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dynamic simulation and experimental study of the effect of one-dimensional vibration on the packing of wood powder particles

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Particuology 2024年第11期94卷 294-304页

作者： Xiaoneng Chen Fuqiang He Fajiang Chen Yuan Dai School of Mechanical Engineering Guizhou UniversityGuiyang550025China Guizhou Jingmu Building Materials Co. Guiyang550025China

In the industry of production of high-density fiberboards without adhesive,applying vibration to the particle packing system before pressing and molding is an effective way to improve the uniformity of particle packing and reduce *** this work,physical experiments combined with numerical simulations are used to systematically investigate the packing structure behavior of wood powder particles under different vibration *** and microscopic properties such as porosity,coordination number,radial distribution function,and contacts are characterized and *** results indicate that when the vibration frequency is 72 Hz and the vibration amplitude is 1 mm,the porosity of wood powder particles closely packed is *** results of the Discrete Element Method show that the distribution of the coordination number is approximately *** the vibration conditions change,the packing structure becomes tighter,but the main peak of the radial distribution function becomes blurred or even *** does not significantly change the type of contact in the packing *** conclusions can provide more comprehensive vibration conditions and microscopic theories for the uniform spreading of wood powder particles before pressing,ensuring that the finished panels have excellent mechanical and physical properties.

关键词： Vibration Wood powder particle dynamic simulation

dynamic simulation of Kosterlitz-Thouless Transition in Two-Dimensional Fully Frustrated XY Model

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Chinese Physics Letters 2009年第1期26卷 216-219页

作者：雷晓蔚赵晓雨 Department of Physics Chongqing University of Arts and Sciences Chongqing 402160

Relaxation dynamics of the two-dimensional fully frustrated XY model is investigated with Monte Carlo methods. The simulation focuses on the Kosterlitz Thouless phase transition. From the dynamic scaling behaviour of the magnetization above the transition temperature TKT, the correlating time of the dynamic system is extracted. The transition temperature TKT and static exponent v are then determined.

关键词： NONEQUILIBRIUM CRITICAL-dynamicS MONTE-CARLO CRITICAL EXPONENTS PHASE-TRANSITIONS SQUARE-LATTICE BEHAVIOR SYSTEMS SPIN X-Y model critical exponents Frustration Phase transtormations Kosterlitz-Thouless transition dynamic systems Spin Monte Carlo technique Transition Temperature dynamic simulation

dynamic simulation of Distribution Networks Using Multi-stage Discontinuous Galerkin Method

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 185-196页

作者： Ruizhi Yu Wei Gu Weiqi Liu Peixin Li Wei Liu School of Electrical Engineering Southeast UniversityNanjing 210096China. the School of Electrical Engineering Southeast UniversityNanjing 210096China School of Automation Nanjing University of Science and TechnologyNanjing 210094China

dynamic simulation plays a fundamental role in security evaluation of distribution networks(DNs).However,the strong stiffness and non-linearity of distributed generation(DG)models in DNs bring about burdensome computation and noteworthy instability on traditional methods which hampers the rapid response of simulation ***,a novel L-stable approximate analytical method with high accuracy is proposed to handle these *** method referred to as multistage discontinuous Galerkin method(MDGM),first derives approximate analytical solutions(AASs)of state variables which are explicit symbolic expressions concerning system ***,in each time window,it substitutes values for symbolic variables and trajectories of state variables are obtained *** paper applies MDGM to DG models to derive ***-truncation-error-based variable step size strategy is also developed to further improve simulation *** addition,this paper establishes detailed MDGM-based dynamic simulation *** case studies on a numerical problem,a modified 33-bus system and a practical large-scale DN,it can be seen that proposed method demonstrates fast and dependable performance compared with the traditional trapezoidal method.

