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arXiv 2024年

作者： Su, Jinghong Wang, Cheng Zhang, Yi-Bao Xu, Fan Wang, Junwu Sun, Chao New Cornerstone Science Laboratory Center for Combustion Energy Key Laboratory for Thermal Science and Power Engineering Ministry of Education Department of Energy and Power Engineering Tsinghua University Beijing100084 China Beijing Key Laboratory of Process Fluid Filtration and Separation College of Mechanical and Transportation Engineering China University of Petroleum Beijing102249 China Department of Engineering Mechanics School of Aerospace Engineering Tsinghua University Beijing100084 China State Key Laboratory of Mesoscience and Engineering Institute of Process Engineering Chinese Academy of Sciences P. O. Box 353 Beijing100190 China

We investigate the coupling effects of the two-phase interface, viscosity ratio, and density ratio of the dispersed phase to the continuous phase on the flow statistics in two-phase Taylor-Couette turbulence at a system Reynolds number of 6 × 103 and a system Weber number of 10 using interface-resolved three-dimensional direct numerical simulations with the volume-of-fluid method. Our study focuses on four different scenarios: neutral droplets, low-viscosity droplets, light droplets, and low-viscosity light droplets. We find that neutral droplets and low-viscosity droplets primarily contribute to drag enhancement through the two-phase interface, while light droplets reduce the system's drag by explicitly reducing Reynolds stress due to the density dependence of Reynolds stress. Additionally, low-viscosity light droplets contribute to greater drag reduction by further reducing momentum transport near the inner cylinder and implicitly reducing Reynolds stress. While interfacial tension enhances turbulent kinetic energy (TKE) transport, drag enhancement is not strongly correlated with TKE transport for both neutral droplets and low-viscosity droplets. Light droplets primarily reduce the production term by diminishing Reynolds stress, whereas the density contrast between the phases boosts TKE transport near the inner wall. Therefore, the reduction in the dissipation rate is predominantly attributed to decreased turbulence production, causing drag reduction. For low-viscosity light droplets, the production term diminishes further, primarily due to their greater reduction in Reynolds stress, while reduced viscosity weakens the density difference's contribution to TKE transport near the inner cylinder, resulting in a more pronounced reduction in the dissipation rate and consequently stronger drag reduction. Our findings provide new insights into the physics of turbulence modulation by the dispersed phase in two-phase turbulence systems. Copyright © 2024, The Authors. All r

关键词： Kinetic energy

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Effect of Gas Distributor Structure on Fluidization Characteristics in a Gas-Solid Fluidized Bed

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China Petroleum processing & Petrochemical Technology 2020年第2期22卷 102-110页

作者： Jang Kwangbyol Feng Yali Li Haoran School of Civil&Resource Engineering University of Science and Technology BeijingBeijing 100083 National Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100080

In the present paper,the experimental method and computational fluid dynamics(CFD)method were used to investigate the effect of gas distributors with different orifice sizes and orifice pitches on fluidization characteristics in a gas-solid fluidized *** Euler-Euler two fluid model(TFM)approach based on the kinetic theory of granular flow(KTGF)and the standard k-epsilon turbulence model was employed in the numerical simulation by using ANSYS Fluent *** results showed that the orifice size and the orifice pitch of gas distributor had a significant influence on the flow characteristics in the gas-solid fluidized *** a decreasing orifice size and orifice pitch of gas distributor having the same opening area,the distributor pressure drop,the initial bubble size,and the height of dead zone just above the distributor were decreased,and the bed pressure drop was increased more than that of the larger orifice size and orifice pitch of distributors,the distribution of solid volume fraction was also more homogeneous for the smaller orifice size.

关键词： fluidized bed gas distributor orifice size bubble numerical simulation

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Dynamic Graph Learning Soft Sensor in process Industry

Dynamic Graph Learning Soft Sensor in Process Industry

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Data Driven Control and Learning Systems (DDCLS)

作者： Mingwei Jia Danya Xu Tao Yang Yuan Yao Yi Liu Institute of Process Equipment and Control Engineering Zhejiang University of Technology Hangzhou State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang Department of Chemical Engineering National Tsing Hua University Taiwan

The development of an accurate soft sensor modeling method in the process industry remains a great challenge because the coupling relationship between variables is always intricate and difficult to model. In this work, a dynamic graph learning (DGL) soft sensor is proposed to alleviate this problem. The proposed model realizes the ability of the soft sensor to perceive the coupling relationship in real time by automatically learning the dynamic graph. Then, a causal convolutional mechanism and a multi-hop graph attention mechanism are used to systematically construct the dependencies of variables in the spatial-temporal dimension and model their variation patterns effectively. Finally, the proposed method is tested on the penicillin fermentation process and shown to be feasible and effective. The results showed that the change of the dynamic graph in the spatial-temporal dimension was in line with the process mechanism.

