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2017 International Congress on Advances in Nuclear Power Plants: A New Paradigm in Nuclear Power Safety, ICAPP 2017

作者： Yazhe, Lu Yu, Zhang Xu, Ran Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

ISBN: (纸本)9784890471676

During the course of a hypothetical severe accident in a light water reactor, spray systems could be used in the containment in order to prevent overpressure in case of a steam line break and to enhance the gas mixing in case of the presence of hydrogen. Thus these two effects induced by spray might compete with each other having an influence on the hydrogen risk. Focusing on the dynamic effect of spray, the impact of spray on the breakup of a light gas layer in a closed vessel is simulated and the experimental test evaluated here is TOSQAN 113 test that belongs to the dynamic part of SARNET FP6 benchmarks. ANSYS FLUENT 14.5 is chosen for the simulation tool and spray droplets are tracked with using the Euler-Lagrange approach-Discrete Phase Model (DPM). The code validation and several sensitivity studies are done to sum up the basic method of numerical simulation of spray with CFD code and assess the influence of calculation settings and parameters, such as turbulence model and spray boundary condition. The code validation shows that the results of calculations acceptably agree with the experimental data and the sensitivity studies reveal that spray boundary condition is a rather important factor for the accuracy of simulation. Conclusion gained in from the present work can provide some reference of the numerical analysis of containment.

关键词： Boundary conditions

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Computation of fluid thrust force from the pressure release tank of nuclear power plant pressurizer 17

Computation of fluid thrust force from the pressure release ...

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17th International Topical Meeting on Nuclear reactor Thermal Hydraulics, NURETH 2017

作者： Xiong, Fu-Rui Jiang, Nai-Bin Wu, Ge Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

Pressure release tank is a key component of nuclear power plant safeguard. Evaluating the fluid thrust force from high pressure and high temperature flow jet under postulated accidents is an essential task for nuclear system design and safety estimation. In this work, flow jet impingement from pressure release tank to nearby building roof is computed via a two-stage strategy. First, the RELAP5 code is applied to estimate thermal-hydraulic conditions at pressure release tank outlet. The thermal-hydraulic computational model includes key components of pressure release tank and its connection to the pressurizer. Based upon the thermal-hydraulic estimation within the pressure release tank, detailed computational fluid dynamics (CFD) simulation is performed with full considerations of how flow thrust is applied on nearby structures. The two-stage computational strategy provides a practical paradigm for fluid thrust force estimation. © 2016 Association for Computing Machinery Inc. All Rights Reserved.

关键词： Computational fluid dynamics

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A study on the sealing behaviors of the laterally one side restrained C-ring under internal pressure by numerical simulation 25

A study on the sealing behaviors of the laterally one side r...

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2017 25th International Conference on Nuclear Engineering, ICONE 2017

作者： Yuanyuan, Dong Ying, Luo Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China

ISBN: (纸本)9784888982566

C-ring, which is one of the main sealing elements of reactor Pressure Vessels, is composed of a close-wound helical spring surrounded by two metal linings. C-ring has better resilience and sealing characteristics. Just because of the complex structure of C-ring, it was studied by experiments almost. There were also some numerical simulations on C-ring. With these methods, the compression-decompression process of C-ring under ideal condition can be simulated. But them cannot be used to study the sealing behavior of laterally one side restrained C-ring under internal pressure, which is fit for practical condition. This paper will establish a 3D numerical simulation method to study the C-ring which is mentioned as above. In this paper, it can be obtained that with internal pressure forcing and sealing groove squeezing, sealing performance of C-ring will reduce;when p>20MPa, the ratio of reducing becomes bigger;when p>140MPa, it will generate leakage;inner lining and outer lining will generate biggish plastic deformation, while the stress distribution in spring changes much. © Copyright 2017 ASME.

关键词： Numerical methods

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Study on Processing Process of SiC Single Crystal Cut with Wire Saw Excited by Ultrasonic

Study on Processing Process of SiC Single Crystal Cut with W...

