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3rd International Topical Meeting on Advances in Thermal Hydraulics 2016, ATH 2016

作者： Li, Quan Avramova, M. Yu, Junchong Jiao, Yongjun Hou, Jason Department of Engineering Physics Tsinghua University Beijing100084 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Department of Nuclear Engineering North Carolina State University RaleighNC27695 United States

ISBN: (纸本)9780894487330

A new model for active nucleation site density in boiling systems has been developed. The model is based on parametric analysis of existing experimental data and is a function of wall superheat, pressure, and contact angle. The model is applicable for a wide pressure range - from 0.101 MPa to 19.8 MPa. Preliminary studies of temperature dependency of the contact angle have also been performed. The new model is intended to improve the predictions of the interfacial area concentration in two-fluid models and the wall temperature in subcooled boiling simulations. Validation activities have shown that the active nucleation site density predicted by the new model is in a good agreement with various published experimental data, and have demonstrated the achieved improvements as compared to existing models. © 2016, American Nuclear Society. All rights reserved.

关键词： Contact angle

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Numerical analysis of hydrogen risk related severe accident scenario in Chinese PWR 24

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2016 24th International Conference on Nuclear Engineering, ICONE 2016

作者： Yang, Fan Kudriakov, Sergey Etienne, Studer Zou, Zhiqiang Yu, Hongxing Nuclear Power Institute of China Design and Research Sub-institute ChengduSichuan China DEN DM2S SFME LTMF CEA Saclay Gif/YvetteF-91191 France Science and Technology on Reactor System Design Technology Laboratory NPIC ChengduSichuan China Nuclear Power Institute of China ChengduSichuan China

ISBN: (纸本)9780791850046

Based on the fact that the pressure loads generated in hydrogen combustion process may jeopardize the integrity of the containment during severe accident, and the changing rate as well as the maximum value of the pressure loads are governed by the flame propagation process, it is important to simulate the hydrogen combustion process with proper methodology. Due to the insufficiency understanding of the turbulent combustion and the difficulties of hydrogen combustion simulation in large scale and complex geometry, explosion safety applications are always based on simplified combustion model, for which the validation work and specified conservative parameter is required. In this study, an methodology combining CFD analysis and model validation based on large scale combustion experiments(HDR E12 and HYCOM01/02) is built up. And domestic hydrogen combustion process in the containment during severe accident is simulated. This study provides solid basis for structure design and integrity analysis of the containment. Copyright © 2016 by ASME.

关键词： Risk assessment

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Mechanism study and theoretical simulation on heat split phenomenon in dual-cooled annular fuel element

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Annals of Nuclear Energy 2016年 94卷 44-54页

作者： Yangbin Deng Yingwei Wu Yuanming Li Dalin Zhang Wenxi Tian G.H. Su Suizheng Qiu State Key Laboratory of Multiphase Flow in Power Engineering School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an City 710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 610213 China

In this study, the mechanisms that cause heat split, a specific phenomenon in dual-cooled annular fuel elements, were investigated. On the basis of thermal resistance analysis, the developing process of heat split phenomenon was summarized. It was found that thermal expansion, fuel densification, swelling, creep, relocation and fission gas release are the original parameters driving the development of heat split. Due to these factors, thermal resistances for heat flux to internal and external channels change with the operating time, which results in heat split. Furthermore, the theoretical simulation on heat split was performed by FROBA-ANNULAR, which is a coupled thermal–mechanical analysis code for dual-cooled annular fuel elements. Key parameters at different burnup stages, including gap size, gap conductance, temperature profile, coolant flux and heat flux were obtained. The calculation result shows that the fraction of heat flux to the internal cooling channel experiences complicated variation at the range of 32.9–39.7%. In addition, it was found that heat split does not match with the coolant split, especially at the lower burnup stage. Asymmetric heat transfer occurred because of the imbalance between heat split and coolant split, resulting in a substantial asymmetric temperature profile. Furthermore, heat split exerts an influence on DBNRs of inner and outer channels, although the computational values were still within the allowable limits.