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Pompon-Like Ni Doped Zno Mesoporous Microspheres with Superior No2 Sensing Properties at Room Temperature

SSRN

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SSRN 2023年

作者： Fu, Yuehao Wang, Hong Liu, Di Wan, Jiawei Zeng, Zhipeng School of Materials Science and Engineering Sichuan University of Science & Engineering Zigong643000 China Material Corrosion and Protection Key Laboratory of Sichuan Province Sichuan University of Science & Engineering Zigong643000 China Department of Chemistry Tsinghua University Beijing100084 China State Key Laboratory of Biochemical Engineering CAS Center for Excellence in Nanoscience Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China

Rapid detection of NO2 at room temperature plays a significant role in industrial production and daily life. Herein, the hierarchical pompon-like Ni doped ZnO (Ni-ZnO) mesoporous microspheres composed of abundant porous nanosheets were prepared by a facile solvothermal method. For Ni-ZnO composites based sensors, Ni doping not only reduced their working temperature but also enhanced their sensitivity. The test results suggested that the Ni-ZnO-0.03 based sensor showed outstanding gas-sensing properties toward 20 ppm NO2 at 25°C, such as high response (263), speedy response-recovery time (36, 94 s), excellent selectivity and long-term stability. Moreover, the sensor also possessed a low theoretical detection limit of 9 ppb toward NO2 at 25°C. The superior NO2 sensing properties of Ni-ZnO nanostructure composites could owe to the hierarchical and mesoporous structure, high specific surface area as well as increased oxygen vacancies. © 2023, The Authors. All rights reserved.

关键词： Room temperature

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How interfacial tension enhances drag in turbulent Taylor–Couette flow with neutrally buoyant and equally viscous droplets

arXiv

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arXiv 2024年

作者： Su, Jinghong Zhang, Yi-Bao Wang, Cheng Yi, Lei Xu, Fan Fan, Yaning Wang, Junwu Sun, Chao New Cornerstone Science Laboratory Center for Combustion Energy Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power Engineering Tsinghua University Beijing100084 China Beijing Key Laboratory of Process Fluid Filtration and Separation College of Mechanical and Transportation Engineering China University of Petroleum Beijing102249 China Department of Engineering Mechanics School of Aerospace Engineering Tsinghua University Beijing100084 China State Key Laboratory of Mesoscience and Engineering Institute of Process Engineering Chinese Academy of Sciences P. O. Box 353 Beijing100190 China

The presence of dispersed-phase droplets can result in a notable increase in the system’s drag. However, our understanding of the mechanism underlying this phenomenon remains limited. In this study, we use three-dimensional direct numerical simulations with a modified multi-marker volume-of-fluid method to investigate liquid-liquid two-phase turbulence in a Taylor–Couette geometry. The dispersed phase has the same density and viscosity as the continuous phase. The Reynolds number Re ≡ riωid/v is fixed at 5200, the volume fraction of the dispersed phase is up to 40%, and the Weber number (formula presented) is around 8. It is found that the increase in the system’s drag originates from the contribution of interfacial tension. Specifically, droplets experience significant deformation and stretching in the streamwise direction due to shear near the inner cylinder. Consequently, the rear end of the droplets lags behind the fore head. This causes opposing interfacial tension effects on the fore head and rear end of the droplets. For the fore head of the droplets, the effect of interfacial tension appears to act against the flow direction. For the rear end, the effect appears to act in the flow direction. The increase in the system’s drag is primarily attributed to the effect of interfacial tension on the fore head of the droplets which leads to the hindering effect of the droplets on the surrounding continuous phase. This hindering effect disrupts the formation of high-speed streaks, favoring the formation of low-speed ones, which are generally associated with higher viscous stress and drag of the system. This study provides new insights into the mechanism of drag enhancement reported in our previous experiments. Copyright © 2024, The Authors. All rights reserved.

