Capillary Rise Of Liquid Research Articles

CAPILLARY RISE OF LIQUID BETWEEN PLATES WITH A CERTAIN ANGLE UNDER MICROGRAVITY

In space, because the gravity basically disappears and the secondary forces such as surface tension force play a major role, fluid behavior is quite different from that of the ground. Therefore, it is necessary to deeply explore the laws and characteristics of fluid behavior in microgravity environment. The plate-type tank uses plate-type components to manage the fluid in microgravity environment, so as to provide the thruster with gas-free propellant, which is of great significance for the precise attitude control and orbit adjustment of the spacecraft. Plate-type components often include plates with a certain included angle, such as liquid storage blades. The capillary rise of liquid between plates with a certain angle under microgravity is explored in this paper. The influences of the dynamic contact angle between the liquid and the plates wall, the pressure loss caused by convection, the viscous resistance, and the curved liquid surface in the reservoir are all considered. A second order differential equation of the capillary-driven flow is derived, which can be solved with forth-order Runge−Kutta method. By considering two dominant forces at the same time, the flow can be divided into three regions, and approximate equations of climbing height in different regions are obtained. Six kinds of numerical models are created, three kinds of silicone oil is chonsen and Volume of Fluid(VOF) method is used to carry out numerical simulation. Numerical results are in good agreement with theoretical results, which verifies theoretical analysis. This research can be theoretical basis for plate tanks’ design and fluid management in space.

Capillary rivulet rise in real-world corners

The capillary rise of liquid in a perfect corner wedge has been well studied in the past, yielding a t1/3 rise behavior with no upper bound on the height of the rivulet. However, in real-world situations the wedge corner is often not exactly sharp, either because of roughness or fabrication imperfections. In the following study the behavior of capillary rivulet rise in rounded corners is examined experimentally and theoretically, yielding a deviation from the t1/3 behavior and also a maximum rivulet height. The agreement between experiment and theory is very good.

Capillary rise of liquids in thermally sprayed porous copper wicks

Porous copper coatings, which act as wicks for liquid transport, were fabricated using a flame spraying process. Channels to enhance liquid flow were made in some of the porous copper coatings by placing pieces of aluminum wire mesh on the copper substrate before spraying. Coatings were made with porosity varying from 2 to 44%, and groove width ranging from 0.16 to 0.53 mm. The capillary performance of the coatings was evaluated experimentally by measuring the rate-of-rise of ethanol in the coatings. The capillary performance of the porous copper strips were evaluated by standing them vertically in a pool of ethanol and measuring both the rate of liquid rise using an infra-red camera and their weight increase. The rate of rise increased with coating porosity, and decreased with channel width. Increasing channel size improved the permeability of the coatings to liquid flow while decreasing their width increased capillary pressure and the height to which liquid rises. An analytical solution of capillary rise in porous media was used to predict the rate of liquid rise as a function of the effective porosity of the coatings, which combines the volume of both the pores and the channels in the coating.

Meniscus arrest during capillary rise in asymmetric microfluidic pore junctions.

The capillary rise of liquid in asymmetric channel junctions with branches of different radii can lead to long-lasting meniscus arrests in the wider channel, which has important implications for the morphology and dynamical broadening of imbibition fronts in porous materials with elongated pores. Using a microfluidic setup, we experimentally demonstrate the existence of arrest events in Y-shaped junctions, and measure their duration and compare them with theoretical predictions. For various ratios of the channel width and liquid viscosities and for different values of the feeding channel length, we find that the meniscus within the wider branch is arrested for a time that is proportional to the time that the meniscus needed to reach the junction, in very good quantitative agreement with theoretical predictions.

Dynamics of Wicking in Silicon Nanopillars Fabricated with Interference Lithography and Metal-Assisted Chemical Etching

The capillary rise of liquid on a surface, or "wicking", has potential applications in biological and industrial processes such as drug delivery, oil recovery, and integrated circuit chip cooling. This paper presents a theoretical study on the dynamics of wicking on silicon nanopillars based on a balance between the driving capillary forces and viscous dissipation forces. Our model predicts that the invasion of the liquid front follows a diffusion process and strongly depends on the structural geometry. The model is validated against experimental observations of wicking in silicon nanopillars with different heights synthesized by interference lithography and metal-assisted chemical etching techniques. Excellent agreement between theoretical and experimental results, from both our samples and data published in the literature, was achieved.

