Article
Mechanics
Mohammad Kazam Sheykhian, Mohammad Hasan Kayhani, Mahmood Norouzi, Mirae Kim, Kyung Chun Kim
Summary: This study investigated the impact of Boger droplets on spherical surfaces, considering the effects of various liquid and surface properties for the first time. The researchers examined the rheological properties of the droplets and analyzed the influence of elasticity, elongational viscosity, and the first normal stress difference on the impact of Boger droplets on solid surfaces. The results were compared to those of equivalent Newtonian droplets in terms of viscosity and surface tension coefficient. Additionally, the study explored the effects of Weber number, diameter ratio, and surface wettability on the spreading and receding behaviors of viscoelastic droplets.
Article
Multidisciplinary Sciences
David N. Sibley, Pablo Llombart, Eva G. Noya, Andrew J. Archer, Luis G. MacDowell
Summary: This study develops a mesoscopic model of liquid-film mediated ice growth and identifies various growth regimes. Freezing processes at different saturation levels show distinct growth mechanisms, with the liquid layer playing a crucial role. The research provides a general framework for understanding ice growth close to the triple point and offers a first principle theory that may be useful in geosciences.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Mani Azadmand, Stefano Vichi, Federico Guido Cesura, Sergio Bietti, Daniel Chrastina, Emiliano Bonera, Giovanni Maria Vanacore, Shiro Tsukamoto, Stefano Sanguinetti
Summary: The influence of metal droplets on the composition uniformity of InGaN epilayers was investigated. Experimental and theoretical analysis revealed a significant difference in indium incorporation between the region under the droplets and between them.
Article
Physics, Fluids & Plasmas
Alexander C. Castonguay, R. Kailasham, Ciera M. Wentworth, Caleb H. Meredith, Aditya S. Khair, Lauren D. Zarzar
Summary: The study investigates the gravitational settling of oil droplets solubilizing in an aqueous micellar solution contained in a capillary channel. The motion of these active droplets reflects a competition between gravitational and Marangoni forces. The Marangoni force enhances the settling speed of an active droplet compared to the Hadamard-Rybczynski prediction. A simple relation for the crossover radius at which the maximal value of alpha occurs for an active settling droplet is proposed.
Article
Engineering, Aerospace
Gen Zhu, Jiang Li, Kang Li, Shihui Cheng, Zhipeng He
Summary: The impact and aggregation of multiple alumina droplets on the inner wall of the solid rocket motor were studied. It was found that the aggregated droplet would rotate when two droplets aggregate, and when three droplets aggregate, the aggregated droplet is more likely to adhere to the wall. The rebound and adhesion characteristics of the aggregated droplet are of great significance for slag deposition and two-phase flow prediction in the motor.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Mechanics
C. R. Constante-Amores, L. Kahouadji, S. Shin, J. Chergui, D. Juric, J. R. Castrejon-Pita, O. K. Matar, A. A. Castrejon-Pita
Summary: We investigate the influence of insoluble surfactants on the impact of surfactant-free droplets onto surfactant-laden thin liquid films using a three-dimensional numerical simulation approach. Our results show that the presence of surfactants affects the late stages of the dynamics by delaying the end-pinching mechanisms, resulting in longer ligaments. We also demonstrate that the addition of surfactants leads to surface rigidification and retards the flow dynamics.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Energy & Fuels
Siddhant Kumar Prasad, Jitendra S. Sangwai
Summary: This study investigated the impact of chain length of saturated hydrocarbons on methane hydrate formation and dissociation kinetics in oil-in-water dispersions. Sodium dodecyl sulfate was used as a surfactant to simulate natural surfactants. The results showed that an appropriate concentration of SDS enhanced the hydrate formation during initial stages, but higher concentrations disrupted the structure of local water. With a fixed SDS concentration, higher carbon chain length accelerated the hydrate formation during initial stages before reaching similar formation kinetics. Higher concentrations and higher alkane content delayed the gas release during dissociation.
