Article
Energy & Fuels
Jiaying Wang, Zeneng Sun, Yuanyuan Shao, Jesse Zhu
Summary: Circulating fluidized bed combustors are commonly used gas-solid convertors globally. Different operating regimes have been suggested by researchers, but there is still no universally accepted conclusion. Analysis of reported data supports the operation of the bottom part in the bubbling regime and the upper part as an entrained bed in commercial boilers.
Article
Engineering, Chemical
Son Ich Ngo, Young-Il Lim, Doyeon Lee, Myung Won Seo
Summary: This study investigated the hydrodynamic and heat transfer characteristics of a BFB reactor with immersed heat exchange tubes for CO2 methanation using a 2D gas-solid Eulerian computational fluid dynamics model. The results showed that the heat of reaction was effectively removed in the reactor and isothermal conditions were maintained. The CO2 conversion rate reached 92% under specific operating conditions.
Article
Engineering, Chemical
Christoph Eder, Gerhard Hofer, Tobias Proell
Summary: The study investigated wall-to-bed heat transfer in a cross-flow bubbling fluidized bed with continuous solids exchange. Results showed that increasing gas velocity leads to more heat being transported from the probe to the particles, while arranging the tubes more densely in the bed results in less heat transfer.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Engineering, Chemical
Liuyun Xu, Feng Wu, Junwu Wang
Summary: This study investigated the effects of the type of pulsating inlet waveform, pulsation frequency, and pulsation amplitude on the stability of fluidized beds and the erosion of immersed tubes through numerical simulation. It was found that sinusoidal flow induced the lowest immersed-tube erosion rate and pressure-drop fluctuation in the fluidized bed. Furthermore, the proposed dimensionless parameter vp reflects the effect of particle flow characteristics, particle fluidization degree, and pulsation frequency on immersed-tube erosion during pulsating flow.CO 2023 Elsevier Ltd. All rights reserved.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Engineering, Chemical
Liuyun Xu, Feng Wu, Haibo Ren, Wenjing Zhou, Yuan Yan
Summary: The erosion of immersed tube was studied using experimental and simulation methods, revealing severe erosion mainly at the lower sides. The DDPM method was able to simulate the erosion law of the immersed tube. A new dimensionless parameter, It, was defined to characterize the erosion state, showing that particle flow characteristics and fluidization degree have direct and inverse relationships with erosion rate. Additionally, simulation results showed that the erosion rate of EA type elliptical immersed tube was 53.68% lower than circular immersed tube.
Article
Engineering, Chemical
Lei Wang, Hong-Wei Li, Chang-He Du, Wen-Peng Hong
Summary: In this study, the CFD-DEM model was used to investigate the bubbling and flow characteristics in fluidized beds. It was found that adding immersed tubes can reduce bubble size for better particle mixing, while higher superficial gas velocities lead to larger bubbles. Additionally, the frequency of pulsed gas flow affects the periodic fluctuations in electrostatic force applied to particles.
ADVANCED POWDER TECHNOLOGY
(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
Ali Akbar Sarbanha, Faical Larachi, Seyed Mohammad Taghavi
Summary: Floating fluidized beds are hindered by swell/sea waves, limiting their applicability in marine settings as a substitute for fixed beds in exhaust pollutant removal. To address this, experiments were performed using a rectangular fluidized bed mounted on a hexapod to simulate marine operations. The effects of motion on fluidization, bubble growth/shape, void/velocity fields, and gas/solids circulations were analyzed using Digital Image Analysis and Particle Image Velocimetry. The study revealed that non-vertical orientations led to a decrease in minimum fluidization velocity, with the trajectory and shape of bubbles near static and dynamic walls having the most significant impact. This resulted in a slug regime with substantial gas bypass, which has implications for the design and operation of marinized fluidized beds and addressing ship emissions constraints.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Green & Sustainable Science & Technology
Saurabh Gupta, Shikhar Choudhary, Suraj Kumar, Santanu De
Summary: Numerical simulations of biomass gasification in a bubbling fluidized bed were performed using a hybrid approach, incorporating a solver developed in OpenFOAM. The simulations accurately captured transient flow characteristics of gas-solids flows and showed good agreement with experimental measurements under different operating conditions.
Article
Thermodynamics
R. Y. Sakr, M. A. Abd-Rabboh, M. M. Mandour, M. A. Mohammad
Summary: This experimental study investigated the heat transfer characteristics of elliptic tube heat exchangers, showing that the average Nusselt number increases with higher fluidization numbers and smaller particle diameters. Additionally, staggered tube bundles demonstrated improved heat transfer characteristics compared to inline tube arrangements. Good agreement was found between experimental and numerical data, leading to correlation equations for average heat transfer in terms of Nu, fluidization number, and tube to particle diameter ratio.
HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Hirakh Jyoti Das, Pinakeswar Mahanta, Rituraj Saikia
Summary: Conical fluidized beds have unique dynamic features due to their lower pressure drop compared to conventional fluidized beds. This study investigates the fluid dynamics and interphase heat transfer phenomena in a conical bubbling fluidized bed riser, with varying inlet air velocity. The results show that an air velocity of 2 m/s yields the lowest pressure drop and highest heat transfer, making it the optimal value for the study.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
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
Energy & Fuels
Antonio Soria-Verdugo, Eduardo Cano-Pleite, Alberto Passalacqua, Rodney O. Fox
Summary: The effect of biomass particle shape on the conversion of beech wood during pyrolysis in a bubbling fluidized bed was investigated. The experimental results demonstrated that the pyrolysis velocity of the particles was proportional to their characteristic heat transfer length. The pyrolysis time ranged from 43 to 85 s at 500°C and from 27 to 53 s at 600°C.
Article
Engineering, Chemical
Hailang Liu, Guohui Li, Yang Liu
Summary: In this study, a proposed gas-particle second-order moment two-fluid model with particle kinetic-friction stress model is used to numerically simulate the particle and gas flow characteristics in a bubbling fluidized bed. The results show that the behavior of particles in the bed varies with their density, with ultralight particles exhibiting higher voidages, bigger bubbles, higher particle velocities, and stronger dispersion behaviors.
Article
Engineering, Mechanical
Nan Zheng, Huang Liu, Long Huang, Jiabin Fang, Jinjia Wei
Summary: The fluidization characteristics of nonuniform particles in a shallow fluidized bed (SFB) heat exchanger for a new generation of concentrated solar power technology were investigated. A new criterion for identifying the fluidization state, the standard deviation of bed pressure drop in the grid region, was proposed.
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
(2023)
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)