Article
Optics
Can Li, Wenmin Peng, Yang Kang, Xudong Fan, Xiaolong Huang, Ning Li, Chunsheng Weng, Cameron Tropea
Summary: Rainbow refractometry has been developed for spray measurement applications, allowing simultaneous measurement of refractive index and droplet size. This study investigates the feasibility and accuracy of using incomplete rainbow signals for measurement. The newly defined dimensionless signal partial ratio (SPR) quantifies the degree of incompleteness. Simulation and inversion experiments were conducted, and the results showed that inversion using signal fitting is more accurate than using specific characteristic points. Laboratory experiments also verified these findings. For SPR <= 1, rainbow refractometry achieves errors within 6 x 10-4, 3% for monodisperse droplets and 2 x 10-4, 8% for spray droplets in terms of refractive index and size.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Thermodynamics
Qimeng Lv, Yingchun Wu, Xinhao Wang, Lei Zeng, Xuecheng Wu
Summary: This study experimentally investigates the evaporation characteristics of fuel droplets under the combined effects of ambient pressure, temperature, droplet size, and spacing. The results show that the evaporation rate of droplets is influenced by both ambient conditions and droplet interactions. Furthermore, the study reveals the correlations between Nusselt and Sherwood numbers through parametric analysis.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Engineering, Chemical
Yingchun Wu, Qimeng Lv, Xuecheng Wu, Xinhao Wang, Linghong Chen, Kefa Cen
Summary: The oscillation of micron-sized liquid droplets can be measured using time-resolved rainbow refractometry to determine surface tension and viscosity. The method shows potential for improving experimental validation and reducing measurement errors, with relative errors of less than 5% for surface tension and 10% for viscosity.
Article
Thermodynamics
Zhaojing Ni, Camille Hespel, Kai Han, Fabrice Foucher
Summary: The evaporation behavior of binary droplets consisting of ethanol and heptane was studied experimentally and through simulation. The study found that the heavier component preferentially evaporates when the lighter component dominates the liquid mixture. The refractive index of the droplets is influenced by temperature and composition, and a linear relationship between the refractive index gradient and the deviations from the center refractive index was proposed. The accuracy of a non-ideal equilibrium model for predicting the diameter, temperature, and concentration of binary droplets was validated for the first time.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2022)
Article
Physics, Multidisciplinary
Can Li, Wenmin Peng, Tianchi Li, Ning Li
Summary: This study investigates the feasibility and accuracy of rainbow refractometry using the incomplete rainbow signal on the right side. Through comprehensive analysis and simulations, the study explores the utilization of refractive index, droplet diameter, and size distributions retrieved from partial rainbow signals. Laboratory experiments confirm the effectiveness of employing right partial rainbow signals in rainbow refractometry.
FRONTIERS IN PHYSICS
(2023)
Article
Thermodynamics
Mengxian Hu, Xinzhe Que, Yongjin Chen, Zhao Jin, Yixuan Hou, Yongchao Zhou, Yiping Zhang
Summary: This paper investigates the morphology of bubbles in transparent MLPS colloidal suspensions using the gas injection method. Factors such as concentration, sample height, pinhole diameter, and gas flow rate were analyzed. The study finds that the bubble shape is initially controlled by elasticity and then by viscoelasticity, resulting in 'inverted carrot' and 'inverted teardrop' shapes. A identification method is proposed based on bubble shape parameters, and a prediction equation is proposed for detached bubble shape identification based on influencing parameters. The calculated results are in good agreement with the test results.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2023)
Article
Optics
M. F. B. Stodt, T. Wriedt, J. Kiefer, U. Fritsching
Summary: This study investigates the application of global rainbow refractometry to sprays with droplets as small as 1 - 30 µm in diameter, evaluating the influence of varying droplet size distributions and refractive indexes on the global rainbow. The results suggest that GRR experiments in polydisperse applications should be accompanied with an accurate sizing technique.
JOURNAL OF MODERN OPTICS
(2021)
Article
Thermodynamics
Feifei Qin, Jianlin Zhao, Qinjun Kang, Thomas Brunschwiler, Jan Carmeliet, Dominique Derome
Summary: Based on the numerical study, a higher initial nanoparticle concentration leads to larger and more numerous necks, resulting in increased effective thermal conductivity of the NTS. Drying temperature has minimal impact on the effective thermal conductivity of the resultant NTS, but neck size and distribution become more uniform at higher drying temperatures. Decreasing wettability of the cavity's top and bottom surfaces causes necks to shrink or disappear, while the size of necks between filler particles in the middle of the cavity slowly expands, leading to a decrease in the effective thermal conductivity of the NTS.