Article
Chemistry, Multidisciplinary
Swarnak Ray, Arun Roy
Summary: This study reports on the self-propulsion behavior of 5CB liquid crystal droplets in surfactant solution and investigates the effect of droplet size on their motion trajectories. Interestingly, large flattened droplets also exhibit deformation of their apparent cross-section during self-propulsion. These findings provide an important opportunity for studying active biomimetic systems.
Article
Thermodynamics
D. V. Antonov, I. S. Voytkov, P. A. Strizhak
Summary: The article presents experimental research findings on the behavior of micro-explosion and puffing of two-liquid droplets in different droplet formation schemes. The results reveal the effects of fragmentation on the size and composition of combustible and noncombustible liquid droplets, as well as the correlations with heating temperature and mixing sequence.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Mechanics
Jin-Xiang Zhou, Hong-Wei Xiao, Ya-Ping Wang, Adnan Khan, Xiao-Dong Niu, Ming-Fu Wen, Mu-Feng Chen, De-Cai Li, Hiroshi Yamaguchi
Summary: This article investigates the active control of post-impact dynamics of ferrofluid droplets using an external magnetic field. By simulating the flow field, the effects of magnetic field on different phenomena are explored, and it is found that a vertical non-uniform magnetic field and optimal starting moment of magnetic field introduction can effectively improve control.
Article
Engineering, Environmental
Tengxiao Ma, Yabo Zhao, Leping Zhou, Xiaoze Du
Summary: The study focuses on the flow characteristics and interface structure evolution during the chemical reaction of droplets using an observation technique based on evanescent wave illumination. Results show that the mesoscopic interface structure deforms severely and convex interfaces appear at the central regions during the reaction, while the reaction rate decreases exponentially with the increase of height in the thin liquid film. Valuable information is provided for understanding the mechanisms of formation and transport of the mesoscale interface structure during chemical reactions.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Chemistry, Physical
Jiayu Du, Yiyang Zhang, Qi Min
Summary: This study investigated the spreading and retraction dynamics of viscous droplets impact on flat solid surfaces using an efficient continuum-level modeling method. The study analyzed the influence of droplet viscosity, impact velocity, and material wettability on the dynamic characteristics of droplets, and developed multiple general correlations to predict various factors. It was successfully proven that this modeling method can be reliably applied to investigations of both droplet spreading and retraction processes.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2021)
Article
Engineering, Environmental
Eduardo Guzman, Eva Santini, Michele Ferrari, Libero Liggieri, Francesca Ravera
Summary: The interaction between hydrophobic silicon dioxide particles and lung surfactant extract alters the organization of molecules at the water/vapor interface, hindering the ability of lung surfactant layers to reduce surface tension. This modification affects the relaxation mechanisms of lung surfactant films during the respiratory cycle.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Yu Han, Joel Koplik, Charles Maldarelli
Summary: The study found that high elasticity of droplets at high surface concentrations resists deformation, while dilatational viscosity scales with the ratio kappa* and can extend deformation time.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Physical
Xiaoyang Yu, Ke Qiu, Xiao Yu, Qian Li, Ruowen Zong, Shouxiang Lu
Summary: The stability and thinning behavior of liquid foam film containing fluorocarbon and hydrocarbon surfactant mixtures were quantitatively investigated using optical interferometry. Multiscale characterization methods were employed to study the relationships between foam stability, film thinning behavior, and bulk and interfacial properties.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Mechanics
C. R. Constante-Amores, T. Abadie, L. Kahouadji, S. Shin, J. Chergui, D. Juric, A. A. Castrejon-Pita, O. K. Matar
Summary: This study investigates the effect of insoluble surfactants on the spatio-temporal evolution of turbulent jets through three-dimensional numerical simulations. The results show that surfactant-induced Marangoni stresses play a crucial role in the formation of coherent vortex structures and greatly influence the development of three-dimensional interfacial dynamics. The study also provides theoretical expressions for the mechanisms influencing the circulation production rate in the presence of surfactants.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Thermodynamics
Odumuyiwa A. Odumosu, Huashi Xu, Tianyou Wang, Zhizhao Che
Summary: Flow boiling in microchannels utilizes the latent heat of the fluid and can efficiently remove heat. Numerical simulations provide detailed information about the flow and vapor bubble dynamics, which cannot be obtained experimentally. This study focuses on the growth of vapor bubbles in straight and wavy microchannels using numerical simulations. The results show that the wavy structure of the microchannel enhances bubble growth and wall heat transfer due to deformation, expansion, and perturbation of the bubbles. The local Nusselt number in the wavy channel can be up to 2.6 times higher than in the straight channel.