关键词： Dual-cooled annular fuel Heat split FROBA-ANNULAR code MDNBR

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An Algorithm for Global Path Planning and Multi-objective Optimization Using Cell Mapping

An Algorithm for Global Path Planning and Multi-objective Op...

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第十届动力学与控制学术会议

作者： XUE Yang XIONG Fu-rui SUN Jian-qiao Department of Mechanics Tianjin University Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China School of Engineering University of California

AThis paper presents a study of multi-objective path planning. The goal is to find paths and meanwhile minimize multiple conflicting performance indices. Terrain information is well known priori. The algorithm about cell mapping method is presented as follows: Constructing cell space converts continuous domain into discrete domain and all cells are stratified. Then transfer indices data from inner layer to outer layer. Next evolution all over the space is proposed for finding all cells' complete Pareto front. Subsequently covering region of optimal paths can be obtained. The indices information are stored in database. Finally a global information database about Pareto front is constructed by the cell mapping method. All cells have complete Pareto front and the number of corresponding optimal paths can be read from the Database. Covering region of optimal paths is presented. Case studies are presented to demonstrate the method.

关键词： Global path planning Multi-objective optimization Cell mapping Static obstacle avoidance Grid space

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A Two-level Multi-objective Optimal Control design of Diesel Engine Common Rail system

A Two-level Multi-objective Optimal Control Design of Diesel...

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第十届动力学与控制学术会议

作者：贾苏 Fu-Rui Xiong 孙建桥 School of Mechanics Tianjin University Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China School of Engineering University of California

The common rail fuel injection technology is widely applied in diesel engines to reduce PM and NO emissions. Proper control of common rail pressure can lead to better fuel combustion efficiency and lower emissions. The dynamics of the common rail system is usually complex, nonlinear and time varying. It is important to develop a reliable model of the common rail system in order to design optimal controls that are effective for different operational conditions including the start, idle and acceleration. In this study, we develop a model of the common rail system from experimental data. The model encompass several subsystems including the high-pressure pump and fuel injector. With the help of the model, we present a two-level multi-objective optimal control design. First, optimal common rail pressure profiles for various operational conditions are developed by minimizing the fuel combustion and emission, while maximizingthe power output. Second, the time varying common rail pressure profiles are tracked by a nonlinear feedback control. The nonlinear feedback control is optimally design to meet the objectives of minimum integrated tracking error and control energy. The performance of the proposed optimal control design is tested through simulation and experiments.

关键词： Diesel engine Common rail system Data-driven model Multi-objective optimal control design

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Multi-objective Optimization of Elastic Beams For Minimum Weight and Sound Radiation

Multi-objective Optimization of Elastic Beams For Minimum We...

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第十届动力学与控制学术会议

作者： Meng-xin He Fu-Rui Xiong Yousef Naranjani Qian Ding Jian-Qiao Sun Department of Mechanics Tianjin University Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China School of Engineering University of California Merced

Engineering structures are often designed and optimized to meet multiple and possibly conflicting objectives such as the minimum weight and maximum strength. The merit of multiobjective optimization is to obtain a wide range of choices of structural design so that the best trade-off among different objectives can be achieved. This paper presents a multi-objective optimization of elastic beams for minimum radiated sound power and weight. The transfer matrix method is used to compute the structural and acoustic responses of the beam accurately andefficiently. Both Euler-Bernoulli and Timoshenko models are considered. The multi-objective particle swarm optimization technique is applied to search the Pareto optimal solutions representing various compromises between the weight and sound radiation. Several constraints are imposed, which substantially reduce the volume fraction of feasible solutions in the design space. Two cases of elastic beams with different boundary conditions are studied to demonstrate the multi-objective optimal designs of the structure. We have discovered that when the practical constraints such as the smoothness and lower bound of the fundamental frequency of the structure are imposed, the feasible solutions can be found only in a very small subset of the design space. Numerical results of multi-objective optimal design of non-uniform beams with two different boundary conditions are presented. We have shown that the optimized non-uniform beam indeed has smaller radiated sound power and radiation efficiency in the targeted frequency range as compared with the uniform beam of the same mass.

