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2022 3rd International Conference on Mechanical engineering and Materials, ICMEM 2022

作者： Liu, Qiuyuan Qiu, Xiaopan Liu, Xin Zhao, Xingyuan Jiang, Sheming Zhang, Qifu Laboratory of Advanced Coating Technology for Metals China Iron and Steel Research Institute Group National Engineering Beijing100081 China State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China

Zinc coatings have been served as a barrier and a galvanic protection for steel products for over a century. However, with the depletion of zinc resources, it becomes an urgent issue to obtain a new type of zinc coating that uses less zinc and has higher corrosion resistance. In order to develop Zn/ZnMg coatings with better corrosion resistance than traditional galvanized steel and suitable for advanced high strength steel, the vacuum thermal evaporation technique was used to simultaneously deposit Zn/ZnMg coating onto interstitial free steel plates and single-crystal silicon wafers in a high vacuum environment. The microstructure, morphology, adhesion and corrosion resistance behavior of the Zn/ZnMg coating were studied by scratch test, salt spray test and electrochemical method. The results shows that the grain size in the Zn/ZnMg coating tended to increase with the increase of the substrate temperature. After deposited the pure Zn transition layer, the adhesion of the coating has been obviously improved. When the substrate temperature was increased to 200°C, the obtained coating exhibited strong corrosion resistance. © Published under licence by IOP Publishing Ltd.

关键词： Corrosion resistance

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Effects of Inherent Aaems on Catalytic Gasification of Biomass with Large Particle Size Under Oxygen-Steam Atmosphere

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SSRN 2023年

作者： Ren, Jiyun Li, Yuhang Li, Yang Huang, Xiaole Jin, Xiaoling Yang, Chenglong Zhao, Hanchen Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China Xi’an Thermal Power Research Institue Co. Ltd. Xi’an710032 China

Oxygen-steam gasification of biomass is a promising technology because of its ability to improve syngas quality and reduce energy consumption. In this study, a fixed-bed reactor is employed to assess the effects of inherent alkali and alkaline earth metals (AAEMs) on the catalytic gasification of candlenut wood with large particle size under oxygen-stream atmosphere. The results show that the acid-washing would remarkably remove the inherent AAEMs in biomass, which is affected by the grain direction. In terms of the gasified chars derived from acid-washed biomass, AAEMs content gradually decreases along the end surface and radial direction, which could also be observed from the 3D reconstruction of X-ray CT images. A large number of mesopores (20-30 μm) align along the grain direction in the biomass sample. Numerous micropores (10-20 μm), mesopores (20-30 μm), and macropores (30-50 μm) are present in the gasified char derived from the biomass sample. Micropores (10-20 μm) prevail in the gasified char from the acid-washed biomass sample. Inherent AAEMs facilitate an augmentation in char yield as well as BET and total pore volume of gasified char. AAEMs and grain direction have a slight effect on functional groups of gasified char. The tar component is remarkably affected by the grain direction. Acid-washing pretreatment augments the content and organic species of M2-M4 compounds (containing 2-4 benzene rings) in the tar. It also leads to a decrement in concentrations of H2, CH4, and CO2 by 14.49% and 13.35%, 0.51% and 0.89%, 2.32% and 1.37% in syngas for two-grain direction, respectively. But it raises the CO concentration by 17.1% and 15.18%, resulting in a reduction of 4.09% and 1.53% in syngas calorific value. A decrement in the volume fraction of CnHx induced from AAEMs is significantly affected by the grain direction. © 2023, The Authors. All rights reserved.

