Article
Engineering, Chemical
Ying Jia, Yong Zhang, Ji Xu, Chenlong Duan, Yuemin Zhao, Wei Ge
Summary: This study utilized a coarse-grained CFD-DEM method to analyze the bed expansion rates and solid concentration in ADMFB, and evaluated the microscale and mesoscale behaviors of ADMFB through power spectrum density and wavelet decomposition. The research found that pressure fluctuation mainly resulted from bubbles motion of mesoscale rather than from particles motion of microscale and global bed expansion of macroscale.
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
Mechanics
Junsheng Zeng, Baoqing Meng, Jun Chen, Baolin Tian
Summary: In this study, a coarse-grained criterion for simulating compressible particulate two-phase flows was proposed based on similarity invariants and regime transition behaviors. Benchmark cases were used to investigate the validity of the proposed criterion. It was shown that scaling the stiffness coefficient according to the parcel size and reducing the restitution coefficient can maintain the invariance of the spreading velocity of the particle stress wave and recover the internal energy dissipation inside the parcels. An adaptive interpolation operator was introduced to adjust the influencing range of the Lagrangian parcels dynamically for more accurate description of regime transition behaviors.
Article
Thermodynamics
Shuai Wang, Yansong Shen
Summary: A coarse-grained CFD-DEM model is developed to simulate dense gas-solid reacting flow, which significantly reduces computational costs. This research is important for simulating dense gas-solid reacting flow in chemical reactors.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Review
Chemistry, Medicinal
Sameera Sansare, Hossain Aziz, Koyel Sen, Shivangi Patel, Bodhisattwa Chaudhuri
Summary: The fluidized bed is an essential equipment in process development and has been extensively studied for its wide application in various areas. This review paper focuses on the computational modeling of a fluidized bed in pharmaceutical applications, discussing the background of modeling and summarizing relevant research papers on pharmaceutical unit operations.
JOURNAL OF PHARMACEUTICAL SCIENCES
(2022)
Article
Engineering, Chemical
Yan Zhang, Wanlong Ren, Peng Li, Xuhui Zhang, Xiaobing Lu
Summary: This paper presents a numerical simulation study on dense particulate flows with coarse particles in an inclined pipe using computational fluid dynamics-discrete element method. Different flow regimes and their transitions are identified and described. The influence of Stokes number St, Froude number Fr, inclination angle fl, etc., on critical flow regimes is analyzed, and a new diagram for recognizing regime transition is given. Two dimensionless numbers, collision stress and fluid-particle interaction stress, are defined to explain the regime transition mechanism.
Article
Mechanics
Wan-Long Ren, Yan Zhang, Xu-Hui Zhang, Xiao-Bing Lu
Summary: This paper uses an optimized Euler-Lagrange method to study the characteristics and formation mechanisms of layer inversion in binary liquid-solid fluidized beds with coarse particles. Through qualitative and quantitative analysis, the underlying mechanisms of layer inversion with coarse particles are revealed, providing important insights for understanding the dynamic behavior of fluidized beds.
Article
Engineering, Chemical
Victor O. Ferreira, Toni El Geitani, Daniel Silva Junior, Bruno Blais, Gabriela C. Lopes
Summary: In this study, the accuracy of the unresolved CFD-DEM method was evaluated by comparing simulated and experimental results of a pilot-scale cylindrical liquid-solid fluidized bed. Different densities of particles were used to test various flow regimes. The comparison between experimental and simulated particles' dynamics revealed the importance of the Saffman lift force in predicting particle dispersion and preventing unphysical plumes. The results showed that the unresolved CFD-DEM method is valid for simulating liquid-solid fluidized beds.
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
Engineering, Chemical
Lixiang Zhong, Dandan Xu, Yiyang Jiang, Yu Guo
Summary: Gas-fluidized beds of wet flexible fibers are investigated using a coupled approach of Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD). The effects of cohesion and fiber flexibility on fluidization characteristics are examined. It is found that cohesion and fiber flexibility affect the pressure drop, minimum fluidization velocity, and solids mixing rate.
Article
Engineering, Environmental
Laurien A. Vandewalle, Victor Francia, Kevin M. Van Geem, Guy B. Marin, Marc-Olivier Coppens
Summary: Adequate use of gas pulsation can create an ordered and dynamically structured bubble flow in a bed of Geldart B particles, leading to a more homogeneous, controllable, and scalable bed. The structured bed exhibits significant differences in solid circulation and mixing behavior compared to a traditional fluidized bed, with mixing driven by advection rather than diffusion. Compartmentalization in the structured bed decouples the time scales of micro- and macromixing, providing tight control of mixing and narrower stress distribution in the solid phase compared to traditional devices.
