Article
Chemistry, Multidisciplinary
Sheng Mi, Chunying Zhu, Youguang Ma, Taotao Fu
Summary: This study investigates the bubble formation process in high-viscosity liquids using step-emulsification microdevices and analyzes the flow patterns and interface evolution.
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
(2022)
Article
Biochemical Research Methods
Yu Chang, Lin Sheng, Junjie Wang, Jian Deng, Guangsheng Luo
Summary: By establishing a universal database and model, we have developed a neural network model that combines mechanistic and data modeling to predict and design the performance of gas-liquid microdispersion. We have also proposed a design method that controls the deviation of bubble size to be less than 5%.
Article
Thermodynamics
Kuankui Guo, Jiaying Wang, Meng Hua Pan, Jingtao Wang
Summary: This paper investigates the bubble formation with temperature difference between the gas and liquid phases through experimental and numerical methods. The results show that the temperature ratio of the liquid to gas phases has an impact on the bubble length, and a new method for calculating the bubble length is proposed. The findings are important for designing microreactors with temperature difference between the continuous and dispersed phases.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Mechanics
Somasekhara Goud Sontti, Arnab Atta
Summary: We developed a computational fluid dynamics model based on the coupling of the level set and volume of fluid methods to study droplet formation in a square flow-focusing microchannel. By modifying the microchannel with a constricted orifice, we were able to manipulate droplet formation and flow regimes. We investigated the effects of geometrical confinement, flow rate, and interfacial tension on droplet characteristics and identified squeezing, dripping, and jetting as the three flow regimes observed.
Article
Mechanics
Alienor Riviere, Wouter Mostert, Stephane Perrard, Luc Deike
Summary: This study investigates the dynamics and statistics of bubble break-up in homogeneous and isotropic turbulence through direct numerical simulations, focusing on the influence of the Weber number on bubble break-up dynamics. The findings reveal that during the transition to stable conditions, bubble break-up occurs through both local and non-local production processes, resulting in a range of bubble sizes.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Daniel J. Ruth, Marlone Vernet, Stephane Perrard, Luc Deike
Summary: The study shows that the average rising speed of bubbles in liquid decreases with increasing turbulence intensity, following a specific proportional relationship. This is mainly due to the effects of nonlinear drag and the nearly isotropic behavior of the slip velocity on the mean rise speed.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Matthias Kramer, Daniel Valero
Summary: High-Froude-number flows become self-aerated when turbulence overcomes gravity and surface tension forces. Instead of using single-layer approaches, a new two-state formulation is presented to explain the complete air concentration profile through the weak interaction between turbulent boundary layer and turbulent wavy layer. The proposed flow conceptualization allows for more physically based numerical modeling of turbulent mass diffusion in self-aerated flows.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Kazuki Maeda, Masanobu Date, Kazuyasu Sugiyama, Shu Takagi, Yoichiro Matsumoto
Summary: A series of experiments and modelling were conducted to study the interaction of a pair of spherical bubbles rising in a vertical channel. The results showed that bubbles take two preferential configurations depending on their mutual distance, which helps to elucidate the clustering mechanisms.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Youssef Saade, Maziyar Jalaal, Andrea Prosperetti, Detlef Lohse
Summary: The study reveals that the formation mechanism of the crown is a combination of pressure distortion and induced flow focusing on the curved interface, as well as flow reversal caused by the second expansion of the toroidal bubble. A parametric study with control parameters such as Weber number, Reynolds number, pressure ratio, and dimensionless bubble distance to the free surface shows their effects on both the central jet and the crown formation. High Weber numbers lead to the formation of weaker 'secondary crowns', highly correlated with the third oscillation cycle of the bubble.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Thermodynamics
Il Woong Park, In Yeop Kang, Hyun Jin Yong
Summary: This study classified bubbles in two-phase flow and revealed the relationship between periodic bubble behavior and flow instability, providing an important theoretical basis for improving the application of flow boiling systems.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Mechanics
Stephane Perrard, Alienor Riviere, Wouter Mostert, Luc Deike
Summary: In this study, the deformation modes and lifetime of a bubble in a turbulent flow are investigated through numerical simulations and theoretical analysis. Two temporal regimes are observed during the bubble deformation process, with the first regime driven by inertial forces and the second regime resulting from a balance between inertial forces and surface tension.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
D. Raciti, P. Brocca, A. Raudino, M. Corti
Summary: We present a new interferometric method to study the interactions between two gas bubbles in a liquid undergoing small-amplitude oscillations. The technique allows for accurate measurement of the amplitude, frequency, and phase of oscillation, as well as probing the interactions between the bubbles. This method is of great importance for understanding bubble interactions.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Mirko Gallo, Francesco Magaletti, Carlo Massimo Casciola
Summary: This study investigates the impact of solid walls on bubble formation in heterogeneous nucleation processes, exploring the direct effects of boundary conditions compliant with fluctuation-dissipation balance on nucleation.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Timothy T. K. Chan, Chong Shen Ng, Dominik Krug
Summary: In this study, the spatial distribution and influencing factors of bubble-particle collisions in turbulence are investigated through direct numerical simulations. It is found that the segregation of bubbles and particles reduces the collision rate, while the approach velocities for bubble-particle pairs increase accordingly. The adequacy of existing theoretical models is yet to be evaluated due to limited available data.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Jie Zhang, Ming-Jiu Ni, Jacques Magnaudet
Summary: Highly resolved simulations were used to study the buoyancy-driven motion of two identical gas bubbles released in a liquid at rest. Two distinct evolutions were observed depending on the values of Galilei (Ga) and Bond (Bo) numbers, with the bubbles either moving in a side-by-side motion or with the trailing bubble drifting laterally. Bubble deformation played a key role in determining the system's evolution.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Agricultural Engineering
Yuying Hu, Xiaohuan Zheng, Shihao Zhang, Wenjie Ye, Jing Wu, Souhila Poncin, Huai Z. Li
Summary: High solid anaerobic digestion (HSAD) is a potential organic waste treatment method with advantages of small footprint, less digestate, and low heating energy. Studying the hydrodynamics of HSAD showed that optimizing mixing can greatly increase its processing capacity.