APPLIED THERMAL ENGINEERING
(2021)
Article
Optics
Tomasz Jakubczyk, Daniel Jakubczyk, Andrzej Stachurski
Summary: Convolution neural networks were used to classify speckle images of nanoparticle suspensions, showing superior recognition capabilities compared to human experimenters. The system demonstrated potential for generalization but with limitations. SVM was found to be more resource-intensive compared to neural networks.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2021)
Article
Engineering, Environmental
Wai Kuan Wong, Jason Ting Yi Chin, Saif A. Khan, Frederic Pelletier, Elena Cristina Corbos
Summary: This study presents a robust triphasic flow millireactor for the synthesis of catalytic nanoparticles and their deposition onto support materials with tunable metal loading and high control over spatial distribution. The supported nanoparticles produced by flow synthesis show consistency and quality superior to their batch-synthesized counterparts. The versatility of the method is demonstrated for different nanoparticle types and support materials.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Nanoscience & Nanotechnology
Yiquan Fang, Huateng Li, Xiuli Wang, Mengjing Zhu, Jia Guo, Changchun Wang
Summary: In this study, liquid colloidal crystals were prepared and used as a reflective unit for fabricating dynamic ECPC devices. The researchers successfully achieved controllable structural color under low voltages and established regulatory rules and relations for the dynamic ECPC device. They also revealed the dynamic mechanism of reflection spectra during the electrical modulation, which is significant for future development of ECPC devices.
ACS APPLIED NANO MATERIALS
(2022)
Article
Mechanics
P. V. Krauzin, M. T. Krauzina
Summary: Numerical solution of the solute convection problem in a spherical cavity reveals that flow is induced by the concentration inhomogeneity near the surface, forming two toroidal structures. Furthermore, convection accelerates the separation of the mixture.
JOURNAL OF APPLIED MECHANICS AND TECHNICAL PHYSICS
(2021)
Article
Engineering, Chemical
Simon Assmann, Franz J. T. Huber, Stefan Will
Summary: Wide-angle light scattering was used for in situ measurements of droplet and nanoparticle size distributions during the synthesis process. The addition of different precursors led to altered evaporation behavior and different types of particle formations.
Article
Physics, Multidisciplinary
I. N. Cherepanov, B. L. Smorodin
Summary: This study investigated the linear instability and nonlinear convective flows of a colloidal suspension in a gravity field, taking particle interactions into account. The results showed that nonlinear terms reduced the convection threshold and neutral oscillation frequency, and the spatial structure was successfully described by the first harmonic with weak spatial anharmonism compared to ideal colloidal solutions.
JOURNAL OF EXPERIMENTAL AND THEORETICAL PHYSICS
(2021)
Article
Engineering, Environmental
L. M. Reitter, H. Lohmann, M. Schremb, I. Roisman, J. Hussong, C. Tropea
Summary: Ice particle impact causes deformation and fragmentation, leading to the formation of a residual ice cone. High-speed video system is used to observe the impact, deformation, and fragmentation of nearly spherical ice particles, as well as measuring the size and mass of the residual ice cone. A theoretical model based on fluid dynamics is used to estimate the size of the residual ice cone, which can predict the maximum radius of impression and collision duration.
COLD REGIONS SCIENCE AND TECHNOLOGY
(2022)
Article
Optics
Wenting Wang, Haitao Yu, Jianqi Shen, Cameron Tropea
Summary: Rainbow scattering can provide information about the size, refractive index, temperature, and composition of droplets. Using a highly focused Gaussian illumination beam can improve the spatial resolution in dense spray situations. This study investigates rainbow scattering from spherical droplets and explores different inversion algorithms and the effect of beam incident position on droplet characterization. For water droplets in the size range of 50-200 μm, high accuracy in measuring the relative refractive index and small relative error in size can be achieved.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2022)
Editorial Material
Engineering, Mechanical
Alexander Yarin, Ilia V. Roisman, Hyoungsoo Kim, Cameron Tropea
EXPERIMENTS IN FLUIDS
(2022)
Article
Engineering, Environmental
M. Gloerfeld, M. Schremb, I. V. Roisman, J. Hussong, C. Tropea
Summary: The initial stage of solidification of a free supercooled water drop involves the formation of dendritic structures surrounded by liquid water. However, the impact dynamics and material properties of these partially frozen water drops have not been thoroughly studied. This study examines the kinematics of spreading and the geometry of the residual splat during the impact of dendritically frozen water drops. A theoretical model is then used to simulate the impact process, assuming plastic flow in the mushy drop. The model provides insights into the fluid flow near the impact axis and allows estimation of the apparent yield strength of the solid-liquid mixture for different initial temperatures.