CHEMICAL ENGINEERING JOURNAL
(2022)
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, Environmental
Xi Gao, Jia Yu, Liqiang Lu, Cheng Li, William A. Rogers
Summary: A new SuperDEM-CFD coupled model was developed for simulating the hydrodynamics of non-spherical particles in fluidized beds. The model includes algorithms for modeling and distributing non-spherical particles, as well as drag models that consider particle orientation and cell voidage effects. Experimental validation was conducted, and large-scale simulations demonstrated the solver's capabilities for industrial-relevant flows.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Chemical
Wenjian Cai, Xu Kong, Qing Ye, Lizhen Wang, Depeng Ren, Huilin Lu
Summary: In this study, the molten salt fluid-particles transition state is modelled using KTGF-based TFM and CFD-DEM in fluidized beds. The results show the existence of wavy-like flow near the bottom and aggregates/fluid voids flow at the upper part along bed height. The simulation results agree with experimental data and predictions in literature, and the effect of molten salt temperature on fluid stresses is analyzed.
Article
Engineering, Chemical
V. Brandt, J. Grabowski, N. Jurtz, M. Kraume, H. Kruggel-Emden
Summary: DEM-CFD is computationally demanding and limited to lab-scale systems, so coarse-graining approaches are used to summarize particles. This study compares force scaling models in different beds to eliminate influences and identifies optimal scaling rules based on physical parameters. It also analyzes fluidized beds to determine the suitability of scaling models for systems governed by both contact and hydrodynamic forces, providing recommendations for future simulations of industrial-scale particle systems.
Article
Thermodynamics
Hualin Xiao, Kun Luo, Tai Jin, Jiangkuan Xing, Min Chai, Jianren Fan
Summary: This study investigates the influence of combustion on scaled kinetic energy transport in a swirling partially premixed flame under gas turbine conditions.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Jiangkuan Xing, Kun Luo, Ryoichi Kurose, Jianren Fan
Summary: Coal/biomass co-firing is a sustainable alternative to reduce emissions from fossil fuel utilization. An extended FPV model was developed to study the combustion characteristics of the co-firing flame, and it was found that the model could well reproduce the flame behaviors in different combustion stages.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Engineering, Chemical
Linhang Zhu, Zhongyang Zhao, Chang Liu, Wenjun Li, You Zhang, Yongxin Zhang, Chenghang Zheng, Kun Luo, Xiang Gao
Summary: This study investigates the hydrodynamics and cohesive-like characteristics of solid particles in a pseudo-2D droplet gas-solid fluidized bed using two-way coupled CFD-DEM numerical simulations. The results show that the presence of droplets leads to poorer fluidization characteristics, with increased surface tension resulting in inadequate mixing and higher liquid viscosity causing slower particle motion. The choice of contact angle is crucial for optimizing the fluidization quality, and injecting more droplets results in worse mixing, although the number of injected droplets has no significant effect on the flow pattern and particle motion.
ADVANCED POWDER TECHNOLOGY
(2023)
Article
Engineering, Chemical
Dali Kong, Shuai Wang, Kun Luo, Jianren Fan
Summary: Biomass gasification combined with CO2 absorption-enhanced reforming was numerically studied in a BFB reactor using the MP-PIC method. The effects of operating parameters on particle behaviors, bubble dynamics, and reactor performance were analyzed. A lower operating pressure improved gas-solid contact efficiency and performance, while higher temperature and S/B ratio promoted H2 generation but deteriorated gasification performance. Mixed bed material significantly improved gasification performance by enhancing H2 generation and CO2 removal.
Article
Engineering, Environmental
Dali Kong, Shuai Wang, Kun Luo, Qilong Xu, Jianren Fan
Summary: Biomass gasification combined with CO2 absorption enhanced reforming (AER) is a clean and efficient technology for H2 enrichment and CO2 removal. This study numerically investigates AER gasification in an industrial-scale DFB reactor using the multi-phase particle-in-cell (MP-PIC) framework. The effects of key operating parameters on AER gasification performance are studied, and it is found that AER gasification improves H2 concentration by 15.3% and reduces CO2 concentration by 55.8%. The study also provides recommendations for improving AER gasification performance in the DFB reactor.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Mechanics
Mengzhen Cheng, Haiou Wang, Kun Luo, Jianren Fan
Summary: In this study, the flow-flame structures and turbulence-flame interactions of a laboratory-scale lean premixed reacting jet in cross-flow were explored through direct numerical simulation. Both non-reacting and reacting cases were simulated, and it was found that the reacting jet penetrates deeper in the cross-flow with a weaker shear layer compared with the non-reacting one. The flame structure in the reacting case showed significant variations in reaction intensity in different flame zones.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Dong Li, Yuqi Liu, Kun Luo, Jianren Fan
Summary: This study proposes an integral method to accurately determine the mean skin friction in a zero-pressure-gradient turbulent boundary layer. By assuming a linear relation for the weighted total shear stress in the near-wall region, the method requires only one streamwise location to evaluate the skin friction using the wall-normal profiles of the mean streamwise velocity and Reynolds shear stress. The method is validated using direct numerical simulation and experimental data, and is found to provide accurate results within +/- 4% compared to published values.
