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Experimental Investigation on the Hydrodynamic Characteristics of Fluidized Bed Particle Solar Receiver with Gas-Solid Countercurrent Flow Pattern

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Journal of Thermal Science 2021年第6期30卷 2241-2253页

作者： JIANG Kaijun WANG Fengli KONG Yanqiang XU Chao DU Xiaoze MOE Key Laboratory of power Station Energy Transfer Conversion and system North China Electric Power UniversityBeijing 102206China School of Energy and power Engineering Lanzhou University of TechnologyLanzhou 730050China

To design a particle solar receiver(PSR),a vital energy conversion system,is still a bottleneck for *** study presents a novel PSR based on countercurrent fluidized bed(CCFB)technology,named CCFB *** this design,downward-moving particles are subjected to the action of an up-flow gas to reduce the falling speed and enhance the radial disturbance,and hence increase the residence time of particles and improve the heat transfer.A cold-mold visual experimental setup is *** influence factors are investigated experimentally,including the superficial gas velocity,solid flux,aeration gas,particle size and transport tube *** results indicate that the maximum solid holdup can exceed 9%or so with fine particles of diameter d_(p)=113.5 μm and a tube diameter of 40 *** is proved that the CCFB can operate stably and adjust the solid flux *** results of this study provide a new structure for PSRs in the concentrated solar power field and could fill the research insufficiency in the gas-solid counterflow field.

关键词： particle solar receiver gas-solid two-phase flow countercurrent fluidized bed solid holdup

Characteristics of Axial and Radial Development of Solids Holdup in a Countercurrent Fluidized Bed Particle Solar Receiver

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Journal of Thermal Science 2021年第6期30卷 2223-2240页

A novel particle solar receiver(PSR)with gas-solids countercurrent fluidized bed(CCFB)was *** cold-mold prototype was set up to investigate the gas-solids flow structure by using optical fiber *** local solids holdup distribution,its evolution with various operating conditions and the fluctuations of the local flow structures were investigated *** results show that the novel CCFB can achieve much higher solids holdup(~9%)compared to the traditional downer ones(~l%).The solid particles are mainly distributed in the near-wall region and the particles are more difficult to get a fully developed state in the near-wall *** excellent gas-solids mixing and contacting demonstrated by the standard deviation and intermittency index means a better wall-to-bed heat transfer *** distribution of the solid particles in the CCFB transport tube is revealed,which can provide a significant reference for the structure design of the hot-mold ***,the research can fill in the research gap in the gas-solids counterflow field.

关键词： concentrated solar power particle solar receiver countercurrent fluidized bed optical fiber probe local solids holdup

Research on current decoupling control of six-phase permanent magnet linear synchronous motor for electromagnetic launch

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International Journal of Mechanical system Dynamics 2021年第2期1卷 267-277页

作者： Xingfa Sun Jin Xu Junjie Zhu department of Electrical Engineering National Key Laboratory of Science and Technology on Vessel Integrated Power SystemNaval University of EngineeringWuhanChina

Six-phase permanent magnet linear synchronous motor(PMLSM)for electromagnetic launch(EML)system presents the characteristics of a high order,nonlinearity,multivariable,strong coupling,and nonperiodic transient operation in the synchronous rotating coordinate system,posing a great challenge to the dynamic response ability of the current *** research on current decoupling control(CDC)mainly focuses on cross decoupling within a three-phase system,even though there are neither decoupling methods for multiphase systems nor effective evaluation criteria for the decoupling and dynamic response *** this perspective,this paper first presents an equivalent reduced-order complex-matrix dynamic mathematical model of six-phase PMLSM and analyze its transient coupling characteristics during the process of ***,the CDC methods of six-phase PMLSM based on direct compensation and matrix diagonalization principles are realized,respectively,to accomplish the cross decoupling and back electromotive force decoupling within and between different three-phase ***,an all-round method is proposed,for the first time,to evaluate the decoupling performances and dynamic response performances of different CDC strategies for six-phase *** superiority of deviation decoupling regulator in decoupling performance and robustness are verified based on high-speed EML experimental platform of six-phase PMLSM.

