Article
Physics, Fluids & Plasmas
Riccardo Artoni, Patrick Richard, Michele Larcher, James T. Jenkins
Summary: In this letter, the effects of flow inhomogeneity on self-diffusion behavior in granular flows are discussed. Measurements of self-diffusion coefficients in steady, inhomogeneous, and collisional shearing flows are presented. The results show that a scaling based on the granular temperature is more effective in describing the self-diffusion behavior. These findings lay the groundwork for diffusion models in inhomogeneous shearing flows, which are important for understanding mixing and segregation.
Article
Physics, Fluids & Plasmas
Mengqi Yu, Julio M. Ottino, Richard M. Lueptow, Paul B. Umbanhowar
Summary: The flow of size-bidisperse particle mixtures in a spherical tumbler generates segregation patterns that correspond to the predicted location of nonmixing islands. The formation of these patterns is attributed to the interaction between size-driven radial segregation and the weak spanwise component of the advective surface flow. Small perturbations in the flow can lead to unexpected physical phenomena by altering key features of the dynamical system.
Article
Mechanics
Aurelien Neveu, Michele Larcher, Renaud Delannay, James T. Jenkins, Alexandre Valance
Summary: We have discovered a segregation pattern in high-speed granular flows, where size segregation is driven by two-dimensional granular temperature gradients instead of gravity. In contrast to slower flows, large particles in high-speed flows on steep slopes are not accumulated in the upper layers but trapped in the interior due to strong temperature gradients. Interestingly, these segregated flows run at a much faster speed than similar monodisperse flows, indicating potential for enhanced efficiency in granular material transportation. Importantly, we have shown that the kinetic theory for dense, inclined flows of binary mixtures can explain the segregation patterns observed in numerical simulations.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Chemistry, Physical
Riccardo Artoni, Michele Larcher, James T. Jenkins, Patrick Richard
Summary: This study reports measurements of self-diffusion coefficients in collisional shearing flows of frictional, inelastic spheres, highlighting the impact of solid volume fractions on diffusivity. Comparison with empirical scaling and kinetic theory predictions reveals discrepancies, suggesting the need for further investigation into the diffusion behavior of such systems.
Article
Physics, Fluids & Plasmas
Umberto D'Ortona, Nathalie Thomas, Richard M. Lueptow
Summary: Friction at the endwalls induces curvature and axial drift in the particle trajectories in a partially filled rotating tumbler. The roughness of the endwalls increases curvature, while a smooth cylindrical wall enhances drift near the endwalls. The competition between the endwall and cylindrical wall effects determines the width and drift amplitude of the recirculation cells.
Article
Physics, Fluids & Plasmas
Meng Liu, Christoph R. Muller
Summary: The lift force model for intruders in dense, granular shear flows takes into account granular temperature, pressure differences, and density differences between the intruder and the bed particles. The model accurately predicts and explains the behavior of intruders in shear flows.
Article
Engineering, Chemical
Shih-Hao Chou, Po-Han Huang, Shu-San Hsiau
Summary: This study used an experimental approach to investigate the effects of filling degrees and rotation speeds on particle segregation behavior. The concentrations of the particles and the dynamics of the mixture flow were measured and calculated. The study found that different segregation patterns were observed with changes in filling degrees and rotation speeds.
MINERALS ENGINEERING
(2022)
Article
Engineering, Chemical
Yifei Duan, Jack Peckham, Paul B. Umbanhowar, Julio M. Ottino, Richard M. Lueptow
Summary: In bidisperse particle mixtures with varying size or density, smaller particles sink and lighter particles rise. However, when particles differ in both size and density, percolation and buoyancy can either enhance or oppose each other. By specifying particle size ratio, density ratio, and mixture concentration, minimally segregating mixtures can be designed. DEM simulations and tumbler experiments with steel and glass particles validate the potential for designing such mixtures.
Article
Physics, Fluids & Plasmas
Tomas Trewhela, J. M. N. T. Gray, Christophe Ancey
Summary: The study investigates the segregation of single large intruder particles in granular materials, finding that segregation rate is influenced by size ratio and local strain rate. Larger size ratios result in faster segregation rates, while ratios closer to unity lead to stronger rotation effects.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Physics, Fluids & Plasmas
Arjun Yennemadi, Devang Khakhar
Summary: In this study, we investigate the effects of size segregation on a large particle (intruder) within a granular layer. By using discrete element method simulations, we determine the drag, lift, and buoyancy forces experienced by the intruder in different flow systems. Our results show that while the drag force follows Stokes' Law, the lift force does not follow the Saffman relation and can be effectively described using a modified Stokes' Law. The calculated buoyancy forces are consistent with previous studies. We also propose a continuum model for the segregation flux based on the computed forces.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Mechanics
Yi Liu, Zhaosheng Yu, Kun Luo, Yu Guo
Summary: Three-dimensional simulations of polydisperse shear flows of rod and disk mixtures show that particle shape distribution significantly affects flow behaviors, especially in terms of particle alignment and the structural anisotropy of interparticle contacts.
