024] [Accepted: 03/04/2024] [Indexed: 03/23/2024]
Abstract
The performance of nano- and micro-porous materials in capturing and releasing fluids, such as during CO2 geo-storage and water/gas removal in fuel cells and electrolyzers, is determined by their wettability in contact with the solid. However, accurately characterizing wettability is challenging due to spatial variations in dynamic forces, chemical heterogeneity, and surface roughness. In situ measurements can potentially measure wettability locally as a contact angle - the angle a denser phase (e.g water) contacts solid in the presence of a second phase (e.g. hydrogen, air, CO2) - but suffer from difficulties in accurately capturing curvatures, contact areas, and contact loops of multiphase fluids. We introduce a novel extended topological method for in situ contact angle measurement and provide a comparative review of current geometric and topological methods, assessing their accuracy on ideal surfaces, porous rocks containing CO2, and water in gas diffusion layers. The new method demonstrates higher accuracy and reliability of in situ measurements for uniformly wetting systems compared to previous topological approaches, while geometric measurements perform best for mixed-wetting domains. This study further provides a comprehensive open-source platform for in situ characterization of wettability in porous materials with implications for gas geo-storage, fuel cells and electrolyzers, filtration, and catalysis.
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Affiliation(s)
- Ying Da Wang
- School of Minerals and Energy Resources Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Luke M Kearney
- Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, United Kingdom
| | - Martin J Blunt
- Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Chenhao Sun
- State Key Laboratory of Petroleum Resources and Prospecting & College of Geosciences, China University of Petroleum, Beijing 102249, China
| | - Kunning Tang
- School of Minerals and Energy Resources Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Peyman Mostaghimi
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Ryan T Armstrong
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
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Sun C, McClure J, Berg S, Mostaghimi P, Armstrong RT. Universal description of wetting on multiscale surfaces using integral geometry. J Colloid Interface Sci 2021; 608:2330-2338. [PMID: 34774316 DOI: 10.1016/j.jcis.2021.10.152] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 10/11/2021] [Accepted: 10/25/2021] [Indexed: 10/19/2022]
Abstract
HYPOTHESIS Emerging energy-related technologies deal with multiscale hierarchical structures, intricate surface morphology, non-axisymmetric interfaces, and complex contact lines where wetting is difficult to quantify with classical methods. We hypothesise that a universal description of wetting on multiscale surfaces can be developed by using integral geometry coupled to thermodynamic laws. The proposed approach separates the different hierarchy levels of physical description from the thermodynamic description, allowing for a universal description of wetting on multiscale surfaces. THEORY AND SIMULATIONS The theoretical framework is presented followed by application to limiting cases of wetting on multiscale surfaces. Limiting cases include those considered in the Wenzel, Cassie-Baxter, and wicking state models. Wetting characterisation of multiscale surfaces is explored by conducting simulations of a fluid droplet on a structurally rough surface and a chemically heterogeneous surface. FINDINGS The underlying origin of the classical wetting models is shown to be rooted within the proposed theoretical framework. Integral geometry provides a topological-based wetting metric that is not contingent on any type of wetting state. The wetting metric is demonstrated to account for multiscale features along the common line in a scale consistent way; providing a universal description of wetting for multiscale surfaces.
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Affiliation(s)
- Chenhao Sun
- State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China
| | - James McClure
- Advanced Research Computing, Virginia Tech, Wright House, W. Campus Drive, Blacksburg, VA 24061, USA
| | - Steffen Berg
- Shell Global Solutions International B.V., Grasweg 31, 1031 WG Amsterdam, Netherlands; Imperial College London, Department of Earth Science & Engineering and Chemical Engineering, Exhibition Rd, South Kensington, London SW7 2BX, United Kingdom
| | - Peyman Mostaghimi
- School of Minerals & Energy Resources Engineering, University of New South Wales, Kensington, New South Wales 2052, Australia
| | - Ryan T Armstrong
- School of Minerals & Energy Resources Engineering, University of New South Wales, Kensington, New South Wales 2052, Australia.
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Lin Q, Bijeljic B, Foroughi S, Berg S, Blunt MJ. Pore-scale imaging of displacement patterns in an altered-wettability carbonate. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2021.116464] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Blunt MJ, Alhosani A, Lin Q, Scanziani A, Bijeljic B. Determination of contact angles for three-phase flow in porous media using an energy balance. J Colloid Interface Sci 2021; 582:283-290. [PMID: 32823129 DOI: 10.1016/j.jcis.2020.07.152] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 11/16/2022]
Abstract
HYPOTHESIS We define contact angles, θ, during displacement of three fluid phases in a porous medium using energy balance, extending previous work on two-phase flow. We test if this theory can be applied to quantify the three contact angles and wettability order in pore-scale images of three-phase displacement. THEORY For three phases labelled 1, 2 and 3, and solid, s, using conservation of energy ignoring viscous dissipation (Δa1scosθ12-Δa12-ϕκ12ΔS1)σ12=(Δa3scosθ23+Δa23-ϕκ23ΔS3)σ23+Δa13σ13, where ϕ is the porosity, σ is the interfacial tension, a is the specific interfacial area, S is the saturation, and κ is the fluid-fluid interfacial curvature. Δ represents the change during a displacement. The third contact angle, θ13 can be found using the Bartell-Osterhof relationship. The energy balance is also extended to an arbitrary number of phases. FINDINGS X-ray imaging of porous media and the fluids within them, at pore-scale resolution, allows the difference terms in the energy balance equation to be measured. This enables wettability, the contact angles, to be determined for complex displacements, to characterize the behaviour, and for input into pore-scale models. Two synchrotron imaging datasets are used to illustrate the approach, comparing the flow of oil, water and gas in a water-wet and an altered-wettability limestone rock sample. We show that in the water-wet case, as expected, water (phase 1) is the most wetting phase, oil (phase 2) is intermediate wet, while gas (phase 3) is most non-wetting with effective contact angles of θ12≈48° and θ13≈44°, while θ23=0 since oil is always present in spreading layers. In contrast, for the altered-wettability case, oil is most wetting, gas is intermediate-wet, while water is most non-wetting with contact angles of θ12=134°±~10°,θ13=119°±~10°, and θ23=66°±~10°.
