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Extension of flow Behaviour and Damage Models for Cast Iron Alloys with Strain Rate Effect

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 297-310页

作者： Chuang Liu Dongzhi Sun Xianfeng Zhang Florence Andrieux Tobias Gersterc School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China Fraunhofer institute for mechanics of Materials(IWM) 79108 FreiburgGermany Fraunhofer institute for High Speed Dynamics Ernst-Mach-Institute(EMI)79104 FreiburgGermany

Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive *** study the mechanical behavior of a typical ductile cast iron(GJS-450)with nodular graphite,uni-axial quasi-static and dynamic tensile tests at strain rates of 10^(-4),1,10,100,and 250 s^(-1)were carried *** order to investigate the influence of stress state on the deformation and fracture parameters,specimens with various geometries were used in the *** strain curves and fracture strains of the GJS-450 alloy in the strain rate range of 10^(-4)to 250 s^(-1)were obtained.A strain rate-dependent plastic flow model was proposed to describe the mechanical behavior in the corresponding strain-rate *** available damage model was extended to take the strain rate into account and calibrated based on the analysis of local fracture *** with the proposed plastic flow model and the damage model were conducted to observe the deformation and fracture *** results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 *** predictions with the proposed plastic flow and damage models at various strain rates agree well with the experimental results,which illustrates that the rate-dependent plastic flow and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain *** proposed plastic flow and damage models can be used to describe the deformation and fracture analysis of materials with similar properties.

关键词： Dynamic behavior of materials Strain rate dependency Damage model Voce model Cast iron

Formation of Water Quality of Surface Water Bodies Used in the Material Processing

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fluid Dynamics & Materials Processing 2024年第4期20卷 815-828页

作者： Tatyana Lyubimova Anatoly Lepikhin Yanina Parshakova Irina Zayakina Alibek Issakhov Laboratory of Computational fluid Dynamics Laboratory Institute of Continuous Media Mechanics UB RASPerm614068Russia Laboratory of Land Hydrology Problems Mining Institute UB RASPerm614000Russia Department of Theoretical Physics Perm State UniversityPerm614990Russia Department of Mathematical and Computer Modeling Al-Farabi Kazakh National UniversityAlmaty050040Republic of Kazakhstan

In the process of production or processing of materials by various methods,there is a need for a large volume of water of the required *** in many regions of the world,there is an acute problem of providing industry with water of a required *** solution is an urgent and difficult *** water quality of surface water bodies is formed by a combination of a large number of both natural and anthropogenic factors,and is often significantly heterogeneous not only in the water area,but also in *** a rule,the water supply of large industrial enterprises is located along the river *** are the most important nodes of river *** the mechanism of transport of pollutants at the confluence of rivers is critical for assessing water *** recent years,thanks to the data of satellite images,the interest of researchers in the phenomenon of mixing the waters of merging rivers has *** nature of the merger is influenced by the formation of transverse *** the framework of this work,a study of vorticity,as well as the width of the mixing zone,depending on the distance from the confluence,the speeds of the merging rivers and the angle of confluence was carried *** the consumer properties of water are largely determined by its chemical and physical indicators,the intensity of mixing,determined largely by the nature of the secondary circulation,is of fundamental importance for assessing the distribution of hydrochemical indicators of water quality in the mixing *** characteristics are important not only for organizing water intake for drinking and technical purposes with the best consumer properties,but also for organizing an effective monitoring system for confluence zones.

关键词： Water for material processing water quality formation of transverse circulation

HORIZONTAL WELL PRESSURE ANALYSIS IN BOX-BOUNDED RESERVOIRS

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维普期刊数据库

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Applied Mathematics and mechanics(English Edition) 1998年第4期19卷 315-320页

作者：王晓冬刘慈群 institute of porous flow and fluid mechanics Academia Sinica Langfang P. R. China

In this paper, solutions to the 3D transient flow mathematical model for horizontal wells in box-rounded reservoirs are presented. The solutions are derived in Laplace transform domain by employing integral transform and point-source superposition. Both efficient computation of pressure responses and practical technology of oil field application mentioned here may be used to interpret the data from unsteady-state horizontal well testing.