关键词： Approximate analytical method distribution network distributed generation dynamic simulation multi-stage discontinuous Galerkin method variable step size

dynamic simulation and efficiency analysis of beam pumping system

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Journal of Central South University 2015年第9期22卷 3367-3379页

作者：邢明明董世民童志雄田然凤陈慧玲 School of Mechanical Engineering Yanshan University

An improved whole model of beam pumping system was built. In the detail, for surface transmission system(STS), a new mathematical model was established considering the influence of some factors on the STS's torsional vibration, such as the time variation characteristic of equivalent stiffness of belt and equivalent rotational inertia of crank. For the sucker rod string(SRS), an improved mathematical model was built considering the influence of some parameters on the SRS's longitudinal vibration, such as the nonlinear friction of plunger, hydraulic loss of pump and clearance leakage. The dynamic response and system efficiency of whole system were analyzed. The results show that there is a jumping phenomenon in the amplitude frequency curve, and the system efficiency is sensitive to motor power, pump diameter, stroke number, ratio of gas and oil, and submergence depth. The simulation results have important significance for improving the efficiency of beam pumping system.

关键词： beam pumping system surface transmission system(STS) sucker rod string(SRS) system efficiency dynamic simulation

dynamic simulation of GEH-IES with distributed parameter characteristics for hydrogen-blending transportation

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Frontiers in Energy 2024年第4期18卷 506-524页

作者： Dengji ZHOU Jiarui HAO Wang XIAO Chen WANG Chongyuan SHUI Xingyun JIA Siyun YAN Key Laboratory of Power Machinery and Engineering of the Ministry of Education Shanghai Jiao Tong UniversityShanghai 200240China Sichuan Research Institute Shanghai Jiao Tong UniversityChengdu 610042China West Pipeline Company National Petroleum and Natural Gas Pipe Network Group Co.Ltd.Urumqi 830012China Institute of Intelligent Manufacturing Modern Industry Xinjiang UniversityUrumqi 830046China

For the purpose of environment protecting and energy saving,renewable energy has been distributed into the power grid in a considerable ***,the consuming capacity of the power grid for renewable energy is relatively *** an effective way to absorb the excessive renewable energy,the power to gas(P2G)technology is able to convert excessive renewable energy into ***-blending natural gas pipeline is an efficient approach for hydrogen ***,hydrogen-blending natural gas complicates the whole integrated energy system(IES),making it more problematic to cope with the equipment failure,demand response and dynamic ***,dynamic simulation of distribution parameters of gas-electricity-hydrogen(GEH)energy system,especially for hydrogen concentration,still remains a *** dynamics of hydrogen-blending IES is *** tackle the issue,an iterative solving framework of the GEH-IES and a cell segment-based method for hydrogen mixing ratio distribution are proposed in this *** typical numerical cases studying the conditions under which renewables fluctuate and generators fail are conducted on a real-word *** results show that hydrogen blending timely and spatially influences the flow parameters,of which the hydrogen mixing ratio and gas pressure loss along the gas pipeline are negatively correlated and the response to hydrogen mixing ratio is ***,the hydrogen-blending amount and position also have a significant impact on the performance of the compressor.

关键词： gas-electricity IES dynamic simulation hydrogen blending power to gas(P2G) renewable energy

dynamic simulation of urbanization and eco-environment coupling:Current knowledge and future prospects

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Journal of Geographical Sciences 2020年第2期30卷 333-352页

作者： CUI Xuegang FANG Chuanglin LIU Haimeng LIU Xiaofei LI Yonghong Institute of Geographic Sciences and Natural Resources Research CASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Institute of Water Ecology Beijing Orient Landscape&Environment Co.Ltd.Beijing 100015China

Urbanization and eco-environment coupling is a research *** simulation of urbanization and eco-environment coupling needs to be improved because the processes of coupling are complex and statistical methods are *** science and cross-scale coupling allow us to define the coupled urbanization and eco-environment system as an open complex giant system with multiple feedback *** review the current state of dynamic simulation of urbanization and eco-environment coupling and find that:(1)The use of dynamic simulation is an increasing trend,the relevant theory is being developed,and modeling processes are being improved;(2)dynamic simulation technology has become diversified,refined,intelligent and integrated;(3)simulation is mainly performed for three aspects of the coupling,multiple regions and multiple elements,local coupling and telecoupling,and regional ***,we also found some shortcomings:(1)Basic theories are inadequately developed and insufficiently integrated;(2)The methods of unifying systems and sharing data are behind the times;(3)Coupling relations and the dynamic characteristics of the main driving elements are not fully understood or completely ***,simulation of telecoupling does not quantify parameters and is not systemically unified,and therefore cannot be used to represent spatial *** the future,we must promote communication between research networks,technology integration and data sharing to identify the processes governing change in coupled relations and in the main driving elements in urban ***,we must build decision support systems to plan and ensure regional sustainable urbanization.