关键词： complex-matrix mathematical model current decoupling control electromagnetic launch strong transient

Space Charge Transient Kinetic Characteristics in DC Air Corona Discharge at Atmospheric Pressure

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Plasma Science and technology 2014年第8期16卷 749-757页

作者：刘兴华咸日常孙学峰王涛吕学宾陈素红杨帆 State Grid Zibo power Supply Company State Grid Shandong Electric power Company State Grid Shandong Electric power Research Institute State Key Laboratory of power Transmission Equipment & system Security and New technology Chongqing University

Investigating the corona mechanism plays a key role in enhancing the performance of electrical insulation systems. Numerical simulation offers a better understanding of the physical characteristics of air corona discharges. Using a two-dimensional axisymmetrical kinetics model, into which the photoionization effect is incorporated, the DC air corona discharge at atmosphere pressure is studied. The plasma model is based on a self-consistent, multi-component, and con- tinuum description of the air discharge, which is comprised of 12 species and 22 reactions. The discharge voltage-current characteristic predicted by the model is found to be in quite good agree- ment with experimental measurements. The behavior of the electronic avalanche progress is Mso described. 0＋ and N＋ are the dominant positive ions, and the values of 0- and 02 densities are much smaller than that of the electron. The electron and positive ion have a low-density thin layer near the anode, which is a result of the surface reaction and absorption effect of the electrode. As time progresses, the electric field increases and extends along the cathode surface, whereas the cathode fall shrinks after the corona discharge hits the cathode; thus, in the cathode sheath, the electron temperature increases and the position of its peak approaches to the cathode. The present computational model contributes to the understanding of this physical mechanism, and suggests ways to improve the electrical insulation system.

关键词： air corona discharge atmospheric pressure numerical simulation mechanism

Combination Approach of FEM and Circuit system in IR Drop Analysis and Its Applications

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Tsinghua Science and technology 2008年第6期13卷 850-857页

作者：唐章宏袁建生 State Key Laboratory of power system Department of Electrical EngineeringTsinghua University

A method was developed to solve the combined system of the current field and the circuit. The ＂super-node＂ was used to transform the matrix for conventional nodal analyses of a circuit system from non-positive definite to positive definite. Then, a positive definite matrix for the overall system was obtained by combining the matrix from the circuit nodal analysis method and the matrix resulted from finite element method （FEM） formulation to solve the FEM fields. This approach has been successfully applied to simulate the electrical potential and current distributions on each metal layer of printed circuit boards （PCBs） and integrated circuit （IC） packages for a given power supply. The simulation results can then be used to analyze the properties of the PCBs and IC packages such as the port resistances and IR drops. The results can also be used to optimize PCB and IC package designs, such as by adjusting the power/ground distribution networks.

关键词： finite element method printed circuit board integrated circuit package IR drop voltage regulator module modified nodal analysis

Transient fuel performance analysis of UO_(2)–BeO fuel with composite SiC coated with Cr cladding based on multiphysics method

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Nuclear Science and Techniques 2023年第12期34卷 93-108页

作者： Chun‑Yu Yin Shi‑Xin Gao Sheng‑Yu Liu Rong Liu Guang‑Hui Su Li‑Bo Qian School of Nuclear Science and technology Xi’an Jiaotong UniversityXi’an 710049China Science and technology on Reactor system Design technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China School of Electric power South China University of TechnologyGuangzhou 510640China