关键词： Biomass

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Study of Unforced Unsteadiness in Centrifugal Pump at Partial flow Rates

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Journal of Thermal Science 2021年第1期30卷 88-99页

作者： YANG Jun XIE Tian LIU Xiaohua SI Qiaorui LIU Jun School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Key Laboratory of Fluid and Power Machinery(Xihua University) Ministry of EducationChengdu 610039China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai 200093China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China Research Center of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013China

In order to explore the unforced unsteadiness of centrifugal pumps,a 2-D frequency domain imaging display technology was used to study the development of these unsteady flow structures at partial flow *** results showed that,the unsteady flow field was not only affected by rotor and stator interaction,but also appeared an unforced unsteadiness with fundamental frequency of St≈0.23 around the impeller throat ***,as the flow rates decreased,this unsteady flow structure gradually weakened and *** the flow rate was reduced to 0.6 times of design flow rate,another two unforced unsteady flow structures with characteristic frequencies of St≈0.0714 and St≈0.12 began to appear in the same ***,with the operating condition smaller than design flow rate,the internal flow became more and more *** addition to the forced unsteadiness,the unforced unsteadiness which is not connected with the blade passage frequency became more and more obvious.

关键词： centrifugal pumps partial flow conditions pressure pulsations unforced unsteadiness 2-D frequency domain visualization method

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Effects of Inherent Aaems on Catalytic Gasification of Biomass with Large Particle Size Under Oxygen-Steam Atmosphere

SSRN

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SSRN 2023年

作者： Ren, Jiyun Li, Yuhang Jin, Xiaoling Huang, Xiaole Li, Yang Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China Xi’an Thermal Power Research Institue Co. Ltd. Xi’an710032 China

Oxygen-steam gasification of biomass is a promising technology because of its ability to improve syngas quality and reduce energy consumption. In this study, a fixed-bed reactor is employed to assess the effects of inherent alkali and alkaline earth metals (AAEMs) on the catalytic gasification of candlenut wood with large particle size under oxygen-stream atmosphere. The results show that the acid-washing would remarkably remove the inherent AAEMs in biomass, which is affected by the grain direction. In terms of the gasified chars derived from acid-washed biomass, AAEMs content gradually decreases along the end surface and radial direction, which could also be observed from the 3D reconstruction of X-ray CT images. In all biomass samples and gasified chars, micropores (0-10 μm) dominate and are distributed along the grain direction. In general, pores of 20-30 μm and above 30 μm comprise a minor proportion. Inherent AAEMs facilitate an augmentation in char yield as well as BET and total pore volume of gasified char. AAEMs and grain direction have a slight effect on functional groups of gasified chars. The tar component is remarkably affected by the grain direction. Acid-washing pretreatment augments the content and organic species of M2-M4 compounds (containing 2-4 benzene rings) in the tar. It also leads to a decrement in concentrations of H2, CH4, and CO2 by 14.49% and 13.35%, 0.51% and 0.89%, 2.32% and 1.37% in syngas for two-grain direction, respectively. But it raises the CO concentration by 17.1% and 15.18%, resulting in a reduction of 4.09% and 1.53% in syngas calorific value. A decrement in the volume fraction of CnHx induced from AAEMs is significantly affected by the grain direction. © 2023, The Authors. All rights reserved.

关键词： Biomass

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Thermal-Mechanical Influence Aspects and Evaluation of Helical Cruciform Single Rod in Fluoride-Salt-Cooled High-Temperature Advanced Reactor

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SSRN 2024年

作者： Chen, Yiwen Zhang, Dalin Jiang, Dianqiang Li, Wei Wu, Xiaoli Tian, Wenxi Qiu, Suizheng Su, Guanghui Lu, Qi 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 State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong University Xi’an710049 China Science Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China China

