ORCID Profile
0000-0002-4771-7573
Current Organisations
Aarhus University
,
Jiangsu University
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Publisher: Elsevier BV
Date: 10-2022
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 03-2023
DOI: 10.1016/J.JCIS.2022.11.100
Abstract: Dynamics of polymer-coated silica composite nanoparticles (CPs) during bubble coarsening is highly dominated by the behaviour of the polymer layer, while in-situ particle aggregation would lead to accelerated bubble coalescence. CPs-stabilized foams were prepared in 0.1 M and 0.55 M Na The 0.1 M bubble-stabilizing interface buckles in uniaxial compression due to coarsening, with the CPs being observed to desorb from the interface. While the CPs were visualized to rearrange into crumpled particle multi-layers surrounding the shrinking 0.55 M bubbles, due to the adhesion between interpenetrating polymer chains and the unique lubrication effect of the PVP layers. The 0.1 M to 0.55 M transition foaming behaviour was also studied. Cracks and voids were observed at interfaces surrounding the transition bubbles driven by in-situ particle aggregation, resulting in accelerated bubble coalescence during the transition process.
Publisher: Elsevier BV
Date: 02-2020
Publisher: AIP Publishing
Date: 07-2023
DOI: 10.1063/5.0158051
Abstract: Electrocoalescence is a time-saving and energy-efficient technology for dehydrating crude oil. The microscopic coalescence mechanism of nanoparticle-laden water droplet pair in the coupling of electric field and flow field was studied by molecular dynamics simulations. The present numerical results agreed well with the experimental work in the literature and the theoretical predictions. The effects of electric field strength and direction, flow field strength and type, droplet intersection angle, and multiple droplets on nanoparticle-laden droplet pair coalescence in the coupling fields were systematically discussed. The results illustrate that four coalescence modes occurred in the coupling of electric field and shearing flow field (E& S coupling fields), and the coalescence efficiencies ranked as: rolling coalescence mode & temporary coalescence mode & stretching mode & slipping mode. Electric fields dominate droplet coalescence, while flow fields enhance droplet coalescence in the coupling fields. Furthermore, parallel direction of electric field and flow field generally leads to high coalescence efficiencies. As to the multiple droplet systems, in the coupling of x-axis electric field and rotating flow field (E& R coupling fields), the coalescence efficiencies ranked as structure I & structure IV & structure III & structure II, whereas, in the y-axis E& R coupling fields, the coalescence efficiencies ranked as structure I & structure III & structure IV & structure II. Finally, the coalescence efficiencies of the E& R coupling fields were always higher than those of the E& S coupling fields. The results will be potentially valuable for optimizing the design of compact and efficient crude oil dehydrators.
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 04-2022
Publisher: AIP Publishing
Date: 03-2023
DOI: 10.1063/5.0141648
Abstract: The dynamics of the growth and detachment of a single hydrogen bubble on both the horizontal and vertical microelectrode surfaces in water electrolysis were synthetically investigated by combining the numerical simulation, force balance analysis, and available experimental data. Approximately, multiple steady simulation cases with different bubble diameters for different growth instances were conducted to state the actual unsteady bubble growth and detachment behavior. The numerical simulations of the temperature distribution considering the heat transfer caused by the liquid microlayer and induced Marangoni convection effects were performed. Then, a force balance model for predicting the bubble detachment diameter was developed by fully utilizing the simulated multi-physical field parameters and the experimental results of some key bubble geometric parameters. The presented numerical model and the force balance model were validated by comparing them with previous experimental data on the potential and the bubble detachment diameter, respectively. The simulation results indicate a significantly larger potential value occurs within the microlayer, and hence, the Joule heat of the electrolyte is mainly generated in the microlayer and then transferred to the bulk flow region. Obviously, the temperature gradient distribution is formed at the bubble interface, causing unstable Marangoni convection structure. The distribution patterns and evolutions of the electrolyte temperature, Marangoni convection velocity, and microlayer thickness for the horizontal and vertical microelectrode systems are significantly different. The present force balance model presents higher prediction accuracy for the bubble detachment diameters. Moreover, the in-depth force analysis results reveal that some dominant forces influence the bubble growth and detachment.
