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2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices, ASEMD 2020

作者： Wang, Yu Yu, Xiwen Xiong, Youxing Huang, Wen Chen, Junquan National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan430033 China

ISBN: (纸本)9781728152158

In this paper, mathematical models for three types of MHD propeller are built. And they are used to achieve the most efficient propeller with the given design constraints. Based on the design result and current status of practical magnet technology, we can infer that it is very difficult for these three types of MHD propeller to be used practically. © 2020 IEEE.

关键词： Superconducting magnets

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Measurement of Equivalent Electrical Conductivity of Carbon Fiber Sleeve

Measurement of Equivalent Electrical Conductivity of Carbon ...

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2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices, ASEMD 2020

作者： Yu, Xiwen Xiong, Youxing Wang, Yu Chen, Junquan Wang, Dong National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan430033 China

ISBN: (纸本)9781728152158

In this paper, a method for measuring electrical conductivity of the carbon fiber sleeve is introduced. Different from traditional method using the bar, the ring shaped specimen is adopted, where eddy current is induced and flows in the closed loop. An air-gapless reactor was designed, based on this, the reactor was given a sinusoidal excitation with a certain frequency and different amplitudes. By separating the joule loss from the measured total loss, the equivalent electrical conductivity along the circumferential direction can be computed according to the theoretical formula. The result is validated by a finite element model established in Ansoft/Maxwell 3D. © 2020 IEEE.

关键词： Carbon fibers

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Using Neural Networks to Reduce the Ill-Posedness of Inverse Heat Transfer Problems in the Temperature Rise Transient Process of a Rotating Disk

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SSRN 2024年

作者： Qiu, Tian Deng, Changchun Liu, Peng Ding, Shuiting Luo, Xiang Research Institute of Aero-Engine Beihang University Beijing102206 China Aircraft Engine Integrated System Safety Beijing Key Laboratory Beihang University Beijing100191 China Collaborative Innovation Center for Advanced Aero-Engine Beihang University Beijing102206 China National Key Laboratory of Science and Technology on Aero-Engine Aero thermodynamics Beihang University Beijing100191 China

The working state change of the rotating disk cavities caused by the transient heat transfer is one of the main reasons for the high failure risk of aero-engines in the transient process, which makes the accurate measurement of transient heat transfer characteristics in the transient process of rotating disk cavities become an extremely important issue for the safety design of aero-engines. However, as one of the most widely used methods for measuring heat transfer characteristics, the inverse heat transfer problem method has the characteristics of ill-posed, and the errors of heat transfer characteristics are extremely sensitive to temperature errors. In this paper, a back propagation (BP) neural network approximation technique is used to reduce the ill-posedness of transient inverse heat transfer problems of a rotating disk. The numerical experimental results show that the application of this method in transient inverse heat transfer problems will generate a time-space end edge effect, that is, the ill-posedness in the area near the end edge of time and space has not been effectively reduced, and the wall heat flux still has significant errors in this area. To address this issue, the radial basis function (RBF) neural network local data correction method and time dimension data extension method are proposed to effectively suppress the time-space end edge effect. After improvement, the method proposed in this paper can reduce the transient wall heat flux errors in most time-space regions by 1 ~ 2 orders of magnitude;Within the scope of this study, the minimum proportion of the area where the ill-posedness of transient inverse heat transfer problem is reduced in the entire time-space region is about 91.7%, and the maximum proportion can reach about 98.6%. Finally, the advantages and disadvantages of the two improved methods are compared. © 2024, The Authors. All rights reserved.

关键词： Numerical methods

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An Ontology-based Knowledge Modeling towards Eco-design for Additive Manufacturing

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Procedia CIRP 2024年 122卷 760-765页

作者： Yanan Wang Tao Peng Samyeon Kim Yi Xiong Yunlong Tang Renzhong Tang State Laboratory of Fluid Power Components and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou 310058 China Department of Mechanical Engineering Jeonju University Jeonju-si Jeollabuk-do 55069 South Korea School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen 518055 China Mechanical and Aerospace Engineering Department Monash University Melbourne 3800 Australia Materials Science and Engineering Department Monash University Melbourne 3800 Australia Zhejiang Province Key Laboratory of Advanced Manufacturing Technology School of Mechanical Engineering Zhejiang University Hangzhou 310058 China

Owing to the unique technological merits of additive manufacturing (AM), design for AM, particularly eco-design for AM, has been gaining attention in improving the sustainable performance of AM-fabricated (AMed) parts. The main challenge in harvesting potential sustainability benefits is how to capture the impact of design on sustainable performance. Though several existing studies adopted quantitative evaluation on AM sustainability and investigated the relationships between design information and sustainability information of AMed part, the sustainability information is still unavailable in the design phase. This hardly guides eco-design for AM in practice. To support the increasing industrial applications of AM, this paper illustrates related knowledge, that is, material-process-structure-ecoProperty (MPSeP) relationships to connect design and sustainability information in eco-design for AM. An ontology-based method is proposed to model the MPSeP relationships of the AMed part in a structured way. An example of an AMed hydraulic valve body was used to demonstrate the MPSeP modeling process. It is discussed that how the constructed model effectively assists AM designers through providing eco-design recommendation, and enables design software tools to perform sustainability analysis towards eco-design for AM.