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International Conference on Mechanical, Control and Computer Engineering (ICMCCE)

作者： Lun Li Shaodong Yang Bofeng Du Shiyu Xu Jishun Li Henan Key Laboratory for Machinery Design and Transmission System Henan University of Science and Technology Luoyang China Zhongqi Changxing (Luoyang) Mechanical and Electrical Equipment Engineering Co. Ltd. Luoyang China Shenzhen Zhaowei Machinery & Electronics Co. Ltd. Shenzhen China

ISBN: (数字)9781728146898

ISBN: (纸本)9781728146904

Owing to high hardness and brittleness, SiC single crystal is the typical difficult-to-machine material. The SiC single crystal workpiece was cut by wire saw excited by transverse ultrasonic, and the cutting process was analyzed in current research. The kinematics equation of ultrasonic excitation wire saw and ordinary wire saw were established, and two different kinematics characteristics were analyzed respectively. The trajectory of abrasive particles in two cutting mode changed fundamentally. The finite element simulation model of single diamond abrasive cutting SiC single crystal was established. The influence of processing parameters on sawing force, surface morphology of SiC single crystal cut with abrasive excited by ultrasonic and ordinary diamond abrasive cutting was analyzed. The results show that sawing force of diamond abrasive excited by ultrasonic is much less than that of ordinary diamond abrasive cutting and the surface morphology is fairly flat. The cutting depth of abrasive has a significant influence on the sawing force and wafer surface.

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A method for optimization design of multiple degrees of freedom micro gyroscope 25

A method for optimization design of multiple degrees of free...

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25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018

作者： Hao, Shuying Song, Yuhao Zhang, Chenqing Feng, Jingjing Zhang, Qichang Tianjin University of Technology School of Mechanical Engineering Tianjin Key Laboratory of Advanced Electromechanical System Design and Intelligent Control National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin China Tianjin University School of Mechanical Engineering Tianjin Key Laboratory of Nonlinear Dynamics and Control Tianjin China

ISBN: (纸本)9781510868458

In order to obtain ideal bandwidth and high sensitivity of multiple degrees of freedom micro gyroscopes, a kind of optimization design method of combining dynamic characteristic extraction with orthogonal experiment is presented in this paper. Firstly, the effect of vibrator mass ratio, structural frequency ratio and damping ratio on dynamic characteristic that is bandwidth and sensitivity of micro gyroscopes was studied, and then the constraint conditions of optimization design was determined according to dynamic characteristic. And on this basis the orthogonal experiment was adopted to set the level range of each factors and optimize sensitivity and bandwidth of the micro gyroscopes by orthogonal table of five factors and four levels. After optimization, the sensitivity of the micro gyroscopes is only slightly increased, but the bandwidth which compares to result of second order sequence optimization is increased by 1590Hz. Therefore, the optimization design method can greatly improve the bandwidth of the micro gyroscopes and be applied to the optimization design of the multiple degrees of freedom micro gyroscopes with wide-bandwidth. © 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling. All rights reserved.

关键词： Bandwidth

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Transient numerical simulation on the performance of a neon-charged cryogenic loop heat pipe for space applications 69

Transient numerical simulation on the performance of a neon-...

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69th International Astronautical Congress: #InvolvingEveryone, IAC 2018

作者： He, Fa-Long Du, Wang-Fang Zhao, Jian-Fu Chen, Yue-Yong He, Jiang Zhang, Hong-Xing Miao, Jian-Yin National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences. Beijing100190 China School of Engineering Science University of the Chinese Academy of Sciences Beijing100049 China Beijing Key Laboratory of Space Thermal Control Technology Beijing100094 China Institute of Spacecraft System Engineering China Academy of Space Technology Beijing100094 China

A transient mathematical model for cryogenic loop heat pipe (CLHP), which possesses high pumping capability and good heat transfer performance that are important for effective and efficient cryogenic heat transport with considerable applications in space and terrestrial surroundings, is established and used to study the performance of a neon-charged CLHP (Ne-CLHP) in the present work. The numerical results are benchmarked with experimental data and a good agreement is achieved. The effects of parasitic heat loss, charged pressure of the working fluid, and heat sink temperature on the performance of the Ne-CLHP are conducted under a constant heat loads applied to the secondary evaporator (1.5 W), which is selected based on the previous experimental study. Based on the numerical results, it is found that the heat sink temperature affects slightly the resistance loss of the system, but markedly the wall temperature of primary evaporator and the maximum heat transport capability. There existed an optimum charged pressure of the working fluid to achieve the maximum heat transport capability. The detailed temperature and pressure characteristics of the Ne-CLHP are also captured which can provide a better understanding of the inherent mechanisms responsible for the phenomena and then provide guidance for the design and optimization of Ne-CLHPs, which can realize efficient cryogenic heat transport in the temperature range of 30-40 K, and promises great application potential in the thermal control of future space infrared exploration system. Copyright © 2018 by Fa-Long He and Jian-Fu Zhao. Published by the IAF, with permission and released to the IAF to publish in all forms. .

