Modeling of Contact Angles and Wetting Effects With Particle Methods

刘谋斌,; Jz, Chang; HT, Liu; Tx, Su

doi:10.1142/s0219876211002733

Cited by 15 publications

(7 citation statements)

References 30 publications

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“…The contact angle has been used to describe the wetting capability of a liquid to a solid, 46 being a measurement of hydrophobic/ hydrophilic character of a surface, 24 and is defined as the angle formed from tangential lines of fluid−fluid and fluid−solid interfaces. 40 Static water contact angle measurements at air-side with values ≥90°d escribe a hydrophobic behavior or a partial wetting. Contact angles between a water droplet and photografted PDMS surfaces having various hydrophobic or hydrophilic characters were experimentally determined for two systems: (i) placing a droplet of deionized water on the air-side surface of the photografted PDMS samples at room temperature, (ii) and using a blunt syringe needle, a droplet of deionized water was placed on photografted PDMS samples immersed in a silicone oil media.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…In DPD simulations, to represent the effects of a solid wall, fixed particles are usually used to represent a solid matrix. 40 All particles located at solid layer regions were constrained on its motion, by fixing positions. The simulation box mimicking the fully grafted surface system is composed of fixed center of mass (CoM) of DPD beads in different slabs (slabs 2, 3, and 4, see Figure 1) of average density of 3 in reduced units.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…This is due to strong and more probable hydrogen bonding between COOH groups and water. , An alternative methodology is dissipative particle dynamics (DPD), which is a mesoscopic scale simulation technique that uses coarse-grained particles (beads) to represent clusters of atoms or molecules . DPD can be seen as an extension of MD simulations to higher time and length scales, and an interesting candidate to study complex fluids − and wetting effects. − DPD simulations are usually used to qualitatively describe systems, but quantitative comparisons between experiments and DPD simulation results remain scarce. Hereafter, we describe an innovative use of DPD simulation results leading to quantitative predictions of contact angle values.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Surface Photografting of Acrylic Acid on Poly(dimethylsiloxane). Experimental and Dissipative Particle Dynamics Studies

et al. 2015

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This work includes both experimental and theoretical studies of the wetting property changes of water on a surface of poly(dimethylsiloxane) (PDMS) modified with different amounts of acrylic acid (AA). The default surface properties of PDMS were changed from hydrophobic to hydrophilic behavior which was characterized with contact angle measurements by two approaches: (i) experimental tests of samples subjected to a photografting polymerization procedure to obtain a functionalized surface and (ii) DPD (dissipative particle dynamics) simulations which also involve the calculation of sets of repulsive parameters determined following two methods: the use of the "Blends" module in the Materials Studio software and the calculation of cohesive energy density with molecular simulations. Changes of contact angle values observed from both experimental and numerical simulation results provide qualitative and quantitative information on the wetting behavior of photografted surfaces.

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Section: ■ Materials and Methodsmentioning

confidence: 99%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Surface Photografting of Acrylic Acid on Poly(dimethylsiloxane). Experimental and Dissipative Particle Dynamics Studies

et al. 2015

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“…Surface tension Surface tension effects are very important for liquid drop dynamics especially when the spatial scale reduces. For particle methods such as SPH, there are basically two approaches to model multiphase contact line dynamics with SPH method [11] . The first approach is to incorporate the continuum surface force (CSF) model and introduced directly surface tension force into the momentum equation as expressed in equation (6).…”

Section: B Sph Equations Of Motionmentioning

confidence: 99%

SPH modeling of multiphase drop dynamics

Liu

et al. 2012

2012 7th IEEE Conference on Industrial Electronics and Applications (ICIEA)

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Abstract-This paper presents an SPH (smoothed particle hydrodynamics) model for numerical simulation of multiphase drop dynamics including liquid drop formation and deformation, coalescence and separation, liquid drop impacting, spreading and splashing. SPH is a Lagrangian, meshfree particle method. It has special advantages in modeling multiphase drop dynamics. Surface tension effects are modeled using a particle-particle interaction force, which avoids the calculation of surface and interface curvature. Solid boundaries are modeled using a coupled dynamic boundary treatment algorithm, which ensures the accuracy and flexibility of the SPH method. Numerical investigations of a liquid drop oscillation and a single liquid drop impacting onto a liquid film are conducted. The inherent physics of multiphase drop dynamics are well described.

