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Hierarchically mesoporous carbon spheres coated with a single atomic Fe-N-C layer for balancing activity and mass transfer in fuel cells

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Carbon Energy 2022年第1期4卷 1-11页

作者： Chengyong Shu Qiang Tan Chengwei Deng Wei Du Zhuofan Gan Yan Liu Chao Fan Hui Jin Wei Tang Xiao-dong Yang Xiaohua Yang Yuping Wu School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'anChina State Key Laboratory for Mechanical Behavior of Materials School of Material Science and EngineeringXi'an Jiaotong UniversityXi'anChina State Key Laboratory of Space Power-Sources Technology Shanghai Institute of Space Power SourcesShanghaiChina State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'anChina College of Materials Science and Engineering Huaqiao UniversityXiamenChina Institute of Quantum and Sustainable Technology(IQST) School of Chemistry and Chemical EngineeringJiangsu UniversityZhenjiangChina State Key Laboratory of Materials-Oriented Chemical Engineering School of Energy Science and Engineering and Institute of Advanced MaterialsNanjing Tech UniversityNanjingChina

Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The high-cost PGM catalyst in fuel cells can be replaced by earth-abundant transition-metalbased catalysts,that is,an Fe-N-C catalyst,which is considered one of the most promising ***,the performance of the Fe-N-C catalyst is hindered by the low catalytic activity and poor stability,which is caused by insufficient active sites and the lack of optimization of the triple-phase interface for mass ***,a novel Fe–N–C catalyst consisting of mono-dispersed hierarchically mesoporous carbon sphere cores and single Fe atom-dispersed functional shells are *** synergistic effect between highly dispersed Fe-active sites and well-organized porous structures yields the combination of high ORR activity and high mass transfer *** half-wave potential of the catalyst in 0.1M H_(2)SO_(4) is 0.82 V versus reversible hydrogen electrode,and the peak power density is 812 mW·cm^(−2) in H_(2)–O_(2) fuel ***,it shows superior methanol tolerance,which is almost immune to methanol poisoning and generates up to 162 mW·cm^(−2) power density in direct methanol fuel cells.

关键词： fuel cell hierarchically mesoporous carbon spheres oxygen reduction reaction single‐atom catalysts

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Heat transfer behaviors of some supercritical fluids: A review

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Chinese Journal of Aeronautics 2022年第1期35卷 290-306页

作者： Gongnan XIE Xiaoxiao XU Xianliang LEI Zhouhang LI Yong LI Bengt SUNDEN School of Marine Science and Technology Northwestern Poly technical UniversityXi'an 710072China Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing UniversityChongqing 400044China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming University of Science and TechnologyKunming 650093China School of Mechanical Engineering Northwestern Polyteclwical UniversityXi'an 710072China Department of Energy Sciences Lund UniversitySE-22100 LundSweden

Supercritical fluids(e.g.,hydrocarbon fuels,water,carbon dioxide,and organic working medium,etc)have been recognized as working media to improve thermal efficiencies in power cycles and energy conversion,and have been used or selected as the working fluids in engineering fields such as aerospace,nuclear power,solar energy,refrigeration,geothermal energy,chemical technology,and so *** better understand the interesting characteristic or abnormal behaviors of supercritical fluids,most valuable research works(including experimental results and numerical studies)from domestic and abroad have been *** such,this paper presents a comprehensive review on heat transfer behaviors of some supercritical fluids in engineering *** review focuses on recently available articles published mainly from 2016 up to the present *** common problems(i.e.,heat transfer enhancement and heat transfer deterioration particularly for the supercritical hydrocarbon fuels)in the supercritical field are summarized and some perspectives on future prospects are also included.