Article
Geochemistry & Geophysics
Elbasher Mohamed Elbasher Ahmed, Indresan Govender, Aubrey Njema Mainza
Summary: Experiments and simulations show that polydisperse granular mixtures in rotating drums exhibit axial segregation, forming (alternating) bands which coarsen over time due to logarithmic merging. Current models mainly focus on bidisperse mixtures and struggle to reproduce band coarsening, with one suggesting that grains diffuse into axial bands due to concentration fluctuations caused by limited mobility. Generalizing this model to multi-species mixtures reveals more complex banding evolution compared to binary mixtures, including sinusoidal-like variations that evolve nonlinearly in time. Interestingly, the study successfully recovers band coarsening over time, a phenomenon that is generally difficult to reproduce, even experimentally. Contrary to previous findings, configurations in this study did not produce nested bands for ternary and quaternary mixtures.
Article
Engineering, Chemical
Zhijian Zuo, Jiajie Wang, Xintao Chen, Shuguang Gong, Haishan Lu
Summary: This study explores a novel horizontal split drum design to drive axial segregation of granular matter by two reverse rotating sub-drums. It was found that true axial segregation occurs in the split drum with heavier particles accumulating near the split. Increasing the drum speed accelerates the segregation process but has no significant influence on the final particle distribution. These findings have important implications for the design of particle processing industries.
ADVANCED POWDER TECHNOLOGY
(2022)
Article
Optics
V. Sridhar, K. Hiraki, S. L. Gai, H. Kleine
Summary: This paper discusses the characteristics, advantages, and limitations of a digital version of the traditional streak imaging technique combined with various flow visualization methods. It also presents several applications in fluid mechanics. Streak images are useful for tracking and quantifying the development and propagation of different flow features over time and can graphically reveal the onset of certain flow phenomena. The digital technique also has the ability to filter and display less prominent elements of the flow.
OPTICS AND LASERS IN ENGINEERING
(2023)
Article
Physics, Fluids & Plasmas
Joyjit Chattoraj, Nguyen Hoang Huy, Saurabh Aggarwal, Mohamed Salahuddin Habibullah, Farzam Farbiz
Summary: This study investigates granular flows during a shear-induced mixing process using discrete element methods. The research reveals a strain rate-dependent transition from quasistatic to purely inertial flow, as well as a correlation between mixing dynamics and the formation of shear bands at the granular scale. The results show a profound system size dependence in contact stresses at a macroscopic scale and significantly different timescales of mixing depending on the regions in the system.
Article
Engineering, Chemical
C. C. Liao, S. S. Hsiau, S. F. Wen
ADVANCED POWDER TECHNOLOGY
(2016)
Article
Energy & Fuels
Yi-Shun Chen, Shu-San Hsiau, Jiri Smid, Jian-Feng Wu, Sheng-Ming Ma
Article
Mechanics
Chun-Chung Liao, Hung-Wen Lan, Shu-San Hsiau
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2016)
Article
Thermodynamics
Yi-Shun Chen, Shu-San Hsiau, Chia-Jen Hsu, Sheng-Ming Ma, Yi-Lun Chang
Article
Thermodynamics
Yi-Shun Chen, Chia-Jen Hsu, Shu-San Hsiau, Sheng-Ming Ma
Article
Engineering, Chemical
Li-Tsung Sheng, Shao-Li Chiu, Shu-San Hsiau
CHEMICAL ENGINEERING SCIENCE
(2018)
Article
Thermodynamics
Yi-Shun Chen, Shu-San Hsiau, Duan-You Shu
Article
Energy & Fuels
Yi-Shun Chen, Shu-San Hsiau, Jhan-Ruei Syu, Yi-Lun Chang
Article
Engineering, Chemical
S. H. Chou, L. T. Sheng, W. J. Huang, S. S. Hsiau
ADVANCED POWDER TECHNOLOGY
(2020)
Article
Energy & Fuels
Cong-Binh Dinh, Shu-San Hsiau, Chien-Yuan Su, Hou-Peng Wan
Summary: This study developed a 3D computational fluid dynamics full-loop model to predict the pressure and sand circulation rates under various operating conditions. The model was validated against experimental data and showed reasonable predictions of air-sand flow patterns and undesirable problems, providing valuable information for designing and operating practical DFB hot flow systems.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Article
Geosciences, Multidisciplinary
W. Sun, X. Meng, Y. Wang, S. S. Hsiau, Z. You
Summary: This paper presents a depth-averaged theory for studying submarine landslides and related water waves. The theory considers both a pure fluid regime and a mixture regime of grains and fluid, separated by an interface. The established theory consists of five coupled conservation equations, which accurately describe the behavior of particles in underwater collapse experiments and the profiles of free-surface waves. The computed results are in good agreement with previous experimental findings.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2023)
Article
Mechanics
Shu-San Hsiau, Kolumban Hutter, Li-Shin Lu, Andreas Teufel, Shih-Hao Chou, Li-Tsung Sheng
Summary: Experiments were conducted to investigate the effect of rapid shear flow on the properties of granular particles, using particles from the food industry and quartz grains. It was found that shear flow resulted in changes in surface roughness and subsequently affected the internal and wall friction angles. This highlights the importance of considering roughness changes in theoretical descriptions of granular flows.
JOURNAL OF MECHANICS
(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.