关键词： additive manufacturing eco-design for additive manufacturing ontology model sustainability

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Investigation of Heat Transfer and Flow Boiling Characteristics of a New Symmetric Cosine Mini-Channel Heat Exchanger with High Heat Flow Density

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SSRN 2023年

作者： Xu, Zhanying Liu, Huan-Ling Xie, Gongnan Shaanxi Key Laboratory of Space Solar Power Station System School of Electromechanical Engineering Xidian University Xi’an710071 China Key Laboratory of Electronic Equipment Structure Design Ministry of Education School of Electromechanical Engineering Xidian University Xi’an710071 China School of Marine Science and Technology Northwestern Polytechnical University Xi’an710072 China

A novel symmetric cosωx mini-channel heat exchanger (SCMC) with a combined bionic leaf vein diverter with ethanol as coolant is designed to meet the heat dissipation requirements for high heat flux chips. The mini-channel is firstly passed through a bionic leaf vein diverter to ensure the uniformity of the liquid distribution in the different mini-channels. Firstly, the homogeneity of the liquid distribution in different mini-channels is ensured by a bionic leaf vein divertor. Then, in order to obtain the flow characteristics and bubble features in the channel under conjugate conditions, a systematic three-dimensional numerical study is carried out by coupling the phase transition model with the volume of fluid (VOF) model. It is found that the symmetric distribution structure of the SCMC flow channel not only provides nucleation points for bubble generation, but also provides rupture points for large bubbles that can block the flow channel due to bubble aggregation, which reduces the instability of phase transition heat. Compared with the smooth flow channel structure of ω=1 and ω=1.5, the steep structure of ω=2 not only helps the mixing of coolant, but also increases the probability of bubbles hitting the sharp structure, which is more helpful for the rupture of large bubbles. In addition, the effects of waviness (ω ~ 0-2) and inlet velocity (Re ~ 234.07-1170.37) on the heat transfer performance under non-constant flow boiling conditions are investigated. The results show that the heat transfer capacity of SCMC increases firstly and then decreases with the increase of ω and subsequently increases again with the constant Re. The performance factor shows a decrease and then increases, which gets the maximum value at ω=2 and still shows an increasing trend. In the case of constant ω, the heat transfer capacity of SCMC is enhanced with the increase of Re, but the enhancement trend gradually slows down, and the performance factor shows a trend of increasing at first an

关键词： Heat exchangers

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Weakening s-d orbital hybridization of metallic iridium by tungsten atoms for acidic water splitting

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Applied Catalysis A: General 2023年 649卷 1页

作者： Chang, Chaofeng Xie, Yuhua Luo, Fang Zhou, Shaowei Yang, Zehui Sustainable Energy Laboratory Faculty of Materials Science and Chemistry China University of Geosciences Wuhan 388 Lumo RD Wuhan430074 China State Key Laboratory for Hubei New Textile Materials and Advanced Processing Technology School of Materials Science and Engineering Wuhan Textile University Wuhan430200 China Power system and new energy China Ship Development and Design Center Wuhan430074 China

To economically realize proton electrolyte membrane water splitting technology, stable and high-performance oxygen evolution reaction (OER) electrocatalyst is significantly demanded. In this work, we invite tungsten atoms to metallic iridium (Ir) to weaken s-d hybridization of Ir-Ir bond due to the higher electronegativity accepting electron from Ir atoms;as a result, the adsorbed O* species become electrophilic favorable for the nucleophilic attack by H2O leading to 22 % decrement in energy barrier for the formation of OOH* species. Therefore, iridium-tungsten (IrW) electrocatalyst exhibits 3.7-fold higher turnover frequency (TOF) than metallic Ir at overpotential of 370 mV in acidic OER catalysis. Moreover, stable OER performance is recorded due to the high cohesive energy of tungsten atoms. Additionally, TOF of IrW electrocatalyst reaches 10.1 s−1 at overpotential of 100 mV in acidic hydrogen evolution reaction (HER) test, 7.6-time higher than Pt/C and metallic Ir. IrW electrocatalyst only needs 1.52 V to attain 10 mA cm−2 in acidic overall water splitting. © 2022 Elsevier B.V.

关键词： Chemical bonds

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design of an inductor-integrated transformer applied to inverter power supply 1

Design of an inductor-integrated transformer applied to inve...

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1st IEEE China International Youth Conference on Electrical Engineering, CIYCEE 2020

作者： Zhang, Xinsheng Wang, Ruitian Xiao, Fei Jie, Guisheng Lou, Xujie Yang, Beichao Naval University of Engineering National Key Laboratory of Science and Technology on Vessel Integrated Power System Wuhan430033 China

ISBN: (纸本)9781728196596

The cascaded H-bridges with carrier phase-shift SPWM can increase the equivalent switching frequency and improve the output voltage quality. When the cascaded H-bridges topology is applied to the line-frequency inverter power supply, the bulky magnetic components limit the power density of the power supply. This paper integrates the isolation transformers and filter inductors in the power supply, and develops an optimization design method of the transformer. Through integration and optimization design, the volume power density of the transformer is increased by 69.6%, and the weight power density is increased by 44.8%. © 2020 IEEE.