BIORESOURCE TECHNOLOGY
(2021)
Article
Engineering, Chemical
Daofan Ma, Di Liang, Chunying Zhu, Taotao Fu, Youguang Ma, Xigang Yuan, Huai Z. Li
Summary: The study visually investigated the breakup process of viscous droplets in Y-shaped microchannels, highlighting the dynamics of droplet breakup with partial obstruction. The rupture process of droplets is divided into squeezing, transition, and rapid pinch-off stages, each displaying unique characteristics related to time, two-phase viscosity ratio, capillary number, and other factors. The findings provide insights into the factors influencing droplet breakup in microscale flow systems.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Engineering, Environmental
Yuying Hu, Shihao Zhang, Xin Wang, Xiaoming Peng, Fengping Hu, Chuqiao Wang, Jing Wu, Souhila Poncin, Huai Z. Li
Summary: This study proposed a novel approach for experimentally quantifying the mass transfer in the mixing process of HSAD using the Laser Induced Fluorescence technique. The results showed that the feedstock tended to accumulate around the impeller in the HSAD system, and diffusion around the 1st impeller was rapid while around the 2nd impeller was tough. Prolonging mixing time did not significantly improve the flow pattern and mixing in HSAD.
Article
Engineering, Chemical
You Ma, Chunying Zhu, Taotao Fu, Youguang Ma, Huai Z. Li
Summary: The dynamics of non-Newtonian droplet breakup in a microfluidic Y-junction with partial obstruction was visually investigated. Three breakup stages were identified: squeezing, transition, and pinch-off. Factors such as the concentration of CMC, continuous capillary number, and dispersed phase local capillary number were found to affect the breakup process, with the pinch-off stage primarily determined by surface tension.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Engineering, Chemical
Xiaofeng Jiang, Shixing Chen, Enle Xu, Xianliang Meng, Guoguang Wu, Huai Z. Li
Summary: This study investigates the downhill motion of liquid drops and liquid marbles using two distinct particle-laden interfaces. It is found that liquid marbles have a lower velocity than liquid drops but a higher maximum aspect ratio, indicating different interactions due to particles present on different surfaces.
Article
Agricultural Engineering
Fengping Hu, Shihao Zhang, Xin Wang, Chuqiao Wang, Jing Wu, Souhila Poncin, Li Xu, Gaoping Xu, Yuying Hu, Huai Z. Li
Summary: The study investigates the impact of impeller width on the correlation of mixing-fluidity-energy at different rotating speeds, as well as the scale-up effect based on rotating speed and a generalized Reynolds number. Results show that impeller widths of 100 mm (10 rpm), 200 mm, and 300 mm (5 and 10 rpm) are preferred for improving hydrodynamics and energy efficiency in HSAD. Additionally, the study suggests that Reynolds number similarity has significant implications for scale-up applications in practical engineering.
BIORESOURCE TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Nicolas Dietrich, Gaelle Lebrun, Kalyani Kentheswaran, Mathias Monnot, Patrick Loulergue, Carine Franklin, Florence Tedde-Zambelli, Chafiaa Djouadi, Sebastien Leveneur, Mallorie Tourbin, Yolaine Bessiere, Carole Coufort-Saudejaud, Annabelle Couvert, Eric Schaer
Summary: Despite the increasing presence of women in the field of engineering, the programs fail to include references to women scientists. A survey showed that the majority of students were unaware that all the scientists mentioned in their classes were men, and 90% of them couldn't identify a woman in the field of chemical engineering. Addressing gender inequalities in education requires considering the type and content of education.