关键词： Heat transfer behavior Supercritical fluids Thermo-physical property Turbulence model Working condition

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Review, Numerical Validation, and Experiment Verification for Definite Solution Analogy Theory (Dsat) in Thermal-Hydraulic Scaling

SSRN

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SSRN 2024年

作者： Li, Xinyu Zhang, Dalin Jiang, Dianqiang Zhou, Xingguang Lv, Xindi Tian, Wenxi Qiu, Suizheng Su, Guanghui State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China China

The new generation of reactor technology: Fluoride-Salt-cooled high-Temperature Advanced Reactor (FuSTAR), mainly applied to the steady supply of stable electricity and high-temperature process heat for remote, underground, and arid areas. So far, the design of the heat transport system and Passive Residual Heat Removal System (PRHRS) of FuSTAR has been finished, but the scaling and experiment verification still needs to be carried out. In this study, the Definite Solution Analogy Theory (DSAT) was used for scaling analysis, and the scaling experiment platform of PRHRS was built. DSAT was verified through numerical simulation and experiment results, which can support the design and optimization of the PRHRS. The numerical test results show that the similar distribution of physical fields in dimensionless space on the prototype and experiment is realized under the DSAT framework. The steady-state experiment results show that the prototype of PRHRS can take away more than 1% of the decay heat of the total thermal power and has a margin of about 15% under a stable natural cycle. The maximum deviation between the measured temperature and the calculated value with DSAT is more than 4°C. The transient experiment results show that the maximum deviation of dimensionless solutions is less than 4%, which proves the high accuracy of DSAT and the PRHRS based on this framework can effectively remove the decay heat in the reactor. This work can be used to extend the scaling method of thermal-hydraulic in high dimensional space and transient conditions. © 2024, The Authors. All rights reserved.

关键词： Fluorine compounds

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Molecular dynamics study of shale oil adsorption and diffusion behavior in reservoir nanopores: Impact of hydrocarbon composition and surface type

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Journal of Molecular Liquids 2024年第PartA期414卷

作者： Zheng, Lichen Zhao, Qiuyang Adams, Michael J. Alexiadis, Alessio Wang, Yechun Jin, Hui Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China School of Chemical Engineering University of Birmingham BirminghamB15 2TT United Kingdom

Understanding shale oil adsorption in reservoir nanopores is essential for efficient extraction. This study used MD simulations to analyze the adsorption and diffusion of two- and multi-component hydrocarbons (Aromatics, Alkanes, Resin) on various shale surfaces (Calcite, Montmorillonite, Quartzite, Organic) at 353 K and 25 MPa. Hydrocarbons formed a bilayer adsorption structure comprising a high-concentration adsorption layer (L1, 0.35–0.90 g/cm3) and a low concentration weak adsorption layer (L2), with adsorption density ranked as Resin > Aromatics > Alkanes. Reservoir surfaces were classified as ionic (e.g., calcite, montmorillonite) and non-ionic (e.g., quartz, graphite), and polar hydrocarbons exhibited higher adsorption densities and energies on ionic surfaces due to combined electrostatic and van der Waals interactions, while non-ionic surfaces showed smaller adsorption differences. For multicomponent hydrocarbons, adsorption layer densities followed the order: graphite > MMT-SiO > quartz > calcite > MMT-Na, with competitive adsorption observed. The polar component exhibited a greater adsorption advantage on the calcite, MMT-SiO side and graphite surfaces due to electrostatic interactions and π-π interactions, and a lesser advantage on the MMT-Na side and quartz surfaces. Hydrocarbon diffusivity was influenced by molecular mass and polarity and ordered as Alkanes > Aromatics Resin. Polar molecules had a weaker diffusion than nonpolar molecules at similar molecular masses. Among the multicomponent hydrocarbons, the self-diffusion coefficient (Self-D) of Resin increased, while that of lighter components decreased compared to two-component systems. These findings offer strategies for improving shale oil recovery by tailoring injection fluids to reservoir types, anionic surfactants or chelating agents may be used to reduce electrostatic interactions in carbonate and clay reservoirs, while nonionic surfactants may be more effective in quartz reservoirs. © 2024

关键词： Nonionic surfactants

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Front tracking simulation of droplet displacement on solid surfaces by soluble surfactant-driven flows

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Physical Review Fluids 2024年第1期9卷 014002-014002页