关键词： urbanization and eco-environment coupling dynamic simulation theory methods applications

dynamic simulation based on Jacobian-free Newton-GMRES methods with adaptive preconditioner for power systems

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Science China(Technological Sciences) 2013年第8期56卷 2037-2045页

作者： HUANG ShaoWei CHEN Ying SHEN Chen MEI ShengWei State Key Laboratory of Control and simulation of Power Systems and Generation Equipments(Department of Electrical Engineering Tsinghua University)

dynamic simulation is one of the most complex and important computations for power systems *** solutions based on normal Newton iterations almost all depend on evaluations of Jacobian matrixes,which increases the programming complexity of and limits the parallelizability of the whole *** this paper,a new adaptive preconditioned Jacobian-free Newton-GMRES(m)method is proposed to be applied to dynamic simulations of power *** new method has totally Jacobian-free characteristics,which saves calculations and storages of Jacobian matrixes and features strong ***,several speedup strategies are introduced to enhance efficiency and parallelizability of overall *** tests are carried out on IEEE standard test systems and results show that in series computing environment,simulations based on the proposed method have comparable speed to those based on classical Newton-Raphson methods.

关键词： dynamic simulation Newton-GMRES preconditioner power system

dynamic simulation OF ROTATING SHELLS COUPLED WITH LIQUID

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Acta Mechanica Solida Sinica 2001年第2期14卷 169-175页

作者： Wei Fayuan Li Shiqi Huang Yuying~1 Zhong Yifang (College of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China) (1 Department of Mechanics, Huazhong University of Science and Technology, Wuhan 430074,China) ***

The dynamic behaviors of rotating shells coupled with liquid areshown. The shell under con- sideration has arbitrary boundaryconditions and a complex shape. A modified boundary element methodand finite strip technique are used to improve the computingefficiency and to guarantee the continuity conditions on theliquid-shell interaction plane. The effects of various parameterssuch as shell's thickness and liquid depth are investigated. dynamicsimulations are applied to several typical shell-liquid systems, andthe natu- ral frequencies, mode shapes and response of vibration arecalculated numerically.

关键词： rotting shells dynamic simulation fluid-solid interaction

dynamic simulation OF FLUID-STRUCTURE INTERACTION PROBLEMS INVOLVING LARGE-AMPLITUDE SLOSHING

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Chinese Journal of Mechanical Engineering 2004年第1期17卷 117-120页

作者： ChenJianping ZhouRurong WuWenlong ResearchCenterofCAD／CAMEngineering NanjingUniversityofAeronauticsandAstronauticsNanjing210016China CollegeofAerospace NanjingUniversityofAeronauticsandAstronauticsNanjing210016China

An effective computational method is developed for dynamic analysis offluid-structure interaction problems involving large-amplitude sloshing of the fluid andlarge-displacement motion of the structure. The structure is modeled as a rigid container supportedby a system consisting of springs and dashpots. The motion of the fluid is decomposed into twoparts: the large-displacement motion with the container and the large-amplitude sloshing relative tothe container. The former is conveniently dealt with by defining a container-fixed noninertiallocal frame, while the latter is easily handled by adopting an ALE kinematical description. Thisleads to an easy and accurate treatment of both the fluid-structure interface and the fluid freesurface without producing excessive distortion of the computational mesh. The coupling between thefluid and the structure is accomplished through the coupling matrices that can be easilyestablished. Two numerical examples, including a TLD-structure system and a simplified liquid-loadedvehicle system, are presented to demonstrate the effectiveness and reliability of the proposedmethod. The present work can also be applied to simulate fluid-structure problems incorporatingmultibody systems and several fluid domains.

关键词： Fluid-structure interaction Large-amplitude sloshing dynamic simulation Arbitrary Lagrangian-Eulerian (ALE) description