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SSRN 2024年

作者： Ning, Zhiyuan Zhou, Qulan Li, Na Macdonald, Digby D. Zhou, Jie State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Departments of Nuclear Engineering and Materials Science and Engineering University of California at Berkeley BerkeleyCA94720 United States Xi’an Aerospace Propulsion Institution Xi’an China

The laboratory simulated copper corrosion in a bentonite/groundwater solution, analyzing the kinetics of metal passivation through potentiodynamic polarization, potentiostatic polarization, and electrochemical impedance spectroscopy experiments. Corrosion development patterns were inferred from morphological characterization, and the mechanisms by which bentonite affects copper corrosion were comprehensively elucidated based on the point defect model. The research revealed that bentonite affects copper corrosion resistance through Donnan exclusion, cation adsorption, and hydrolysis of salts. Based on the point defect model, the study elucidated the microscopic mechanism of pitting corrosion induced by bentonite hydrolysis salts, calculating the polarizability of the passive layer/outer layer interface as α = 0.1. The reliability of the cation adsorption and adsorption-desorption mechanisms was confirmed through experimental data fitting, point defect model fitting, and theoretical analysis. © 2024, The Authors. All rights reserved.

关键词： Hydrolysis

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EMMS-based modeling of gas-solid generalized fluidization:Towards a unified phase diagram

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Chinese Journal of Chemical engineering 2021年第1期34卷 27-34页

作者： Juanbo Liu Xinhua Liu Wei Ge State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Dalian National Laboratory for Clean Energy Dalian 116023China

Hydrodynamic features of gas-solid generalized fluidization can be well expressed in the form of phase diagrams,which are important for engineering *** structure presents almost universally in generalized fluidization and should be considered in such phase ***,current phase diagrams were mainly proposed for cocurrent upward flow according to experimental data or empirical correlations with homogeneous *** energy-minimization multiscale(EMMS)model has shown the capability of capturing mesoscale structure in generalized fluidization,so EMMS-based phase diagrams of generalized fluidization were proposed in this article,which describe more reasonable global hydrodynamics over all regimes including the important engineering phenomena of choking and *** characteristics were also found in discrete particle simulation under various *** wider range of application,the typical hydrodynamic parameters of the phase diagrams were correlated to non-dimensional numbers reflecting the effects of material properties and operation *** study thus shows a possible route to develop a unified phase diagram in the future.

关键词： Fluidization Phase diagram Dimensionless correlation Mesoscale Mathematical modeling EMMS

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Effect of compressibility on instability of boundary layer over a spinning cone in hypersonic flow 3

Effect of compressibility on instability of boundary layer o...

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2024 3rd International Conference on Aerospace, Aerodynamics and Mechatronics engineering, AAME 2024

作者： Gu, Yiyang Dong, Hao Liu, Shicheng Jiang, Yinglei College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics Jiangsu Nanjing China State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and Astronautics No. 29 Yudao Street Nanjing210016 China Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information Technology Nanjing University of Aeronautics and Astronautics Jiangsu Nanjing China

Spinning vehicles achieve gyroscopic effects by rotating around their axis. However, transition significantly influences the stability of flight. In this work, a study of instability on the unstable modes in boundary layers over a rotating cone with a 7° half-apex angle in hypersonic flows is presented with linear instability analysis (LST). To quantify the effect of compressibility, Mach numbers (5-10) are considered, and a higher rotational velocity is considered for analysis of centrifugal mode. MMM, CFM, and CM shift towards low frequency, low streamwise, and circumferential wavenumbers. Also, the maximum amplification rate of MMM, CFM, and CM decreases with Mach number, suggesting a stabilizing effect of compressibility on the boundary layer over a spinning cone in hypersonic flows. © Published under licence by IOP Publishing Ltd.

关键词： Mach number

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Dual diffraction bands of heliconical liquid crystal gratings

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Physical Review Materials 2024年第8期8卷 085201-085201页

作者： Sha Liu Hao Yu Miao Jiang Ling-Ling Ma Yan-Qing Lu Qi-Huo Wei Department of Mechanical and Energy Engineering National Laboratory of Solid State Microstructures Key Laboratory of Intelligent Optical Sensing and Manipulation Collaborative Innovation Center of Advanced Microstructures and College of Engineering and Applied Sciences Center for Complex Flow and Soft Matter Research

Gratings composed of cholesteric liquid crystals as an important optical element for emerging applications such as augmented and virtual reality and are renowned for their characteristic single reflective diffraction band. Heliconical liquid crystal is a newly discovered state where the constituent molecules self-organize into helical structures with a non-90° polar angle between the director and the helical axis. Here, we present a numerical study on the reflective diffraction of gratings made of heliconical liquid crystals. Remarkably, numerical results demonstrate that there exist two diffraction bands at the same diffraction angle, with one peak wavelength being twice the other. We show that the short-wavelength diffraction originates from the Pancharatnam-Berry phase acquired by the reflected light while the long-wavelength diffraction stems from the reflection of the slanted volume grating, and that the wavelengths of these two diffraction bands can be attributed to the first and second band gaps of the slanted volume grating as a one-dimensional photonic crystal. We further show that the polarization of the reflected diffraction light is circular, exhibiting the same handedness as the liquid crystal for the short-wavelength band, whereas it is perfectly linearly polarized along the grating direction for the long-wavelength band.

