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Shan F, Chai Z, Shi B. Auto-ejection of liquid from a nozzle. Phys Rev E 2024; 109:045302. [PMID: 38755830 DOI: 10.1103/physreve.109.045302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 02/13/2024] [Indexed: 05/18/2024]
Abstract
Auto-ejection of liquid is an important process in engineering applications, and is also very complicated since it involves interface moving, deforming, and jet breaking up. In this work, a theoretical velocity of meniscus at nozzle exit is first derived, which can be used to analyze the critical condition for auto-ejection of liquid. Then a consistent and conservative axisymmetric lattice Boltzmann (LB) method is proposed to study the auto-ejection process of liquid jet from a nozzle. We test the LB model by conducting some simulations, and find that the numerical results agree well with the theoretical and experimental data. We further consider the effects of contraction ratio, length ratio, contact angle, and nozzle structure on the auto-ejection, and observe some distinct phenomena during the ejection process, including the deformation of meniscus, capillary necking, and droplet pinch off. Finally, the results reported in the present work may play an instructive role on the design of droplet ejectors and the understanding of jetting dynamics in microgravity environment.
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Affiliation(s)
- Fang Shan
- School of Mathematics and Statistics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhenhua Chai
- School of Mathematics and Statistics, Huazhong University of Science and Technology, Wuhan 430074, China
- Hubei Key Laboratory of Engineering Modeling and Scientific Computing, Huazhong University of Science and Technology, Wuhan 430074, China
- Institute of Interdisciplinary Research for Mathematics and Applied Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Baochang Shi
- School of Mathematics and Statistics, Huazhong University of Science and Technology, Wuhan 430074, China
- Hubei Key Laboratory of Engineering Modeling and Scientific Computing, Huazhong University of Science and Technology, Wuhan 430074, China
- Institute of Interdisciplinary Research for Mathematics and Applied Science, Huazhong University of Science and Technology, Wuhan 430074, China
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2
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Quintero JSM, Majhy B, Caesar M, Waghmare PR. Electrowetting-Induced Coalescence of Sessile Droplets in Viscous Medium. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:4917-4923. [PMID: 36996262 DOI: 10.1021/acs.langmuir.2c03194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Manipulating the coalescence of microdroplets has recently gained enormous attention in digital microfluidics and biological and chemical industries. Here, coalescence between two sessile droplets is induced by spreading them due to electrowetting. The electrocoalescence dynamics is investigated for a wide range of operating parameters such as electrowetting number, Ohnesorge number, driving frequency, and drop to surrounding medium viscosity ratio. Here, the characteristic time scale from the classical lubrication theory is modified with an additional driving and resisting force due to the electrostatic pressure force and liquid-liquid viscous dissipation, respectively. With the revised characteristic time scale, a universal bridge growth is shown between the two merging droplets following a 1/3 power law during early coalescence followed by a long-range linear variation. To ensure precise control on droplet coalescence, a geometric analysis is also performed to define the initial separation distance.
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Affiliation(s)
- Juan Sebastian Marin Quintero
- Interfacial Science and Surface Engineering Lab (iSSELab), Department of Mechanical Engineering, University of Alberta, Edmonton T6G 2R3, Canada
| | - Butunath Majhy
- Interfacial Science and Surface Engineering Lab (iSSELab), Department of Mechanical Engineering, University of Alberta, Edmonton T6G 2R3, Canada
| | - Markus Caesar
- Interfacial Science and Surface Engineering Lab (iSSELab), Department of Mechanical Engineering, University of Alberta, Edmonton T6G 2R3, Canada
| | - Prashant R Waghmare
- Interfacial Science and Surface Engineering Lab (iSSELab), Department of Mechanical Engineering, University of Alberta, Edmonton T6G 2R3, Canada
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3
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Marques F, Mitra SK. Dip-and-Fold Device: A Paper-Based Testing Platform for Rapid Assessment of Insecticides in Water Samples. ACS APPLIED BIO MATERIALS 2021; 4:8456-8465. [PMID: 35005921 DOI: 10.1021/acsabm.1c00986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The contamination of water and food in agricultural areas, where an enormous volume of pesticides is widely employed to enhance crop production, is a challenging reality. The rapid assessment of these contaminants is fundamental to assure water and food quality and safety, particularly for local community members. This work presents a nonexpensive and easy-operational paper-based testing device for the fast detection of insecticides (carbamates and organophosphates) in water samples. The structural design "dip-and-fold" allows us to carry out the analysis without introducing reagents or samples. The device is prepared using different high-quality papers to support the active acetylcholinesterase (AChE) and the customized chemical formulation for colorimetric detection. The chemical principle is based on the AChE inhibition reaction and Ellman's method. The experiments using standard solutions of carbofuran, propoxur, and chlorpyriphos indicated satisfactory detection at concentrations between 0.1 and 0.0001 mM, and the color results are revealed within 10 min. Therefore, this technique represents a promising alternative for implementing low-cost and efficient water monitoring and management solutions.