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“…Following the development of computer technology, it is already allowed to use the numerical method to do the researches in the recent decades [Shang et al (2008);Liu et al (2011);Shang et al (2012)]. Therefore, many researchers employ the numerical method, called as Computational fluid dynamics (CFD), to study the details of the flows.…”

mentioning

confidence: 99%

A New Multidimensional Drift Flux Mixture Model for Gas–Liquid Droplet Two-Phase Flow

Shang

Lou

2015

Int. J. Comput. Methods

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A new multidimensional drift flux mixture model was developed to simulate gas-liquid droplet two-phase flows. The new drift flux model was modified by considering the centrifugal force on the liquid-droplets. Therefore the traditional 1D drift flux model was upgraded to multidimension, 2D and 3D. The slip velocities between the continual phase (gas) and the dispersed phase (liquid droplets) were able to calculate through the multidimensional diffusion flux velocities based on the new modified drift flux model. Through the numerical simulations comparing with the experiments and the simulations of other models on the backward-facing step and the water mist spray two-phase flows, the new model was validated.A good understanding of the liquid droplet dynamics of the spray will help the engineers to design the high efficient facilities under optimized operating parameters. Due to the complex two-phase or multiphase flow and turbulence, normally the flow in spray system is under transient regime [Desantes et al. (2014)]. The time average values of the parameters, such as liquid holdup distributions, liquid phase back mixing, gas-liquid interface disturbing, mass and heat transfer between gas and liquid phases, liquid droplet distributions, liquid droplet velocities etc., have to be considered by the influence of turbulence. Although the operation of spray system is simple, the actual physical flow phenomena are still lack of complete understanding of the fluid dynamics [Husted (2007)].Many experimental facilities and methods were introduced to study the multiphase flows in gas-liquid droplet systems. Ruck and Makiola [1988] used a Laser Doppler anemometer (LDA) to study the gas-oil droplet passing over a backward facing step. Ferrand et al. [2003] used a phase Doppler and Laser induced fluorescence technique to study the gas-droplet turbulent velocity and two-phase interaction through a jet with partly responsive droplets. Esposito et al.[2010] used a monochrome charge-coupled device (CCD) camera to study the growing of the droplets. The experimental methods can provide very useful information about the liquid droplets at certain measurement points, but they are difficult to show the details of the flow fields and parameters inside the spray.Following the development of computer technology, it is already allowed to use the numerical method to do the researches in the recent decades [Shang et al. (2008);Liu et al. (2011);Shang et al. (2012)]. Therefore, many researchers employ the numerical method, called as Computational fluid dynamics (CFD), to study the details of the flows. Griffiths et al. [1996] employed the coupled particle Lagrangian model with Eulerian continual fluid flow model to simulate a cyclone sampler and compared the numerical results with the empirical models. Barton [1999] used the stochastic Monte Carlo scheme coupled with k − ε turbulence model to study the particle trajectories in turbulent flow over a backward facing step. Husted [2007] used the Eulerian-Lagrangian model provided by Fire Dyna...

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Modeling of Contact Angles and Wetting Effects With Particle Methods

Cited by 15 publications

References 30 publications

Surface Photografting of Acrylic Acid on Poly(dimethylsiloxane). Experimental and Dissipative Particle Dynamics Studies

Surface Photografting of Acrylic Acid on Poly(dimethylsiloxane). Experimental and Dissipative Particle Dynamics Studies

SPH modeling of multiphase drop dynamics

A New Multidimensional Drift Flux Mixture Model for Gas–Liquid Droplet Two-Phase Flow

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