作者： Xinglong Shang Zhengyuan Luo Bofeng Bai Long He Guoqing Hu Hangzhou Institute of Technology Xidian University Hangzhou 311200 China Department of Engineering Mechanics and State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Hangzhou 310027 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China College of Mechanical and Electrical Engineering Shaanxi University of Science and Technology Xi'an 710021 China

We provide comprehensive numerical insights into the displacement of droplets subject to soluble surfactant-driven flows. The effects of soluble surfactants on the dynamics of moving contact lines are introduced by the surfactant-dependent generalized Navier boundary condition. We show that surfactant transport significantly influences the displacement patterns of droplets on solid surfaces, affecting both the equilibrium state of the sliding motion and the critical conditions for detachment. In particular, a linear increase in the displacement velocity of a droplet with the dimensionless adsorption depth K is observed. This rate of increase is more pronounced at higher elasticity numbers, as evidenced by a more significant increase in the advancing contact angle. The critical condition for droplet detachment depends on the surfactant's ability to swiftly adsorb from the bulk and replenish at interfaces, which is improved as the Biot number Bi or K increases. Adsorption is enhanced by an increase in Bi, resulting in a decrease in the required time td for droplet detachment. However, this enhancement effect becomes nonmonotonic at high Bi values. In contrast, consistently increasing the bulk Peclet number decreases td, eventually approaching the convection limit where the Marangoni-induced drag force ceases to increase. In addition, surfactant transfer near the moving contact line at a moderate Damköhler number restricts the motion of the advancing contact lines, promoting droplet detachment. For all detachment scenarios, we find that detachment necessitates a critical effective capillary number, and an increase in this number results in an exponential decline in td.

关键词： Contact line dynamics Drop & bubble phenomena Marangoni convection Surface tension effects

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An inverse fault detection and diagnosis (IFDD) strategy for practical application on chiller product

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INTERNATIONAL JOURNAL OF REFRIGERATION 2022年 134卷 24-34页

作者： Lu, Hailong Cui, Xiaoyu Han, Hua Liu, Jiangyan Zhang, Yunqian [a]School of Energy and Power Engineering University of Shanghai for Science and Technology 516 Jungong Road Yangpu District Shanghai 200093 PR China [b]Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai 200093 PR China [c]CQ Midea General Refrigeration Equipment Co. Ltd. 15 Qiangwei Road Nanan District Chongqing 401336 PR China [d]School of Energy and Power Engineering Chongqing University Chongqing PR China

Current research on chiller fault detection and diagnosis (FDD) is usually based on the multi-classification method for mixed multiple fault types. The establishment of a multi-classification FDD model requires obtaining extensive test data of normal operation and multiple common faults at different fault levels, so the cost-to benefit ratio will not be accepted. In addition, because of the information interference between different types of fault data, FDD model is hard to avoid over-fitting or under-fitting, and there may be an intolerable high false alarm rate existing in product application. Therefore, it is difficult to promote FDD in actual chiller product applications. This paper proposes an inverse fault detection and diagnosis (IFDD) strategy, which is based on the characteristics of the target fault (the fault to be concerned) to establish a two-classification fault diagnosis model. Compared with the multi-classification method, the amount of fault test data required by the two classification methods to realize fault diagnosis can be greatly reduced. With IFDD strategy, the detection and diagnosis are completed simultaneously, while fast calculation speed, high diagnosis accuracy rate and low false alarm rate are achieved. The core of the IFDD strategy is to concentrate resources to capture the characteristics of the target fault, and no longer classify other types of faults and normal operating conditions, so it can avoid the influence of information interference between multiple types of fault data in the fault diagnosis model. In order to verify the feasibility of this strategy, a 200 ton variable-speed screw chiller has been tested on the laboratory, and a database of normal operation, refrigerant leakage, refrigerant overcharge faults, and a new operating condition of insufficient cooling water flow is initially established. Based on the sensors configured by the chiller unit and using the exponentially weighted moving-average (EWMA) control chart for

关键词： Inverse FDD Strategy Practical application Chiller product EWMA

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Multi-Dimensional Coupling Analysis of the Control Rod Withdraw Accident with Scam in the Typical Lfr