The transient multiphysics models were updated in CAMPUS to evaluate the accident-tolerant fuel performance under accident *** is a fuel performance code developed based on *** simulated results of the UO_(2)–Zircaloy fuel performance under accident conditions were compared with those of the FRAPTRAN code and the experimental data to verify the correctness of the updated ***,multiphysics models of the UO_(2)–BeO fuel and composite SiC coated with Cr(SiC_(f)/SiC-Cr)cladding were implemented in ***,the fuel performance of the three types of fuel cladding systems under Loss of Coolant Accident(LOCA)and Reactivity Insertion Accident(RIA)conditions was evaluated and compared,including the temperature distribution,stress distribution,pressure evolution,and cladding failure *** results showed that the fuel temperature of the UO_(2) fuel under accident conditions without pre-irradiation was lower after being combined with SiC_(f)/SiC-Cr ***,the centerline and outer surface temperatures of the UO_(2)–BeO fuel combined with SiC_(f)/SiC-Cr cladding reduced further under accident *** cladding temperature increased after the combination with the SiC_(f)/SiC-Cr cladding under accident conditions with *** addition,the use of SiC_(f)/SiC-Cr cladding significantly reduced the cladding hoop strain and plenum pressure.

关键词： Accident condition Fuel performance UO2–BeO fuel SiCf/SiC-Cr cladding

Approximation capability of regular fuzzy neural networks to continuous fuzzy functions

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Science China(Technological Sciences) 1999年第2期42卷 175-182页

作者：刘普寅汪浩 department of system Engineering and Mathematics National University of Defence Technology

The approximation capability of regular fuzzy neural networks to fuzzy functions is studied. When σ is a nonconstant, bounded and continuous function of $\mathbb{R}$ , some equivalent conditions are obtained, with which continuous fuzzy functions can be approximated to any degree of accuracy by the four-layer feedforward regular fuzzy neural networks $\sum\limits_{k = 1}^q {\tilde W_k } \cdot \left( {\sum\limits_{j = 1}^p {\tilde V_{kj} \cdot \sigma (\tilde X \cdot \tilde U_j + \tilde \Theta _j )} } \right)$ . Finally a few examples of such fuzzy functions are given.

关键词： regular fuzzy neural networks universal approximation cut-preserving fuzzy mapping

Fault Location Detection of Transmission Lines in Noise Environments Based on Random Matrix Theory

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CSEE Journal of power and Energy systems 2022年第4期8卷 1233-1241页

作者： Jun An Zihan Deng Haipeng Chen Gang Mu Key Laboratory of Modern power system Simulation and Control&Renewable Energy technology Ministry of Education(Northeast Electric Power University)Jilin 132012.Jilin ProvinceChina

Fault detection and location are critically significant applications of a supervisory control system in a smart *** methods,based on random matrix theory(RMT),have been practiced using measurements to detect short circuit faults occurring on transmission ***,the diagnostic accuracy is infuenced by the noise signal in the *** relationship between mean eigenvalue of a random matrix and noise is detected in this paper,and the defects of the Mean Spectral Radius(MSR),as an indicator to detect faults,are theoretically determined,along with a novel indicator of the shifting degree of maximum eigenvalue and its *** comparing the indicator and the threshold,the occurrence of a fault can be ***,an augmented matrix is constructed to locate the fault *** proposed method can effectively achieve fault detection via the RMT without any influence of noise,and also does not depend on system *** experiment results are based on the IEEE 39-bus ***,actual provincial grid data is applied to validate the effectiveness of the proposed method.

关键词： Fault detection maximum eigenvalue noise random matrix theory smart grid

Dynamics of stochastic non-Newtonian fluids driven by fractional Brownian motion with Hurst parameter H∈(1/4,1/2)

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Applied Mathematics and Mechanics(English Edition) 2013年第2期34卷 189-208页

作者：李劲黄建华 department of Mathematics and system Science National University of Defense Technology

A two-dimensional （2D） stochastic incompressible non-Newtonian fluid driven by the genuine cylindrical fractional Brownian motion （FBM） is studied with the Hurst parameter ∈ （1/4,1/2） under the Dirichlet boundary condition. The existence and regularity of the stochastic convolution corresponding to the stochastic non-Newtonian fluids are obtained by the estimate on the and the identity of the infinite double series spectrum of the spatial differential operator in the analytic number theory. The existence of the mild solution and the random attractor of a random dynamical system are then obtained for the stochastic non-Newtonian systems with ∈ （1/2,1） without any additional restriction on the parameter H.

关键词： infinite-dimensional fractional Brownian motion (FBM) stochastic convolution stochastic nomNewtonian fluid random attractor