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SSRN 2023年

作者： Sun, Qishi Han, Ruiyu Guo, Kailun Wang, Chenglong Zhang, Jing He, Xiaoqiang Qiu, Suizheng Su, Guanghui Tian, Wenxi Department of Nuclear Science and Technology State Key Lab. of Multiphase Flow in Power Engineering Shaanxi Key Lab. of Advanced Nuclear Energy and Technology Xi’an Jiaotong University Xi’an710049 China Key Lab. of Nuclear Reactor System Design Technology China Nuclear Power Research and Design Institute Chengdu610213 China

To investigate the best performance wick forms to support the design and fabrication of high-performance heat pipes, in this paper, two kinds of nanostructured wick were prepared by the oxidation-reduction method. The effect of surface nanostructure on the wick performance was investigated by comparing the surface characteristics, capillary properties, permeability, and evaporation properties. The result shows that the nanostructured wick presented excellent super hydrophilic properties. A liquid-lift visualization experimental method for measuring the capillary performance factor M was proposed, and it was verified to be correct by the separation effect of the capillary pumping experiment under a vacuum environment. With the increasing oxidized degree, the densification of nanoparticles on the wick surface increased the capillary performance factor M from 8.68 μm to 13.81 μm, with a maximum enhancement of 59.1%. The effective capillary radius decreased from 4.70×10-5 m to 4.01×10-5 m, with a maximum reduction of 14.9%. The permeability increased from 4.33×10-10 m2 to 5.83×10-10 m2, with a maximum enhancement of 34.7%. The increase in porosity made the effective capillary radius dominate the competition for permeability, and the capillary performance factor decreased by 17.1%. The thermal resistance of the wick decreased with the enhancement of the capillary performance factor, which fell from 2.03×10-3 m2·K/W to 1.26×10-3 m2·K/W. The current study provides a reference for the future design and preparation of high-performance heat pipe wicks. © 2023, The Authors. All rights reserved.

关键词： Heat resistance

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Crack Propagation of Ground Insulation Failure for Large Motor End-Winding Based on Electromechanical Coupling Phase Field Model

Crack Propagation of Ground Insulation Failure for Large Mot...

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IEEE Conference on Electromagnetic Field Computation

作者： Xiaobo Wu Haijun Zhang Bolong Wang Guowen Cao Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle Hubei University of Arts and Science Xiangyang China Xiangyang CRRC Motor Technology Co. Ltd. Xiangyang China

ISBN: (数字)9798350348958

ISBN: (纸本)9798350348965

The ground insulation is a key component for large electrical machine, which may present the crack defect after the process treatment and assembly of manufacturing. In this paper, the crack propagations of the ground insulation failure with initial crack in stator end-winding of the large motor were studied by using the coupled phase field model. In the proposed model, the coupled effects of mechanical and electrical fields on the crack propagation and the evolutions were considered by using phase field method and finite element analysis. The results in this paper may provide a new way for the research of multi-factor damage diagnosis and life prediction of motor insulation coupling.

关键词： Couplings Insulation Analytical models Computational modeling Stators Motors Finite element analysis

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On the Theory of Atomic Relaxation in Twisted Van Der Waals Bilayers with Out-of-Plane Deformation

SSRN

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SSRN 2024年

作者： Zhang, Baidu Qiu, Wei Liao, Xiangbiao He, Linghui Ni, Yong CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Anhui Hefei230026 China Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing100081 China

The effects of out-of-plane deformation on atomic relaxation in twisted van der Waals bilayers are investigated by comprehensive multiscale modeling and simulations. The model integrates the DFT-informed generalized stacking-fault energy for interlayer interaction between layers and the Föppl–von Kármán plate theory for elastic energy in each layer with minimization of the total free energy for atomic relaxation governed by a gradient flow method. Our simulation results elucidate twist-angle dependent moiré pattern, strain field, tortional displacement field and stacking domain structures, in good agreement with recent experimental observations. In particular, we derive the strain soliton solution at a small twist angle and the elastic solution at a large twist angle for the reconstructed van der Waals bilayer with out-of-plane deformation. These results show that out-of-plane deformation not only narrows the strain soliton width but also induces substantial alterations in the strain field, local rotation, and stacking structures. Our findings reveal the pivotal role played by out-of-plane deformation in the atomic relaxation of twisted van der Waals bilayers, particularly at smaller twist angles. The intricate interplay between in-plane atomic relaxation and out-of-plane deformation provides opportunities for strain engineering in twisted van der Waals bilayers. © 2024, The Authors. All rights reserved.