关键词： design

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The stress indices study for the pipe with trunnion welding attachment 27

The stress indices study for the pipe with trunnion welding ...

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27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Lu, Xifeng Bai, Xiaoming Zheng, Liangang Zhang, Rui Yuan, Feng Yuan, Yanli Huang, Qian Science and Technology on Reactor System Design Technology Laboratory Chengdu Sichuan China

ISBN: (纸本)9784888983051

In the nuclear power plant, the trunnion welding attachment is widely used to connect the pipe and support. According to ASME Code Cases the stress caused by the welded attachment is considered as the additional stress of the pipe. However, the calculation of the additional stress is very complex and time-consuming. A method based on the concept of stress indices is proposed in present work. To investigate the influence of size and constraint and the stress indices, the finite element analysis for pipe with different sizes trunnion welding attachment under different constraint forms are done. The stress indices are calculated for each case, respectively. Furthermore, the fitted expressions for stress indices are proposed for general case. To verify this method, an analysis according to ASME Code Case for piping with trunnion is done. The comparison of the result between present method and the ASME Code Case method show slight different. Therefore, the stress indices method for the stress analysis of pipe with trunnion welding attachment can be an alternative method for ASME Code Cases. The advantage of present method in that it simplified the analysis process by introduces the stress indices. This method is effective and practical during the design and analysis of piping system in the nuclear power plant. Copyright © 2019 by JSME

关键词： Welding

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Α-Moc@Cs Carrier Modulated Platinum Single Atoms to Enhance Catalytic Activity in Solar Cells

SSRN

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SSRN 2022年

作者： Yao, Jixin Wang, Jie Wang, Wen Meng, Ying Wang, Haibo Lu, Shibin Du, Feng Yang, Li Zuo, Xueqin Li, Guang Anhui Province Key Laboratory of Simulation and Design for Electronic Information System Universitie s Joint Key Laboratory of Photoelectric Detection Science and Technology Hefei Normal University Anhui Province Hefei230601 China School of Materials Science and Engineering Anhui Key Laboratory of Information Materials and Devices Key Laboratory of Structure and Functional Regulation of Hybrid Materials Ministry of Education Institute of Physical Science and Information Technology Anhui University Hefei230601 China Institute of Materials Science and Devices School of Materials Science and Engineering Suzhou China University of Science and Technology Suzhou215011 China

Single-atom electrocatalysts have been proven to be the great promising catalysts for energy-related fields yet their active site structure remains elusive, especially in dye-sensitized solar cell (DSSC). Herein, atomically dispersed Pt is confined into α-MoC@CS carrier (Pt/α-MoC@CS), which vigorously stimulates the activity of Pt single atoms under strong interactions. As expected, the Pt/α-MoC@CS as the cathode in DSSC exhibits high power conversion efficiency (PCE) of 9.87%, exceeding Pt electrode (7.61%). X-ray photoelectron spectroscopy combined with density functional theory calculations reveals that the high activity is mainly derived from charge re-distribution of Pt/α-MoC@CS caused by the interaction between Pt atoms and α-MoC. This interaction not only achieves the optimized adsorption/desorption energy of reactants but also brings synergic advantages to expedite the reaction kinetics of the overall system. This work paves further research prospects for charge re-distribution, stimulating electrocatalysts to effectively enhance their catalytic properties by an atomic-level engineering strategy. © 2022, The Authors. All rights reserved.

关键词： Cathodes

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Uncertainty quantification research of reactor system under seismic load 27

Uncertainty quantification research of reactor system under ...

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27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Huang, Qian Xiong, Furui Bai, Xiaoming Yu, Xiaofei Zheng, Liangang Lu, Xifeng Song, Haiyang Science and Technology on Reactor System Design Technology Laboratory Chengdu Sichuan China

ISBN: (纸本)9784888983051

In the dynamic analysis of reactor system, the key mechanical input parameters are uncertain due to the design change, manufacturing, installation and calculation deviation, which affects the dynamic response, load distribution and final mechanical evaluation results. In order to quantify the influence of the uncertainty on seismic responses and load distribution, the uncertainty quantification of key structural input parameters of reactor system under seismic load is studied. Firstly, according to the fundamental characters of key input parameters (contact stiffness and gap among various assemblies), maximum entropy principle is adopted to construct the probability density function(PDF). Then, Markov Chain Monte Carlo technique is applied to sample according to the PDF, and the input and output data pool is constructed via finite element transient computations. According to the results, probabilistic distributions of dynamic responses caused by uncertainty from inputs parameters are evaluated and the reliability of nominal model is investigated. The studies show that the probabilistic distribution of reactor system dynamic response differs greatly with different output mechanical parameters, degrees of freedom and frequency bands. The uncertainty quantification method and process for reactor system are proposed in this paper. This method can be extended to other equipments easily. Therefore, it is an effective tools for the reliability of dynamic response. Copyright © 2018-2019 by JSME

关键词： Markov processes

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