Flow in an open channel capillary

Romero, Louis A.; Yost, F.G.

doi:10.1017/s0022112096002728

Cited by 152 publications

(172 citation statements)

References 9 publications

Supporting

Mentioning

161

Contrasting

Order By: Relevance

“…The invading fluid bypasses the pore bodies as a result of capillary suction in the corners where the posts meet the top and bottom surfaces of the flow cell. This phenomenon is known as corner flow, and has been studied extensively in the context of spontaneous imbibition into angular capillaries (32)(33)(34)(35)(36)(37). For the wetting fluid to invade the corners, the contact angle must satisfy the geometric relation θ < ðπ − αÞ=2, where α is the corner angle (32).…”

Section: Resultsmentioning

confidence: 99%

Wettability control on multiphase flow in patterned microfluidics

Zhao

MacMinn

Juanes

2016

Proc. Natl. Acad. Sci. U.S.A.

491

480

View full text Add to dashboard Cite

Multiphase flow in porous media is important in many natural and industrial processes, including geologic CO 2 sequestration, enhanced oil recovery, and water infiltration into soil. Although it is well known that the wetting properties of porous media can vary drastically depending on the type of media and pore fluids, the effect of wettability on multiphase flow continues to challenge our microscopic and macroscopic descriptions. Here, we study the impact of wettability on viscously unfavorable fluid-fluid displacement in disordered media by means of high-resolution imaging in microfluidic flow cells patterned with vertical posts. By systematically varying the wettability of the flow cell over a wide range of contact angles, we find that increasing the substrate's affinity to the invading fluid results in more efficient displacement of the defending fluid up to a critical wetting transition, beyond which the trend is reversed. We identify the pore-scale mechanisms-cooperative pore filling (increasing displacement efficiency) and corner flow (decreasing displacement efficiency)-responsible for this macroscale behavior, and show that they rely on the inherent 3D nature of interfacial flows, even in quasi-2D media. Our results demonstrate the powerful control of wettability on multiphase flow in porous media, and show that the markedly different invasion protocols that emerge-from pore filling to postbridging-are determined by physical mechanisms that are missing from current pore-scale and continuum-scale descriptions.porous media | capillarity | wettability | microfluidics | pattern formation M ultiphase flow in porous media is important in many natural and industrial processes, including geologic CO 2 sequestration (1), enhanced oil recovery (2), water infiltration into soil (3), and transport in polymer electrolyte fuel cells (4). Much of the research on multiphase flow in porous media has focused on the effect of fluid properties and flow conditions. Much less emphasis has been given to the fluids' affinity to the porous media (i.e., wettability), even though wettability has a profound influence on fluid-fluid interactions in the presence of a solid surface (5-7). Despite recent advances in our ability to accurately measure wettability under reservoir conditions (8, 9), and to engineer wettability in the subsurface (10-13), the complex physics of wetting continues to challenge our microscopic and macroscopic descriptions (14).Fluid-fluid displacement in the presence of a solid surface can be characterized as either drainage or imbibition, depending on the system's wettability. Drainage refers to the regime where the invading fluid is less wetting to the solid surface than the defending fluid. Imbibition refers to the opposite case, where the invading fluid is more wetting to the solid surface than the defending fluid. Drainage in porous media has been studied extensively through laboratory experiments and computer simulations (15-18), and we now have a fairly good understanding of the different displacement ...

show abstract

Section: Resultsmentioning

confidence: 99%

Wettability control on multiphase flow in patterned microfluidics

Zhao

MacMinn

Juanes

2016

Proc. Natl. Acad. Sci. U.S.A.

