Visual Study of Liquid Flow in a Spinning Disk Reactor with a Hydrophobic Surface

Wu, Xiang-Sen; Luo, Yong; Chu, Guang‐Wen; Xu, Ying-Chun; Sang, Le; Sun, Baochang; Chen, Jianfeng

doi:10.1021/acs.iecr.8b00673

Cited by 21 publications

(10 citation statements)

References 34 publications

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“…Microfluidic systems extensively use the latter to generate controlled size drops continuously. Drop formation from a hydrophobic disc is qualitatively different, as shown by the high-speed images of Wu et al 22 and is not addressed in this study. Figure 1 schematically brings up the basic difference between direct drop and ligament modes of drop formation.…”

Section: Introductionmentioning

confidence: 66%

Dynamics of Drop Release from the Edge of a Spinning Disc

Sahoo

Kumar

2021

Ind. Eng. Chem. Res.

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The direct formation of drops at the edge of a spinning disc is of fundamental interest. We use high-speed imaging to report here on the process of release of drops from a perfectly wetted disc at low inflow rates. A drop-detachment event begins by forming an incipient bulge on the disc edge, which grows into a series of shapestriangle, inverted U, pear, and finally a nearly spherical bulge connected to the disc with an elongated neck. Neck pinching at the base of the bulge releases a primary drop followed by several secondary drops. The drop shape versus time plots show high variability under fixed conditions, which disappears on a single curve for time scaled with individual drop cycle time. The measurements at a different disc speed show the same scaled time evolution, pointing to a universal drop release process. The rapid stretching of the liquid thread as the bulge moves away before pinch-off follows a parabolic relationship with time but with only half the relative acceleration of a free object released from the disc edge. The mean values of cycle time and necking time follow a power-law decrease with disc speed. All of the drops generated in a single event move with the speed of the disc. There is no slip, which is not the case with the ligament mode of breakup. The intervals of quiescence between the successive release of drops from the entire disc follow the Poisson process.

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Section: Introductionmentioning

confidence: 66%

Dynamics of Drop Release from the Edge of a Spinning Disc

Sahoo

Kumar

2021

Ind. Eng. Chem. Res.

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“…Since the 1930s, engineers’ pioneering works focus on the centrifugal force induced droplet production process widely used in industrial processes as atomization or spin coating . However, liquids that deposited on the round substrate typically spill out with unstable polymer liquid ligaments, which typically break up into multiple droplets with random sizes. , In recent years, experiments including the design of a rotary round disk with different surface morphology − and surface modification with hydrophobicity have been studied. However, little progress has been achieved due to the lower controllability of the liquid jet.…”

Section: Resultsmentioning

confidence: 99%

“…Droplets are emitted from cluster fibers of the distortion shaking of a wet dog . Researchers employ a similar strategy to produce droplets, such as impacting spraying, ultrasonic nebulizer spraying, , and rotary disk spraying, − for application in plant protection, medical treatment, and metal granulation. Recently, a gradient surface also has been introduced to produce droplets, such as droplet emission via a filament controlled by wettability. , Even though there is a lower hydrodynamic resistance of a liquid in an open system, the drop size is difficult to control and drop production efficiency still needs to be improved.…”

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confidence: 99%

Bioinspired Tip-Guidance Liquid Jetting and Droplet Emission at a Rotary Disk via a Surface Energy Gradient

Wang

et al. 2019

ACS Nano

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Effective droplet emission is of fundamental importance for practical application, such as agricultural sprays to painting, atomization, emulsification, and catalytic action. Highly viscous liquids are commonly used, such as printing inks, which hinder the ejection at the nozzle. A big challenge faced by people is how to obtain stable and controllable liquid droplets in a wide range of viscosities. Inspired by the rotation shaking of droplets on fiber clusters and the rotary spraying disk technique, here, we demonstrate uniform microdroplet (1–2000 mPa·s) generation in a tip-guided way that replaces the commonly confined nozzle by a double-layer spinning “sandwich” multitip disk (SSMD). A surface energy gradient induced by the margin structure of the alternating gas wedge and solid tip guides liquid to move along the solid tip, which is ejected at the end of the tip, forming a ring of droplet clusters. SSMD improves the effective droplet-jet process to 7/10 of the whole drainage process and enhances the efficiency with a production drop volume of ∼3.19 × 107 μL/h and production droplet numbers of ∼3.3 × 104 per second. Droplets can be fine-tuned between 0.1 and 1.0 mm via the tip structure, liquid property, and spinning angular velocity with a narrow size distribution. This facile tip-guided design could inspire the possibility of energy-efficient droplet production techniques in various fluid applications, such as spraying and printing. It may further improve other fluid systems that serve as a crucial component for high-speed droplet manipulation, liquid transport, and water vapor capturing.

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“…Water droplets impacting hydrophobic surfaces is a typical process in many applications [58][59][60].…”

Section: The Droplet Dynamics and 2d Axisymmetric Model Validationmentioning

confidence: 99%

Analysis and prediction of the gas-liquid interfacial area for droplets impact on solid surfaces

Xie

Ding

Ingham

et al. 2020

Applied Thermal Engineering

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Highlights The interfacial areas of droplets during impact on solid surfaces are analysed.  A new correlation for predicting the maximum gas-liquid interfacial area is proposed. The dynamic contact angle with local grid refinement is implemented in the CFD model. The impact of droplets on both hydrophobic and hydrophilic surfaces are studied. The inner flow field of droplets during impact onto a solid surface is described.

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Visual Study of Liquid Flow in a Spinning Disk Reactor with a Hydrophobic Surface

Cited by 21 publications

References 34 publications

Dynamics of Drop Release from the Edge of a Spinning Disc

Dynamics of Drop Release from the Edge of a Spinning Disc

Bioinspired Tip-Guidance Liquid Jetting and Droplet Emission at a Rotary Disk via a Surface Energy Gradient

Analysis and prediction of the gas-liquid interfacial area for droplets impact on solid surfaces

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