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
Mathematics, Interdisciplinary Applications
Zhaocheng Li, Baowen Liu, Dongdong Han, Yichang Xie, Yongli Zhao
Summary: The relationship between microcracks of a single particle and crushing strength was investigated through virtual experiments. CT-scanning technology was used to obtain the three-dimensional profile of a single particle. The particle bonding model was employed to construct virtual particles based on the three-dimensional contour, and virtual crushing experiments were conducted using the discrete element method. The influence of microcracks on the Weibull distribution of crushing strength was considered in terms of quantity, location, and direction.
COMPUTATIONAL PARTICLE MECHANICS
(2023)
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
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
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
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
Mofan Qiu, Lin Jiang, Rongzhen Liu, Yaping Tang, Malin Liu
Summary: This work proposes a local grid and time step refinement method for simulating multiphase and polydisperse particle fluidization reaction system. The method generates refined DEM grids in the computational domain around the fine particles and obtains detailed fluid phase information with an interpolation algorithm. It divides particles into different groups based on physical properties and gives each group its own independent time step. The method improves the accuracy and efficiency of the traditional CFD-DEM method in simulating a polydisperse particle system with wide particle size distribution.
Article
Engineering, Chemical
Zhuo Yang, Bona Lu, Wei Wang
Summary: In this study, a generic EMMS drag model was developed using Artificial Neural Network (ANN) to simulate dense fluidized beds under a wide range of operating conditions and material properties. The model's algorithm was optimized to efficiently provide a large dataset and the performance of ANN was tested by training with different numbers of data and hidden layer structures. The EMMS-ANN model showed reasonable prediction and good applicability to a wide range of dense fluidization.
CHEMICAL ENGINEERING SCIENCE
(2021)
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, 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
Lianyong Zhou, Huaqing Ma, Zihan Liu, Yongzhi Zhao
Summary: This study proposes a coarse-grain CFD-DEM model for nonspherical particles, with the morphology of particles characterized by the super-ellipsoid model. The effectiveness and accuracy of the model are evaluated by comparing hydrodynamic behaviors with traditional CFD-DEM. The results show that the proposed model accurately models gas-solid flow with nonspherical particles and reduces computational costs.
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
Thermodynamics
Lucilla Coelho de Almeida, Joao Americo Aguirre Oliveira Junior, Jian Su
Summary: This paper presents a new approach for computing particle temperatures in simulations coupling computational fluid dynamics (CFD) and discrete element method (DEM) to predict flow and heat transfer in fluidized beds of thermally thick spherical particles. An improved lumped formulation is used to overcome the limitations of classical lumped models, which is validated through comparisons with analytical solutions and experimental data. The results show the importance of accurately accounting for surface temperature in convective heat transfer predictions and surface processes.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2023)
Article
Mechanics
D. M. Balice, C. W. C. Molenaar, M. Fochesato, C. M. Venier, I. Roghair, N. G. Deen, M. van Sint Annaland
Summary: This study investigates the deposition of droplets of size [5-22] μm on the surface of particles in a gas-solid fluidized bed using a one-way coupled CFD-DEM modeling. The deposition factor is calculated as the ratio of deposited droplets to injected droplets, and it is correlated with the droplet Stokes number and particle Reynolds number. The goal is to use the developed correlation in a larger scale CFD-DEM model for a polymerization fluidized bed reactor to improve the heat management.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2022)
Article
Thermodynamics
Xiaodong Wang, Hongxi Zhang, Wen Zhou, Jie Ouyang
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2017)
Article
Thermodynamics
Chuntao Jiang, Jie Ouyang, Lihua Wang, Qingsheng Liu, Xiaodong Wang
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2017)
Article
Engineering, Multidisciplinary
Ying Liu, Xiaodong Wang
MATHEMATICAL PROBLEMS IN ENGINEERING
(2017)
Article
Nanoscience & Nanotechnology
Chuntao Jiang, Jie Ouyang, Wuming Li, Xiaodong Wang, Lihua Wang
MICROFLUIDICS AND NANOFLUIDICS
(2017)
Article
Polymer Science
Xiaodong Wang, Jie Ouyang, Ying Liu
Article
Thermodynamics
Puyang Gao, Xiaodong Wang, Jie Ouyang
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2019)
Article
Mathematics, Applied
Zhen Guan, Xiaodong Wang, Jie Ouyang
Summary: In this paper, an improved finite difference/finite element method is proposed for the fractional Rayleigh-Stokes problem with a nonlinear source term. The method utilizes a linearized difference scheme along with the second-order backward differentiation formula and weighted Grunwald-Letnikov difference formula for time discretization, achieving higher stability and convergence accuracy than previous works. Numerical examples are also provided to validate the theoretical results.