关键词： Non-uniform beam Sound radiation Transfer matrix method Multiobjective optimization Particle swarm technique

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Electro-hydraulic load simulation method for helicopter booster

Electro-hydraulic load simulation method for helicopter boos...

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2016 IEEE/CSAA International Conference on Aircraft Utility systems, AUS 2016

作者： Fang, Yang Yanyan, Hao Peng, He Henan Provincial Key Laboratory of Mechanical Design and Transmission System Henan University of Science and Technology Luoyang Henan province471003 China Beijing Institute of Structure and Environment Engineering Beijing100076 China Science and Technology on Electro-optical Control Laboratory Luoyang Henan province471000 China

ISBN: (纸本)9781509010875

In this paper we present an electro-hydraulic load simulation method for the helicopter booster. Based on electro-hydraulic servo control technology, we construct the load simulation system. And then, the mathematical model of load simulation system for the booster is built. The position servo system controller is combined of hysteresis compensation with PI controller and the force servo system controller is designed by servo-compensation and fuzzy PID controller. Finally, the performance of the proposed elector-hydraulic load simulation method is validated through the position tracking and load simulation experiments. © 2016 IEEE.

关键词： Controllers

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Abstract

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应用力学学报 2015年第1期32卷 I0001-I0016页

作者： Feng Zhipeng Zang Fenggang Zhang Yixiong Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China 610213 Chengdu China

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A flexible nonlinear diffusion acceleration method for the first order eigenvalue SN equations discretized with discontinuous FEM

A flexible nonlinear diffusion acceleration method for the f...

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Physics of reactors 2016: Unifying Theory and Experiments in the 21st Century, PHYSOR 2016

作者： Schunert, Sebastian Wang, Yaqi Ortensi, Javier Gleicher, Frederick Baker, Benjamin DeHart, Mark Martineau, Richard Thermal Science and Safety Idaho National Laboratory Idaho FallsID United States Reactor Physics Analysis and Design Idaho National Laboratory Idaho FallsID United States Nuclear Science and Technology Modeling and Simulation Idaho National Laboratory Idaho FallsID United States

ISBN: (纸本)9781510825734

This work describes a nonlinear diffusion acceleration (NDA) method for the first order SN equations that discretizes both the transport equation and the associated diffusion system using discontinuous finite elements;the diffusion system is solved on a potentially coarser mesh and with a coarser energy group structure than the SN equations. The developed method differs from current methods by allowing the SN and diffusion system to be discretized with arbitrary FEM bases and by using an additive update of the SN system. The benefit of this capability is extension of the stability region to optically thicker mesh cells without underrelaxing the iterative algorithm. The presented method introduces the notion of consistency of the SN and diffusion solutions and derives suitable definitions of the cross sections, drift vectors, and element face closures. The NDA equations are solved using a Picard iteration scheme. Numerical results are presented for the C5G7 benchmark problem highlighting the effectiveness of the methods when deployed with the diffusion system discretized on the same mesh as the SN system. Additional results are presented for cases where the diffusion system features a coarser mesh, coarser energy group structure, or both, demonstrating its stability and effectiveness in these cases. It is observed that the effectiveness of the NDA method reduces when reducing the resolution of the associated diffusion system.

关键词： Finite element method

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Model development of Uo2-zr Plate-Type fuel behavior at early phase of severe accident and molten fuel meat relocation 16

Model development of Uo2-zr Plate-Type fuel behavior at earl...

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16th International Topical Meeting on Nuclear reactor Thermal Hydraulics, NURETH 2015

作者： Zhuohua, Zhang Shinian, Peng Science and Technology on Reactor System Design Technology Laboratory Chengdu610041 China

ISBN: (纸本)9781510811843

According to former study on oxygen diffusion, Nb-Zr solid reaction and Uo2-zr solid reaction, models of oxidation, solid reaction in fuel meat and relocation of molten fuel meat are developed based on structure and material properties of Uo2-zr plate. The new models can supply theoretical elements for safety analysis of core assembled with dispersion plate-type fuel under severe accident.

关键词： Uranium dioxide

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