Computational fluid dynamics to analyze the effects of initial wetting film and triple contact line on the efficiency of immiscible two-phase flow in a pore doublet model

Nabizadeh, Ali; Adibifard, Meisam; Hassanzadeh, Hossein; Fahimpour, Jalal; Moraveji, Mostafa Keshavarz

doi:10.1016/j.molliq.2018.10.029

Cited by 21 publications

(8 citation statements)

References 44 publications

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“…The displacement is controlled by the interplay between various surface and body forces, including capillary, gravity, inertial, and viscous forces. Surface tension, which acts only at the interface between displacing and displaced phases, becomes an important factor in fluid displacement under low viscous forces or high capillary forces (Nabizadeh et al, ; Wu et al, ). At a low fluid velocity of a given two‐phase system, inertial force is negligible relative to the viscous force (Kundu et al, ).…”

Section: Resultsmentioning

confidence: 99%

Factors Influencing Dynamic Nonequilibrium Effects in Drainage Processes of an Air‐Water Two‐Phase Fine Sandy Medium

Li¹,

He²,

et al. 2019

Water Resources Research

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In efforts to reduce uncertainties about effects of minor changes in the pore structure of porous media on dynamic nonequilibrium effects (DNEs), we monitored water saturation‐capillary pressure relationships in both dynamic flow and static states in stepwise drainage processes of a sandy medium. The acquired data were used to detect DNE and their changes with time in each drainage step and construct new parameters to characterize DNE. Effects of factors affecting water flow—including capillary number, water saturation, rate of change of water saturation with time (△Sw/△t), and the maximum value of this rate (RSMAX)—on the magnitude of the DNE were then determined. Results show that entry pressures are considerably larger under dynamic flow conditions than under static flow conditions, and DNE only occurs when the water saturation exceeds a threshold value in a drainage process. During either a smooth drainage or drainage step, the maximum capillary pressure (PMAX) is reached before the minimum water saturation (SMIN). Moreover, in drainage steps RSMAX occurs before the maximum difference between the capillary pressures associated with the static and dynamic states (DPMAX), except when they start from the saturated state. Accordingly, DNEs in a drainage step are mainly reflected in the time between PMAX and SMIN (△t), DPMAX, the average sum of the squares of the difference between capillary pressures of the static and dynamic states (DPAVE), and the dynamic coefficient τ (which is often used to characterize DNE). Furthermore, our results indicate that the water saturation and its rate of change with time are more important parameters than the capillary number for modeling DNE in a drainage process, and we detected no clear correlation between either maximum or minimum values of τ and the timing of the most significant DNE during drainages. τ appears to characterize DNE effectively in smooth drainage processes, while △t, DPAVE, and DPMAX constitute meaningful supplementary parameters for the characterization of DNE in a drainage step of a stepwise drainage.

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Section: Resultsmentioning

confidence: 99%

Factors Influencing Dynamic Nonequilibrium Effects in Drainage Processes of an Air‐Water Two‐Phase Fine Sandy Medium

Li¹,

He²,

et al. 2019

Water Resources Research

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“…Viscous fingering is a complex phenomenon which controls the flow patterns and the efficiency of the displacement, and it has been the subject of extensive research thanks to its many engineering and industrial applications. Examples include cleaning of equipment and environmental surfaces, chromatographic separation of solvents, printing devices, fluid mixing in microfluidics, food processing, carbon dioxide sequestration, and infiltration of water into soils. − Note that the appearance of viscous fingering in the aforementioned applications involves physicochemical effects, including adsorption, chemical reactions, phase change, and double diffusivity, ,− for instance, the viscosity change of a sample during the adsorption of chemical species in a packed column or the distortion in the chromatographic band profiles in a liquid chromatographic separation, in which an interaction between hydrodynamics and chemistry takes place. Another topic of interest in the context of Hele-Shaw displacement flows is cleaning or removal of unwanted residual layers of viscoplastic materials by air or water from interior geometries in various chemical and food and pharmaceutical operations.…”

Section: Introductionmentioning

confidence: 99%

Multiphase Viscoplastic Flows in a Nonuniform Hele-Shaw Cell: A Fluidic Device to Control Interfacial Patterns

Eslami

Basak

Taghavi

2020

Ind. Eng. Chem. Res.

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Inspired by the problem of the removal of in situ gel-like materials via a displacement flow process, we use a fluidic device known as Hele-Shaw cell to study the flow parameters related to the displacement flow efficiency. In a displacement flow process, when a less viscous fluid displaces a more viscous fluid, exotic interfacial patterns known as viscous fingering appear. Motivated by the recent developments in the literature, we experimentally study the effects of a simple cell nonuniformity with various gap gradients in the flow passage on the viscous fingering problem in the displacement of a viscoplastic gel (Carbopol) by air. We show that a linearly converging/diverging cell can be used to control certain interfacial patterns and improve the displacement efficiency. We classify the flow regimes into smooth finger and rough finger patterns, using the average capillary number ( a) and the average Bingham number ( n) or their combinations.

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“…Surface wetting properties can be imperative in anticipating and manipulating precision microfluidic flow control, [ 71 ] particularly in multiphase flow. [ 72–75 ] Goniometer measurements of water and diiodomethane on Fluoroflex sheets showed hydrophobic surface behavior of Fluoroflex (θ Water = 105.0 ± 1.2°, θ Diiodomethane = 64.9 ± 0.7°; n = 5) (Figure S4a–b). Exposure of samples to acetone prior to contact angle measurements had negligible effect on the sTPE surface wetting properties (θ Water = 105.1 ± 0.8°, θ Diiodomethane = 64.6 ± 1.3°; n = 5).…”

Section: Resultsmentioning

confidence: 99%

Self‐sealing thermoplastic fluoroelastomer enables rapid fabrication of modular microreactors

et al. 2021

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A novel fluorinated soft thermoplastic elastomer (sTPE) for microfluidics is presented. It allows the rapid fabrication of microfluidic devices through a 30‐second hot embossing cycle at 220°C followed by self‐sealing through simple conformal contact at room temperature, or with baking. The material shows high chemical resistance, particularly in comparison to polydimethylsiloxane (PDMS), to many common organic solvents and can be rapidly micropatterned with high fidelity using a variety of microfluidic master molds thanks to its low mechanical stiffness. Self‐sealing of the material is reversible and withstands pressures of up to 2.8 bar with room temperature sealing and four bar with baking at 185°C for 2 hours. The elastomeric, transparent sTPE exhibits material characteristics that make it suited for use as a microreactor, such as low absorption, surface roughness and oxygen permeability, while also allowing a facile and scalable fabrication process. Modular microfluidic devices, leveraging the fast and reversible room temperature self‐sealing, are demonstrated for the generation of water droplets in a toluene continuous phase using T‐junctions of variable size. The sTPE offers an alternative to common microfluidic materials, overcoming some of their key drawbacks, and giving scope for low‐cost and high‐throughput devices for flow chemistry applications.

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Computational fluid dynamics to analyze the effects of initial wetting film and triple contact line on the efficiency of immiscible two-phase flow in a pore doublet model

Cited by 21 publications

References 44 publications

Factors Influencing Dynamic Nonequilibrium Effects in Drainage Processes of an Air‐Water Two‐Phase Fine Sandy Medium

Factors Influencing Dynamic Nonequilibrium Effects in Drainage Processes of an Air‐Water Two‐Phase Fine Sandy Medium

Multiphase Viscoplastic Flows in a Nonuniform Hele-Shaw Cell: A Fluidic Device to Control Interfacial Patterns

Self‐sealing thermoplastic fluoroelastomer enables rapid fabrication of modular microreactors

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