Publisher: AIP Publishing
Date: 02-2023
DOI: 10.1063/5.0137724
Abstract: When a fluid is subject to an electric field, it usually processes unique features compared to the conventional fluid that arises from coupling between charged particles and fluid interface. Based on this commonality, we defined the concept of “charged multiphase flow” and constructed a generalized charged multiphase flow system using the “Tai Chi Diagram” to analyze the properties and features of different study objects, with an emphasis on the bubble dynamics on the charged liquid–gas flow object, covering the processes of bubble generation, motion, and interaction, as well as the important dynamic behaviors, involved such as bubble deformation, coalescence, and breakup. Furthermore, in light of the special plasma–liquid interface phenomenon formed by the ionization of the gas/vapor phase in the liquid phase in strong electric fields, the traditional gas–liquid–solid three-phase flow system is expanded into a broader range of multiphase flow systems involving plasma, which enriches the theoretical and frontier scientific problems of the multiphase flow. In addition, technical innovations, remaining work, and future trends in the development of the charged liquid–gas flow, and their potential applications are discussed.
Publisher: American Chemical Society (ACS)
Date: 24-03-2020
Publisher: AIP Publishing
Date: 10-2021
DOI: 10.1063/5.0066381
Abstract: Impact behaviors of an electrically charged water droplet on different solid substrates and subsequent dynamic mechanisms were experimentally investigated in this study. Droplets were generated from a metal capillary by a syringe pump with a constant diameter of about 2.2 mm. The capillary was directly connected to a high voltage direct current power supply, while a lower counter ring electrode was grounded. A high-speed camera was utilized to visualize the droplet impact morphology. The influences of the droplet charge density, substrate wettability, and surface temperature were analyzed. The results showed that the impact on hydrophilic surfaces exhibited a greater spreading diameter but a smaller recoiling height than that on a hydrophobic surface, which was attributed to the increased viscous dissipation on the substrate. In addition, compared with a neutral droplet, the maximum spreading diameter of a charged droplet was found to be improved by about 8.4%, where the enhancing effects were proportional to the droplet charge ratio. This was due to the weakening effects of the Coulomb repulsion on the liquid surface tension. Moreover, the impact of charged droplets on a hot copper substrate in three different boiling regimes, called convection, nucleate and film boiling, was also discussed. Finally, a model of the maximum spreading ratio of a charged droplet based on the Weber number, charge ratio, and wettability was established. This study demonstrated that the free charges in a droplet was able to influence its impact behaviors, which would hold great promise for some related technologies.
Publisher: Elsevier BV
Date: 02-2022
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 12-2022
Publisher: AIP Publishing
Date: 11-2022
DOI: 10.1063/5.0127299
Abstract: Based on our previous visual experiments and the volume of fluid (VOF) multiphase model, the growth and detachment characteristics of a single hydrogen bubble on the horizontal microelectrode surface under the electrode-normal magnetic field have been numerically investigated. The mass transfer contributions of supersaturated dissolved hydrogen to the bubble growth from the liquid microlayer under the direct injection model and from the bulk bubble interface under the gas–liquid diffusion-controlled model are adopted. The bubble shapes and diameters predicted from the numerical investigation agree well with experimental results under the same conditions. The simulated results indicate that the supersaturated dissolved hydrogen concentration and the mass transfer source at the wedge-shaped areas adjacent to the bubble foot are obviously higher than those in the wider bulk bubble interface regions. The mass transfer contribution to the bubble growth from the liquid microlayer beneath the bubble base directly plays a dominant role. The higher current density and corresponding Lorentz force mainly appears in the wedge-shaped areas, while the higher rotational electrolyte flow velocity appear at oblique positions of the bubble equator. The bubble detachment behavior makes the rotational electrolyte flows is significantly more complex.
Publisher: Elsevier BV
Date: 05-2023
No related grants have been discovered for Zhang Wei.