关键词： Atoms

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Distributed Time-Varying Optimization with Equality Constraints

Distributed Time-Varying Optimization with Equality Constrai...

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International Conference on Control and Automation (ICCA)

作者： Zheng Yang Ji Ma Xiang Xu Department of Automation Xiamen University Xiamen Fujian China Shenzhen Key Laboratory of Control Theory and Intelligent Systems School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China

ISBN: (数字)9798350354409

ISBN: (纸本)9798350354416

In this paper, we consider the distributed time-varying optimization problem with coupled equality constraints over a connected undirected network. To address this issue, we design a novel distributed constraint optimization algorithm, and establish its ISS stability with external disturbances and tracking errors as the input and state, respectively. Moreover, the obtained result includes distributed constrained optimization with static objective functions as a special case. In comparison to existing relevant works, the proposed algorithm demonstrates exponential convergence for cases involving static objective functions. Finally, the theoretical results are validated via a numerical example.

关键词： Constraint optimization Automation Linear programming Trajectory Optimization Numerical stability Convergence

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Coordinated Defense Allocation in Reach-Avoid Scenarios with Efficient Online Optimization

arXiv

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arXiv 2023年

作者： Liu, Junwei Ouyang, Zikai Yang, Jiahui Chen, Hua Lu, Haibo Zhang, Wei School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China Peng Cheng Laboratory Shenzhen518000 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China

In this paper, we present a dual-layer online optimization strategy for defender robots operating in multiplayer reach-avoid games within general convex environments. Our goal is to intercept as many attacker robots as possible without prior knowledge of their strategies. To balance optimality and efficiency, our approach alternates between coordinating defender coalitions against individual attackers and allocating coalitions to attackers based on predicted single-attack coordination outcomes. We develop an online convex programming technique for single-attack defense coordination, which not only allows adaptability to joint states but also identifies the maximal region of initial joint states that guarantees successful attack interception. Our defense allocation algorithm utilizes a hierarchical iterative method to approximate integer linear programs with a monotonicity constraint, reducing computational burden while ensuring enhanced defense performance over time. Extensive simulations conducted in 2D and 3D environments validate the efficacy of our approach in comparison to state-of-the-art approaches, and show its applicability in wheeled mobile robots and quadcopters. © 2023, CC BY-NC-ND.

关键词： Iterative methods

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Facility Layout in Horizontal Cylindrical Space Based on Adaptive Gradient Descent Algorithm

Facility Layout in Horizontal Cylindrical Space Based on Ada...

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第40届中国控制会议

作者： Peng Yuan Yiran Miao Deqing Huang Junkai Hao Na Qin School of Electrical Engineering Southwest Jiaotong University Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China

FLP（Facility layout problem） is a common problem in engineering field. The past research tend to focus on the twodimensional space and a small amount of three-dimensional box space as well as vertical cylinder space. The FLP in horizontal cylinder space is less researched. Lots of FLP of box space and vertical cylinder space can transform to FLP of two-dimensional space easily, however, the FLP of horizontal cylinder space need design special calculation method of overlap constraint and boundary constraint. This paper designed the calculation method of overlap constraint and boundary constraint, used adaptive gradient descent algorithm with heuristic strategy to optimize the facility layout in horizontal cylinder space. On this basis,added symmetry constraint, absolute height constraint and relative distance constraint to close to the real engineering *** experiment results confirm the feasible of proposed scheme.

关键词： facility layout problem horizontal cylinder space gradient descent algorithm

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Optimal design of water immersion sensor layout for helicopter emergency flotation system based on the nsgaII algorithm 2

Optimal design of water immersion sensor layout for helicopt...

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2023 2nd International Conference on Aerospace and Control Engineering, ICoACE 2023

作者： Wang, Bingqian Wang, Zhe Sun, Zhi Hou, Bin College of Civil Aviation Nanjing University of Aeronautics and Astronautics Nanjing211106 China Key Laboratory of Aircraft Environment Control and Life Support MIIT Nanjing University of Aeronautics and Astronautics Nanjing210016 China Key Laboratory of Civil Aviation Emergency Science and Technology CAAC Nanjing University of Aeronautics and Astronautics Nanjing211106 China Environment Control System Research Department COMAC Shanghai Aircraft Design & Research Institute Shanghai201210 China

Aiming at the problem of sensor layout in an emergency flotation system, a sensor layout scheme design method based on the NSGAII method is proposed. The ALE method is used to simulate the water landing process of the helicopter on different pitch angles. The logic relationship of the 4/5 voting system is used to improve the sensor module reliability. Further, a mathematical model of layout scheme is established to maximize the detection coverage and minimize the force acting on the water immersion sensors when helicopter emergent water landing as the objective functions. Based on the mathematical model of water immersion sensor layout optimization constructed in this paper, NSGAII is used to solve this problem. The results show that the proposed method can realize the optimization of the layout of the water immersion sensor, the detection coverage of optimized schemes is increased by 3.26% on average compared with the value under the original scheme, and the force acting on the water immersion sensors is reduced by 61.86%. © Published under licence by IOP Publishing Ltd.