Article
Biology
Jingyang Luan, Yonghui Qiao, Le Mao, Jianren Fan, Ting Zhu, Kun Luo
Summary: This study investigates the role of the aorta distal to the stent in distal stent graft-induced new entry tear (dSINE) in thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). The findings suggest that the inverted pyramid structure and increased von Mises stress in the true lumen distal to the stent may contribute to the occurrence of dSINE. The enlargement of the true lumen distal to the stent appears to be a prelude to dSINE.
COMPUTERS IN BIOLOGY AND MEDICINE
(2023)
Article
Energy & Fuels
Qingqing Xue, Jiangkuan Xing, Xinzhou Tang, Kun Luo, Haiou Wang, Jianren Fan
Summary: This study aims to identify accurate and general heat release rate markers for ammonia-methane cofiring flames. Through calculations and database construction, the study successfully determined the chemical formulas that can accurately approximate the heat release rate.
Article
Energy & Fuels
Runhui Zhang, Xiaoke Ku, Jianzhong Lin, Kun Luo
Summary: This work presents the development of an efficient three-dimensional pyrolysis model for large biomass particles with arbitrary shapes. The model utilizes the composed-sphere concept and the Voronoi tessellation to account for the shrinkage of the parent particle and resolve heat transfer and porosity inside the particle. The model is validated using six different particles and pyrolysis processes, showing good agreement with experimental data, and sensitivity analyses of three different parameters are conducted. The developed model not only characterizes different-shaped particles effectively but also provides more intra-particle details during the pyrolysis of large biomass particles.
Article
Engineering, Chemical
Jiahui Yu, Shuai Wang, Kun Luo, Jianren Fan
Summary: This study develops a coupled framework by combining computational fluid dynamics (CFD) with discrete element method (DEM), and further introduces the volume-of-fluid (VOF) method for studying multiphase flow systems. A smoothing method is implemented to ensure accurate calculation of interphase and interfacial interactions. An advanced VOF-based surface-capturing method, Iso-Advector, is introduced to effectively describe interface evolution and interfacial interactions. The integrated model is verified through three benchmark cases, with good agreement between numerical results and experimental measurements, demonstrating the reliability of the model in simulating multiphase flow systems.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Engineering, Multidisciplinary
Yonghui Qiao, Jianren Fan, Kun Luo
Summary: The mechanism of energy loss in healthy aortic blood flow is explored using clinical measurements and computational modeling techniques. The primary causes of energy loss are viscous friction and aortic wall deformation. These findings can inform the development of new hemodynamic markers and clinical assessment tools for vascular wall health.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Mechanics
Yanlu Chen, Buyun Xu, Yuzhou Cheng, Kun Luo, Jianren Fan, Meixiang Xiang
Summary: This study compares the hemodynamic differences between thrombus-positive and thrombus-negative patients in the early stages of the disease. The results show that the velocity and shear strain rate of the endocardial and epicardial geometries exhibit relative consistency. Differences in wall shear stress mainly occur at the LAA entrance, while oscillatory shear index differences are affected by geometry. Endothelial cell activation potential and relative residence time differences are concentrated at the tip of the LAA, but reliable parameters can be obtained after excluding outliers.
Article
Thermodynamics
Yicun Wang, Changxiao Shao, Kun Luo, Ruipeng Cai, Tai Jin, Jianren Fan
Summary: In this paper, the authors focus on the development and validation of the TSFPV model for simulating turbulent spray flames. The improved SEST model is used to generate the spray flamelet library, and the TSFPV model is verified on different flame configurations. The results show good agreement with experimental measurements, indicating the potential of the TSFPV model for spray combustion modeling.
Article
Thermodynamics
Xin Liu, Qiang Wang, Kun Luo, Yanfei Mu, Haiou Wang, Jianren Fan
Summary: The study finds that using a liquid-cooled plate and metallic phase change material can improve battery thermal management. Gallium filling significantly reduces cell temperature and improves temperature dispersion uniformity, but a higher coolant mass flow rate has less impact on cell temperature and increases system energy consumption.
APPLIED THERMAL ENGINEERING
(2024)
Article
Engineering, Chemical
Yongxiang Wu, Nguyen Thi Hong Nhung, Deqian Zeng, Nengneng Luo, Akira Otsuki, Gjergj Dodbiba, Toyohisa Fujita
Summary: This study proposed a novel method for synthesizing flower-like vaterite calcium carbonate using nanobubble-containing ethanol and water mixed solution as the solvent and discussed the formation mechanism of vaterite with different shapes. The synthesized vaterite has significant practical interest in the integrated treatment of wastewater contaminated by heavy metals with effective Cd(II) removal, providing a promising field for studying heavy metal and pollutant adsorption in the liquid phase.
ADVANCED POWDER TECHNOLOGY
(2024)
Article
Engineering, Chemical
Jian Gong, Lipo Cheng, Ming Liu, Jie Jiang, Xiaoduo Ou
Summary: This study investigates the effects of particle shape on the collapse of granular columns using the discrete element method. The results show that particle shape has a significant impact on deposition morphology, energy evolution, and mechanical coordination number. Sphericity and angularity are identified as the most important macroscale factors, while roughness has a weaker microscale influence.
ADVANCED POWDER TECHNOLOGY
(2024)