COLD REGIONS SCIENCE AND TECHNOLOGY
(2023)
Article
Mechanics
Bastian Stumpf, Ilia V. V. Roisman, Alexander L. L. Yarin, Cameron Tropea
Summary: Drop impact on a liquid film results in a new mode of splash called simultaneous corona detachment, which is caused by the breakup of the wall film. The sudden displacement of the film leads to the thinning and rupture of the corona wall, triggering propagating rims that undercut and detach the entire corona. Experimental evidence and a proposed self-consistent theory support this mechanism.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Optics
Can Li, Wenmin Peng, Yang Kang, Xudong Fan, Xiaolong Huang, Ning Li, Chunsheng Weng, Cameron Tropea
Summary: Rainbow refractometry has been developed for spray measurement applications, allowing simultaneous measurement of refractive index and droplet size. This study investigates the feasibility and accuracy of using incomplete rainbow signals for measurement. The newly defined dimensionless signal partial ratio (SPR) quantifies the degree of incompleteness. Simulation and inversion experiments were conducted, and the results showed that inversion using signal fitting is more accurate than using specific characteristic points. Laboratory experiments also verified these findings. For SPR <= 1, rainbow refractometry achieves errors within 6 x 10-4, 3% for monodisperse droplets and 2 x 10-4, 8% for spray droplets in terms of refractive index and size.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Chemistry, Physical
Marija Gajevic Joksimovic, J. Benedikt Schmidt, Ilia V. Roisman, Cameron Tropea, Jeanette Hussong
Summary: The effect of graphite lubricant additives on the dynamics of drop impact on a heated surface has been studied. The addition of particles increases the drop residence time and lowers the rebound temperature, suppressing splash and preventing coalescence of bubbles.
Article
Engineering, Mechanical
Shubham Sharma, Saini Jatin Rao, Navin Kumar Chandra, Aloke Kumar, Saptarshi Basu, Cameron Tropea
Summary: The two-sensor depth from defocus technique is developed to achieve higher spatial and temporal resolution, improve estimates of spatial size distribution and number concentration, and provide guidelines for the calibration and design of optical systems. The technique and improvements are demonstrated in the case of secondary atomization with a shock wave and a single drop, where high-resolution number density and size distributions of secondary droplets are necessary.
EXPERIMENTS IN FLUIDS
(2023)
Article
Physics, Multidisciplinary
Marija Gajevic Joksimovic, Jeanette Hussong, Cameron Tropea, Ilia V. V. Roisman
Summary: Spray cooling is a method used in various industrial processes and for cooling of electrical devices. The process is influenced by hydrodynamic and thermodynamic processes, and becomes more challenging when dealing with multicomponent liquids. In this study, the impact of spray onto a heated substrate was visualized and the heat transfer was characterized. The presence of a small concentration of lubricant significantly increased the heat flux and shifted the Leidenfrost point.
