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A new non-destructive method for fault diagnosis of reciprocating compressor by measuring the piston rod strain

IOP Conference Series: Materials Science and engineering 2019年第1期604卷

作者： Xueying Li Xueyuan Peng Xi'an Jiaotong University Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

As an established method to analyse the thermodynamic process inside the cylinder, the p-V diagram can identify typical faults such as leakages through the sealing rings and self-acting valves, loosening and fluttering of the vales, etc. However, the installation of the pressure sensor within the cylinder for recording the p-V diagram may lead to degradation of the cylinder integrity, and hereby potential leakage and lowered strength of the cylinder. This paper presents a new non-destructive method for fault diagnosis of the reciprocating compressor by measuring the piston rod strain, from which the p-V diagram was transformed. An algorithm for reconstruction of the p-V diagram was proposed based on the key feature points on the piston rod load curve that reflect the opening and closing events of the compressor valves. The reconstruction method was validated by comparing the calculated p-V diagrams with the experimental results. The reconstructed p-V diagrams were further used for fault diagnosis of the reciprocating compressors, with which the acoustic emission method was integrated. The results show that this method can easily monitor the working conditions and identify whether and where leakage, fluttering and delayed closing of the valves occur, which indicates that this method can be utilized as a powerful tool of non-destructive condition monitoring and fault diagnosis of the reciprocating compressors.

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Improve the Conversion Rate and Selectivity of Aromatic Monomers in Lignin Photocatalytic Conversion Reaction Via Phase Junction Cadmium Sulphide Nanoparticles and External Hydrogen Supplier

SSRN

引用

SSRN 2023年

作者： Yue, Zongyang Shao, Shibo Yu, Jialin Lu, Guanchu Wei, Wenjing Huang, Yi Zhang, Kai Wang, Ke Fan, Xianfeng Institute for Materials and Processes School of Engineering The University of Edinburgh EdinburghEH9 3BF United Kingdom Petrochemical Research Institute PetroChina Company Limited Beijing102206 China Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex Systems Innovation Academy for Green Manufacture Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China Longzihu New Energy Laboratory Zhengzhou Institute of Emerging Industrial Technology Henan University Zhengzhou450000 China Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation North China Electric Power University Beijing102206 China

Photocatalysis has the potential for lignin valorisation to generate functionalised aromatic monomers, but its large-scale application has been limited by the slow conversion rate and the low selectivity to desirable products. In this work, record-high lignin model compound Cβ-O bonds cleavage rate and excellent selectivity to aromatic monomers has been achieved over the development of new hexagonal-cubic phase junction CdS nanoparticles, enhanced external hydrogen donor supply and hydrogen transfer, and improved separation efficiency of photo-excited electron-hole pairs. Water is employed as external hydrogen supplier, resulting in significant increase in the conversion rate of 2-Phenoxy-1-phenylethanol (PP-ol) as lignin model from 21.8% to 100% and the selectivity of aromatic monomers from ~45% to ~94% under 1h of visible light irradiation. 2-phenoxyacetophenone (PP-one) as by-product from PP-ol conversion can be further completely cleaved to aromatic monomers with assistance of TEA and reaction time is reduced from 2-12 hrs to10 min under visible-light irradiation. © 2023, The Authors. All rights reserved.

关键词： Lignin

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High-Ni Low-Co High-Capacity Li-Rich Cathode Materials Via Adjusting Li2mno3 Content and Li/Ni Mixing Structures

SSRN

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SSRN 2023年

作者： Wu, Zhen Zou, Kunyang Dai, Xin Zhang, Yu-Han Zhang, Xudong Wang, Hao Hou, Zhufeng Ma, Lijing Liu, Yan Chen, Yuanzhen Guo, Shengwu Liu, Yongning State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University Xi’an710049 China Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao266101 China Center for High Performance Computing Network Information Center Xi’an Jiaotong University Xi’an710049 China Hefei Advanced Computing Center Operation Management Corp Ltd Hefei230088 China State Key Laboratory of Structural Chemistry Fujian Institute of Research the Structure of Matter Chinese Academy of Sciences Fuzhou350002 China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Li-rich layered oxides (LLOs) are considered as the promising cathode materials for next-generation high energy density lithium-ion batteries (LIBs). However, severe voltage fade and capacity decay hinder their commercial applications. Increasing the Ni content in LLOs effectively improves the stability and discharge voltage, but shows reduced capacities, typically © 2023, The Authors. All rights reserved.

