Article
Engineering, Chemical
Woo Chang Sung, Hyun Seung Jung, Jong Wook Bae, Jun Young Kim, Dong Hyun Lee
Summary: This study conducted segregation tests using a cold-bed system in a pulsed fluidized bed, and investigated the effects of superficial gas velocity, pulse frequency, and amplitude on segregation efficiency. The results showed that these parameters had significant influence on segregation, and the effect of pulsation on segregation was observed under certain conditions.
Article
Engineering, Chemical
Jikai Huang, Huanan Li, Chongliang Huang, Yake Jiang, Zhigang Liu
Summary: A novel method is developed to measure the micro mixing ratio of binary solids in dense fluidizations. The mixing process within a bubbling fluidized bed is resolved and dispersion co-efficient and mixing index methods are applied. The results indicate that diffusion plays a crucial role in mixing at the bottom and top of the fluidized bed, while convection is the primary mechanism of mixing at the center.
Article
Engineering, Chemical
Chao Li, He Kang, Ai Wang, Boai Zhang, Yijun Cao
Summary: Fluidized-bed flotation is a novel process that combines flotation and density separation. It has been increasingly used in grinding circuits to reject coarse gangues for sulfide ores. However, there is a lack of research on the simultaneous effects of mineral liberation, particle size, and bubble size on fluidized-bed flotation efficiency. This study investigated the effects of different bubble and particle sizes on the separation of molybdenite ores. The results showed that the matching of bubble and particle sizes is crucial for successful separation, and this work could contribute to the optimization of fluidized-bed flotation for sulfide ores.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Engineering, Chemical
Zeneng Sun, Bowen Han, Tianzi Bai, Shahzad Barghi, Jesse Zhu
Summary: The study found that as the sand volume fraction increases, the minimum fluidization velocity decreases in two different binary particle systems. Bubble size and rise velocity increase along the bed height, with a linear correlation between the two.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Engineering, Chemical
N. Torres Brauer, B. Serrano Rosales, H. de Lasa
Summary: The proposed model involves Computational Fluid Dynamics Multiphase Particle-In-Cell (CFD-MPPIC) simulations for biomass gasification in dense phase fluidized beds, allowing evaluation of bubble dynamics and correlations. This model could be valuable for designing scaled-up biomass units operated under dense phase fluidization conditions.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Engineering, Chemical
Suyang Pan, Jiliang Ma, Daoyin Liu, Xiaoping Chen, Cai Liang
Summary: This paper studies the liquid transport behaviors in a top-sprayed fluidized bed using bed conductance analysis, pressure fluctuation analysis, and bubble image processing. The results show that liquid initially gets trapped in agglomerates before converting to free liquid and spreading from the upper-middle bed to the bottom bed. The disintegrating pattern of agglomerates affects the increase and saturation of free liquid in the bed. The liquid transport process is accelerated by increasing superficial air velocity and particle diameter, while it slows down with increased liquid viscosity and surface tension.
Article
Engineering, Environmental
Shiliang Yang, Zhanghao Wan, Shuai Wang, Hua Wang
Summary: Gas-solid reactive flows during biomass fast pyrolysis in a three-dimensional bubbling fluidized bed reactor were numerically modeled and validated. The study explored the physical and thermal dynamics of bubbles under high-temperature biomass pyrolysis conditions, with a focus on the spatial distributions and characteristics of gas-solid flows.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2021)
Article
Energy & Fuels
Rajan Jaiswal, Britt M. E. Moldestad, Marianne S. Eikeland, Henrik K. Nielsen, Rajan Kumar Thapa
Summary: This study investigates the bubble properties of a bubbling fluidized bed reactor using computational particle fluid dynamic simulations and electrical capacitance tomography measurements. The results show that the bubble properties, such as average diameter, rise velocity, and frequency, are significantly influenced by the superficial gas velocity. The CPFD model and method employed in this work can be useful for studying the influence of bubble properties on conversion efficiency of a gasification reactor operating at high temperatures.
Article
Engineering, Chemical
C. J. McIntyre, R. W. Hughes, A. Macchi, P. Mehrani
Summary: The hydrodynamics of ilmenite particles in a high pressure cylindrical fluidized bed were modeled using the multiphase particle-in-cell approach. The model was validated against experimental data and showed good agreement for the minimum fluidization velocity at a close pack factor of 0.58. The model accurately represented the trends in bed expansion with fluidization ratio and pressure, but consistently underestimated the values. Bubble size distribution was also predicted by the model, with some deviation from experimental results. The importance of this study lies in its contribution to understanding the hydrodynamics of ilmenite particles in fluidized bed reactors.