Capillary Rise of Liquids over a Microstructured Solid Surface

The location of the triple line as a function of time has been recorded for a series of organic liquids, with various surface tension to viscosity ratios, wicking upward a rough Cu(6)Sn(5)/Cu intermetallic (IMC) substrate. The complex topographical features of such an IMC rough surface are characterized by surface porosity and surface roughness. A theoretical model for wicking upward a rough surface has been established by treating the rough IMC surface as a two-dimensional porous medium featuring a network of open microtriangular grooves. The model is verified against experimental data. The study confirms that the kinetics of capillary rise of organic liquids in a nonreactive flow regime over a porous surface having arbitrary but uniformly distributed topographical features involves (i) surface topography metrics (i.e., permeability, tortuosity/porosity, and geometry of the microchannel cross section); (ii) wicking features (i.e., contact angle and filling factor); and (iii) physical properties of liquids (i.e., surface tension and viscosity). An excellent agreement between theoretical predictions and experimentally obtained data proves, for a selected filling factor η, validity of the analytically established model. Scaled data sets show that, for a given rough surface topography, (i) wicking kinetics of considered liquids depend on properties of liquids, that is, surface tension to viscosity ratios and contact angles; (ii) the filling factor for all tested liquids is an invariant, offering good prediction within the range of ~0.9-1.0. The distance of the wicking front versus square root of time relationship was well established throughout the whole considered wicking evolution time.

Bending of nanoscale filament assemblies by elastocapillary densification

We report a mechanism by which nanoscale filaments self-assemble into asymmetric aggregates by elastocapillary action. Specifically, capillary rise of liquid into an asymmetric pattern of vertically aligned filaments causes the filaments to deflect laterally during elastocapillary densification. We quantitatively show that the lateral deflection can be controlled precisely by the pattern shape and the coupling strength among the filaments. We exploit this mechanism to fabricate asymmetric micropillars and multidirectional bridges of densely packed carbon nanotubes. Analogous behavior occurs as biological filaments interact with liquids, and these findings enable scalable fabrication of anisotropic filament assemblies for manipulating surface interactions between solids and liquids.

Capillary impregnation into cylinder banks

The capillary rise of liquid in a cylinder bank is examined in order to study the capillary pressure variation perpendicular to the direction of the cylinders. The calculations consider the local geometric variation of the flow channel and the position-dependent capillary pressure. The capillary flow around each cylinder is calculated by balancing the capillary pressure and the viscous drag along the flow path. The rate of filling for several layers of cylinders is used to estimate the equivalent capillary pressure. The method is also applied to the underfill of a flip chip system, which is modeled as a cylinder bank between parallel plates.

Capillary rise between two TiO2 thin-films: evaluating photo-activated wetting

The measurement of capillary rise was used for evaluating the photo-enhanced wetting ability of TiO 2 . Two glass plates, which were coated with TiO 2 thin-films, were vertically oriented having a small gap and immersed in the several solutions. In the channel between two TiO 2 thin-films, the capillary rise of liquids is determined by the surface tension of liquids and the physical–chemical nature of the contacting surfaces. The capillary rise of water was measured to be 28 mm for a TiO 2 samples equilibrated in the dark for 2 h (immediately after the calcination), 29 mm for the surface pre-illuminated with UV light and 11 mm for aged samples (i.e. kept in a dark box for several weeks). A companion FT-IR study supported the fact that the capillary rise has a strong relation with the amount of adsorbed water on the surface of the TiO 2 thin-films. While contact angles have been routinely measured for photoactive TiO 2 systems, capillary rise is an alternative criterion for the wetting ability without expensive equipment. We also show that capillary rise can be expanded to photo-responsive motion of liquids in the TiO 2 channel. The capillary rise of water tested between the two TiO 2 thin-film surfaces increased by a factor of three under UV light exposure.