JOURNAL OF APPLIED MATHEMATICS AND COMPUTING
(2021)
Article
Computer Science, Interdisciplinary Applications
Yong Chai, Jie Ouyang, Xiaodong Wang
Summary: This article introduces an efficient stabilized finite element scheme for solving viscoelastic flow problems at high Weissenberg numbers. The scheme uncouples velocity and pressure variables in momentum balance equations using an incremental fractional step method and introduces techniques to bypass LBB constraints, showing accuracy and convergence in numerical tests. Additionally, the scheme enables the use of equal low-order interpolations for all variables and requires no iterative process, making it computationally efficient and easy to implement.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS
(2021)
Article
Computer Science, Interdisciplinary Applications
Mengxia Ma, Jie Ouyang, Xiaodong Wang, Chenhui Zhang
Summary: In this work, a high-order dual splitting scheme is used for an equal-order discontinuous Galerkin (DG) solver for incompressible Navier-Stokes equations. The stability of the method is influenced by the spatial resolution and the effect of the pressure gradient term in the projection step. Increasing spatial resolution is crucial for maintaining stability, especially at small time steps. Integration by parts of terms and an appropriate penalty parameter in the pressure Poisson equation can improve the stability of the scheme for high-Reynolds-number flow problems.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS
(2021)
Article
Engineering, Multidisciplinary
Xiaodong Wang, Haidan Wang, Ying Liu
Summary: A new numerical method, combining semi-Lagrangian method and element free Galerkin method, is developed to solve convection-diffusion partial differential equations with dominated convection terms. The method shows better performance and several advantages compared to existing methods, and can achieve good results in challenging convection-dominated problems.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Computer Science, Interdisciplinary Applications
Mengxia Ma, Jie Ouyang, Xiaodong Wang
Summary: This paper presents a new stabilized high-order discontinuous Galerkin method for simulating highly elastic fluid flows at high Weissenberg numbers. The method is able to accurately and stably simulate different viscoelastic flow problems, and it has high-order accuracy and robustness. Compared with existing schemes, this method is more flexible and easier to implement.
ENGINEERING WITH COMPUTERS
(2023)
Article
Mechanics
Mengxia Ma, Jie Ouyang, Xiaodong Wang
Summary: The numerical investigation of the Oldroyd-B fluid flow around an oscillating circular cylinder provides a better understanding of the lock-in phenomenon and wake topology. The study utilizes the high-order dual splitting scheme with the square-root-conformation representation approach and implements the arbitrary Lagrangian-Eulerian formulation to handle complex boundary movements. The force coefficients and wake structures of vortex and stress are discussed in detail, revealing different wake modes for various frequencies at Re=60 and Wi=0.1.
Article
Chemistry, Multidisciplinary
Xin Li, Jie Ouyang, Xiaodong Wang, Jingxi Dou
Summary: Most granular flow exhibits polydispersity, but we often resort to using a monodisperse drag force model in simulations due to the difficulty in establishing a polydisperse drag force model. This often leads to significant deviations between simulation and experimental results. Recently, the artificial neural network (ANN) model has provided better accuracy in estimating such outcomes. In this work, we adopt the ANN model to simulate the drag force in polydisperse granular flows. The results show that the ANN drag model effectively scales the polydispersity of the system and produces results that agree well with experimental data.
APPLIED SCIENCES-BASEL
(2023)
Article
Chemistry, Physical
Yi Wang, Jie Ouyang, Xiaodong Wang
Summary: This study utilizes an active learning strategy based on Gaussian process regression to significantly reduce the number of simulations needed for lubrication corrections in colloidal suspensions, successfully applying the corrections to multiscale simulations. The machine learning approach proves effective, with the corrected DPD-DEM model accurately capturing hydrodynamic interactions and reproducing the dynamic and rheological properties of colloidal suspensions. The technique is not limited to this specific simulation but can easily be applied to other particle-based simulations of particulate suspensions.