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Mukherjee A, Basu DN, Mondal PK, Chen L. Characterization of condensation on nanostructured surfaces and associated thermal hydraulics using a thermal lattice Boltzmann method. Phys Rev E 2022; 105:045308. [PMID: 35590537 DOI: 10.1103/physreve.105.045308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 03/24/2022] [Indexed: 06/15/2023]
Abstract
The dynamics of the condensation process on nanostructured surfaces can be modulated substantially by tuning the surface architecture. Present study uses the mesoscopic framework of lattice Boltzmann method (LBM) to explore the role of surface morphology and cold spot temperature in determining the visual state of the condensate droplet, mode of nucleation, and associated rates of energy and mass interactions. A multiple relaxation time-(MRT)-based LBM solver, coupled with pseudopotential model, has been developed to simulate a rectangular domain of saturated vapor, housing a cold spot on the bottom rough surface. Superhydrophobicity has been achieved for certain combinations of surface parameters, with the intercolumn spacing being the most influential one. Gradual increase in the spacing modifies the nucleation mode from top through side to bottom, while the droplet changes from Cassie to Wenzel state. The Cassie drop in top nucleation mode exhibits the largest contact angle and least rate of surface heat transfer. Both types of Wenzel drops display large rate of condensation and two peaks in heat transfer, along with very short nucleation time in comparison with Cassie drops. Couple of phase diagrams have been developed combining all four scenarios of condensation predicted by the present model. One important novelty of the present study is the consideration of nonisothermal condition within LB structure. Enhancement in the degree of subcooling at the cold spot encourages greater condensation and Cassie-to-Wenzel transition.
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Affiliation(s)
- Aritra Mukherjee
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Dipankar N Basu
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
- Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
| | - Pranab K Mondal
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Lin Chen
- Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Zhang Y, Yan S, Yang X, Bai Z. Hydrodynamics and morphologies of droplets coalescence on fiber. AIChE J 2022. [DOI: 10.1002/aic.17673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yan Zhang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Mechanical and Power Engineering East China University of Science and Technology Shanghai China
| | - Shenglin Yan
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Mechanical and Power Engineering East China University of Science and Technology Shanghai China
| | - Xiaoyong Yang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Mechanical and Power Engineering East China University of Science and Technology Shanghai China
| | - Zhishan Bai
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Mechanical and Power Engineering East China University of Science and Technology Shanghai China
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Heterogeneous nucleation of argon vapor on the nanostructure surface with molecular dynamics simulation. J Mol Graph Model 2020; 100:107674. [PMID: 32750651 DOI: 10.1016/j.jmgm.2020.107674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 11/21/2022]
Abstract
The study of vapor condensation on surface has important engineering significance. The condensation nucleation process of vapor on substrates with different pillar structures is studied through molecular dynamic simulation. The condensation droplets on the pillar with various heights and solid fractions exhibit Wenzel state, Cassie state and the transformation from Wenzel state to Cassie state. The results show that the condensation efficiencies are correlated with the state of droplet and it is explained from the perspective of heat transfer. For the Wenzel state, the droplet fills the gap of pillar and the form of the heat conduction change with the growth of cluster. In the initial of condensation droplets, the heat conduction is similar with various heights of pillar. As the condensation droplets grow, the efficiency of heat conduction enhances with the increasing of height of pillar. For the Cassie state, the form of heat conduction is perpetual during the condensation process with the thermal resistance of the droplet dominated due to the droplets suspended on the pillar. The efficiency of heat transfer is insensitive to the height of pillar. The form of heat conduction for the transformation state transforms from Wenzel state to Cassie state leading to the reduction of condensation rate. The droplet formed in the Wenzel state has the higher transfer efficiency than the Cassie one.
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Jiao X, Li M, Cheng Z, Yu X, Yang S, Zhang Y. Recyclable Superhydrophobic, Antimoisture-Activated Carbon Pellets for Air and Water Purification. ACS APPLIED MATERIALS & INTERFACES 2020; 12:25345-25352. [PMID: 32390416 DOI: 10.1021/acsami.0c06274] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Activated carbon (AC) is a low-cost, highly porous material with large internal surface areas. It is highly efficient in absorbing moisture and a variety of chemical pollutants. Therefore, it has been widely used in air and water purification. However, the strong affinity to moisture often dominates, thus limiting AC's adsorption capacity of other pollutants in a humid environment and reducing its overall lifetime. In the study, superhydrophobic and anti-moisture AC (SA-AC) pellets are fabricated through one-step modification of commercially available AC with a solution consisting of superhydrophobic silica nanoparticles. The SA-AC pellets exhibit excellent water repellency with a static water contact angle reaching 160.3°. More importantly, they are moisture-resistant and air-permeable. Therefore, they preferably adsorb organic gases at humid conditions. The absorbed organic vapor can be released when they are transferred back to the dry atmosphere, for example, releasing approximately 35% of absorbed ethanol. The recoverability significantly reduces energy requirement compared to calcination or conventional extraction. Great adsorption capacity of organic dyes such as methylene blue, removal of oil-in-water microemulsions, and recyclability of SA-AC pellets are demonstrated. The morphology of the microporous structures of the SA-AC pellets is characterized against processing conditions, surface functional groups, and hierarchical structures tailored by the deposition of low-surface energy silica nanoparticles. The resulting micro-/sub-micropores on the pellet surface promote droplet condensation, thus displaying greater damp-proof performance than those treated by traditional modification. The study here presents a promising alternative for the efficient purification on large-scale air/water treatment.
