A generalized scaling theory for spontaneous spreading of Newtonian fluids on solid substrates

[Display omitted] •Spreading dynamic of a deposited drop on a solid substrate is studied.•Viscous timescale mainly governs the spreading at a certain Bond number and static contact angle.•Droplet spreading master curves to capture the dynamic shape of the droplet are developed.•A correlation to pred...

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Bibliographic Details
Published in:Journal of colloid and interface science 2023-04, Vol.636, p.677-688
Main Authors: Azimi Yancheshme, Amir, Palmese, Giuseppe R., Alvarez, Nicolas J.
Format: Article
Language:English
Subjects:
CFD
Droplet spreading dynamics
Dynamic contact angle
Equilibrium droplet shape
Moving Mesh
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Summary:[Display omitted] •Spreading dynamic of a deposited drop on a solid substrate is studied.•Viscous timescale mainly governs the spreading at a certain Bond number and static contact angle.•Droplet spreading master curves to capture the dynamic shape of the droplet are developed.•A correlation to predict the equilibrium shape of droplet is developed. There exists a generalized solution for the spontaneous spreading dynamics of droplets taking into account the influence of interfacial tension and gravity. This work presents a generalized scaling theory for the problem of spontaneous dynamic spreading of Newtonian fluids on a flat substrate using experimental analysis and numerical simulations. More specifically, we first validate and modify a dynamic contact angle model to accurately describe the dependency of contact angle on the contact line velocity, which is generalized by the capillary number. The dynamic contact model is implemented into a two-phase moving mesh computational fluid dynamics (CFD) model, which is validated using experimental results. We show that the spreading process is governed by three important parameters: the Bo number, viscous timescale τviscous, and static advancing contact angle, θs. More specifically, there exists a master spreading curve for a specific Bo and θs by scaling the spreading time with the τviscous. Moreover, we developed a correlation for prediction of the equilibrium shape of the droplets as a function of both Bo and θs. The results of this study can be used in a wide range of applications to predict both dynamic and equilibrium shape of droplets, such as in droplet-based additive manufacturing.
ISSN:0021-9797
1095-7103
DOI:10.1016/j.jcis.2023.01.025