关键词： Reynolds number

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Preparation of High Stability Hollow Hierarchical Bimetallic Nimo-Hmgo Catalyst for Co2 Reforming with Methane

SSRN

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SSRN 2024年

作者： Peng, Wencai Yan, Xirui Liang, Haixia Wang, Ruicong Li, Da Li, Jun Zhang, Jinli School of Chemistry and Chemical Engineering Shihezi University Xinjiang Shihezi832000 China State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China School of Chemical Engineering and Technology Key Laboratory for Green Chemical Technology Tianjin University Tianjin300072 China

CO2 reforming with methane (DRM) is a potential effective carbon neutralization strategy to convert greenhouse gases into syngas. The key to the DRM process is to design active and coking resistant catalysts. Herein, hollow hierarchical bimetallic NiMo-HMgO catalysts were prepared via hydrothermal-impregnation method. The prepared NiMo-HMgO catalysts exhibited higher catalytic performance and lower coke deposition during the DRM process than commercial NiMo-CMgO catalysts, due to the formation of Ni-Mo-MgO composite on hierarchical MgO (HMgO), which is promoted by exposed (111) polar surface of HMgO with alternate arrangement of anion and cation layers. The deposited carbon and stability can be effectively regulated by adjusting the molar ratio of Ni to Mo. The synergistic effect of metal and HMgO can provide reference for the research in other related fields. © 2024, The Authors. All rights reserved.

关键词： Carbon

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Optimization design of frame for hydrogen-oxygen engine with multiple forms based on iSIGHT platform 3

Optimization design of frame for hydrogen-oxygen engine with...

引用

3rd International Conference on Electronics, Electrical and Information engineering, ICEEIE 2023

作者： Liu, Zhaojun Wu, Qiong Gao, Hanjun Du, Xueqin Yang, Shuai He, Kun Li, Xuefei Liu, Zhaoyu State Key Laboratory of Virtual Reality Technology and Systems Beijing Engineering Technological Research Center of High-efficient & Green CNC Machining Process and Equipment Beihang University Beijing100191 China Beijing Aerospace Propulsion Institute Beijing Beijing100048 China Jingdezhen Research Institute of Beihang University Jingdezhen333000 China

ISBN: (纸本)9781510671423

Based on iSIGHT optimization platform and ABAQUS, the frames of rocket liquid engine with multiple forms are optimized. Fast parametric modeling method, sensitivity analysis method and multi-objective genetic algorithm NCGA are combined to optimize the dimensions of frames. The frame modeling of different forms can be accomplished by using specified frame design parameters, thus greatly improving design efficiency. Finite element analysis and optimization were carried out on a single four-point pusher frame as an example. The influence of different section size parameters on the frame performance is analyzed. The optimized structure of frame reduces the amount of material used and increases the 1st order natural frequency within the constraints. © 2023 SPIE.

关键词： Finite element method

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Fabrication and Application of Graphdiyne-based Heterogeneous Compositions:from the View of Interaction

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Chemical Research in Chinese Universities 2021年第6期37卷 1158-1175页

作者： QI Qi XU Lekai DU Jiang YANG Nailiang WANG Dan School of Materials Science and Engineering Henan Province Industrial Technology Research Institute of Resources and MaterialsZhengzhou UniversityZhengzhou450001P.R.China Green Catalysis Center College of ChemistryZhengzhou UniversityZhengzhou450000P.R.China State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing100190P.R.China University of Chinese Academy of Sciences Beijing100049P.R.China

Graphdiyne(GDY)has the unique feature in the topological ordered arranged sp-and sp^(2)-hybridized carbon atoms,thus deriving a series of 2D *** to inhomogeneousπ-bonding and carbon orbital overlap between different hybrid carbon atoms,GDY possesses a natural band gap with a Dirac cones *** GDY exhibits semiconductor property with a conductivity of 2.516×10^(−4) S/m at room *** topological distribution of alkyne and benzene bonds of GDY makes its surface charge distribution extremely uneven,which produces high intrinsic activity for further *** unique molecular structure endows the specific interaction with various species,such as ions,atoms,molecules and nanoparticles,showing excellent charge transport capability and unique advantages in mass transfer and energy *** the view of the interaction principle between GDY and different compositions,we summarized the application of GDY-based materials in the fields of catalysis,energy conversion and storage,biological detection and so on.