APPLIED THERMAL ENGINEERING
(2023)
Article
Engineering, Environmental
Juan Pablo Valdes, Lyes Kahouadji, Fuyue Liang, Seungwon Shin, Jalel Chergui, Damir Juric, Omar K. Matar
Summary: The internal dynamics of static mixers handling liquid-liquid flows have been comprehensively explored over the past decade. The effect of the inlet configuration and its relationship with the performance of the mixer in terms of droplet size distribution has been investigated. The study provides new insight into droplet deformation and breakage in SMX mixers for industrially-relevant scenarios using three-dimensional numerical simulations.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Chemical
Jianhua Chen, Charitos Anastasiou, Sibo Cheng, Nausheen Mehboob Basha, Lyes Kahouadji, Rossella Arcucci, Panagiota Angeli, Omar K. Matar
Summary: This study performs Computational Fluid Dynamics (CFD) simulations to investigate the separation characteristics of silicone oil and water two-phase flow in a horizontal pipe. The Eulerian-Eulerian simulations coupled with population balance models capture the impact of complex flow behavior on droplet rising and coalescence. The influence of turbulent dispersion force is also explored and found to improve the radial distribution prediction but worsen the separation characteristics along the flow direction. Although the simulation results only qualitatively agree with experiments, this work demonstrates the potential for improving prediction accuracy through drag and coalescence modeling.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Thermodynamics
Fuquan Tian, Lei Shi, Zhizhao Che, Zhen Lu, Kai Sun, Tianyou Wang
Summary: It is found that the cycle-to-cycle variations (CCV) of flow near the spark plug position can be effectively reduced by manipulating the opening and shutting of a tumble flap in the intake manifold. Closing the tumble flap can also increase the kinetic energy and turbulent kinetic energy of the flow near the spark plug position.
FLOW TURBULENCE AND COMBUSTION
(2023)
Article
Energy & Fuels
Houpeng Zhang, Zhen Lu, Tianyou Wang, Zhizhao Che
Summary: The micro-explosion of emulsion droplets is important for atomization, combustion efficiency improvement, and pollutant emissions reduction. Mist generation during heating of emulsion droplets is closely related to the micro-explosion process. Two micro-explosion modes, intense and weak, are observed, and mist can be produced for all tested emulsified fuels. The water and surfactant contents in emulsion droplets affect the micro-explosion and mist concentration.