FRONTIERS IN PHYSICS
(2023)
Article
Thermodynamics
Kilian Koebschall, Benjamin Traut, V. Ilia Roisman, Cameron Tropea, Jeanette Hussong
Summary: This study presents an experimental setup and a theoretical model for studying snowflake melting. The experimental results agree well with the model predictions, and an accurate value of the particle mass fractal dimension is required for accurately estimating the melting duration.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Mechanics
Niklas Apell, Cameron Tropea, Ilia V. Roisman, Jeanette Hussong
Summary: With the increasing economic importance of metal additive manufacturing by laser powder bed fusion, the demand for high-quality metal powders is also rising. However, the physics involved in supersonic close-coupled gas atomization, which is often used for producing these powders, are not well understood due to scarce experimental data, resulting in a lack of reliable predictive modeling capabilities.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2023)
Article
Thermodynamics
Yasir A. Malik, Kilian Koebschall, Stephan Bansmer, Cameron Tropea, Jeanette Hussong, Philippe Villedieu
Summary: Ice crystal icing is a significant hazard in aviation, and accurate modeling of sticking efficiency is essential. In this study, icing wind tunnel experiments were conducted to quantify the volumetric liquid water fraction, sticking efficiency, and maximum thickness of ice layers. Two measurement techniques, calorimetry and capacitive measurements, were used to measure the liquid water content and distribution in the ice layers. The experiments showed that increasing wet bulb temperatures and substrate heat flux significantly increased sticking efficiency and maximum ice layer thickness.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
J. B. Schmidt, F. Tenzer, C. Tropea, J. Hussong, I. V. Roisman
Summary: Spray cooling is a technology that provides uniform and intense cooling for surfaces with complex geometry. It can be used in a wide range of surface temperatures for various applications. The performance of spray cooling depends on factors such as surface temperature, spray parameters, and the thermal properties of the liquid and substrate. This study focuses on the transitional boiling regime, which is the least studied due to its complexity. A model is developed to predict the heat flux during spray cooling in this regime and shows good agreement with experimental results.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Engineering, Mechanical
Bastian Stumpf, Jonas H. Ruesch, Ilia Roisman, Cameron Tropea, Jeanette Hussong
Summary: This study introduces an imaging technique supported by a machine learning algorithm to determine the volume fraction of each liquid component in two-component droplets. It demonstrates the application of this technique by measuring the volume fraction in splashed secondary droplets following the impact of a drop of one liquid onto a film of a different liquid.
EXPERIMENTS IN FLUIDS
(2022)
Article
Engineering, Chemical
Ri Zhang, Shasha Zhang, Mengyan Ding
Summary: A thin liquid film method is proposed to evaluate sand erosion in annular flow. This method considers the direct interaction between the liquid film and gas core, as well as the entrainment and deposition of droplets. The erosion rate is calculated by considering the effects of liquid entrainment and particle velocity decay. The method is fully verified by comparing with experimental data.
Article
Engineering, Chemical
Yu Suo, Xianheng Su, Wenyuan He, Xiaofei Fu, Zhejun Pan
Summary: This research investigates the mechanical properties of sandstone-shale composite through orthogonal experimental method and discrete element simulation. The results show that different lithologies and thickness ratios can affect the strength and fracture mode of the composite rock samples.
Article
Engineering, Chemical
Maurizio Troiano, Andrea El Hassanin, Roberto Solimene, Alessia Teresa Silvestri, Fabrizio Scala, Antonino Squillace, Piero Salatino
Summary: This study investigates the potential of Fluidized Bed Finishing (FBF) for square flat AlSi10Mg specimens manufactured via Laser-Powder Bed Fusion (L-PBF) additive manufacturing technology. The results show that good finishing can be achieved using rotation-assisted tests, with a maximum reduction of surface roughness by 67%. Steel particles are found to be the most effective bed material.
Review
Engineering, Chemical
Ningbo Song, Wanzhong Yin, Jin Yao
Summary: Seawater's dissolved salts and minerals have various effects on the flotation process, including influencing the characteristics and behavior of flotation factors, as well as affecting the surface of sulfide minerals. In most cases, seawater has adverse effects on the flotation of sulfide minerals, but these effects can be mitigated by adjusting the reagents.
Article
Engineering, Chemical
Kaiqiao Wu, Shuxian Jiang, Victor Francia, Marc-Olivier Coppens
Summary: In rectangular and cylindrical annular fluidized beds, pulsating gas flow can create regular bubble patterns, overcoming challenges seen in conventional units. This study provides new opportunities for modularization of fluidized bed operations.
Article
Engineering, Chemical
Shuo Li, Huili Zhang, Jan Baeyens, Miao Yang, Zehao Li, Yimin Deng
Summary: The paper assesses the behavior of cohesive Geldart C-type particles when fluidized by air with the aid of vibration. It determines that mechanical vibration is a simple and effective method to improve the fluidity of cohesive particles during fluidization.
Article
Engineering, Chemical
Zhenfei Feng, Qingyuan Zhang, Shanpan Liang, Zhenzhou Li, Fangwen Guo, Jinxin Zhang, Ding Yuan
Summary: A new micro/mini-channel heat sink (MCHS) with a combined structure of longitudinal and transverse vortex generators is designed, using Al2O3 nanofluid as the working medium. The study explores the effects of transverse vortex generator shape and longitudinal vortex generator angle on the hydraulic and thermal characteristics, comprehensive performance, entropy generation, and exergy efficiency. The results show that the triangular transverse vortex generator improves the comprehensive performance and exergy efficiency. Combined with the longitudinal vortex generator, the MCHS achieves the best comprehensive performance, entropy generation, and exergy efficiency when the Reynolds number is 742.
