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Transport equation for the drift velocity in predicting the filtered Eulerian drag force: A theoretical development

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arXiv

arXiv 2018年

作者： Chen, Xiao Jiang, Ming Zhou, Qiang School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The drift velocity has been proven to have significant relevance to the filtered Eulerian drag force by numerous correlative analyses of fully resolved simulations. It is a sub-grid quantity defined as the difference between the filtered gas velocity seen by the particle phase and the resolved filtered gas velocity. In literature, it is shown that various algebraic models for the drift velocity fail to give entirely satisfactory prediction of the filtered drag force. Unlike previous works, we theoretically derived the transport equation for the drift velocity from the standard two-fluid model (TFM) equations without any additional assumptions. The new approach, though requires additional closures for the new unresolved terms, is believed to have the potential to improve the precision of the estimation of this sub-grid quantity and hence give better prediction of the filtered drag force for gas-solid fluidization problems. Copyright © 2018, The Authors. All rights reserved.

关键词： Drag

Effect of Tungsten Size on Thermal Analysis and Mechanism of Lithium Perchlorate-Based Electrically Controlled Solid Propellant

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SSRN 2023年

作者： Yang, Meng Yoh, Jack J. Tang, Chenglong Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Department of Aerospace Engineering Seoul National University Seoul08826 Korea Republic of

Electrically controlled solid propellant (ECSP) is a novel and potential of propellant with excellent properties, which can achieve multiple ignitions and extinguishments through supplying and cutting electric power. At present, thermochemistry coupled with electrochemical reaction processes are complex and not understood clearly, especially its based thermal decomposition mechanism without electric power. In this work, the baseline ECSP was prepared using lithium perchlorate (LiClO4, LP) as oxidant, and tungsten as metal additive to obtain high energy ECSP samples. The scanning electron microscope (SEM), differential scanning calorimeter (DSC) and thermogravimetry (TGA) were used to investigate thermal analysis characteristics of ECSP and the effect of metal tungsten sizes on reaction process and mechanism. The heat release and effective activation energy (Eα) of baseline ECSP were lower than those of metalized ECSP. In addition, with W size increasing, heat release and Eα of ECSP increase. Based on thermal analysis and kinetic results, the decomposition mechanisms of ECSP main components and samples were proposed. The absorbed and crystal water evaporated, then main components molten for all cases at low temperature ( © 2023, The Authors. All rights reserved.

关键词： Thermogravimetric analysis

ABACUS: An Electronic Structure Analysis Package for the AI Era

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arXiv

arXiv 2025年

作者： Zhou, Weiqing Zheng, Daye Liu, Qianrui Lu, Denghui Liu, Yu Lin, Peize Huang, Yike Peng, Xingliang Bao, Jie J. Cai, Chun Jin, Zuxin Wu, Jing Zhang, Haochong Jin, Gan Ji, Yuyang Shen, Zhenxiong Liu, Xiaohui Sun, Liang Cao, Yu Sun, Menglin Liu, Jianchuan Chen, Tao Liu, Renxi Li, Yuanbo Han, Haozhi Liang, Xinyuan Bao, Taoni Chen, Nuo Ren, Hongxu Zhang, Xiaoyang Liu, Zhaoqing Fu, Yiwei Liu, Maochang Li, Zhuoyuan Wen, Tongqi Tang, Zechen Xu, Yong Duan, Wenhui Wang, Xiaoyang Gu, Qiangqiang Dai, Fu-Zhi Zheng, Qijing Zhao, Jin Zhang, Yuzhi Ou, Qi Jiang, Hong Liu, Shi Xu, Ben Xu, Shenzhen Ren, Xinguo He, Lixin Zhang, Linfeng Chen, Mohan AI for Science Institute Beijing100080 China HEDPS CAPT School of Physics College of Engineering Peking University Beijing100871 China College of Engineering Peking University Beijing100871 China Institute of Artificial Intelligence Hefei Comprehensive National Science Center Hefei230026 China Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China Supercomputing Center University of Science and Technology of China Anhui Hefei230026 China Institute of Physics Chinese Academy of Sciences Beijing100190 China School of Materials Science and Engineering Peking University Beijing100871 China School of Electrical Engineering and Electronic Information Xihua University Chengdu610039 China Academy for Advanced Interdisciplinary Studies Peking University Beijing100871 China College of Chemistry and Molecular Engineering Peking University Beijing100871 China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow Xi’an Jiaotong University Shaanxi Xi’an710049 China Suzhou Academy of Xi’an Jiaotong University Jiangsu Suzhou215123 China Center for Structural Materials Department of Mechanical Engineering The University of Hong Kong Hong Kong The University of Hong Kong Shenzhen China State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing100084 China Frontier Science Center for Quantum Information Beijing China Saitama Wako351-0198 Japan Institute for Advanced Study Tsinghua University Beijing100084 China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Fenghao East Road 2 Beijing100094 China School of Artificial Intelligence and Data Science University of Science and Technology of China Hefei230026 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing100083 China Department of Physics University of Science and

