Pinch-off of liquid bridge during droplet coalescence under constrained condition

Peng, Leqin; Luo, Zhengyuan; Zuo, Yi Y.; Yan, Gang; Bai, Bofeng

doi:10.1016/j.ces.2017.12.014

Cited by 9 publications

(5 citation statements)

References 39 publications

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“…35 Unlike a conventional liquid bridge between two infinite plates, 34 the state of the liquid bridge in Figure 4b is in a nonequilibrium condition, induced by both static asymmetric geometry and dynamic flow. The stability of the liquid bridge is dominated primarily by three forces, namely, surface tension force (correlated to the droplet shape upon coalescence [39][40][41][42] ), and geometrical constraint forces 33,34,43 from the nozzle (correlated to the nozzle size) and the reservoir (correlated to the reservoir size), in which the surface tension force promotes the pinch-off, while the two constraint forces inhibit the pinch-off. These forces govern the shape evolution of the liquid bridge and the droplet remanent volume after pinch-off, and they are intrinsically correlated to the multiple geometrical dimensions, including the nozzle size, the separation distance, and the reservoir size.…”

Section: Resultsmentioning

confidence: 99%

Droplet Laplace valve‐enabled glaucoma implant for intraocular pressure management

Wang,

Fang,

et al. 2024

Droplet

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Glaucoma, the leading cause of irreversible blindness worldwide, is closely linked to aqueous overaccumulation and elevated intraocular pressure (IOP). For refractory glaucoma, aqueous shunts with valves are commonly implanted for effective aqueous drainage control and IOP stabilization. However, existing valved glaucoma implants have the disadvantages of inconsistent valve opening/closing pressures, poor long‐term repeatability due to their reliance on moving parts, and complex architectures and fabrication processes. Here, we propose a novel valving concept, the droplet Laplace valve (DLV), a three‐dimensional printable moving‐parts‐free microvalve with customizable and consistent threshold valving pressures. The DLV uses a flow discretization unit governed by capillarity, comprising a droplet‐forming nozzle, and a separated reservoir to digitize continuous flow into quantifiable droplets. Unlike the classic one‐time‐use Laplace valves, the DLV's unique design allows for its reusability. The opening pressure is adjustable by varying the nozzle size, like the classic Laplace valves (following the Young–Laplace equation), while the closing pressure can be modified by tuning the separation distance and the reservoir size. Various DLVs with customizable opening pressures from 5 to 11 mmHg have been demonstrated, with opening/closing pressure differences suppressed down to <0.5 mmHg (<0.15 mmHg under the best conditions). Thanks to its moving‐parts‐free nature and digitized flow properties, the DLV shows a highly repeatable valving performance (<1.7%, 1000 cycles) and a predictable linear flow rate–pressure correlation (R2 > 0.99). Preliminary ex vivo validation in an enucleated porcine eye confirms the DLV's efficiency in aqueous shunting and prompt IOP stabilization. The DLV technology holds great promise in glaucoma implants for IOP management and various microsystems for flow control.

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Section: Resultsmentioning

confidence: 99%

Droplet Laplace valve‐enabled glaucoma implant for intraocular pressure management

Wang,

Fang,

et al. 2024

Droplet

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“…Experimental setups for coalescence can be distinguished into static drop contacts or dynamic drop collisions. In the static drop contact case, drops are produced and fixed on nozzles or lying on the top or next to each other where film drainage and liquid bridge can be observed in detail [121]. However, during extraction process, drop coalescence is a dynamic behavior influenced by droplet movement.…”

Section: Experimental Studiesmentioning

confidence: 99%

A state-of-the-art review on single drop study in liquid–liquid extraction: Experiments and simulations

Zhang

Wang

Stevens

et al. 2019

Chinese Journal of Chemical Engineering

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“…In more recent years, there has been a growing interest in investigating the interactive dynamics of droplet arrays in engineered devices for manipulating various chemical and biological processes (Anna 2016;Sánchez Barea, Lee & Kang 2019;Panigrahi et al 2021;. Furthermore, in industrial applications like ink-jet printing, surface coating and fuel injectors, frequent events of drop collision appear inevitable (Aarts et al 2005;Tang et al 2012;Peng et al 2018;Varma et al 2020). In oil-water segregation processes, for instance, the coalescence of water droplets is preferred for efficient sedimentation of the dispersed phase (Kavehpour 2015).…”

Section: Introductionmentioning

confidence: 99%

Electric-field-mediated morpho-dynamic evolution in drop–drop coalescence phenomena in the inertio-capillary regime

Behera

Chakraborty

2023

J. Fluid Mech.

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When two drops collide, they may either exhibit complete coalescence or selectively generate secondary drops, depending on their relative sizes and physical properties, as dictated by a decisive interplay of the viscous, capillary, inertia and gravity effects. Electric field, however, is known to induce distinctive alterations in the topological evolution of the interfaces post-collision, by influencing a two-way nonlinear coupling between electro-mechanics and fluid flow as mediated by a topologically intriguing interfacial deformation. While prior studies primarily focused on the viscous-dominated regime of the resulting electro-coalescence dynamics, several non-intuitive features of the underlying morpho-dynamic evolution over the intertio-capillary regime have thus far remained unaddressed. In this study, we computationally investigate electrically modulated coalescence dynamics along with secondary drop formation mechanisms in the inertio-capillary regime, probing the interactions of two unequal-sized drops subjected to a uniform electric field. Our results bring out an explicit mapping between the observed topological evolution as a function of the respective initial sizes of the parent drops as well as their pertinent electro-physical property ratios. These findings establish electric-field-mediated exclusive controllability of the observed topological features, as well as the critical conditions leading to the transition from partial to complete coalescence phenomena. In a coalescence cascade, an electric field is further shown to orchestrate the numbers of successive stages of coalescence before complete collapse. However, an increase of the numbers of cascade stages with the electric field strength and parent droplet size ratio is non-perpetual, and the same is demonstrated to continue until only a threshold number of cascade stages is reached. These illustrations offer significant insights into leveraging the interplay of electrical, inertial and capillary-driven interactions for controllable drop manipulation via multi-drop interactions for a variety of applications ranging from chemical processing to emulsion technology.

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Pinch-off of liquid bridge during droplet coalescence under constrained condition

Cited by 9 publications

References 39 publications

Droplet Laplace valve‐enabled glaucoma implant for intraocular pressure management

Droplet Laplace valve‐enabled glaucoma implant for intraocular pressure management

A state-of-the-art review on single drop study in liquid–liquid extraction: Experiments and simulations

Electric-field-mediated morpho-dynamic evolution in drop–drop coalescence phenomena in the inertio-capillary regime

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