Article
Engineering, Chemical
Kizuku Kushimoto, Kaya Suzuki, Shingo Ishihara, Rikio Soda, Kimihiro Ozaki, Junya Kano
Summary: The collision behaviors of particles in spiral jet milling were analyzed using a simulation that tracked particle motion with the discrete element method (DEM) and represented air flow with computational fluid dynamics (CFD). The DEM and CFD were coupled with a one-way coupling method. The simulated air flow was validated by comparing it with the measured fluid velocity field in a model experiment. The air flow and particle behaviors in a commercially used spiral jet mill were also analyzed using the simulation, revealing that particles in a region balancing centrifugal and radial drag forces were mainly ground by high-speed collisions near the top and bottom walls of the grinding chamber.
ADVANCED POWDER TECHNOLOGY
(2023)
Article
Engineering, Chemical
Lewis Scott, Antonia Borissova, Alan Burns, Mojtaba Ghadiri
Summary: The study demonstrated that the grinding nozzles pressure has a significant impact on particle dynamics and fluid flow. As the particle mass loading increases, the radial velocity gradient decreases, leading to a reduction in shearing effect.
Article
Engineering, Chemical
Kizuku Kushimoto, Kaya Suzuki, Shingo Ishihara, Rikio Soda, Kimihiro Ozaki, Junya Kano
Summary: A new simpler coarse-grain model (SCG) for analyzing particle behaviors under fluid flow was developed using a discrete element method (DEM) to reduce calculation load. The SCG model focuses on fluid drag force acceleration, imposing a simple rule that the product of particle density and squared particle diameter is constant. The model's usability was confirmed by comparing behaviors of CG particles with original particles and representing particle behavior in a classifier.
Article
Engineering, Chemical
Musango Lungu, John Siame, Lloyd Mukosha
Summary: This study validates a detailed coarse-grained CFD-DEM model in the open-source code MFIX. The validation metrics include fluidization behavior, minimum fluidization velocity, averaged pressure drop, mean particle velocity, and rms particle velocity. The choice of spring constant impacts fluidization dynamics, and the Tang et al. (2015) drag correlation performs well at higher velocities. The coarse-grained model predicts a lower minimum fluidization velocity, and the error in average pressure drop reduces with increasing statistical weight at low gas velocities. The mean particle velocity profiles show no significant differences between the coarse-grained and conventional CFD-DEM models, while the rms profiles decrease with increasing statistical weight. Additionally, there is a gain in wall clock time for completing a case using the coarse-grained model.
Article
Mechanics
Yann Dufresne, Micael Boulet, Stephane Moreau
Summary: CGDEM is a valuable option for large-scale industrial applications to reduce the cost of classic DEM computations. This study compares three solutions from the literature to overcome the reduction in collision frequency in CGDEM simulations. The results confirm the existence of an inverse law for the drop in collision frequency and suggest that CGDEM simulations may be more stable than regular DEM simulations.
Article
Engineering, Chemical
Tarun De, Jayanta Chakraborty, Jitendra Kumar, Anurag Tripathi, Maitraye Sen, William Ketterhagen
Summary: Large scale industrial simulations of bulk solids often require the use of the Discrete Element Method, which can be computationally demanding due to the large number of particles involved. Coarse-graining techniques have been used to reduce the computational burden, but current methods typically employ a uniform coarse-grain ratio throughout the system. This limits the level of coarse-graining that can be achieved without sacrificing accuracy. To address this limitation, a multilevel coarse-graining technique that allows for spatial variation in the coarse-grain ratio has been proposed. In this study, a particle location based method for multi-level coarse-graining is introduced, which can be implemented using the open-source software LIGGGHTS Public. The efficiency of this method is demonstrated through successful simulations of discharge from a conical hopper, showing a significant reduction in computational time compared to uniform coarse-graining while maintaining accuracy.