关键词： Graphdiyne Two-dimensional material Carbon material Interaction Hetero-composition

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Kinetic and HPLC-MS analyses revealed the catalysis behavior of total saponins from MOF-based solid acids

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Journal of Molecular Liquids 2025年 429卷

作者： Zhang, YanXiao Gao, XiaoNing Xu, Juan Feng, Lu School of Chemistry and Environmental Engineering Key Laboratory of Green Chemical Engineering Process of Ministry of Education Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education State Key Laboratory of Green and Efficient Development of Phosphorus Resources Wuhan Institute of Technology Wuhan430073 China Hubei Key Laboratory of Processing and Application of Catalytic Materials Huanggang Normal University Huanggang438000 China Laboratory Department of Central Theater General Hospital of the Chinese People's Liberation Army Wuhan430000 China

Diosgenin is an influential intermediate for the preparation of various steroidal drugs, and has the reputation of "mother of hormones" and "medicinal gold". In this work, UiO-66-NH2 is quaternary ammoniated by functional modification of 3,5-diamino-1,2,4-triazole and then ion-exchanged with different concentrations of CF3SO3H to produce ionic liquids grafted MOF-based solid acids, namely UNS-0.96 and UNS-1.28, where 0.96 and 1.28 represent the volume (mL) of CF3SO3H consumed. They were used to extract diosgenin from total saponins, suggesting that UNS-1.28 can achieve high diosgenin extraction with a shorter time (2.5 h) and a lower addition amount (0.15 g) and the optimum diosgenin yield of 22.5 % was obtained. The extraction efficiency is higher than that obtained by hydrolysis of 2 M H2SO4 and commercial ion exchange resins. Kinetic studies have shown that the catalytic of total saponins by UNS-1.28 is in perfect agreement with the pseudo-first-order kinetic model, and that the activation energy required for extraction is low, only 2.83 × 104 J/mol. In addition, HPLC-MS was used to analyze the total saponins and products at different extraction times. The fragmentation peak types and relative abundances of the different extracted products are compared to reveal the cleavage pathways of the total saponins and the optimal period of diosgenin production, and to suggest the mechanism of action of the solid acid on the total saponins. © 2025 Elsevier B.V.

关键词： Kinetic parameters

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A Facile Synthesis of Iron Single-Atom Electrocatalyst for High-Performing Oxygen Reduction Reaction and Remarkable Rechargeable Zinc-Air Battery

SSRN

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SSRN 2023年

作者： Zhang, Yuanyuan Lu, Fenghong Fan, Kaicai Zhao, Jiayi Wang, Zumin Zong, Lingbo Key Laboratory of Eco-chemical Engineering College of Chemistry and Molecular Engineering Qingdao University of Science and Technology Qingdao266042 China College of Materials Science and Engineering Qingdao University of Science and Technology Qingdao266042 China State Key Laboratory of Biochemical Engineering Institute of Process Engineering Chinese Academy of Sciences 1 North 2nd Street Zhongguancun Haidian District Beijing100190 China

Iron-based single-atom catalysts (SACs) are considered to the most promising catalysts to replace Pt for efficient oxygen reduction reaction (ORR). However, the precise synthesis of high-performance SACs and the understanding of their ORR origin remain challenging. In this work, microporous nitrogen-doped carbon with abundant and accessible atomically dispersed N-coordinated Fe sites (Fe-N-C) is prepared by molecular-confined coupling pyrolysis strategy. The Fe-N-C exhibits excellent ORR activities in acid (E1/2 of 0.78 V vs. RHE) and alkaline (E1/2 of 0.91 V vs. RHE) electrolytes. When integrated into a rechargeable aqueous Zinc-air battery (ZAB), both large specific capacity (770 mAh g−1) and high peak power density (240 mW cm-2) are achieved. Remarkably, the as-prepared ZAB presents amazing charge-discharge cycle performance of 1600 h at the large current density, which is 52.5 times of that using Pt/C+RuO2. Furthermore, all-solid-state ZAB delivers ultra-robust cycling stability even under bending. This work may advance a critical step towards the design of rational and controlled preparation of remarkable and ultra-stable catalysts. © 2023, The Authors. All rights reserved.

关键词： Molecular oxygen

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