Evaporation of a sessile droplet on a slope

Timm, Mitch

doi:10.37099/mtu.dc.etdr/755

Cited by 3 publications

(4 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, a droplet on a sloped surface will be perturbed away from a spherical cap profile by gravity, which leads to a change in the angular dependence of the evaporative flux (Timm et al. 2019; Tredenick et al. 2021).…”

Section: Introductionmentioning

confidence: 99%

“…The geometry of a sessile drop can be controlled readily in a laboratory setting, which makes it a valuable tool for potential control of the deposition pattern. For example, a droplet on a sloped surface will be perturbed away from a spherical cap profile by gravity, which leads to a change in the angular dependence of the evaporative flux (Timm et al 2019;Tredenick et al 2021). The droplet contact set can also be manipulated by machining or treating the substrate in such a way that pinning at particular points is promoted, altering the shape of the deposit (He et al 2017;Sáenz et al 2017;Kubyshkina et al 2020).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The nascent coffee ring with arbitrary droplet contact set: an asymptotic analysis

2022

View full text Add to dashboard Cite

We consider the effect of droplet geometry on the early-stages of coffee-ring formation during the evaporation of a thin droplet with an arbitrary simple, smooth, pinned contact line. We perform a systematic matched asymptotic analysis of the small capillary number, large solutal Péclet number limit for two different evaporative models: a kinetic model, in which the evaporative flux is effectively constant across the droplet, and a diffusive model, in which the flux is singular at the contact line. For both evaporative models, solute is transported to the contact line by a capillary flow in the droplet bulk, while local to the contact line, solute diffusion counters advection. The resulting interplay leads to the formation of the nascent coffee-ring profile. By exploiting a coordinate system embedded in the contact line, we solve explicitly the local leading-order problem, deriving a similarity profile (in the form of a gamma distribution) that describes the nascent coffee ring. Notably, for an arbitrary contact line geometry, the ring characteristics change due to the concomitant asymmetry in the shape of the droplet free surface, the evaporative flux (for diffusive evaporation) and the mass flux into the contact line. We utilize the asymptotic model to determine the effects of contact line geometry on the growth of the coffee ring for a droplet with an elliptical contact set. Our results offer mechanistic insight into the effect of contact line curvature on the development of the coffee ring from deposition up to jamming of the solute; moreover, our model predicts when finite concentration effects become relevant.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The nascent coffee ring with arbitrary droplet contact set: an asymptotic analysis

2022

View full text Add to dashboard Cite

show abstract

“…Under CR mode, the radius of curvature of an evaporating droplet increases over time (provided the initial contact angle is less than π/2), which results in a decrease in the magnification of the distorted dot pattern. To relate this to the droplet height h, each droplet is treated as a plano-convex lens with an upper surface assumed spherical due to the Bond number being small (see, for example, [11]), i.e., Bo = ∆ρgh 2 /σ 1, where ∆ρ is the density difference between the water and air, g is the gravitational acceleration, and σ is the water surface tension. An optics transfer matrix method is used to trace a ray of light from the pattern through the substrate, droplet, and air, and to derive an equation relating the magnification of the distorted dots to height.…”

Section: B Experimental Approachmentioning

confidence: 99%

Drying dynamics of sessile-droplet arrays

et al. 2023

View full text Add to dashboard Cite

We analyze the diffusion-controlled evaporation of multiple droplets placed near each other on a planar substrate. Specifically, we calculate the change in the volume of sessile droplets with various initial contact angles that are arranged in different configurations. The calculations are supplemented by experimental measurements using a technique that interprets the variable magnification of a pattern placed beneath the droplet array, which is applied to the case of initially hemispherical droplets deposited in four distinct arrangements. We find excellent agreement between the predictions based on the theory of Masoud et al. [Evaporation of multiple droplets, J. Fluid Mech. 927, R4 (2021)] and the data gathered experimentally. Perhaps unexpectedly, we also find that, when comparing different arrays, the droplets with the same order of disappearance within their respective array, i.e., fastest evaporating, second-fastest evaporating, etc., follow similar drying dynamics. Our study provides not only experimental validation of the theoretical framework introduced by Masoud et al., but also offers additional insights into the evolution of the volume of individual droplets when evaporating within closely-spaced arrays.

show abstract

“…The case of a sessile drop evaporation (see [17,18] for a review) is more complex because of the diverging evaporative flux at the triple line [19,20,21] and several studies have been devoted to the nature of the substrate. For instance, the case of a drop on a tilted surface [22], on crossed fibers [23], on superhydrophobic surfaces [24] or with complex wetting patterns [25] can be cited. The situation of a droplet on a curved surface such as a convex or concave surface [26,27] has been studied as well, the latter corresponding to a clamshell on a fiber.…”

Section: Introductionmentioning

confidence: 99%

Evaporation of liquid coating a fiber

Corpart,

Dervaux,

Poulard

et al. 2022

Preprint

View full text Add to dashboard Cite

We investigate theoretically and numerically the diffusion-limited evaporation of a liquid deposited on a fiber in two configurations: a sleeve and a axisymmetric barrel-shaped droplet. For a sleeve, the local flux depends on both the aspect ratio and the smallest length of the problem. By using analytical calculations and 3D finite elements simulations, we predict a divergence of this flux further localized at the edge as the aspect ratio increases. The evaporation of axisymmetric drops on a fiber is studied with numerical simulations. For sufficiently large volumes, we evidence that the evaporation rate is almost independent of the wetting properties of the liquid, even for small contact angles, and that the droplets evaporate as spheres of the same volume.

show abstract

Evaporation of a sessile droplet on a slope

Cited by 3 publications

References 37 publications

The nascent coffee ring with arbitrary droplet contact set: an asymptotic analysis

The nascent coffee ring with arbitrary droplet contact set: an asymptotic analysis

Drying dynamics of sessile-droplet arrays

Evaporation of liquid coating a fiber

Contact Info

Product

Resources

About