ABACUS (Atomic-orbital Based Ab-initio Computation at USTC) is an open-source software for first-principles electronic structure calculations and molecular dynamics simulations. It mainly features density functional theory (DFT) and is compatible with both plane-wave basis sets and numerical atomic orbital basis sets. ABACUS serves as a platform that facilitates the integration of various electronic structure methods, such as Kohn-Sham DFT, stochastic DFT, orbital-free DFT, and real-time time-dependent DFT, etc. In addition, with the aid of high-performance computing, ABACUS is designed to perform efficiently and provide massive amounts of first-principles data for generating general-purpose machine learning potentials, such as DPA models. Furthermore, ABACUS serves as an electronic structure platform that interfaces with several AI-assisted algorithms and packages, such as DeePKS-kit, DeePMD, DP-GEN, DeepH, DeePTB, etc. Copyright © 2025, The Authors. All rights reserved.

关键词： Stochastic systems

Failure Analysis of Tube-Burst on T91 Platen Superheater of 600 MW Supercritical Boiler

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Failure Analysis of Tube-Burst on T91 Platen Superheater of ...

Artificial Intelligence and Electromechanical Automation (AIEA), International Conference on

作者： Ke Sun Jia'an Wang Yu Yan Jiahao Jiang Lei Deng State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an China China Huadian Electric Power Research Institute Co. Ltd. Hangzhou China

ISBN: (数字)9781728182889

ISBN: (纸本)9781728182896

In this paper, the specimen of the bursting tubes, original tube and oxide-like debris are analysed in-depth by macroscopic examination, chemical composition analysis, mechanical properties, metallographic examination, scanning electron microscopy and energy spectrum analysis etc.,. It shows that the main reason for the tube-burst is that the original oxide matters or time-original oxide matters blocks the tube, reducing the cooling effect of the steam, and resulting in a short-term overheating of the tube. It is recommended to control the internal cleanliness of boiler equipment and pipest.

关键词： component tube burst failure analysis oxide matters over temperature FAILURE ANALYSIS excess temperature platen superheater Energy Dispersive X-Ray Spectroscopy oxides Cooling effects tube reducing

Analysis of Frequent Tube Burst of High Temperature Reheater in 600 MW Unit

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Analysis of Frequent Tube Burst of High Temperature Reheater...

Sustainable power and Energy Conference (iSPEC)

作者： Ke Sun Jia'an Wang Yu Yan Jiahao Jiang Lei Deng Defu Che China Huadian Electric Power Research Institute Co. Ltd. Hangzhou China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an China

ISBN: (数字)9781728191645

ISBN: (纸本)9781728191652

The reasons of frequent tube burst of the high temperature reheater in a supercritical 600 MW unit were systematically investigated via the examination of macroscopic inspection, chemical composition, mechanical properties, microstructures, scanning electron microscope and energy disperse spectroscopy detection. It is demonstrated that the tube burst of the high temperature reheater results from not only design factors, but also manufacture quality. Due to the absence of solid solution treatment in spare elbow, the inner dislocations and residual stress increase obviously, which accelerates the precipitation of carbide containing Cr and the formation of Cr depleted zone on grain boundary(GB) subsequently, leading to the decrease of GB corrosion resistance and the final leakage of high temperature reheater tube induced by intergranular corrosion.

关键词： Temperature Corrosion Welding Electron tubes Residual stresses Acceleration Elbow

Investigation on the Effect of Hydrothermal Reaction with Cuso4 on Rheological Property of Heavy Oil

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SSRN 2023年

作者： Zhou, Yantao Zhao, Qiuyang Wang, Xuetao Miao, Yan Song, Zhiwei Jin, Hui Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Xinjin Weihua Institute of Clean Energy Research Foshan528216 China

The rheological property is one of important physical properties evaluating heavy oil and asphalt. This work investigated the rheological changes during hydrothermal reaction with CuSO4. The results showed that the addition of CuSO4 at a high reaction temperature had an effect similar to asphalt modifiers, increasing the viscosity and elasticity. Further analysis suggested that the Cu atoms from CuSO4 entered heavy oil molecules, enhancing the interaction attraction between oil molecules. While, at a low reaction temperature, the CuSO4 acted as a catalyst, reducing both viscosity and elasticity. Based on these findings, this work proposed a novel and potential asphalt modification method, which changed the association effect between oil molecules by the chemical reaction to adjust the rheological properties permanently. This method would not fail due to the separation of modifiers and can adjust performance by changing reaction conditions. © 2023, The Authors. All rights reserved.

