Numerical Modeling of Liquid Drop Spreading Behavior on Inclined Surfaces

Author(s):  
Young-Gil Park ◽  
Anthony M. Jacobi

A numerical study was conducted on the spreading behavior of liquid drops on flat solid surfaces. The model predicts the shape of liquid-vapor interface under static equilibrium using an unstructured surface grid composed of triangular elements. Incremental movement of base contour, i.e. solid-liquid-vapor contact line, is also captured such that the constrained boundary conditions, i.e. advancing and receding contact angles, can be satisfied. The numerical model is applied to a common experiment that studies the behavior of liquid drops on inclined surfaces, where the shape of the drops change in response to an alteration of total volume or gravitational direction. On a heterogeneous surface that has contact angle hysteresis, the shape of the base contour on the solid surface is not determined uniquely but rather dependent upon history. This study demonstrates such dependence by comparing the spreading of a liquid drop on a solid surface with different quasi-equilibrium paths.

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Yong-Ming Liu ◽  
Zi-Qing Wu ◽  
Sheng Bao ◽  
Wei-Hong Guo ◽  
Da-Wei Li ◽  
...  

The contact angle, as a vital measured parameter of wettability of material surface, has long been in dispute whether it is affected by gravity. Herein, we measured the advancing and receding contact angles on extremely low contact angle hysteresis surfaces under different gravities (1-8G) and found that both of them decrease with the increase of the gravity. The underlying mechanism is revealed to be the contact angle hysteresis and the deformation of the liquid-vapor interface away from the solid surface caused by gradient distribution of the hydrostatic pressure. The real contact angle is not affected by gravity and cannot measured by an optical method. The measured apparent contact angles are angles of inclination of the liquid-vapor interface away from the solid surface. Furthermore, a new equation is proposed based on the balance of forces acting on the three-phase contact region, which quantitatively reveals the relation of the apparent contact angle with the interfacial tensions and gravity. This finding can provide new horizons for solving the debate on whether gravity affects the contact angle and may be useful for the accurate measurement of the contact angle and the development of a new contact angle measurement system.


2015 ◽  
Vol 1120-1121 ◽  
pp. 369-377 ◽  
Author(s):  
Jia Feng Jin ◽  
Yan Ling Wang ◽  
Fei Liu

Wettability is one of most important characteristics for governing the flow and distribution of reservoir fluids in the porous media,the wetting and spreading behavior of liquids on the solid surfaces changes if the wettability of solid surface is altered. Recent studies show the spreading behavior of liquids on solid surface can be significantly improved after nanofluid treatment. In order to investigate the influence of wettability alternation on enhancing oil recovery after nanofluid treatment,flushing oil experiment and contact angle measurement were conducted in the laboratory. The first experiment involved flushing crude oil with the nanofluid and conventional surfactants, respectively. In the second case, the contact angles of oil phase in nanofluid (conventional surfactant solutions)-crude oil-slide systems were measured after treating 36 hours. The results indicated that nanofluid can produce a better flushing efficiency compared with that of conventional surfactant, and the contact angles of oil phase increased from 33° to 118° after nanofluid treatment in nanofluid/crude-oil/slide system. The mechanism of enhanced oil recovery of nanofluid is mainly wettability alternation.


Langmuir ◽  
2012 ◽  
Vol 28 (32) ◽  
pp. 11819-11826 ◽  
Author(s):  
M. J. Santos ◽  
S. Velasco ◽  
J. A. White

2021 ◽  
Vol 33 (6) ◽  
pp. 061707
Author(s):  
Alexander E. Dubinov ◽  
Djamilya N. Iskhakova ◽  
Valeria A. Lyubimtseva

Biomimetics ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 38
Author(s):  
Quentin Legrand ◽  
Stephane Benayoun ◽  
Stephane Valette

This investigation of morphology-wetting links was performed using a biomimetic approach. Three natural leaves’ surfaces were studied: two bamboo varieties and Ginkgo Biloba. Multiscale surface topographies were analyzed by SEM observations, FFT, and Gaussian filtering. A PDMS replicating protocol of natural surfaces was proposed in order to study the purely morphological contribution to wetting. High static contact angles, close to 135∘, were measured on PDMS replicated surfaces. Compared to flat PDMS, the increase in static contact angle due to purely morphological contribution was around 20∘. Such an increase in contact angle was obtained despite loss of the nanometric scale during the replication process. Moreover, a significant decrease of the hysteresis contact angle was measured on PDMS replicas. The value of the contact angle hysteresis moved from 40∘ for flat PDMS to less than 10∘ for textured replicated surfaces. The wetting behavior of multiscale textured surfaces was then studied in the frame of the Wenzel and Cassie–Baxter models. Whereas the classical laws made it possible to describe the wetting behavior of the ginkgo biloba replications, a hierarchical model was developed to depict the wetting behavior of both bamboo species.


2020 ◽  
Vol 146 ◽  
pp. 03004
Author(s):  
Douglas Ruth

The most influential parameter on the behavior of two-component flow in porous media is “wettability”. When wettability is being characterized, the most frequently used parameter is the “contact angle”. When a fluid-drop is placed on a solid surface, in the presence of a second, surrounding fluid, the fluid-fluid surface contacts the solid-surface at an angle that is typically measured through the fluid-drop. If this angle is less than 90°, the fluid in the drop is said to “wet” the surface. If this angle is greater than 90°, the surrounding fluid is said to “wet” the surface. This definition is universally accepted and appears to be scientifically justifiable, at least for a static situation where the solid surface is horizontal. Recently, this concept has been extended to characterize wettability in non-static situations using high-resolution, two-dimensional digital images of multi-component systems. Using simple thought experiments and published experimental results, many of them decades old, it will be demonstrated that contact angles are not primary parameters – their values depend on many other parameters. Using these arguments, it will be demonstrated that contact angles are not the cause of wettability behavior but the effect of wettability behavior and other parameters. The result of this is that the contact angle cannot be used as a primary indicator of wettability except in very restricted situations. Furthermore, it will be demonstrated that even for the simple case of a capillary interface in a vertical tube, attempting to use simply a two-dimensional image to determine the contact angle can result in a wide range of measured values. This observation is consistent with some published experimental results. It follows that contact angles measured in two-dimensions cannot be trusted to provide accurate values and these values should not be used to characterize the wettability of the system.


Soft Matter ◽  
2021 ◽  
Author(s):  
Marie-Jean Thoraval ◽  
Jonas Schubert ◽  
Stefan Karpitschka ◽  
Munish Chanana ◽  
François Boyer ◽  
...  

The presence of nanoparticles in a millimetric liquid drop impacting on a solid surface can suppress splashing at higher impact velocities. This mechanism is affected by the nanoparticles concentration and the coating molecules at their surface.


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