SSRN

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SSRN 2023年

作者： Qiu, Hanrui Zhang, Jing Wang, Mingjun Tian, Wenxi Su, Guanghui State Key Laboratory of Multiphase Flow in Power Engineering School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China

MYRRHA is the Gen IV liquid metal cooled fast reactor, which is a pool-type reactor system developed and designed by the Belgian Nuclear Research Center SCK·CEN. Regarding the safety assessment of the installation, the major challenge is to analyze the complex coolant flow field characteristics in the large open regions of the reactor vessel. In this paper, a coupled sub-channel/CFD multi-scale platform is developed through implementing the sub-channel code SACOS-PB to the CFD code FLUENT based on the domain decomposition and explicit numerical scheme. The flow field characteristics in the upper plenum of reactor emergency shutdown after a reactivity insertion accident (RIA) were investigated. Based on the RIA analysis, the thermal stratification effect has been observed in the upper plenum. The analysis results well demonstrated the 3D flow and local phenomenon of the fluid in the upper plenum, which is significant to reactor design and reactor safety analysis of LFRs. © 2023, The Authors. All rights reserved.

关键词： Control rods

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Cooperative structure of Li/Ni mixing and stacking faults for achieving high-capacity Co-free Li-rich oxides

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Journal of Energy Chemistry 2024年第8期95卷 315-324,I0007页

作者： Zhen Wu Yu-Han Zhang Hao Wang Zewen Liu Xudong Zhang Xin Dai Kunyang Zou Xiaoming Lou Xuechen Hu Lijing Ma Yan Liu Yongning Liu State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao 266101ShandongChina Hefei Advanced Computing Center Operation Management Corp Ltd Hefei 230088AnhuiChina Center for High Performance Computing Network Information CenterXi’an Jiaotong UniversityXi’an 710049ShaanxiChina Wuhan Dongfeng Motor Corporation Ltd Wuhan 430056HubeiChina School of Materials Science and Intelligent Engineering Nanjing UniversitySuzhou 215163JiangsuChina Key Laboratory of MEMS of the Ministry of Education Southeast UniversityNanjing 210096JiangsuChina International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina

Co-free Li-rich layered oxides(LLOs)are emerging as promising cathode materials for Li-ion batteries due to their low cost and high ***,they commonly face severe structural instability and poor electrochemical activity,leading to diminished capacity and voltage ***,we introduce a Co-free LLO,Li_(1.167)Ni_(0.222)Mn_(0.611)O_(2)(Cf-L1),which features a cooperative structure of Li/Ni mixing and stacking *** structure regulates the crystal and electronic structures,resulting in a higher discharge capacity of 300.6 mA h g^(-1)and enhanced rate capability compared to the typical Co-free LLO,Li_(1.2)Ni_(0.2)Mn_(0.6)O_(2)(Cf-Ls).Density functional theory(DFT)indicates that Li/Ni mixing in LLOs leads to increased Li-O-Li configurations and higher anionic redox activities,while stacking faults further optimize the electronic interactions of transition metal(TM)3d and non-bonding O 2p ***,stacking faults accommodate lattice strain,improving electrochemical reversibility during charge/discharge cycles,as demonstrated by the in situ XRD of Cf-L1 showing less lattice evolution than *** study offers a structured approach to developing Co-free LLOs with enhanced capacity,voltage,rate capability,and cyclability,significantly impacting the advancement of the next-generation Li-ion batteries.