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Affiliation(s)
- Xuan Jiao
- Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Southeast Road 2nd, Nanjing 211189, P. R. China
| | - Meiting Li
- Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Southeast Road 2nd, Nanjing 211189, P. R. China
| | - Zhen Cheng
- Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Southeast Road 2nd, Nanjing 211189, P. R. China
| | - Xinquan Yu
- Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Southeast Road 2nd, Nanjing 211189, P. R. China
| | - Shu Yang
- Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Youfa Zhang
- Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Southeast Road 2nd, Nanjing 211189, P. R. China
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Shen C, Liu X, Yu C, Chen Y. Visualization study on coalescence of droplets with different sizes in external liquid. CAN J CHEM ENG 2017. [DOI: 10.1002/cjce.23040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Chaoqun Shen
- School of Hydraulic, Energy and Power Engineering; Yangzhou University; Yangzhou 225127 P. R. China
| | - Xiangdong Liu
- School of Hydraulic, Energy and Power Engineering; Yangzhou University; Yangzhou 225127 P. R. China
| | - Cheng Yu
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment; Southeast University; Nanjing 210096 P. R. China
| | - Yongping Chen
- School of Hydraulic, Energy and Power Engineering; Yangzhou University; Yangzhou 225127 P. R. China
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment; Southeast University; Nanjing 210096 P. R. China
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Li H, Yang W, Aili A, Zhang T. Insights into the Impact of Surface Hydrophobicity on Droplet Coalescence and Jumping Dynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:8574-8581. [PMID: 28767250 DOI: 10.1021/acs.langmuir.7b02146] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Droplet coalescence jumping on superhydrophobic surfaces attracts much research attention owing to its capability in enhancing condensation for energy and water applications. In this work, we reveal the impact of the finite surface adhesion to explain velocity discrepancies observed in recent droplet jumping studies, particularly when droplet sizes are a few micrometers (1-10 μm). Surface adhesion, which is usually neglected, can significantly affect both droplet coalescence and departure dynamics. It causes oscillations on velocity and contact area in the droplet coalescence process, as observed numerically and experimentally. Comparing the increasing rate of jumping velocity with contact angle for three different droplet sizes, we show that smaller droplets exhibit higher sensitivity to the change of surface hydrophobicity. We also specify the range of surface superhydrophobicity where the jumping velocity monotonically decreases (θ ≳ 170°), increases (θ ≲ 160°), or changes non-monotonically in transition (160° ≲ θ ≲170°) with droplet size. As a result, there exists a broad jumping velocity range for micrometer-sized droplets on a superhydrophobic surface with a slight contact angle variation. This work offers an extended understanding of the droplet coalescence and jumping dynamics to resolve the discrepancies in recent experimental observations.
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Affiliation(s)
- Hongxia Li
- Department of Mechanical and Materials Engineering, Masdar Institute, Khalifa University of Science and Technology , P.O. Box 54224, Abu Dhabi, UAE
| | - Weilin Yang
- Department of Mechanical and Materials Engineering, Masdar Institute, Khalifa University of Science and Technology , P.O. Box 54224, Abu Dhabi, UAE
| | - Abulimiti Aili
- Department of Mechanical and Materials Engineering, Masdar Institute, Khalifa University of Science and Technology , P.O. Box 54224, Abu Dhabi, UAE
| | - TieJun Zhang
- Department of Mechanical and Materials Engineering, Masdar Institute, Khalifa University of Science and Technology , P.O. Box 54224, Abu Dhabi, UAE
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Li Q, Yu Y, Zhou P, Yan HJ. Droplet migration on hydrophobic–hydrophilic hybrid surfaces: a lattice Boltzmann study. RSC Adv 2017. [DOI: 10.1039/c6ra28665h] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Droplet migration on textured hydrophobic–hydrophilic surfaces.
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Affiliation(s)
- Q. Li
- School of Energy Science and Engineering
- Central South University
- Changsha 410083
- China
| | - Y. Yu
- School of Energy Science and Engineering
- Central South University
- Changsha 410083
- China
| | - P. Zhou
- School of Energy Science and Engineering
- Central South University
- Changsha 410083
- China
| | - H. J. Yan
- School of Energy Science and Engineering
- Central South University
- Changsha 410083
- China
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Si Y, Guo Z. Superhydrophobic nanocoatings: from materials to fabrications and to applications. NANOSCALE 2015; 7:5922-46. [PMID: 25766486 DOI: 10.1039/c4nr07554d] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Superhydrophobic nanocoatings, a combination of nanotechnology and superhydrophobic surfaces, have received extraordinary attention recently, focusing both on novel preparation strategies and on investigations of their unique properties. In the past few decades, inspired by the lotus leaf, the discovery of nano- and micro-hierarchical structures has brought about great change in the superhydrophobic nanocoatings field. In this paper we review the contributions to this field reported in recent literature, mainly including materials, fabrication and applications. In order to facilitate comparison, materials are divided into 3 categories as follows: inorganic materials, organic materials, and inorganic-organic materials. Each kind of materials has itself merits and demerits, as well as fabrication techniques. The process of each technique is illustrated simply through a few classical examples. There is, to some extent, an association between various fabrication techniques, but many are different. So, it is important to choose appropriate preparation strategies, according to conditions and purposes. The peculiar properties of superhydrophobic nanocoatings, such as self-cleaning, anti-bacteria, anti-icing, corrosion resistance and so on, are the most dramatic. Not only do we introduce application examples, but also try to briefly discuss the principle behind the phenomenon. Finally, some challenges and potential promising breakthroughs in this field are also succinctly highlighted.
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Affiliation(s)
- Yifan Si
- Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials and Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan 430062, People's Republic of China.
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