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Numerical modeling and experimental investigation of a two-phase sink vortex and its fluid-solid vibration characteristics

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第1期25卷 47-62页

作者： Zichao YIN Yesha NI Lin LI Tong WANG Jiafeng WU Zhe LI dapeng tan College of Mechanical Engineering Zhejiang University of TechnologyHangzhou310014China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou310058China

A sink vortex is a common physical phenomenon in continuous casting,chemical extraction,water conservancy,and other industrial processes,and often causes damage and loss in ***,the real-time monitoring of the sink vortex state is important for improving industrial production ***,its suction-extraction phenomenon and shock vibration characteristics in the course of its formation are complex mechanical dynamic factors for flow field state *** address this issue,we set up a multi-physics model using the level set method(LSM)for a free sink vortex to study the two-phase interaction ***,a fluid–solid coupling dynamic model was deduced to investigate the shock vibration characteristics and reveal the transition mechanism of the critical flow *** numerical results show that the coupling energy shock induces a pressure oscillation phenomenon,which appears to be a transient enhancement of vibration at the vortex penetration *** central part of the transient enhancement signal is a high-frequency *** on the dynamic coupling model,an experimental observation platform was established to verify the accuracy of the numerical *** water-model experiment results were accordant with the numerical *** above results provide a reference for fluid state recognition and active vortex control for industrial monitoring systems,such as those in aerospace pipe transport,hydropower generation,and microfluidic devices.

关键词： Free sink vortex Fluid-solid coupling Level set method(LSM) Multi-physics model Vibration characteristics

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Multi-physical Modeling and Adjusting for Ultrasonic Assisted Soft Abrasive Flow Processing

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Chinese Journal of Mechanical Engineering 2023年第4期36卷 111-124页

作者： Yesha Ni Yunfeng tan dapeng tan Key Lab of E&M Ministry of Education and Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310014China Collaborative Innovation Center of High-end Laser Manufacturing Equipment Zhejiang Province&Ministry of EducationHangzhou 310014China

The polishing efficiency of the soft abrasive flow(SAF)method is low,which is not in line with the concept of carbon emission reduction in industrial *** address the above issue,a two-phase fluid multi-physics modeling method for ultrasonic-assisted SAF processing is *** acoustics-fluid coupling mechanic model based on the realizable k-ε model and Helmholtz equation is built to analyze the cavitation *** results show that the pro-posed modeling and solution method oriented to ultrasonic-assisted SAF processing have better revealed the flow field evolution *** turbulence kinetic energy at different ultrasonic frequencies and amplitudes is *** results show that the ultrasonic vibration can induce a cavitation effect in the constrained flow chan-nel and promote the turbulence intensity and uniformity of the abrasive flow.A set of comparative polishing experiments with or without ultrasonic vibration are conducted to explore the performance of the proposed *** can be found that the ultrasonic-assisted SAF method can improve the machining efficiency and uniformity,to achieve the purpose of carbon emission *** relevant result can offer a helpful reference for the SAF method.

关键词： Soft abrasive flow Ultrasonic vibration Cavitation effect Polishing efficiency Turbulent kinetic energy

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A collaborative assembly for low-voltage electrical apparatuses

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Frontiers of Information Technology & Electronic Engineering 2023年第6期24卷 890-905页

作者： Huanpei LYU Libin ZHANG dapeng tan Fang XU College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310014China College of Digital Technology and Engineering Ningbo University of Finance and EconomicsNingbo 315175China

Low-voltage electrical apparatuses(LVEAs)have many workpieces and intricate geometric structures,and the assembly process is rigid and labor-intensive,and has little *** assembly process cannot readily adapt to changes in assembly *** address these issues,a collaborative assembly is *** on the requirements of collaborative assembly,a colored Petri net(CPN)model is proposed to analyze the performance of the interaction and self-government of robots in collaborative ***,an artificial potential field based planning algorithm(AFPA)is presented to realize the assembly planning and dynamic interaction of robots in the collaborative assembly of *** an adaptive quantum genetic algorithm(AQGA)is developed to optimize the assembly ***,taking a two-pole circuit-breaker controller with leakage protection(TPCLP)as an assembly instance,comparative results show that the collaborative assembly is cost-effective and flexible in LVEA *** distribution of resources can also be optimized in the *** assembly robots can interact dynamically with each other to accommodate changes that may occur in the LVEA assembly.

关键词： Low-voltage electrical apparatus Collaborative assembly Artificial potential field based planning Adaptive quantum genetic algorithm Dynamic interaction

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Key technologies and development trends of the soft abrasive flow finishing method

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第12期24卷 1043-1064页

作者： Yunfeng tan Yesha NI Weixin XU Yuanshen XIE Lin LI dapeng tan Key Lab of E&M Ministry of Education&Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310014China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310058China Collaborative Innovation Center of High-end Laser Manufacturing Equipment Zhejiang Province&Ministry of EducationHangzhou 310014China

This paper reviews recent developments of the soft abrasive flow finishing(SAF)method in constraint *** multiphase fluid dynamics modeling,material removal mechanism,auxiliary strengthening finishing techniques,and observation of surface impact effects by abrasive particles and cavitation bubbles are presented in *** prospects and challenges are given for four aspects:thin-walled curved surfaces,biomedical functions,electronic information,and precise optical components.