关键词： Transition metals

A High-Performance VS2-Modifed Separator for Lithium–Sulfur Batteries

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A High-Performance VS2-Modifed Separator for Lithium–Sulfur...

中国化学会第三届中国能源材料化学研讨会

作者： Jianan Wang Guorui Yang Shanshan Yi Ling Wang Silan Wang Wei Yan Shujiang Ding Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong University Department of Applied Chemistry School of ScienceState Key Laboratory for Electrical Insulation and Power EquipmentXi'an Jiaotong Univrsity School of Electronic and Information Engineering Xi'an Jiaotong University

Lithium–sulfur（Li-S） batteries are a promising candidate to couple renewable energy sources for green transportation and large-scale energy storage because of their relatively low cost and high theoretical specific capacity(1,675 mA h g).However,a major problem preventing the practical applications of Li-S batteries is the rapid capacity fading,predominantly due to the "shuttle effect" of polysulphides（LiPSs）.

关键词： A High-Performance VS2-Modifed Separator for Lithium Sulfur Batteries

Preparation and Application of Red Mud-Based Zero-Valent Iron Heterogeneous Fenton Catalyst: A New Idea for Red Mud Recycling

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SSRN 2022年

作者： Li, Hang Shi, Bofang Fu, Xiaojie Zhang, Haowen Yang, Honghui Xi’an Key Laboratory of Sustainable Energy Materials Chemistry School of Chemistry Xi'an Jiaotong University Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China

As an abundant hazardous waste, red mud needs a simple and effective mean of resource utilization. Herein, a novel zero-valent iron heterogeneous Fenton catalyst RMB-900 was synthesized by pyrolysis (900°C) using red mud and straw with a facile solvent-free carbothermal redox approach. X-ray diffraction analysis showed that Fe2O3 in the red mud was reduced to Fe0. Characterization data showed that RMB-900 was a zero-valent iron loaded porous material. Under the conditions of 2.86 mM H2O2, 100 mg/L acid red G, and 1 g/L RMB-900, 98% of acid red G was removed within 10 min, the reaction rate constant is 6.7 folds higher than that of commercial zero-valent iron. The RMB-900/H2O2 system also showed good degradability to antibiotics (Sulfamethoxazole, Ibuprofen and Carbamazepine). H2O2 is mainly catalysed by Fe0 in RMB-900 to generate •OH for ARG degradation. RMB-900 still showed excellent catalytic performance after standing for four months and after being reused nine times. This study not only prepared a catalyst with low cost, high stability, and great potential for wastewater treatment through a simple and green solvent-free method, but also provided a research basis for further exploration of red mud-based catalysts. © 2022, The Authors. All rights reserved.

关键词： Wastewater treatment

Numerical and Experimental Investigation of Proton Exchange Membrane Fuel Cell with Perpendicular Gas Supply Through the Ridge

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SSRN 2023年

作者： Zhang, Yan Lu, Xinyu Su, Jinzhan School of International Trade and Economics China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering School of Energy & Power Engineering Xi’an Jiaotong University Xi’an710049 China

The structural design of the cathode flow field in proton exchange membrane fuel cell (PEMFC) is essential for efficient gas supply and effective water removal. For investigating the mechanism behind the effect of gas flow direction on improving the performance of PEMFC, a novel modified serpentine flow channel with vertical inlets through the ridge for PEMFC was proposed and investigated by numerical and experimental methods. Under the operating voltage of 0.4 V, the vertical air supply mode exhibits a 7% higher current density compared to the parallel air supply mode. Compared with conventional air supply mode through the serpentine flow channel, vertical air supply mode modified serpentine through a tunnel inside the ridge exhibited higher oxygen uniformity and higher current density. Furthermore, we conducted research on the impact of physical parameters, including the porosity and thickness of the GDL, as well as the vertical gas supply pore density, on the performance of the PEMFC within the vertical gas supply mode. At an operating voltage of 0.4 V, the current density of PEMFC with a GDL thickness of 0.28 mm is 1.0009 A/cm2, which is 3.02% and 6.13% higher than that of PEMFC with vertical inlets with GDL thickness of 0.38 and 0.48 mm, respectively. With a porosity of 0.6, the current density of PEMFC reaches 1.0395 A/cm2, surpassing that of PEMFCs with porosities of 0.2 and 0.4 by approximately 24.8% and 6.6%, respectively. Moreover, higher vertical inlet densities lead to improved PEMFC performance. Simulation and experimental results demonstrate that this modified flow field effectively addresses uneven current density distribution and enhances power output at low voltage. © 2023, The Authors. All rights reserved.

关键词： Porosity