491

480

View full text Add to dashboard Cite

show abstract

“…Strage et al, 2003), rectangular (e.g. Ichikawa et al, 2004;Jong et al, 2007;Zhu and Petkovic-Duran, 2010) and grooved/triangular (Yost and Holm, 1995;Romero and Yost, 2006;Baret et al, 2007). Moreover, the same approach has been taken for channels defined by hydrophilic paths on a hydrophobic substrate (Darhuber et al, 2001) and by the space between two parallel plates (Rosendahl et al, 2004) under the assumption of flow with low Reynolds number and liquid imbibing in a tube/slablike manner.…”

Section: Introductionmentioning

confidence: 99%

Wetting considerations in capillary rise and imbibition in closed square tubes and open rectangular cross-section channels

Ouali

McHale

Javed

et al. 2013

Microfluid Nanofluid

149

View full text Add to dashboard Cite

The spontaneous capillary-driven filling of microchannels is important for a wide range of applications. These channels are often rectangular in cross-section, can be closed or open, and horizontal or vertically orientated. In this work, we develop the theory for capillary imbibition and rise in channels of rectangular cross-section, taking into account rigidified and non-rigidified boundary conditions for the liquid-air interfaces and the effects of surface topography assuming Wenzel or Cassie-Baxter states. We provide simple interpolation formulae for the viscous friction associated with flow through rectangular cross-section channels as a function of aspect ratio. We derive a dimensionless cross-over time, T c , below which the exact numerical solution can be approximated by the Bousanquet solution and above which by the visco-gravitational solution. For capillary rise heights significantly below the equilibrium height, this cross-over time is T c  (3X e /2) 2/3 and has an associated dimensionless crossover rise height X c  (3X e /2) 1/3 , where X e =1/G is the dimensionless equilibrium rise height and G is a dimensionless form of the acceleration due to gravity. We also show from wetting considerations that for rectangular channels, fingers of a wetting liquid can be expected to imbibe in advance of the main meniscus along the corners of the channel walls. We test the theory via capillary rise experiments using polydimethylsiloxane oils of viscosity 96.0, 48.0, 19.2 and 4.8 mPa s within a range of closed square tubes and open rectangular cross-section channels with SU-8 walls. We show that the capillary rise heights can be fitted using the exact numerical solution and that these are similar to fits using the analytical visco-gravitational solution. The viscous friction contribution was found to be slightly higher than predicted by theory assuming a non-rigidified liquid-air boundary, but far below that for a rigidified boundary, which was recently reported for imbibition into horizontally mounted open microchannels. In these experiments we also observed fingers of liquid spreading along the internal edges of the channels in advance of the main body of liquid consistent with wetting expectations. We briefly discuss the implications of these observations for the design of microfluidic systems.

show abstract

“…16,17 Now consider the case BoӶ 1, which is the relevant limit for the dip coating of chemically patterned surfaces with arrays of vertical wetting microstripes. Because of the restriction CaӶ 1, an x = const cross section of the free surface of the liquid along the microstripe must be an arc of a circle, 18 which, within the lubrication approximation, simplifies to a parabola. The substitution h͑x , y͒ = h o ͑x͓͒1 −4͑y / W ͒ 2 ͔ then reduces the analysis to a one-dimensional matching problem to determine h o , the film thickness along the centerline of the stripe, which is governed by…”

mentioning

confidence: 99%

Asymptotic analysis of liquid films dip-coated onto chemically micropatterned surfaces

Davis

2005

Physics of Fluids

View full text Add to dashboard Cite

The dip coating of chemically heterogeneous surfaces is a useful technique for attaining selective material deposition. For the case of vertical, wetting stripes surrounded by nonwetting regions, experiments have demonstrated that the thickness of the entrained film on the stripes is significantly different than on homogeneous surfaces because of the lateral confinement of the liquid. In the present work, the asymptotic matching of equations based on lubrication theory is used to determine the film thickness, and necessary restrictions on the capillary and Bond numbers are provided. The predictions are in excellent agreement with the existing experimental data, and the classical Landau–Levich formula for homogeneous surfaces is recovered from the analysis in the limit of very wide stripes.

show abstract

Flow in an open channel capillary

Cited by 152 publications

References 9 publications

Wettability control on multiphase flow in patterned microfluidics

Wettability control on multiphase flow in patterned microfluidics

Wetting considerations in capillary rise and imbibition in closed square tubes and open rectangular cross-section channels

Asymptotic analysis of liquid films dip-coated onto chemically micropatterned surfaces

Contact Info

Product

Resources

About