关键词： Soft abrasive flow finishing(SAF) Dynamic modeling Material removal mechanism Processing optimization Strengthening finishing control technology

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Improved Soft Abrasive Flow Finishing Method Based on Turbulent Kinetic Energy Enhancing

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Chinese Journal of Mechanical Engineering 2017年第2期30卷 301-309页

作者： Jun LI Shiming JI dapeng tan Key Laboratory of E&M Zhejiang University of Technology of Ministry of Education and Zhejiang Province School of Information Science and Engineering Hangzhou Normal University

Soft abrasive flow（SAF） finishing can process the irregular geometric surfaces, but with the matter of low processing efficiency. To address the issue, an improved SAF finishing method based on turbulent kinetic energy enhancing is proposed. A constrained flow passage with serration cross-section is constructed to increase the turbulence intensity. Taking the constrained flow passage as the objective, a two-phase fluid dynamic model is set up by using particle trajectory model and standard k-ε turbulence model, and the flow field characteristics of the flow passage are acquired. The numerical results show that the serration flow passage can enhance the turbulence intensity, uniform the particles distribution, and increase the particle concentration near the bottom wall. The observation results by particle image velocimetry（PIV） show that the internal vortex structures are formed in flow passage, and the abrasive flow takes on turbulence concentrating phenomenon in near-wall region. The finishing experiments prove that the proposed method can obtain better surface uniformity, and the processing efficiency can be improved more 35%. This research provides an abrasive flow modeling method to reveal the particle motion regulars, and canoffer references to the technical optimization of fluid-based precision processing.

关键词： Soft abrasive flow Serration flow passage ·Kinetic energy enhancing Particle image velocimetry

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Monitoring Surface Water Change in Northeast China in 1999–2020:Evidence from Satellite Observation and Refined Classification

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Chinese Geographical Science 2024年第1期34卷 106-117页

作者： LIU Kai ZHANG dapeng CHEN tan CUI Peipei FAN Chenyu SONG Chunqiao Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing210008China University of Chinese Academy of Sciences Nanjing(UCASNJ)Nanjing211135China Geographic Information and Tourism College Chuzhou UniversityChuzhou239000China

As a typical region with high water demand for agricultural production,understanding the spatiotemporal surface water changes in Northeast China is critical for water resources management and sustainable ***,the long-term variation characteristics of surface water of different water body types in Northeast China remain rarely *** study investigated how surface water bodies of different types(e.g.,lake,reservoir,river,coastal aquaculture,marsh wetland,ephemeral water) changed during1999–2020 in Northeast China based on various remote sensing-based *** results showed that surface water in Northeast China grew dramatically in the past two decades,with an equivalent area increasing from 24 394 km^(2) in 1999 to 34 595 km^(2) in *** surge of ephemeral water is the primary driver of surface water expansion,which could ascribe to shifted precipitation *** wetlands,rivers,and reservoirs experienced a similar trend,with an approximate 20% increase at the interdecadal *** contrast,coastal aquacultures and natural lakes remain relatively *** study is expected to provide a more comprehensive investigation of the surface water variability in Northeast China and has important practical significance for the scientific management of different types of surface water.

关键词： surface water spatiotemporal variation water body classification remote sensing Northeast China

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Key Technologies and Development Trends in Advanced Intelligent Sawing Equipments

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Chinese Journal of Mechanical Engineering 2021年第3期34卷 175-194页

作者： Yangyu Wang Yongle Zhang dapeng tan Yongchao Zhang College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China Key Laboratory of Special Purpose Equipment and Advanced Processing Technology Ministry of Education and Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310023China Collaborative Innovation Center of High-end Laser Manufacturing Equipment(National“2011 Plan”) Zhejiang University of TechnologyHangzhou 310023China School of Aeronautical Engineering Taizhou UniversityTaizhou 318000China.

As a starting point in equipment manufacturing,sawing plays an important role in industrial *** manufacturing equipment is an important carrier of intelligent manufacturing *** to the backwardness of intelligent technology,the comprehensive performance of sawing equipments in China is obviously different from that in foreign *** of the art of advanced sawing equipments is investigated along with the technical bottleneck of sawing machine tool manufacturing,and a new industrial scheme of replacing turning-milling by sawing is *** key technologies of processing-measuring integrated control,multi-body dynamic optimization,the collaborative sawing network framework,the distributed cloud sawing platform,and the self-adapting service method are analyzed;with consideration of the problems of poor processing control stableness,low single machine intelligence level,no on-line processing data service and active flutter suppression of sawing with wide-width and heavy-load working *** directions for further research,industry implementation,and industry-research collaboration are provided.