Article
Engineering, Chemical
Kostas Giannis, Christoph Thon, Guoqing Yang, Arno Kwade, Carsten Schilde
Summary: This study presents a 3D convolutional neural network (3D-CNN) methodology for generating realistic 3D models of particles. The method trains on 2D projections of particle images to predict their 3D shapes, and evaluates the accuracy of the predictions using Fourier shape descriptors (FSDs). This methodology has wide applications in particle shape analysis.
Article
Engineering, Chemical
Zheng-qing Zhou, Lu-jia Chai, Yu-long Zhang, Ya-bin Wang, Ze-chen Du, Tian-yi Wang, Yu-zhe Liu
Summary: The dynamic oxidation and shell-breaking processes of aluminum nanoparticles (ANPs) during heating were studied using in situ transmission electron microscopy. The results revealed that the changes in shell thickness can be divided into three stages, and the active aluminum content of ANP decreased before shell-breaking.
Article
Engineering, Chemical
Fulei Chen, Huaqing Ma, Zihan Liu, Lianyong Zhou, Yongzhi Zhao
Summary: A particle breakage model based on the particle replacement scheme, using the polyhedral model to describe particles, is proposed in this work to accurately describe the breakage of a large number of particles. Additionally, a fast-cutting algorithm is proposed to reproduce the size distribution of progeny particles determined by the breakage model. The validation and simulation results show satisfactory accuracy, efficiency, and stability of the algorithm.
Review
Engineering, Chemical
Matteo Errigo, Christopher Windows-Yule, Massimiliano Materazzi, Dominik Werner, Paola Lettieri
Summary: Gas-solid fluidized-bed systems have advantages in terms of chemical reaction efficiency and temperature control, making them widely used in industrial applications. However, the design, scale-up, and optimization of these complex units are limited by the lack of deep physical understanding. Non-invasive and non-intrusive diagnostic techniques provide a way for researchers to study these systems without affecting the flow field or directly contacting the medium under study.
Article
Engineering, Chemical
Saeed Fateh, Mohammad Behshad Shafii, Mohammad Najafi, Cyrus Aghanajafi
Summary: Applying a magnetic field to ferrofluids alters their flow characteristics and enhances heat transfer. Through visualization and quantitative investigation, it is found that the magnetic field influences the flow patterns and velocity profiles, improving fluid mixing and vorticity magnitude.
Article
Engineering, Chemical
Lei Gao, Bingbing Wei, Xiaochuan Hu, Zaifeng Yao, Yiwen Fang, Xuejian Gao
Summary: In this study, a numerical model of sand triaxial test was established using discrete element software PFC3D, and an indoor triaxial test was conducted to calibrate the numerical model. The influence of microscopic parameters on the macroscopic mechanical response of sand was analyzed. The results showed that the friction coefficient had the greatest impact on the peak strength and residual strength of the sand's stress-strain curve, and it was positively correlated. The normal tangential stiffness ratio was negatively correlated, while the porosity and boundary flexibility stiffness had minimal influence on it.
Article
Engineering, Chemical
Xuan Liu, Jie Gong, Kai Jiang, Xiaojuan Lai, Yu Tian, Kang Zhang
Summary: This study aimed to improve the performance of lignite coal water slurries (CWSs) by synthesizing a series of three-arm amphiphilic block copolymers. By controlling the relative molecular weight, hydrophilic/hydrophobic ratio, and ionic group content, the apparent viscosity of CWSs was significantly reduced and the static stability was improved. Thermogravimetric testing and XPS analysis were conducted to reveal the mechanism behind the improved performance.
Article
Engineering, Chemical
Lanka Dinushke Weerasiri, Daniel Fabijanic, Subrat Das
Summary: Fluidization at low pressure offers significant benefits for the fine chemical industry. This study investigates the behavior of bubbles and bed expansion under low pressure conditions. It is found that lower pressure leads to larger bubbles, increased bubble quantity, and higher aspect ratio. The predictability is affected by the inhomogeneous fluidization, but low pressure fluidization can generate similar bubble sizes with lower fluidizing mass compared to atmospheric pressure.