JOURNAL OF CHEMICAL EDUCATION
(2022)
Article
Chemistry, Multidisciplinary
Olfa Beji, Nouceiba Adouani, Souhila Poncin, Huai-Zhi Li
Summary: Biogas production from anaerobic digestion of different wastes is of growing interest in renewable energy. This study investigates the use of liquid digestate and slurry as substrates for microalgae-bacterial flocs growth and methane production. The results showed that 30% dilution of digestate and 10% dilution of slurry were optimal for nutrient removal and biomass production. The anaerobic digestion without flocs performed better in terms of methane production compared to digestion with flocs.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Physical
Xiaofeng Jiang, Yi Zhou, Enle Xu, Xiangliang Meng, Guoguang Wu, Huai Z. Li
Summary: The impact of water drops on superhydrophobic surfaces (SHSs) with or without cavities was experimentally investigated in this study. Compared to plane SHSs, the cavity with different geometries reduces the maximum spreading diameter and contact time, and leads to complex drop deformation under higher We numbers. The dimensionless contact time on plane SHSs remains constant at about 0.88, while that on the cavity-textured SHSs is about 0.82. The drop impact on SHSs with macro-textured cavities exhibits different behaviors, which is important for applications such as self-cleaning and anti-icing.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2023)
Article
Thermodynamics
Kalyani Kentheswaran, Nicolas Dietrich, Sebastien Tanguy, Benjamin Lalanne
Summary: Direct Numerical Simulations were conducted to investigate the gas-liquid mass transfer around a rising spherical bubble contaminated by insoluble surfactants. The study considered the surfactant transport and the Marangoni effect, leading to the stagnant-cap condition. The analysis revealed the crucial role of contamination angle and maximum velocity in quantifying the mass transfer rate. The presence of surfactants resulted in decreased mass transfer, thickened boundary layer, and reduced transfer rate in the mobile zone of the interface.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Chemistry, Multidisciplinary
Qindan Zhang, Souhila Poncin, Christian Blanchard, Youguang Ma, Huai Z. Li
Summary: The coalescence behavior of ferrofluid drop on its bulk surface was studied experimentally using a high-speed camera. Shape deformations of both the pendant ferrofluid drop and the bulk surface were observed in the axial direction during the approaching process, even without a magnetic field. The angle of the upper pendant peak decreases with increasing magnetic flux density, while the lower ferrofluid peak shows the opposite trend. The coalescing width of the ferrofluid drop follows a power-law relationship.
Article
Physics, Fluids & Plasmas
Naila Bouayed, Manon Montaner, Claude Le Men, Johanne Teychene, Christine Lafforgue, Nicolas Dietrich, Chung-Hak Lee, Christelle Guigui
Summary: This article focuses on the study of mass transfer in membrane bioreactors (MBRs) using a bacterial antifouling technique. The results showed that the total amount of dye transferred into sheets was greater than that transferred into cylinders or beads, due to the larger exchange area. The global transfer coefficient from the sheets to the liquid was found to be higher for MBRs, indicating a faster transfer phenomenon. The study also investigated the effect of aeration and found the optimal air flowrate for promoting transfer.
Article
Engineering, Chemical
Hao Jiang, Chunying Zhu, Taotao Fu, Xiqun Gao, Youguang Ma, Huai Z. Li
Summary: A new droplet sieving method using grooved microchannel is proposed for achieving droplet monodispersity. The sieving performance and mechanism are experimentally investigated, revealing three different sieving flow regimes: incomplete sieving, complete sieving, and main droplet rupture. The effects of different operating conditions on sieving efficiency are systematically studied.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Review
Engineering, Chemical
Dong Lin, Zhiwei Mao, Jingyuan Shang, Huihong Zhu, Tiebin Liu, Yining Wu, Huai Z. Li, Chong Peng, Xiang Feng
Summary: The second-generation biodiesel, generated through the deoxygenation of vegetable oils, is an ideal green fuel that can help address environmental pollution and the energy crisis. This review summarizes the catalyst design strategies, including the selection of metal active species, adjustment of coordination environment, and regulation of the metal-support interface, to provide insights into the catalytic mechanisms and guide the synthesis of catalysts for the deoxygenation of vegetable oils, promoting the industrialization process of second-generation biodiesel.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Biochemical Research Methods
C. Y. Tong, Huai Z. Z. Li, C. J. C. Derek
Summary: This study investigates cell detachment of Chlorella vulgaris from porous substrates in early cultivation stage using a microfluidic platform. Results show that increasing flow velocity enhances nutrient transport but also triggers cell detachment. The effect of flow velocity on cell detachment differs at different locations. These findings contribute to optimizing operating conditions and reactor design for algae cultivation systems.