关键词： Lithium compounds

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Performance enhancement for nanofluid-cooled microchannel heat sink

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Yingyong Jichu yu Gongcheng Kexue Xuebao/Journal of Basic Science and engineering 2012年第SUPPL.期20卷 169-180页

作者： Lin, Lin Wang, Xiaodong Wang, Zhenhua Department of Thermal Engineering University of Science and Technology Beijing Beijing 100083 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing 102206 China Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy North China Electric Power University Beijing 102206 China Xi'an Shaangu Power Co. LTD Xi'an 710075 China

Based on selecting the proper formulas of thermal conductivity and viscosity for nanofluids, a three-dimensional fluid-solid conjugated model was developed to analyze the effect of the heat sink structure, the nanoparticle kind, diameter and volume fraction, and the base fluid kind on the cooling performance of microchannel heat sink. The results showed that: (1) thermal dispersion effect caused by nanoparticle random motion enhanced the thermal convection of nanofluid thus enhances significantly the cooling performance of heat sink;(2) the enhancement of nanofluids was closely dependent on the heat sink structure and the dependence was distinct from the pure fluid, hence the heat sink structure was needed to be optimized for nanofluids as coolants;(3) as the nanoparticle volume fraction increases, the thermal resistance reduced and the pressure increased, the water-based Al2O3 nanofluid with 0.5% volume fraction was the optimal coolant which caused 10.1% decrease in the thermal resistance and only 0.38% increased in the pressure drop;(4) although the nanoparticle size had a small effect on the thermal resistance, nanoparticles with small diameter were recommended with consideration of stability of nanofluids;(5) Al2O3 nanoparticle was superior to TiO2 and CuO, and water was the better base fluid than ethylene glycol and engine oil.

关键词： Nanoparticles

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Performance of V-Cone flowmeter applied to cryogenic fluid measurement considering cavitation

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IOP Conference Series: Earth and Environmental Science 2019年第6期240卷

作者： Denghui He Bofeng Bai Senlin Chen Jie Zhang Pengcheng Guo State Key Laboratory of Eco-hydraulic in Northwest Arid Region Xi'an University of Technology Xi'an 710048 Shaanxi China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi China

The V-Cone flowmeter is a promising differential pressure flowmeter for metering the cryogenic fluid for its many advantages. When the cryogen velocity increases to a certain value, the cavitation may occur in flowmeter, which may significantly affect the performance of V-Cone flowmeter. However, the effect of cavitation on performance of V-Cone flowmeter remains unclear and there are no published studies to our knowledge on this issue. Here we investigate the performance of V-Cone flowmeter when measuring the cryogenic fluids, especially the effects of cavitation on the discharge coefficient and pressure loss coefficient of the flowmeter. Two cryogenic fluids are investigated, including liquid nitrogen (LN2) and liquid hydrogen (LH2). For comparison, the water is also investigated. The realizable κ-ε model is used to describe the turbulence. The Schnerr-Sauer cavitation model is used to investigate the effect of cavitation on the performance of the V-Cone flowmeter. The results show that there was little effect of cavitation on the discharge coefficient and pressure loss coefficient at the initial stage of cavitation. When the cloud cavitation occurred downstream of V-Cone, the discharge coefficient decreases rapidly with Reynolds number increasing, while the pressure loss coefficient rises quickly. The average discharge coefficient is almost the same for different fluids in the stable region; while the cryogenic fluids have wider stable Reynolds number ranges than the water. The lower limits of the Reynolds number for the constant discharge coefficient is very close for three fluids, however, for the upper limits of Reynolds number are quite different. We conclude that measurement range of the cryogenic fluid is much larger than that of the water, which shows that the V-Cone flowmeter exhibits great potential in the measurement of cryogenic fluid. This study provides insights into the effect of cavitation on the measurement of V-Cone flowmeter and opens a new aven