关键词： Co-free Li-rich oxides Li/Ni mixing Stacking faults Electronic structure

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Large contributions of emission reductions and meteorological conditions to the abatement of PM_(2.5)in Beijing during the 24th Winter Olympic Games in 2022

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Journal of Environmental Sciences 2024年第2期136卷 172-188页

作者： Yaping Jiang Shaocai Yu Xue Chen Yibo Zhang Mengying Li Zhen Li Zhe Song Pengfei Li Xiaoye Zhang Eric Lichtfouse Daniel Rosenfeld Key Laboratory of Environmental Remediation and Ecological Health Ministry of EducationResearch Center for Air Pollution and HealthCollege of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China College of Science and Technology Hebei Agricultural UniversityBaoding 071000China Chinese Academy of Meteorological Sciences China Meteorological AdministrationBeijing 100081China Aix-Marseille Univ CNRSColl FranceCNRSIRDINRAEEuropole Mediterraneen de l’ArboisAvenue Louis Philibert13100 Aix en ProvenceFrance Xi’an Jiaotong University State Key Laboratory of Multiphase Flow in Power EngineeringXi’an 710049China Institute of Earth Sciences The Hebrew University of JerusalemJerusalemIsrael

To guarantee the blue skies for the 2022 Winter Olympics held in Beijing and Zhangjiakou from February 4 to 20,Beijing and its surrounding areas adopted a series of emission control *** provides an opportunity to determine the impacts of large-scale temporary control measures on the air quality in Beijing during this special ***,we applied the WRF-CMAQ model to quantify the contributions of emission reduction measures and meteorological *** show that meteorological conditions in 2022 decreased PM_(2.5)in Beijing by 6.9 and 11.8μg/m^(3)relative to 2021 under the scenarios with and without emission reductions,*** emission reduction measures implemented in Beijing and seven neighboring provinces resulted in an average decrease of 13.0μg/m^(3)(-41.2%)in PM_(2.5)in *** the entire period,local emission reductions contributed more to good air quality in Beijing than nonlocal emission *** the emission reduction scenario,local,controlled regions,other regions,and boundary conditions contributed 47.7%,42.0%,5.3%,and 5.0%to the PM_(2.5)concentrations in Beijing,*** results indicate that during the cleaning period with the air masses from the northwest,the abatements of PM_(2.5)were mainly caused by local emission ***,during the potential pollution period with the air masses from the east-northeast and west-southwest,the abatements of PM_(2.5)were caused by both local and nonlocal emission reductions almost *** implies that regional coordinated prevention and control strategies need to be arranged scientifically and rationally when heavy pollution events are forecasted.

关键词： PM_(2.5) WRF-CMAQ Meteorological conditions Emission reductions Winter Olympic games

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Control of two-phase flow around a cylinder with a cylindrical attachment: A numerical study

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Ocean engineering 2025年 334卷

作者： Wang, Ziqing Hu, Yu Huang, Shengxian Zhang, Yongxing Moghtaderi, Behdad Wang, Ying Shanghai Key Laboratory of Multiphase Flow and Heat Transfer of Power Engineering School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai China National Engineering Laboratory for Pipeline Safety/MOE Key Laboratory of Petroleum Engineering/Beijing Key Laboratory of Urban Oil and Gas Distribution Technology China University of Petroleum – Beijing Beijing102249 China Centre for Innovative Energy Technologies The University of Newcastle CallaghanNSW2308 Australia

Mitigating flow separation, vortex shedding and sediment-induced erosion around cylindrical structures is critical for enhancing marine engineering safety. This study investigates the hydrodynamic performance of a two-phase flow around a cylinder equipped with an auxiliary cylinder under realistic ocean conditions. key parameters include the clearance ratio (G/D), particle characteristics (size and concentration), and vibration modes of the auxiliary body. This study investigates real ocean conditions, focusing on the influence of clearance ratio (G/D) and an auxiliary cylinder on flow field changes with varying particle characteristics. The results demonstrate that: (1) A clearance ratio G/D = 0.1 yields the optimal drag reduction (57.18 %) for the primary cylinder in single-phase flow;(2) Larger particles weaken vortex-particle interactions, while higher particle concentrations exacerbate uneven deposition near the cylinder;(3) Transverse vibration of the auxiliary body (amplitude ratio = 0.025, frequency ratio = 0.65) reduces drag by 18.7 % compared to stationary configurations. These findings provide insights into flow control strategies for offshore structures subjected to sediment-laden flows. © 2025 Elsevier Ltd

关键词： Marine safety

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