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Affiliation(s)
- Martin J Blunt
- Department of Earth Science and Engineering, Imperial College London, London SW7 2BP, UK.
| | - Abdulla Alhosani
- Department of Earth Science and Engineering, Imperial College London, London SW7 2BP, UK
| | - Qingyang Lin
- Department of Earth Science and Engineering, Imperial College London, London SW7 2BP, UK
| | - Alessio Scanziani
- Department of Earth Science and Engineering, Imperial College London, London SW7 2BP, UK
| | - Branko Bijeljic
- Department of Earth Science and Engineering, Imperial College London, London SW7 2BP, UK
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Abstract
AbstractIn this work, we calculate contact angles in X-ray tomography images of two-phase flow in order to investigate the wettability. Triangulated surfaces, generated using the images, are smoothed to calculate the contact angles. As expected, the angles have a spread rather than being a constant value. We attempt to shed light on sources of the spread by addressing the overlooked mesh corrections prior to smoothing, poorly resolved image features, cluster-based analysis, and local variations of contact angles. We verify the smoothing algorithm by analytical examples with known contact angle and curvature. According to the analytical cases, point-wise and average contact angles, average mean curvature and surface area converge to the analytical values with increased voxel grid resolution. Analytical examples show that these parameters can reliably be calculated for fluid–fluid surfaces composed of roughly 3000 vertices or more equivalent to 1000 pixel2. In an experimental image, by looking into individual interfaces and clusters, we show that contact angles are underestimated for wetting fluid clusters where the fluid–fluid surface is resolved with less than roughly 500 vertices. However, for the fluid–fluid surfaces with at least a few thousand vertices, the mean and standard deviation of angles converge to similar values. Further investigation of local variations of angles along three-phase lines for large clusters revealed that a source of angle variations is anomalies in the solid surface. However, in the places least influenced by such noise, we observed that angles tend to be larger when the line is convex and smaller when the line is concave. We believe this pattern may indicate the significance of line energy in the free energy of the two-phase flow systems.
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Sun C, McClure JE, Mostaghimi P, Herring AL, Meisenheimer DE, Wildenschild D, Berg S, Armstrong RT. Characterization of wetting using topological principles. J Colloid Interface Sci 2020; 578:106-115. [PMID: 32521350 DOI: 10.1016/j.jcis.2020.05.076] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/17/2020] [Accepted: 05/18/2020] [Indexed: 10/24/2022]
Abstract
HYPOTHESIS Understanding wetting behavior is of great importance for natural systems and technological applications. The traditional concept of contact angle, a purely geometrical measure related to curvature, is often used for characterizing the wetting state of a system. It can be determined from Young's equation by applying equilibrium thermodynamics. However, whether contact angle is a representative measure of wetting for systems with significant complexity is unclear. Herein, we hypothesize that topological principles based on the Gauss-Bonnet theorem could yield a robust measure to characterize wetting. THEORY AND EXPERIMENTS We introduce a macroscopic contact angle based on the deficit curvature of the fluid interfaces that are imposed by contacts with other immiscible phases. We perform sessile droplet simulations followed by multiphase experiments for porous sintered glass and Bentheimer sandstone to assess the sensitivity and robustness of the topological approach and compare the results to other traditional approaches. FINDINGS We show that the presented topological principle is consistent with thermodynamics under the simplest conditions through a variational analysis. Furthermore, we elucidate that at sufficiently high image resolution the proposed topological approach and local contact angle measurements are comparable. While at lower resolutions, the proposed approach provides more accurate results being robust to resolution-based effects. Overall, the presented concepts open new pathways to characterize the wetting state of complex systems and theoretical developments to study multiphase systems.
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Affiliation(s)
- Chenhao Sun
- School of Minerals & Energy Resources Engineering, University of New South Wales, Kensington, NSW 2052, Australia
| | - James E McClure
- Advanced Research Computing, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA
| | - Peyman Mostaghimi
- School of Minerals & Energy Resources Engineering, University of New South Wales, Kensington, NSW 2052, Australia
| | - Anna L Herring
- Department of Applied Mathematics, Australian National University, Canberra, ACT 2601, Australia
| | - Douglas E Meisenheimer
- Department of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Dorthe Wildenschild
- Department of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Steffen Berg
- Hydrocarbon Recovery, Shell Global Solutions International B.V., Grasweg 31, 1031 HW Amsterdam, The Netherlands; Department of Earth Science & Engineering, Imperial College London, London SW7 2AZ, UK; Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Ryan T Armstrong
- School of Minerals & Energy Resources Engineering, University of New South Wales, Kensington, NSW 2052, Australia.
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