Capillary rise between two TiO 2 thin-films: evaluating photo-activated wetting

The measurement of capillary rise was used for evaluating the photo-enhanced wetting ability of TiO 2. Two glass plates, which were coated with TiO 2 thin-films, were vertically oriented having a small gap and immersed in the several solutions. In the channel between two TiO 2 thin-films, the capillary rise of liquids is determined by the surface tension of liquids and the physical–chemical nature of the contacting surfaces. The capillary rise of water was measured to be 28 mm for a TiO 2 samples equilibrated in the dark for 2 h (immediately after the calcination), 29 mm for the surface pre-illuminated with UV light and 11 mm for aged samples (i.e. kept in a dark box for several weeks). A companion FT-IR study supported the fact that the capillary rise has a strong relation with the amount of adsorbed water on the surface of the TiO 2 thin-films. While contact angles have been routinely measured for photoactive TiO 2 systems, capillary rise is an alternative criterion for the wetting ability without expensive equipment. We also show that capillary rise can be expanded to photo-responsive motion of liquids in the TiO 2 channel. The capillary rise of water tested between the two TiO 2 thin-film surfaces increased by a factor of three under UV light exposure.

Spherical agglomeration during crystallization of an active pharmaceutical ingredient

Lobenzarit disodium (LBD) salt is a drug used in the treatment of rheumatoid arthritis diseases. The objective of this work is to propose and validate a method for selecting the best wetting agent allowing to obtain spherical agglomerates during crystallization. This method is based on the so-called Washburn's test (capillary rise of liquids in a granular medium). Crystallization tests carried out at different conditions showed that the best results were obtained in the presence of n-hexane that was effectively found to be a better wetting liquid of the lobenzarit crystals than the other solvents.

Capillary Rise of Liquid between Parallel Plates under Microgravity

The liquid flow between parallel plates under microgravity due to capillary forces is studied. Experiments were performed during the free fall in a drop tower to investigate the transient rise of the meniscus (free surface). A linear momentum balance around the fluid in the capillary gap leads to a second-order nonlinear differential equation for the height of the meniscus. Good agreement was found between the numerical solution and the experimental data. The meniscus runs through three time domains. In the beginning the inertia force due to the acceleration of fluid in the reservoir acts against the capillary force, which is always the driving force. After that the convective force due to the fluid flow at the entrance becomes dominant, leading to a linear meniscus rise h( t). Subsequently, the frictional force in the gap dominates other resisting forces and the increase of h( t) becomes proportional to the square root of time. Approximate solutions for the three time domains have been found.

Capillary rise of liquids in rectangular tubings

The capillary rise of liquids was investigated in square capillary tubings of different dimensions (e. g. 300 μm · 300 μm to 1000 μm · 1000 μm) in the temperature range 25° to 35°C.

Contact Angles from Capillary Rise Between Filaments in a V-Configuration

The capillary rise of liquids between two fibers in a V-configuration can be calculated on the basis of an existing theory for two parallel fibers. Experimental results previously obtained by Miller et al. are in fair agreement with the theory, considering the uncertainty in some of the experimental parameters. Several improvements in the technique are suggested. The theory for fibers in a V-configuration is subject to the same limitations as that for parallel fibers, i.e., reliable results can be expected only when the capillary rise is large compared to the radius of the fibers.

Capillary phenomena in assemblies of parallel cylinders: I. Capillary rise between two cylinders

The capillary rise of liquid in the gap between two closely spaced parallel cylinders has been calculated as a function of distance of separation and contact angle. The solutions are valid only when the height of the meniscus is much greater than the radius of the cylinders. With the same restriction, the capillary rise between a cylinder and a flat plate has been evaluated.

Exchange of liquid between paper pores

The capillary rise of liquid in paper cannot be explained quantitatively by assuming uniform capillaries. The introduction of a distribution function for the capillary radii offers the possibility of calculating a correction term for the capillary pressure and the volume of liquid at any level.

XXX.On the capillary rise of liquids in wide tubes

XXX.<i>On the capillary rise of liquids in wide tubes</i>