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Corrigendum to “Promoting adiabatic core approximation in a rapid compression machine by an optimized creviced piston design” [Fuel 251 (2019) 328–340]

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Fuel 2019年 255卷

作者： Yingtao Wu Meng Yang Chenglong Tang Yang Liu Peng Zhang Zuohua Huang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China Department of Mechanical Engineering The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong

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Facile Synthesis of Bulk Au-Co-Coox-Ceox@Iron Ball and its Photocatalytic Application in 4-Nitrophenol Degradation

SSRN

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SSRN 2023年

作者： Sun, Li Qiao, Zhili Zhi, Yuan Zhang, Hua Dou, Binlin Shan, Yuejin Huang, Weijia School of Energy and Power Engineering University of Shanghai for Science and Technology Jun Gong Road 516 Shanghai200093 China R&D Department Shanghai Minrula Biotechnology Co.Ltd Building 15 Haji Sixth Road 218 Shanghai201306 China Department of Material and Environmental Chemistry Research Division of Functional Materials Design Utsunomiya University Yoto 7-1-2 Utsunomiya321-8585 Japan Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering China

Bulk noble metal-semiconductor composites can be chosen as photocatalysts to carry out the continuous-flow (C-F) degradation of 4-nitrophenol (4-NP) whereas their preparation is complex and uncontrollable. Here, bulk Au/Co-CC@iron ball is designed and prepared by a facile and controllable route without any toxic chemical. The bulk Au/Co-CC@iron ball shows excellent photocatalytic activity and reusability for the 4-NP degradation, which can be ascribed to the synergistic action of active components and foliated iron ball surface. Furthermore, the highly active Au/Co-CC@iron ball is used as packing material to construct a new-type of packed reactor, by which the C-F degradation of 4-NP is successfully achieved. As-fabricated packed reactor and its tandem module exhibit superior photocatalytic performance for the C-F degradation of 4-NP. Noteworthy, based on the tandem module with six reactors, the removal rate of 4-NP can reach up to 2750 µmol/h. Meanwhile, the reactor and its module display satisfactory operational stability and reusability in the C-F degradation of 4-NP. Clearly, the provided route is effective for the preparation of bulk noble metal-semiconductor composites with exceptional performance, which can also be a prospective strategy to obtain bulk packing materials to serve for the C-F degradation. © 2023, The Authors. All rights reserved.

关键词： Precious metals

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Numerical Study of Evaporation and Motion Characteristics of Liquid Nitrogen Droplet in High-Speed Gas flow

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IOP Conference Series: Materials Science and engineering 2017年第1期278卷

作者： Y. Ruan L. Chen X. Liu S. Chen Y. Hou State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 PR China Xi'an Jiaotong University Suzhou Academy Suzhou 215123 PR China

In the cryogenic wind tunnel, cooling the circulating gas to cryogenic temperature by spraying liquid nitrogen (LN2) is an efficient way to increase the Reynolds number. The evaporation and motion of LN2 droplets in the high-speed gas flow is the critical process that determines the cooling rate, cooling capacity and the safe operation of the down-stream compressor. In this study, a numerical model of droplet motion and evaporation in high-speed gas flow is developed and verified against experimental data. The droplet evaporation rate, diameter and velocity are obtained during the evaporation process under different gas temperatures and flow velocities. The results show that the gas temperature has dominant influence on the droplet evaporation rate. High flow speed can increase droplet evaporation effectively at the beginning process. Evaporation of droplets with different diameters follows a similar trend. The absolute evaporation rate increases with the increase of droplet diameter while the relative evaporation amount is highest for the smallest droplet due to its high area-volume ratio. This numerical study provides insight for understanding the evaporation of LN2 droplets in high-speed gas flow and useful guidelines for the design of LN2 spray cooling.