Article
Engineering, Chemical
Daniel Schiochet Nasato, Rodrigo Queiroz Albuquerque, Heiko Briesen
Summary: The quality of discrete element simulations relies on the correct choice of material contact parameters. This study demonstrates the use of artificial neural networks to obtain material contact parameters that replicate the behavior of particles with complex shapes. By utilizing dynamic angle of repose and void fraction as input parameters, and static and rolling friction as output parameters, the neural network successfully predicts the static angle of repose for octahedral and cubic shape particles.
Article
Pharmacology & Pharmacy
Satyajeet Bhonsale, Lewis Scott, Mojtaba Ghadiri, Jan Van Impe
Summary: The study reveals that particles in spiral jet mills significantly decelerate the fluid. Particle velocity is influenced by both particle loading and operating pressure, with slower movement at low pressures and high loadings. Particle-particle collisions outnumber particle-wall collisions.
Article
Engineering, Chemical
L. Scott, A. Borissova, A. Burns, M. Ghadiri
Summary: Particle size reduction in spiral jet mills is caused by high-velocity gas jets leading to collisions between particles and walls, resulting in particle breakage. Despite extensive research, the underlying mechanics of size reduction are still poorly understood. Analyzing particle and fluid motions using Discrete Element Method and Computational Fluid Dynamics reveals the formation of a fast shearing dense particle bed on the wall.
Article
Engineering, Chemical
Jia Yu, Liqiang Lu, Xi Gao, Yupeng Xu, Mehrdad Shahnam, William A. Rogers
Summary: This article proposes a reduced-order modeling approach to accelerate high fidelity three-dimensional simulations of commercial-scale coal gasifiers by using quasi one-dimensional CFD-DEM simulation results as initial conditions. Experimental validation of the simulation results shows that final syngas composition and flowrates are strongly affected by operating conditions.
Article
Mechanics
Zhenjiang Zhao, Ling Zhou, Ling Bai, Mahmoud A. El-Emam, Ramesh Agarwal
Summary: The coarse-grained (CG) CFD-DEM method reduces the number of particles by replacing multiple smaller particles with larger ones called parcels, and fully considers particle collisions. The investigation shows that the CG CFD-DEM method significantly decreases computation time in simulating dense gas-solid flows, and the results agree well with experimental data and fine-grained CFD-DEM method.
Article
Engineering, Chemical
Changhua Xie, Yongzhi Zhao
Summary: A particle wear model that accurately predicts the wear rate of grinding media has been proposed in this study and shows good accuracy at high mill speed. Experimental results indicate the influence of friction coefficient, fluid, and mill speed on wear rate.
Article
Engineering, Environmental
Zechuang Li, Zhibin Liu, Pu Zhou, Junjie Zheng
Summary: In this study, medium-scale shear tests were conducted on slip zone soil specimens with different coarse grain contents. The results show that the coarse grain content has a considerable influence on the shear deformation of slip zone soils and on the meso- and macro-level mechanical properties of the slip zone soil. This study provided important guidance and reference to reveal the influence of coarse grain content on the macro-mesoscopic mechanical properties of slip zone soil and the evolution trends of landslide deformation with high coarse grain content.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2023)
Article
Agriculture, Multidisciplinary
Zheng Ma, Souleymane N. Traore, Yongle Zhu, Yaoming Li, Lizhang Xu, En Lu, Yufei Li
Summary: This study uses a discrete element method to simulate the movement of rice during the discharge process of a grain tank in a combine harvester. The flow type, wall pressure, particle velocity, discharge time, and mass flow rate are analyzed and compared to experimental results. The simulation shows similarities to the experiment and provides insights for the design and improvement of grain tanks.
COMPUTERS AND ELECTRONICS IN AGRICULTURE
(2022)
Article
Engineering, Chemical
Lianyong Zhou, Yongzhi Zhao
Summary: This paper proposes a new coarse-grain (CG) model to address the high computational cost issue of the DEM method in handling large-scale systems with fine particles, and applies it to investigate a fluidized bed with an immersed tube, obtaining good simulation validation results.
CHEMICAL ENGINEERING SCIENCE
(2021)
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.