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Affiliation(s)
- Fernanda Marques
- Micro & Nano-scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Sushanta K Mitra
- Micro & Nano-scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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4
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Effects of Tube Radius and Surface Tension on Capillary Rise Dynamics of Water/Butanol Mixtures. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11083533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Capillary-driven action is an important phenomenon which aids the development of high-performance heat transfer devices, such as microscale heat pipes. This study examines the capillary rise dynamics of n-butanol/water mixture in a single vertical capillary tube with different radii (0.4, 0.6, and 0.85 mm). For liquids, distilled water, n-butanol, and their blends with varying concentrations of butanol (0.3, 0.5, and 0.7 wt.%) were used. The results show that the height and velocity of the capillary rise were dependent on the tube radius and liquid surface tension. The larger the radius and the higher the surface tension, the lower was the equilibrium height (he) and the velocity of rise. The process of capillary rise was segregated into three characteristic regions: purely inertial, inertial + viscous, and purely viscous regions. The early stages (purely inertial and inertial + viscous) represented the characteristic heights h1 and h2, which were dominant in the capillary rise process. There were linear correlations between the characteristic heights (h1, h2, and he), tube radius, and surface tension. Based on these correlations, a linear function was established between each of the three characteristic heights and the consolidated value of tube radius and surface tension (σL/2πr2).
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Gorthi SR, Meher SK, Biswas G, Mondal PK. Capillary imbibition of non-Newtonian fluids in a microfluidic channel: analysis and experiments. Proc Math Phys Eng Sci 2020. [DOI: 10.1098/rspa.2020.0496] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We have presented an experimental analysis on the investigations of capillary filling dynamics of inelastic non-Newtonian fluids in the regime of surface tension dominated flows. We use the Ostwald–de Waele power-law model to describe the rheology of the non-Newtonian fluids. Our analysis primarily focuses on the experimental observations and revisits the theoretical understanding of the capillary dynamics from the perspective of filling kinematics at the interfacial scale. Notably, theoretical predictions of the filling length into the capillary largely endorse our experimental results. We study the effects of the shear-thinning nature of the fluid on the underlying filling phenomenon in the capillary-driven regime through a quantitative analysis. We further show that the dynamics of contact line motion in this regime plays an essential role in advancing the fluid front in the capillary. Our experimental results on the filling in a horizontal capillary re-establish the applicability of the Washburn analysis in predicting the filling characteristics of non-Newtonian fluids in a vertical capillary during early stage of filling (Digilov 2008
Langmuir
24
, 13 663–13 667 (
doi:10.1021/la801807j
)). Finally, through a scaling analysis, we suggest that the late stage of filling by the shear-thinning fluids closely follows the variation
x
~
t
. Such a regime can be called the modified Washburn regime (Washburn 1921
Phys. Rev.
17
, 273–283 (
doi:10.1103/PhysRev.17.273
)).
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Affiliation(s)
- Srinivas R. Gorthi
- Microfluidics and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Sanjaya Kumar Meher
- Microfluidics and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Gautam Biswas
- Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Pranab Kumar Mondal
- Microfluidics and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
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Aksu C, Bradford PD, Jur JS. Microfluidic Behavior of Alumina Nanotube-Based Pathways within Hydrophobic CNT Barriers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8792-8799. [PMID: 32663010 DOI: 10.1021/acs.langmuir.0c01096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The use of porous micro-and nanostructured materials within microfluidic devices results in unique fluid transport characteristics. In this paper, we investigate the microfluidic behavior of hybrid alumina nanotube-based pathways within the hydrophobic carbon nanotube (CNT) barriers. These hybrid systems provide unique benefits for potential liquid transport control in porous structures with real-time sensing of fluids. In particular, we examine how the alignment of the alumina nanostructures with high internal porosity enables increased capillary action and sensitivity of detection. Based on the Lucas and Washburn model (LW) and the modified LW models, the microfluidic behavior of these systems is detailed. The time exponent prediction from the models for capillary transport in porous media is determined to be ≤0.5. The experimental results demonstrate that the average capillary rise in the nanostructured media driven by a capillary force follows t0.7. The hydrophilic/electrically insulating and hydrophobic/electrically conductive patterned structures of the device are used for electronic measurements within the microfluidic channels. The device structure enables the detection of fluid samples of very low analyte concentrations (1 μM) that can be achieved due to the very high surface area of the hybrid structure combined with the electrical conductivity of the CNT support structure.