Article
Thermodynamics
Zhigang Xu, Haicheng Qi, Tianyou Wang, Zhizhao Che
Summary: This study explores the delayed coalescence of hot droplets on a liquid film, which is mediated by the intervening gas layer. The thickness of the gas layer increases with the droplet temperature, explaining the thermal delay of coalescence. The temperature gradient at the bottom of the droplet induces Marangoni flow, which delays the drainage of the intervening gas layer. The residence time of the droplet decreases as the Weber number increases due to the thinner gas layer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Mechanics
M. Kalli, P. Pico, L. Chagot, L. Kahouadji, S. Shin, J. Chergui, D. Juric, O. K. Matar, P. Angeli
Summary: The effect of surfactants on flow characteristics during rapid drop formation in a microchannel was investigated using various techniques. Results showed strong circulation patterns in the forming drop in the absence of surfactants, which decreased with increasing surfactant concentration. The study also observed the surfactant concentration profiles at different stages of drop formation and the impact of Marangoni stresses on the velocity profile inside the drop.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
C. R. Constante-Amores, L. Kahouadji, S. Shin, J. Chergui, D. Juric, J. R. Castrejon-Pita, O. K. Matar, A. A. Castrejon-Pita
Summary: We investigate the influence of insoluble surfactants on the impact of surfactant-free droplets onto surfactant-laden thin liquid films using a three-dimensional numerical simulation approach. Our results show that the presence of surfactants affects the late stages of the dynamics by delaying the end-pinching mechanisms, resulting in longer ligaments. We also demonstrate that the addition of surfactants leads to surface rigidification and retards the flow dynamics.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Tom Savage, Nausheen Basha, Jonathan Mcdonough, Omar K. Matar, Ehecatl Antonio del Rio Chanona
Summary: This article presents a framework to solve the nonlinear, computationally expensive, and derivative-free problem of optimizing complex reactor geometries. The framework uses Gaussian processes to learn a multi-fidelity model of reactor simulations and explores the search space of reactor geometries through lower fidelity simulations.
COMPUTERS & CHEMICAL ENGINEERING
(2023)
Article
Mechanics
Zhikun Xu, Tianyou Wang, Zhizhao Che
Summary: This study experimentally investigated the breakup process of particle-laden droplets in airflow. The results showed that particles have a heterogeneous effect on the breakup process, accelerating the fragmentation of the liquid film and promoting localized rapid piercing. A correlation length was proposed to characterize the concentration fluctuation scale during the breakup process, and the scaling results agreed well with experimental data.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Huadan Xu, Xinjin Ge, Tianyou Wang, Zhizhao Che
Summary: In this study, the coalescence of two immiscible droplets on a partial wetting surface is explored experimentally and theoretically. The coalescence process is divided into three stages and the impact of immiscible interface on the process is investigated. The study provides insights into the time scales and force interactions involved in the coalescence of immiscible droplets.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Chemistry, Physical
Zhen Zeng, Kai Sun, Rui Chen, Mengshan Suo, Zhizhao Che, Tianyou Wang
Summary: Two-dimensional square ice can be formed in graphene nanocapillaries at room temperature, and it has been experimentally confirmed. The critical crystallization pressure for square ice formation strongly depends on the size of the graphene sheet. When the graphene sheet is smaller than a certain threshold, it is difficult for square ice to spontaneously form. The graphene sheet size also affects the stability and crystallization time of square ice.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Biochemistry & Molecular Biology
Keat Yung Hue, Jin Hau Lew, Maung Maung Myo Thant, Omar K. Matar, Paul F. Luckham, Erich A. Mueller
Summary: Injecting formation-strengthening chemicals can mitigate solids production risk and reduce environmental waste in poorly consolidated carbonate rock reservoirs. This study employs atomistic molecular dynamics (MD) simulation to model the interaction between polyacrylamide-based polymer additives and a calcite structure, the main component of carbonate formations. The (1 0 4) plane of calcite is found to be the most suitable surrogate for assessing these interactions. Molecular conformation and binding energies of different polyacrylamide-based polymers are analyzed to understand their adsorption characteristics onto calcite surfaces. The simulation results confirm that hydrolysed polyacrylamide with 33% charge density (HPAM 33%) exhibits superior chemical adsorption performance, consistent with Atomic Force Microscopy experiments.
Article
Thermodynamics
Wei Gao, Qifeng Li, Kai Sun, Rui Chen, Zhizhao Che, Tianyou Wang
Summary: A new flow field structure was studied to improve the performance of fuel cells, which enhances oxygen transport and water removal capabilities for better cell performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