Helical cruciform fuels are novel in nuclear reactors, potential to increase reactor’s power density. However, the geometry is complicated so influence of it on the fuel performance is not identified yet. In this paper, impact of power density, cross-section parameters, and twist pitch on thermal and mechanical characteristics of fuel used in Fluoride-Salt-cooled high-Temperature Advanced Reactor is discussed based on fluid-thermal-mechanical coupling. For thermal features, twist pitch is key while others have few effects. Increase in twist pitch leads to temperature uniformity and rise owing to weaker mixing effects. Fuel center temperature at middle plane of 300mm-pitch rod is 829.58℃, 54.66℃ higher than that of 100mm-pitch rod. Difference of maximum and minimum temperature at 45° cross section of 500mm-pitch rod is 153.62℃, while the figure is only 74.00℃ of 300mm-pitch rod. Besides, axial temperature of cladding outer surface increases wavelike due to complex geometry. For mechanical features, not geometry sizes but temperature affects stress distribution. Maximum Von-Mises stress appears at the elbow, where maximum temperature exists, 116.8MPa under normal conditions, lower than tensile strength of the material. After identifying the influence of these factors, five dimensionless parameters are proposed to evaluate and rate fuel performance based on Technique for Order Preference by Similarity to an Ideal Solution. As a result, an optimization comes up, scoring 0.310, twice more than the original design, owing to the thermal uniformity and mechanical safety. This study provides a reference for identifying and evaluating the performance of helical structure. © 2024, The Authors. All rights reserved.

关键词： Geometry

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Tuning the local electronic structure of oxygen vacancies over copper-doped zinc oxide for efficient CO_(2) electroreduction

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eScience 2022年第5期2卷 518-528页

作者： Ke Wang Dongyu Liu Limin Liu Jia Liu XiaoFei Hu Ping Li Mingtao Li Andrey S.Vasenko Chunhui Xiao Shujiang Ding Xi'an Key Laboratory of Sustainable Energy Materials Chemistry School of ChemistryEnergy Storage Materials and Chemistry of Shaanxi University Engineering Research CenterXi'an Jiaotong University28 Xianning West RoadXi'an710049China International Research Center for Renewable Energy(IRCRE) State Key Laboratory of Multiphase Flow in Power Engineering(MFPE)Xi'an Jiaotong University28 Xianning West RoadXi'anShaanxi710049China HSE University 101000MoscowRussia College of Materials and Environmental Engineering Hangzhou Dianzi UniversityHangzhou310018PR China CNNC Shaanxi Uranium Enrichment Co. Ltd.HanzhongChina

Oxygen vacancies in metal oxides can serve as electron trap centers to capture CO_(2) and lower energy barriers for the electrochemical CO_(2) reduction reaction(CO_(2)RR).Under aqueous electrolytes,however,such charge-enriched active sites can be occupied by adsorbed hydrogen(H∗)and lose their effectiveness for the CO_(2)***,we develop an efficient catalyst consisting of Cu-doped,defect-rich ZnO(Cu–ZnO)for the CO_(2)RR,which exhibits enhanced CO Faradaic efficiency and current density compared to pristine *** introduced Cu dopants simultaneously stabilize neighboring oxygen vacancies and modulate their local electronic structure,achieving inhibition of hydrogen evolution and acceleration of the CO_(2)*** a flow cell test,a current density of more than 45mAcm^(−2) and a CO Faradaic efficiency of>80%is obtained for a Cu–ZnO electrocatalyst in the wide potential range of−0.76V to−1.06V *** Hydrogen Electrode(RHE).This work opens up great opportunities for dopant-modulated metal oxide catalysts for the CO_(2)RR.

关键词： CO_(2)electroreduction Oxygen vacancy Heteroatom doping Metal oxide catalysts

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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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A Dynamic Plunger Lift Model for Shale Gas Wells

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Fluid Dynamics & Materials Processing 2023年第7期19卷 1735-1751页

作者： Shiyu Miao Xiao Liu Xiaoya Feng Haowen Shi Wei Luo Peng Liu Petroleum Engineering Institute of Yangtze University Wuhan430100China Laboratory of Multiphase Pipe Flow Gas Lift Innovation CenterChina National Petroleum Corp.Yangtze UniversityWuhan430100China Key Laboratory of Drilling and Production Engineering for Oil and Gas Wuhan430100China Sichuan Shale Gas Exploration and Development Limited Liability Company Chengdu640000China Sichuan Changning Gas Development Company PetroChina Southwest Oil&Gas Field CompanyChengdu610051China Oil and Gas Technology Research Institute of Changqing Oilfield Company PetroChinaXi’an710018China