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Affiliation(s)
- Cemile Aksu
- Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695-8301, United States
| | - Philip D Bradford
- Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695-8301, United States
| | - Jesse S Jur
- Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695-8301, United States
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Xiao J, Liu X, Luo Y, Cai J, Xu J. Oscillations of free surface at the edge of short capillary tubes. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124572] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Willmott GR, Briole A, Szczepaniak F. Inertial capillary uptake of drops. Phys Rev E 2020; 101:043109. [PMID: 32422711 DOI: 10.1103/physreve.101.043109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 03/25/2020] [Indexed: 11/07/2022]
Abstract
Uptake of liquid drops into capillary tubes has been experimentally studied and quantitatively analyzed. In experiments, drops of water and aqueous glycerol (≤50 wt %) were drawn into cylindrical borosilicate glass and quartz tubes with an inner diameter of 0.50-0.75 mm. The meniscus height rise was measured using high-speed images captured at 4000 frames per second, and results within a conservatively defined inertial regime indicate constant uptake velocity. An increase in the inertial velocity with drop curvature was observed due to increasing Laplace pressure in the drop, as drop sizes were comparable to the width of the capillary tubes. Measured velocities were slower than predicted by a purely inertial-capillary model and best described by introducing a contact line friction, consistent with the observed variability and viscosity dependence of the results. Mean friction coefficients in borosilicate capillaries ranged from 169±1 for 50 wt % glycerol drops to 218±1 for water drops. Peaks in the instantaneous Laplace pressure caused by surface oscillations were also measured. Correlations with uptake velocity were qualitatively apparent, with a delay between peaks of similar magnitude to the inertial-capillary oscillation time.
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Affiliation(s)
- Geoff R Willmott
- Department of Physics and School of Chemical Sciences, The University of Auckland, Auckland, New Zealand, and The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Alice Briole
- Départements Physique et Chimie, École normale supérieure de Lyon, 69342 Lyon, France
| | - Florence Szczepaniak
- Départements Physique et Chimie, École normale supérieure de Lyon, 69342 Lyon, France
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10
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Dhar J, Jaggi P, Chakraborty S. Oscillatory regimes of capillary imbibition of viscoelastic fluids through concentric annulus. RSC Adv 2016. [DOI: 10.1039/c6ra05002f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Here we report the capillary filling dynamics of a viscoelastic fluid through a concentric annulus, which offers a distinct disparity in the dynamical characteristics as compared to the classical cylindrical capillary based paradigm.
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Affiliation(s)
| | - Parth Jaggi
- Indian Institute of Technology Ropar
- Rupnagar
- India
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Dhar J, Ghosh U, Chakraborty S. Electro-capillary effects in capillary filling dynamics of electrorheological fluids. SOFT MATTER 2015; 11:6957-6967. [PMID: 26235842 DOI: 10.1039/c5sm01092f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The flow of electrorheological fluids is characterized by an apparent increase in viscosity manifested by the yield stress property of the fluid, which is a function of the applied electric field and the concentration of the suspended solute phase within the dielectric medium. This property of electrorheological fluids generally hinders flow through a capillary if the imposed shear stress is lower than the induced yield stress. This results in a plug-like zone in the flow profile, thus giving the fluid Bingham plastic properties. In the present work, we study such influences of the yield stress on the capillary filling dynamics of an electrorheological fluid by employing a rheologically consistent reduced order formalism. One important feature of the theoretical formalism is its ability to address the intricate interplay between the surface tension and viscous forces, both of which depend sensitively on the electric field. Our analysis reveals that the progress of the capillary front is hindered at an intermediate temporal regime, which is attributable to the increase of the span of the plug-zone across the channel width with time. With a preliminary understanding on the cessation of the capillary front advancement due to the yield stress property of the electrorheological fluids, we further strive to achieve a basic comparison with an experimental study made earlier. Reasonable agreements with the reported data support our theoretical framework. Comprehensive scaling analysis brings further insight to our reported observations over various temporal regimes.
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Affiliation(s)
- Jayabrata Dhar
- Indian Institute of Technology Kharagpur, Kharagpur, India.
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