关键词： Flotation

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design of an Online Operational Task Reliability Analysis system in Nuclear Power Plant

Design of an Online Operational Task Reliability Analysis Sy...

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system Reliability and Safety Engineering (SRSE), International Conference on

作者： Wei Li Ming Yang Zhengxi He Zhao Gao Yan Xiong Zhongyue Zhang Dehang Jiang Jipu Wang Fundamental Science on Nuclear Safety and Simulation Technology Laboratory College of Nuclear Science and Technology Harbin Engineering University Harbin China Nuclear Reactor System Design Technology Key Laboratory China Nuclear Power Research and Design Institute Chendu China Institute for Advanced Study in Nuclear Energy & Safety College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen China

Human factors play an important role in human- computer interaction systems such as nuclear power plants (NPPs). Especially for the human-computer interaction process in unknown scenarios, incorrect personnel actions will affect the operation of equipment and systems, and finally the achievement of safety goals of NPPs. This paper presents a design of an online operational task reliability analysis (OOTRA) system which provides early warnings to operations in a timely manner by monitoring the states of plant systems and equipment, and operator actions. For any wrong action of operators, the OOTRA system can online evaluate the impact of the wrong action on the operational task and the goals of NPPs.

关键词：

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design of Shocks & Vibrations Monitoring system for Long Distance Transportation in Confined Spaces

Design of Shocks & Vibrations Monitoring System for Long Dis...

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Chinese Automation Congress (CAC)

作者： Shiyong Huang Yuru Geng Yong Han Mingfei Gu Chengdu China Nuclear Haichuan Nuclear Technology Co. Ltd Nuclear Power Institute of China Chengdu China School of Network and Communication Engineering Chengdu Technological University Chengdu China Chengdu Vocational & Technical College of Industry Chengdu China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

In real life, many valuable products and highvalue important products are transported in long distances. Shocks and vibrations are caused during transportation, loading and unloading for various reasons. Any shock and vibration exceeding the regulations may cause damage to the transported products. So, it is necessary to monitor and analyze these data of shocks and vibrations scientifically, while considering that some transportation conditions have special requirements for installation space and transportation time. Therefore, an ultra-thin and long-lasting monitoring system has been developed based on MEMS accelerometer technology to measure shocks and vibrations. After series of independent tests and calibration tests conducted by a third party on the product, the results show that it can record and store the threeaxis acceleration, temperature, humidity, pressure, time and other parameters of the transportation process in real time, and complete the preliminary assessment of the transportation status of high-value products. Then engineers can conduct professional analysis of the data to obtain scientific transportation monitoring reports, and provide scientific basis for taking safety prevention and treatment measures for subsequent transportation.

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Experimental study on multi-channel jets in plate assembly under blockage condition

Experimental study on multi-channel jets in plate assembly u...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Huijian, Huang Peng, Wang Dongyang, Li Tan, Sichao Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Harbin Heilongjiang China

ISBN: (纸本)9780791883785

In the nuclear field, the reactor using plate fuel assembly forms multiple jets at exit. So, it's meaningful to study multiple jets to learn the behavior of the coolant when it leaves the core. This paper uses PIV technology to study the flow characteristics of 9 jets at low Reynolds number. Firstly, the velocity field reveals that the pressure outside the jet is greater than the inside of the jet, which causes the jet to deflect and converge inward at z/w=0-8. Then, the velocity field with different Re number is analyzed in the center plane, and find that the flow distribution is similar. Then, a detailed analysis is performed on the jet under specific conditions, and the merge point is discussed in the paper. At the same time, the first-order velocity tensor are also calculated in this paper. In addition, this article also analyzes the jet flow field after the central narrow channel was blocked. In this experiment, a plug was used to block the No. 5 jet by 1/3. And the flow redistribution is discussed in this case. The methods of flow calculation using PIV technology is established and compared with the real number of flowmeters, it's found that the calculation method is rather accurate. On the other hand, the experiment find that the distribution of flow in each channel is not uniform, and the blocking condition make an increase in the flow of edge channels, which leads to the decreasing of flow in the blocked adjacent channel. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Velocity

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