关键词： Sawing equipments Processing-measuring integrated control Collaborative sawing framework Intelligent network middleware Sawing cloud service platform

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Parameters Optimization of a Novel 5-DOF Gasbag Polishing Machine Tool

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Chinese Journal of Mechanical Engineering 2013年第4期26卷 680-688页

作者： LI Yanbiao tan dapeng WEN Donghui JI Shiming CAI Donghai Key Laboratory of Special Purpose Equipment and Advanced Processing Technology of Ministry of Education Zhejiang University of Technology Zhejiang Provincial Key Laboratory of Special Purpose Equipment and Advanced Processing Technology Zhejiang University of Technology

The research on the parameters optimization for gasbag polishing machine tools, mainly aims at a better kinematics performance and a design scheme. Serial structural arm is mostly employed in gasbag polishing machine tools at present, but it is disadvantaged by its complexity, big inertia, and so on. In the multi-objective parameters optimization, it is very difficult to select good parameters to achieve excellent performance of the mechanism. In this paper, a statistics parameters optimization method based on index atlases is presented for a novel 5-DOF gasbag polishing machine tool. In the position analyses, the structure and workspace for a novel 5-DOF gasbag polishing machine tool is developed, where the gasbag polishing machine tool is advantaged by its simple structure, lower inertia and bigger workspace. In the kinematics analyses, several kinematics performance evaluation indices of the machine tool are proposed and discussed, and the global kinematics performance evaluation atlases are given. In the parameters optimization process, considering the assembly technique, a design scheme of the 5-DOF gasbag polishing machine tool is given to own better kinematics performance based on the proposed statistics parameters optimization method, and the global linear isotropic performance index is 0.5, the global rotational isotropic performance index is 0.5, the global linear velocity transmission performance index is 1.012 3 m/s in the case of unit input matrix, the global rotational velocity transmission performance index is 0.102 7 rad/s in the case of unit input matrix, and the workspace volume is 1. The proposed research provides the basis for applications of the novel 5-DOF gasbag polishing machine tool, which can be applied to the modern industrial fields requiring machines with lower inertia, better kinematics transmission performance and better technological efficiency.

关键词： 5-DOF gasbag polishing machine tool evaluation index kinematics analyses parameter optimization

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Sea level rise along China coast from 1950 to 2020

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Science China Earth Sciences 2024年第3期67卷 802-810页

作者： dapeng MU Tianhe XU Haoming YAN Institute of Space Sciences Shandong UniversityWeihai 264209China Innovation Academy for Precision Measurement Science and Technology Chinese Academy of SciencesWuhan 430071China Institute of Marine and Antarctic Science University of TasmaniaHobartTasmania 7004Australia

Global mean sea level rise has been reconstructed using tide gauges. However, long-term sea level rise along the China coast is unclear. To address this issue, a data assimilation approach is developed to reconstruct sea level rise along the China coast from 1950 to 2020 using a global distribution of tide gauges(TGs). This approach combines climate models and sea level fingerprints. The climate models provide stereodynamic sea level changes. The sea level fingerprints include increases in ocean mass due to global ice melting and changes in water storage on land. The reconstructed global mean sea level rise agrees well with previous studies. We quantify sea level rise at 20 TGs along the China coast. The results suggest that sea level rise along the China coast(1.95±0.33 mm yr^(-1)) is greater than the global mean(1.71±0.17 mm yr^(-1)). We also find that China's coastal sea level rise is more than three times faster after 1980, increasing from 0.84±0.28 mm yr^(-1)for 1950–1980 to3.12±0.21 mm yr^(-1)for 1980–2020. This finding implies a significant sea level acceleration along the China coast. Our results advance the understanding of long-term sea level changes along the China coast.

关键词： Sea level rise China coast Tide gauges Data assimilation

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Record-breaking summer-autumn drought in southern China in 2022:Roles of tropical sea surface temperature and Eurasian warming

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Science China Earth Sciences 2024年第2期67卷 420-431页

作者： Yuepeng HU Botao ZHOU Huijun WANG dapeng ZHANG Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment ChangeNanjing University of Information Science and TechnologyNanjing210044China School of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing210044China

From summer to autumn in 2022,a severe drought lasted in southern China,posing serious effects on economic growth and ecological *** study explored the atmospheric circulations accounting for this persistent drought *** shows that the drought in southern China during the summer of 2022 was strongly linked to the divergence of water vapor flux and descending motions,which were respectively caused by the anomalous anticyclone over the western North Pacific and the northward movement of the East Asian subtropical jet(EASJ).Differently,the atmospheric background responsible for the sustained drought in autumn is manly featured by a cyclonic circulation anomaly over the region from the Bay of Bengal to the South China Sea,which led to decreased moisture and descending motions in southern *** investigation suggests that the rarely strong surface warming over northern Eurasia and the extreme La Nina-like pattern over the tropical Pacific jointly resulted in the anomalous anticyclone over the western North Pacific and the northward shift of the EASJ in the summer of 2022,while the cyclonic circulation anomaly prevailing over the region from the Bay of Bengal to the South China Sea in autumn was largely attributed to the extremely negative anomalies of the tropical Indian Ocean sea surface temperature.

关键词： Summer-autumn drought Southern China Tropical sea surface temperature Eurasian warming

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