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Development of typical processes and key devices for direct air CO2 capture

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Meitan Xuebao/Journal of the China Coal Society 2024年第10期49卷 4203-4221页

作者： Yu, Binpeng Tan, Lei Wang, Ding Wang, Limin Xiang, Xiaofeng Wang, Zhichao Jin, Zhonghua Yang, Bolun Wu, Zhiqiang School of Chemical Engineering and Technology Xi’an Jiaotong University Xi’an710049 China Shaanxi Province Energy and Chemical Process Intensification Key Laboratory Xi’an710049 China School of Engery and Powerl Engineering Xi’an Jiaotong University Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an710049 China Shaanxi Engineering Research Center if Coal Fired Boiler Environmental Protection Xi’an710054 China

Conventional carbon capture and storage technologies and carbon capture, utilization and storage technologies mainly target CO2 emissions from fixed sources, while direct air capture CO2 (DAC) technology, as an emerging negative carbon emission technology, can capture CO2 emissions from distributed sources and further reduce the global atmospheric CO2 concentration. In this paper, the development process of DAC's typical liquid absorption process, solid adsorption process and the construction of relevant demonstration projects are introduced, the technical characteristics of emerging DAC processes are analyzed, and the key equipment schemes and future development trends of existing DAC processes are discussed. The DAC liquid absorption process has the characteristics of low cost of absorbent raw materials and high selectivity, which can realize a large-scale continuous capture, but high energy consumption in the regeneration process. The DAC solid adsorption process has the characteristics of modularity, low investment cost, and relatively low energy consumption in the regeneration process, but requires a regular replacement of adsorption materials and maintenance of adsorption equipment, which is suitable for small-scale DAC application scenarios. Two typical DAC process absorption/adsorption materials are reviewed. In the DAC electric oscillation adsorption process, CO2 is chemically captured in the solid electrode, and CO2 desorption is achieved by changing the polarity of the solid electrode with applied electric field. This process has a higher efficiency than that of the heat or pressure-based separation process. The CO2 in the air is selected through the DAC separation membrane to achieve an efficient carbon capture. The DAC process achieves the CO2 absorption and desorption through the change of humidity, which breaks through the high energy consumption limit of conventional variable temperature/pressure swing adsorption. The DAC bio-absorption process absor

关键词： Adsorption

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Direct numerical simulation of Taylor-Couette flow with vertical asymmetric rough walls

arXiv

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arXiv 2023年

作者： Xu, Fan Su, Jinghong Lan, Bin Zhao, Peng He, Yurong Sun, Chao Wang, Junwu School of Energy Science and Engineering Harbin Institute of Technology Harbin150001 China State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences P. O. Box 353 Beijing100190 China School of Chemical Engineering University of Chinese Academy of Sciences Beijing100049 China Innovation Academy for Green Manufacture Chinese Academy of Sciences Beijing100190 China 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 Department of Engineering Mechanics School of Aerospace Engineering Tsinghua University Beijing100084 China

Direct numerical simulations are performed to explore the effects of the rotating direction of the vertically asymmetric rough wall on the transport properties of Taylor-Couette (TC) flow, up to a Taylor number of Ta = 2.39×107. It is shown that, compared to the smooth wall, the rough wall with vertical asymmetric strips can enhance the dimensionless torque Nuω. More importantly, at high Ta, clockwise rotation of the inner rough wall (where the fluid is sheared by the steeper slope side of the strips) results in a significantly greater torque enhancement compared to counter-clockwise rotation (where the fluid is sheared by the smaller slope side of the strips), due to the larger convective contribution to the angular velocity flux. However, the rotating direction has a negligible effect on the torque at low Ta. The larger torque enhancement caused by the clockwise rotation of the vertically asymmetric rough wall at high Ta is then explained by the stronger coupling between the rough wall and the bulk, attributed to the larger biased azimuthal velocity toward the rough wall at the mid-gap of the TC system, the increased turbulence intensity manifested by larger Reynolds stress and a thinner boundary layer, and the more significant contribution of the pressure force on the surface of the rough wall to the torque. Copyright © 2023, The Authors. All rights reserved.

关键词： Direct numerical simulation

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