关键词： Neon

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design of lossless snubber circuit for phase-shifted full-bridge converter

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Journal of Physics: Conference Series 2020年第2期1650卷

作者： Shengxian Ji Guisheng Jie Shan Gao Hengli Wang Ruitian Wang Xiaohu Liu National key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan 430033 China College of Electrical Engineering Naval University of Engineering Wuhan 430033 China

In the phase-shifted full-bridge circuit, the voltage spike caused by the hard turn-off of the switch tube increases the voltage stress of the switching device. Due to the existence of energy-consuming components such as resistance in the traditional absorption circuit, the efficiency is not always high. Based on the RCD snubber circuit, a low-loss absorption circuit is designed in this paper. This circuit absorbs voltage spikes through an absorption capacitor, and then slowly releases energy through an oscillating circuit consisting of current-limiting inductance, stray inductance, and absorption capacitance. The current-limiting inductance reduces the current stress of the blocking diode effectively, which can be achieved with the absorption not being affected and the power loss being reduced. Finally, the absorption effect and energy loss of the new low-loss absorption circuit and the commonly used RCD circuit were simulated and compared in PSpice software, and verified its feasibility.

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Study of control rod device mechanism missile impact on protection plate

Study of control rod device mechanism missile impact on prot...

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2017 Transactions of the American Nuclear Society, ANS 2017

作者： Ye, Xianhui Xiong, Furui Zhen, Bin Jiang, Naibin Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan610041 China

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A Reduced-order Extrapolation Model Based on Proper Orthogonal Decomposition Technique for Rayleigh-Bénard convection

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Journal of Physics: Conference Series 2019年第2期1176卷

作者： Jinghua Yang Dengfeng Lu Zhiguang Deng Xiang Guan Qing Shi Sichuan Electric Power Design & Consulting Co. Ltd Chengdu Sichuan 610041 China National Key Labortory of Science and Technology on Reactor System Design Technology Sichuan 610213 China

In order to quickly calculate the flow characteristics in the simulated two-dimensional Rayleigh-Bénard convection model, a reduced-order extrapolation difference model for solving two-dimensional Rayleigh-Bénard is established based on the Proper Orthogonal Decomposition (POD) method. Firstly, the classical difference format is used to calculate the flow field on the initial time span, the sample data is to construct the POD basis, and the truncation error generated in the process of constructing the POD base is analysed. Then, the two-dimensional reduced-order extrapolation Rayleigh-Bénard model is constructed by combining the SVD and POD methods. By numerical examples, the classical difference model and the reduced-order extrapolation model are numerically simulated under the given initial boundary value. The reliability and effective of the reduced-order method are verified by comparing the flow field temperature cloud maps in the two calculation stages.

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Research on Hydrodynamic Interference of a DSRV and a Wrecked Submarine

Research on Hydrodynamic Interference of a DSRV and a Wrecke...

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IEEE International Conference on Underwater system technology: Theory and Applications (USYS)

作者： Hao TAN Duanfeng HAN Lei JU Haitao ZHU Yiran MIAO College of Shipbuilding Engineering Harbin Engineering University Harbin 150000 China Science and Technology on Reactor System Design Technology Laboratory Unclear Power Institute of China Chengdu 610041 China

ISBN: (纸本)9781538694060

In this paper, the viscous flow method based on Computational Fluid Dynamics (CFD) is used to simulate the hydrodynamic interaction of the Deep Submergence Rescue Vehicle (DSRV) involved in the rescue of a wrecked submarine. As the object of study, the drag of the DSRV moving in unbounded flow field is numerically calculated and the calculation results are compared with the experimental values to validate the accuracy of the numerical method. When the DSRV approaches the wrecked submarine in a positive flotation in quasi-static way, the effects of different inflow velocities and the distance between the two objects on the DSRV's drag, lift and pitching moment are simulated and monitored. The results show that when the DSRV is far away from the wrecked submarine, it is subject to the repulsive force from the submarine; when the distance is gradually reduced, the repulsive force is reduced until becoming suction; when the two objects are docking, the DSRV is subjected to the repulsive force from the submarine. This study will provide a reference for the operation of DSRV drivers.

关键词： Underwater vehicles Mathematical model Hydrodynamics Force Numerical models Load modeling Drag

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