Steady Vapor Bubbles in Rectangular Microchannels

Ajaev, Vladimir S.; Homsy, G. M.

doi:10.1006/jcis.2001.7562

Cited by 110 publications

(57 citation statements)

References 15 publications

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“…Such a configuration, accounting for an adsorbed microfilm of this nature, has originally been been treated by Potash and Wayner (1972). This line of studies is followed in particular by Moosman and Homsy (1980), Stephan and Busse (1992), DasGupta et al (1993), Morris (2001), Ajaev and Homsy (2001), Ajaev (2005a), Rossomme et al (2006Rossomme et al ( , 2009, Colinet et al (2007), and the present paper also forms part of it.…”

Section: Introductionmentioning

confidence: 81%

Steady Microstructure of a Contact Line for a Liquid on a Heated Surface Overlaid With Its Pure Vapor: Parametric Study for a Classical Model

2009

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Abstract. Based on a standard one-sided lubrication-type model, an analysis is carried out pertaining to a small vicinity of a contact line of a volatile non-polar perfectly-wetting macroscopic liquid sample surrounded with its pure vapour and attached to a smooth uniformly superheated solid surface. The behaviour of the liquid film is governed by the effects of evaporation, capillarity and the disjoining pressure. The kinetic resistance to evaporation, as well as the dependence of the local saturation temperature on the local liquid pressure are accounted for.Within the localized approach pursued, a steady configuration of the film on a flat substrate is studied such that at one end (say, to the left) it asymptotically attains an adsorbed microfilm in equilibrium with the vapour, while to the right it gets on to a constant slope (contact angle of the "microstructure"). For moving contact lines in the situations like drop spreading or bubble growth in the boiling process, this microstructure is relevant in the quasi-steady sense, provided that the displacement velocity is not too large.The paper focuses on a numerically-based parametric study expressing the contact angle and evaporation flux characteristics as functions of the system parameters. Asymptotic expansions at both ends of the film are elaborated in some detail and relied upon in the numerics. Asymptotic results from the literature involving certain limiting cases of the system parameters are critically examined. At last, the Marangoni and the vapour-recoil effects are additionally incorporated and their possible importance is assessed.

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Section: Introductionmentioning

confidence: 81%

Steady Microstructure of a Contact Line for a Liquid on a Heated Surface Overlaid With Its Pure Vapor: Parametric Study for a Classical Model

2009

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“…Equations (1) are solved subject to no-slip and no-penetration conditions at the wall, u = w = 0 at z = 0; we also assume the wall to be highly conducting and set T = T w at z = 0. Normal and tangential stress conditions are applied at z = h in addition to kinematic and thermal flux conditions; following the application of the lubrication approximation, these conditions are respectively given by In order to model evaporative effects, the following non-equilibrium interfacial condition is applied [30,51,52] …”

Section: Formulation a Governing Equationsmentioning

confidence: 99%

Pinning, Retraction, and Terracing of Evaporating Droplets Containing Nanoparticles

2009

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We consider the dynamics of a slender, evaporating droplet containing nanoparticles. We use lubrication theory to derive a coupled system of equations that govern the film thickness and the concentration of nanoparticles. These equations account for capillarity, Marangoni stresses, evaporation and disjoining pressure; the nanoparticles-induced structural component of the disjoining pressure is also considered. Contact line singularities are avoided through the adsorption of ultrathin films wherein evaporation is suppressed by the disjoining pressure; a similar approach has recently been used by Ajaev [J. Fluid Mech., 528, 279-296, 2005] who has built on the previous work of Moosman and Homsy [J. Colloid Interface Sci., 73, 212-223, 1980]. The results of our numerical simulations indicate that, depending on the value of system parameters, the droplet exhibits a variety of different behaviours, which include spreading, evaporation-driven retraction, contact line pinning, and 'terrace'-formation.

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“…To this end, we develop a lubrication model based on the so called one-sided approximation [44][45][46] 49 for studying evaporating films containing nanoparticles. Finally, we fully account for the presence of insoluble surfactant monomers at the liquid-gas interface.…”

Section: 43mentioning

confidence: 99%

“…Finally, we use the following non-equilibrium interfacial condition to model evaporative effects 45,46,58 …”

Section: 53mentioning

confidence: 99%

Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

2016

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We consider the flow dynamics of a thin evaporating droplet in the presence of an insoluble surfactant and non-interacting particles in the bulk. Based on lubrication theory, we derive a set of evolution equations for the film height, the interfacial surfactant and bulk particle concentrations, taking into account the dependence of the liquid viscosity on the local particle concentration. An important ingredient of our model is that it takes into account the fact that the surfactant adsorbed at the interface hinders evaporation. We perform a parametric study to investigate how the presence of surfactants affects the evaporation process as well as the flow dynamics with and without the presence of particles in the bulk. Our numerical calculations show that the droplet life-time is affected significantly by the balance between the ability of surfactant to * To whom correspondence should be addressed † Department of Chemical Engineering, University of Patras, Patras 26500, Greece ‡ Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy 502 285, Telangana, India ¶ Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK 1 enhance spreading suppressing the effect of thermal Marangoni stresses-induced motion and to hinder the evaporation flux through the reduction of effective interfacial are of evaporation, which tend to accelerate and decelerate the evaporation process, respectively. For particle-laden droplets and in the case of dilute solutions, the droplet life-time is found to be weakly-dependent on the initial particle concentration. We also show that the particle deposition patterns are influenced strongly by the direct effect of surfactant on the evaporative flux; in certain cases, the "coffee stain" effect is enhanced significantly. A discussion of the delicate interplay between the effects of capillary pressure, solutal and thermal Marangoni stresses, which drive the liquid flow inside the evaporating droplet giving rise to the observed results is provided herein.

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Steady Vapor Bubbles in Rectangular Microchannels

Cited by 110 publications

References 15 publications

Steady Microstructure of a Contact Line for a Liquid on a Heated Surface Overlaid With Its Pure Vapor: Parametric Study for a Classical Model

Steady Microstructure of a Contact Line for a Liquid on a Heated Surface Overlaid With Its Pure Vapor: Parametric Study for a Classical Model

Pinning, Retraction, and Terracing of Evaporating Droplets Containing Nanoparticles

Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

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