关键词： Liquid crystals Optical materials & elements

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An Operation Optimization of Cooling System for Reactor Shutdown in Pebble Bed Gas-Cooled Reactor

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SSRN 2024年

作者： Liu, Junfeng Wang, Chenglong Qiu, Suizheng Wang, Boyuan Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology Shaanxi Engineering Research Center of Advanced Nuclear Energy Xi’an Jiaotong University Xi’an710049 China Xi’an Thermal Power Research Institute Co. Ltd Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering China

For the emergency shutdown of a high temperature gas-cooled reactor pebble-bed module (HTR-PM) in its operation conditions, in the current design method with a low-flow auxiliary steam cooling technical solution, there are some security and economic issues, i.e. high thermal shock, long cooling time, and temperature drop rate exceeding the limit. To solve these problems, an optimized design method for the shutdown cooling system is presented. Through a simulation model of the shutdown cooling system based on Matlab/Simulink, the dynamic characteristics of the shutdown cooling system in its operation conditions are obtained, involving shutdown, low flow cooling, and water supply start-up stages. The results showed that with the optimized design method, the safety of the core and steam generator can both be ensured during the cooling process, and the cooling rate is significantly improved. Therefore, the optimized design method is feasible and advanced. © 2024, The Authors. All rights reserved.

关键词： Cooling

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Novel Matching Strategy for the Coupling of Heat Flux in Furnace Side and CO_(2)Temperature in Tube Side to Control the Cooling Wall Temperatures

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Journal of Thermal Science 2021年第4期30卷 1251-1267页

作者： LIU Chao MIAO Zheng XU Jinliang XU Zeyu LI Mingjia Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power UniversityBeijing 102206China Key Laboratory of Power Station Energy Transfer Conversion and System North China Electric Power UniversityMinistry of EducationBeijing 102206China Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy&Power EngineeringXi’an Jiaotong UniversityXi’an 710049China

Required by the supercritical carbon dioxide(s CO_(2))coal-fired power cycle,s CO_(2)entering a boiler has a high temperature and can cause overheating of *** eliminate the pressure drop penalty effect,the s CO_(2)boiler consists of several modules,each having different heat flux received from the furnace side(q)and different CO_(2)temperature in the cooling wall tube(T_f).We aim to search for the best matching strategy coupling furnace side and tube side to obtain the lowest temperature of *** theoretically analyzing the wall temperature influenced by q,T_f and a comprehensive thermal resistance C,two matching methods are introduced:the heat flux-temperature matching(HTM)which matches higher q with lower T_f,and the heat flux-heat flux matching(HHM)that matches higher q with higher allowable-heat-flux at the temperature limit of *** is a conventional method but HHM is newly proposed *** show that,if C is identical for different modules,the two methods coincide;otherwise,HHM is *** a s CO_(2)boiler driving 1000 MWe power plant,smaller cooling wall temperatures are obtained by HHM than *** on HHM,the mid-partition wall,heat transfer enhancement,and downward flow are comprehensively used,decreasing the wall temperature significantly.

关键词： sCO_(2)power cycle sCO_(2)modular boiler cooling wall temperature allowable heat flux matching strategy

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X-ray computed tomography (XCT) study of jetting in a fluidized bed: Effects of two-component fluidization

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Particuology 2025年 102卷 264-274页

作者： Xiang, Zhong Chen, Xi Liu, Shuguang Heindel, Theodore J. School of Energy and Environment Southeast University Nanjing210096 China State Key Laboratory of Low-carbon Smart Coal-fired Power Generation and Ultra-clean Emission Southeast University Nanjing210096 China Center for Multiphase Flow Research and Education and Department of Mechanical Engineering Iowa State University AmesIA50011 United States

Fluidization of non-spherical particles is commonly found in the biomass and solid waste processing industry, and the jetting characteristic above the aeration plate is critical to the fluidization performance of these particles. In this study, cylindrical particles are used as typical non-spherical particles and co-fluidized with small bed material particles. X-ray computed tomography (XCT) is used to reconstruct the 3D structure of the aeration plate region, allowing for the identification of individual aeration jets. The effects of jet velocity (Uj), cylindrical particle mass fraction (ω), cylindrical particle density (ρi), and the cylindrical particle sphericity () on jet shape and volume are investigated. The experimental results indicate that decreasing the cylindrical particle mass fraction (ω) and particle density (ρi) increases the jet length (L), maximum jet diameter (D), and maximum jet volume (V), but have little effect on the jet half angle (θ). The cylindrical particle density (ρi) is the most sensitive factor for jet shape, while the effect of cylinder particle sphericity () on jet shape is insignificant. A correlation of jet length (L) in a two-component fluidized bed with cylindrical particles and bed material is proposed based on all the experimental results. © 2025 Chinese Society of Particuology and Institute of Process engineering, Chinese Academy of Sciences

关键词： Binary fluidized bed Cylindrical particle fluidization Jetting X-ray computed tomography

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Optimization of Heliostat Fields Using Advanced Particle Swarm Optimization (APSO) 4

Optimization of Heliostat Fields Using Advanced Particle Swa...

