Two-phase flow in microchannels with surface modifications

Cubaud, Thomas; Ulmanella, Umberto; Ho, Chih‐Ming

doi:10.1016/j.fluiddyn.2005.12.004

Cited by 171 publications

(75 citation statements)

References 16 publications

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“…This film was persistent, remaining in place during an extended period (over 120 seconds). Again, this was an expected observation based on results published by Cubaud et al (2006) and Cho and Wang (2014). The hydrophilic surface has a much greater propensity to produce an annular flow regime compared to the globular hydrophobic surface.…”

Section: Nanoparticle Treatmentssupporting

confidence: 79%

“…As dimensions shrink to a micron scale, surface to volume forces, such as surface tension and viscosity become more important compared to buoyancy (Cubaud et al, 2006). In micron channels the capillary forces become sensitive to changes in surface chemistry and roughness.…”

Section: Surface Wetting State and Fluid Flowmentioning

confidence: 99%

“…There is also a hysteresis in the advancing and receding contact angle of the liquid-gas interface in the direction of the flow. Yet, Cubaud et al (2006) were able to determine three unique flow regimes for the smooth hydrophobic surface illustrated in Figure 2.30. …”

Section: Surface Wetting State and Fluid Flowmentioning

confidence: 99%

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The Effect of Water Occlusion on Gas Production in Coal

Mahoney¹

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Relative permeability is of fundamental importance to understand and model the flow of hydrocarbons and water in porous rocks including coal, and thus relative permeability is critical in prediction of commercial gas and water production rates from coal seam gas (CSG) reservoirs.Despite relative permeability being a primary parameter for determining reservoir performance, the fundamental physics of how or where water may occlude or block cleats in a coal seam, and thereby interfere with gas production rates, is not fully understood. This project aims to improve the understanding of water occlusion in CSG reservoirs through fluid experiments with model coal cleats and to evaluate the potential impact of water occlusion of reservoir performance.The aim of this thesis is to develop a new experimental methodology that can be used identify the main control factors that affect wettability in coal. There are two key objectives to satisfy the thesis aim 1) develop methods to make artificial channels in coal and 2) create a world first microfluidic device that assess micro scale flow through coal cleats, known as the cleat flow cell (CFC). The initial features to be evaluated will include: lithotype, surface roughness, surface composition, specifically chemical functional groups and pressure. oxygen plasma with a photolithography process to make the desired pattern on coal surface, UV Laser ablation, mechanical machining, a mechanical scratch technique, and a chemical etching technique that used potassium permanganate (KMnO4). Characteristics of the artificial channels were assessed using a surface step profiler, scanning electron microscopy, micro-Raman spectroscopy and light microscopy. A sixth methodology to create an artificial channel using pressed coal powder was also used as a means of evaluating the influence of the surface chemistry on the wetting behaviour, without the interference of surface topography.In Chapter Five, I report the effect of rank and lithotype on the wettability of coal in microfluidic experiments in two types of artificial microchannels; (1) reactive ion etched (RIE) channels and (2) die-cast channels prepared by pressing powdered lithotype concentrates. Contact angles and entry pressures of air and water in the artificial cleats were measured in imbibition experiments performed iii with a CFC. The relative contact angles measured in CFC imbibition experiments were in the range 110 -140° in the RIE channels and 85°-115° in the pressed discs, which are larger contact angles than measured on the flat bulk surfaces of these samples by the conventional sessile drop technique (58°-85°). The CFC observations show that the surface roughness of coal in inertinite-rich dull bands effects contact angle and the entry pressure of the air-water interface differently to the vitrinite-rich bright bands, with both lithotypes presenting unique wetting states. Drainage experiments revealed a thin residual water film on the inertinite cleat wall, not observed on the smoother vitrinite channel. were hydr...

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Section: Nanoparticle Treatmentssupporting

confidence: 79%

Section: Surface Wetting State and Fluid Flowmentioning

confidence: 99%

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The Effect of Water Occlusion on Gas Production in Coal

Mahoney¹

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“…The application of surfaces with controlled hydrophobicity leads to a change in the nature of twophase flow [1][2][3], hydraulic resistance [4,5], critical heat flux [6,7], as well as condensation [8] and evaporation [9], and this significantly improves the heat exchangers performance.…”

Section: Introductionmentioning

confidence: 99%

Deposition and Investigation of Hydrophobic Coatings

Сафонов

Sulyaeva

Тимошенко

et al. 2015

MATEC Web of Conferences

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“…With the rapid development of microdroplets [2][3][4][5][6][7][8], their potential applications as optical components have attracted more attention [9]. The unique features of the microdroplets, such as uniformity, periodicity, and self assembly make them particularly suitable for optical gratings.…”

mentioning

confidence: 99%

Microfluidic droplet grating for reconfigurable optical diffraction

Yang

Liu

et al. 2010

Opt. Lett.

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This Letter presents a reconfigurable optical diffraction grating using multiphase droplets on a microfluidic chip. The uniform and evenly spaced circular droplets are generated by continuously dispersing two immiscible liquids into a T junction to produce plugs, which are then transformed into a circular shape at a sudden expansion of the microchannel. In experiments, the droplet grating shows a detection limit of~6:3 × 10 −5 when used as an optofluidic refractometer and produces different colors as a color filter. Such a grating has the advantages of high stability and wide tunability in droplet size, grating period, and refractive index, making it promising for biochemical and biomaterial applications.

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Two-phase flow in microchannels with surface modifications

Cited by 171 publications

References 16 publications

The Effect of Water Occlusion on Gas Production in Coal

The Effect of Water Occlusion on Gas Production in Coal

Deposition and Investigation of Hydrophobic Coatings

Microfluidic droplet grating for reconfigurable optical diffraction

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