At present,the optimization of the plunger mechanism is shale gas wells is mostly based on empirical methods,which lack a relevant rationale and often are not able to deal with the quick variations experienced by the production parameters of shale gas wells in comparison to conventional gas *** order to mitigate this issue,in the present work,a model is proposed to loosely couple the dynamics of gas inflow into shale gas wells with the dynamics of the liquid *** from the flow law that accounts for the four stages of movement of the plunger,a dynamic model of the plunger lift based on the real wellbore trajectory is *** model is then tested against 5 example wells,and it is shown that the accuracy level is higher than 90%.The well‘switch’,optimized on the basis of simulations based on such a model,is tested through on-site *** is shown that,compared with the original switch configuration,the average production of the sample well can be increased by about 15%.

关键词： Shale gas well complex and more complex well bore structure plunger lift loose coupling simulation model

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General analytical equation of state for nanoconfined gases derived from statistical physics

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Physical Review E 2025年第2期111卷 025413-025413页

作者： Chengzhen Sun Haoxuan Li Zhixiang Zhao Mehdi Neek-Amal Bofeng Bai State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 China School of Urban Planning and Municipal Engineering Xi'an Polytechnic University Xi'an Shaanxi 710048 China Department of Physics Faculty of Sciences Shahid Rajaee Teacher Training University 16875-163 Lavizan Tehran Islamic Republic of Iran Department of Physics University of Antwerp Groenenborgerlaan 171 2020 Antwerp Belgium

The pressure prediction of nanoconfined gases is crucial for various industrial applications, yet existing equations of state (EOS) often compromise between accuracy and usability. This study derives a theoretical EOS in analytical form, combining precision and practicality through statistical physics. It begins by examining the pressure drop mechanism due to adsorbed molecules and refines molecular pairing and potential energy interactions. The resulting EOS accurately predicts the pressure of gases in nanoconfined spaces, especially with an average prediction error of about 5% for strongly adsorbing gases like nitrogen, oxygen, and argon. Additionally, it aligns with the Van der Waals EOS under macroscopic conditions, offering a unified framework across scales. This model enhances both engineering applications and the understanding of nanoconfined EOS.

关键词： Van der Waals forces

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Adaptive partitioning-based discrete unified gas kinetic scheme for flows in all flow regimes

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Advances in Aerodynamics 2023年第1期5卷 282-311页

作者： L.M.Yang L.C.Han H.Ding Z.H.Li C.Shu Y.Y.Liu Department of Aerodynamics College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Modern Mechanics University of Science and Technology of ChinaHefei 230027China National Laboratory for Computational Fluid Dynamics Beihang UniversityBeijing 100191China Department of Mechanical Engineering National University of SingaporeSingapore 117576Singapore

To improve the efficiency of the discrete unified gas kinetic scheme(DUGKS)in capturing cross-scale flow physics,an adaptive partitioning-based discrete unified gas kinetic scheme(ADUGKS)is developed in this *** ADUGKS is designed from the discrete characteristic solution to the Boltzmann-BGK equation,which contains the initial distribution function and the local equilibrium *** initial distribution function contributes to the calculation of free streaming fluxes and the local equilibrium state contributes to the calculation of equilibrium *** the contribution of the initial distribution function is negative,the local flow field can be regarded as the continuous flow and the Navier-Stokes(N-S)equations can be used to obtain the solution ***,the discrete distribution functions should be updated by the Boltzmann equation to capture the rarefaction *** this,in the ADUGKS,the computational domain is divided into the DUGKS cell and the N-S cell based on the contribu-tion of the initial distribution function to the calculation of free streaming *** the N-S cell,the local flow field is evolved by solving the N-S equations,while in the DUGKS cell,both the discrete velocity Boltzmann equation and the correspond-ing macroscopic governing equations are solved by a modified *** more and more cells turn into the N-S cell with the decrease of the Knudsen number,a significant acceleration can be achieved for the ADUGKS in the continuum flow regime as compared with the DUGKS.

关键词： Boltzmann-BGK equation Discrete unified gas kinetic scheme Adaptive partitioning Discrete characteristic solution All flow regimes

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