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4th IEEE International Conference on Renewable Energy and Power engineering, REPE 2021

作者： Rizvi, Arslan A. Yang, Dong Khan, Talha Ali Xi'An Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an710049 China University of Europe for Applied Sciences Department of Data Science Potsdam Germany

ISBN: (纸本)9781665443715

Optical losses account for 40% of all the losses in a central receiver system. These optical losses occur due to factors like shading, blocking, atmospheric attenuation, spillage, cosine loss, and mirror reflectivity. These factors are collectively represented using a single factor known as optical efficiency. There exists a tradeoff among these factors. The unavoidable optical loss can be minimized by optimizing the positions of heliostats in a strategic manner. An advanced particle swarm algorithm is used to optimize the position of heliostats around a dense radial staggered field. An efficiency map of the heliostat field is generated. Using instantaneous optical efficiency as an objective function, a single objective optimization is performed using 30 particles and 2 dimensions (each dimension representing an optimization variable). The results highlight the areas in the heliostat field with the highest losses associated with different components of optical efficiency and their solution. The instantaneous efficiency increases by 1.5% after optimization. © 2021 IEEE.

关键词： Particle swarm optimization (PSO)

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Experimental Study and Theoretical Development of Liquid Entrainment in T-Junction with Double Inlets and Single Inlet of Gas Phase

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SSRN 2023年

作者： Li, Kepiao Shi, Yanggen Zhang, Kui Tian, Wenxi Qiu, Suizheng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China School of Nuclear Science and Technology Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology Xi'an Jiaotong University Xi’an710049 China

The liquid phase entrainment through vertical-up branch had been analyzed through scaled and full size of experiment since ADS-4 (the fourth-stage Automatic Depressurization System) valve adopted in advanced PWR (Pressurized Water Reactor). Most of the existed studies focus on the single inlet of gas whereas steam may flow from two sides of the T-junction during the blowdown of primary system. Hence the experimental study on liquid entrainment with double end inlets are carried out. The data on the onset of entrainment (OLE) turns out that double end inlets show small difference with single inlet, whereas the entrainment rate research have great difference with single inlet and there is more than 50% error between the data and existing theoretical models. According to the visible flow phenomenon and flow instability, a new entrainment rate model was proposed which can well predict the double-end inlets and single-inlet entrainment phenomenon with the error within ±20%. © 2023, The Authors. All rights reserved.

关键词： Pressurized water reactors

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Preparation of Core/Shell Electrically Conductive Fibers by Efficient Coating Carbon Nanotubes on Polyester

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Advanced Fiber Materials 2021年第3期3卷 180-191页

作者： Liangyu Ma Yi Nie Yanrong Liu Feng Huo Lu Bai Qian Li Suojiang Zhang College of Chemistry and Chemical Engineering Henan UniversityHenan 475000China Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China Zhengzhou Institute of Emerging Industrial Technology Henan 450040China

Conducting fibers with improved properties and functionalities are needed for diverse *** we report the fabrica-tion of core/shell conductive Dacron fibers by dip-coating method through originating from multi-walled carbon nanotubes(MWCNTs)coated on polyester *** annealing process was conducted to enhance interaction between the conductive shell and polyester core as well as within the MWCNTs *** properties of two kinds of MWCNTs dispersions and the electrical properties of conductive fibers were studied,*** results show that both MWCNTs-polyurethane resin(MWCNTs-WPU)dispersion and MWCNTs-acrylic resin(MWCNTs-PAA)dispersion present a typical characteristic of pseudo-plastic fluid and an excellent wetting ability to polyester *** ultimate tensile stress and elongation at break for the MWCNTs-PAA coated fiber are 261 MPa and 25.43%.The ultimate tensile stress and the elongation at break are both increasing with the increasing of MWCNTs contents,due to the strong interface bonding ability between the conduc-tive shell and polyester core and strengthen the MWCNTs *** electrical resistance of the obtained fibers can be controlled in the range from 732 to 30Ω/cm by changing MWCNTs content,dipping times and annealing *** was found that it is able to light a *** results suggest that the conductive fibers embody a good synergy effect of carbon nanotubes and ***,the fabricated conductive fibers have a widely prospect for being applied in the field of flexible electronics.

关键词： MWCNTs dispersion Conductive polyester fiber Electrical resistance Interface

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