Article
Engineering, Chemical
Anna Kohler, Diana Carolina Guio-Perez, Anna Prati, Michele Larcher, David Pallares
Summary: This study focused on the motion trajectory and drag behavior of solid particles in gas-fluidized beds, revealing the complex rheological characteristics of bed emulsions and their effects on particles. It also discovered the viscoplastic behavior of bed emulsions and their clear dependence on the size and density of tracers.
Article
Engineering, Environmental
M. J. A. de Munck, M. Dullemond, E. A. J. F. Peters, J. A. M. Kuipers
Summary: Fluidized bed drying is a dynamic process that involves changes in bed hydrodynamics, mass and heat transfer, and segregation and mixing tendencies over time. This study used pseudo-2D fluidized bed experiments with binary and ternary solid mixtures to investigate these dynamics. The results, obtained through particle image velocimetry infrared thermography technique and machine learning algorithm, revealed significant hydrodynamic changes and various segregation and mixing tendencies due to water evaporation from the porous gamma-Al2O3 material. The competition between size and density-based segregation and mixing dynamics resulted in changing bed configurations and influenced the local drying behavior. The study also highlighted the potential benefits of drying wider size distributions for more complex and efficient process operation.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Zeneng Sun, Jesse Zhu
Summary: The hydrodynamics and reactor performance in a recently proposed gas-solids circulating turbulent fluidized bed (CTFB) were compared with conventional fluidized beds and a high-density circulating fluidized bed (HDCFB) riser. The study found that the CTFB exhibits characteristics similar to both a conventional fluidized bed and an HDCFB, depending on the G(s)/U-g ratio. The CTFB also showed a larger number of smaller bubbles compared to other bed types, resulting in superior reactor performance in terms of effective reaction rate, mass transfer rates, and solids backmixing.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Engineering, Chemical
Fan Geng, Xinyue Feng, Haixu Teng, Longji Yuan, Jie Cai, Tie Li, Jajun An, Shilong Yuan, Siqi Wu
Summary: In this study, the dynamic movement of cylindrical biomass particles in a fast fluidized bed was investigated to understand the flow dynamics of biomass particles. The study analyzed the particle concentration, orientation distribution, and residence time distribution. The results provide valuable insights for studying cylindrical and other non-spherical biomass particles.
ADVANCED POWDER TECHNOLOGY
(2022)
Article
Thermodynamics
Fengxia Zhang, Shiliang Yang, Bin Yang, Hua Wang
Summary: By simulating the gasification process of biomass feedstock in a pilot-scale dual fluidized bed gasifier, this study investigates the dynamical behavior and properties of bubbles, comparing simulated data with experimental results. The results reveal unique characteristics of bubbles in the gasifier due to its special geometry and the gasification of biomass.
Article
Energy & Fuels
Dali Kong, Shuai Wang, Kun Luo, Jiahui Yu, Jianren Fan
Summary: The methanation process in a bubbling fluidized bed (BFB) reactor is studied using computational fluid dynamics-discrete element method (CFD-DEM) with thermochemical sub-models. A novel algorithm is developed for bubble identification and statistics. The effects of key operating parameters on bubble behaviors are quantified and the underlying mechanism of mesoscale bubble behaviors is elucidated. The results show that the bubble dynamics can be well captured by the algorithm and the interphase heat and mass transfer can be enhanced by adjusting the operating parameters.
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
Engineering, Chemical
Dali Kong, Shuai Wang, Jiahui Yu, Debo Li, Kun Luo, Jianren Fan
Summary: The improvement of external-loop and in-furnace non-uniformity of a 300 MWth industrial-scale circulating fluidized bed (CFB) with multiple cyclones by a dual-side coal feeding mode was numerically quantified. The dual-side coal feeding mode showed superiority over the traditional single-side coal feeding mode in terms of final mixing degree, residence time of coal particles, solid flux characteristics, temperature range, combustion efficiency, and emissions reduction.
ADVANCED POWDER TECHNOLOGY
(2023)
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
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)