关键词： horizontal well transient flow in porous media mathematical model pressure pressure derivatives well test analysis

flow instability of supercritical hydrocarbon fuel in a multi-channel cooling system

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Chinese Journal of Aeronautics 2024年第2期37卷 283-295页

作者： Yichao JIN Kun WU Xuejun FAN institute of Applied Physics and Computational Mathematics Beijing 100094China institute of mechanics Chinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Thermally-induced flow instabilities are a critical issue in multi-channel regenerative cooling *** particular,the interactions between Density-Wave Oscillations(DWO)and flow Maldistribution(FMD)can result in complex and disastrous instability *** study investigates the instability behaviors of hydrocarbon fluid in a four-channel system with a constant heat flux ratio using both frequency-and time-domain *** the heat flux increases,the in-tube flow sequentially destabilizes in each channel and converges to new equilibrium states,leading to the emergence of FMD *** also causes the system eigenvalue to change repeatedly from negative to positive rather than increasing ***,the system eigenvalues are between those of the two most unstable channels,indicating that the stability behavior of the entire system is dictated by the most unstable *** FMD occurs,flow oscillations are activated in channels with weak stability,and the in-tube flow is observed to evolve into various flow patterns,including stable flow,self-sustained oscillation,oscillation divergence,quasiperiodic oscillation,and oscillation *** novel instability mode of oscillation excursion involves a spontaneous transition of operating *** oscillates from an equilibrium state and then stabilizes at a new operational state after oscillation-induced ***,the newfound stable state may also be only temporary,with the in-tube flow regressing to the initial state,resulting in quasi-periodic oscillation.

关键词： Cooling Supercritical fluids Hydrocarbons flow instability flow maldistribution Density-wave oscillations

ANALYTICAL SOLUTIONS FOR EQUATIONS OF UNSTEADY flow OF NON-NEWTONIAN fluidS IN TUBE

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Applied Mathematics and mechanics(English Edition) 1989年第11期10卷 989-996页

作者：刘慈群黄军旗 institute of porous flow fluid mechanics. Langfang

This paper presents analytieal solutions to the partial differential equations for unsteady flow of the second-order fluid and Maxwell fluid in tube by using the integral transform method. It can be used to analyse the behaviour of axial velocity and shear stress for unsteady flow of nun-Newtonian visco-elastie fluids in tube, and to provide a theoretical base for the projection of pipe-line engineering.

关键词： ANALYTICAL SOLUTIONS FOR EQUATIONS OF UNSTEADY flow OF NON-NEWTONIAN fluidS IN TUBE Maxwell

TRANSIENT PRESSURE OF PERCOLATION THROUGH ONE DIMENSION porous MEDIA WITH THRESHOLD PRESSURE GRADIENT

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Applied Mathematics and mechanics(English Edition) 1999年第1期20卷 27-35页

作者：宋付权刘慈群李凡华 institute of porous flow and fluid mechanics Acadimia Sinica 065007 Langfang P. R. China

This paper studies the transient pressure of percolation during one production and one shutting in one dimension porous media with threshold pressure gradient, the differential equations are derived and solved with numerical computation. Basing on numerical solution, it is analyzed that: 1. the relation between the steady pressure at well bore (or at endpoint) and threshold pressure gradient, shut-in time, and the corresponding formulae are derived; 2, the regulation of transient pressure peak. The result is very useful and will help experiments and applications in the development of low permeability reservoirs with threshold pressure gradient.

关键词： low permeability reservoirs threshold pressure gradient moving boundary numerical computation

A Review on Vibration Control of Multiple Cylinders Subjected to flowInduced Vibrations

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China Ocean Engineering 2024年第2期38卷 183-197页

作者： XU Wan-hai MA Ye-xuan State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin 300350China institute of mechanics Chinese Academy of SciencesBeijing 100190China

The fatigue damage caused by flow-induced vibration(FIV)is one of the major concerns for multiple cylindrical structures in many engineering *** FIV suppression is of great importance for the security of many cylindrical *** active and passive control methods have been employed for the vibration suppression of an isolated cylinder undergoing vortex-induced vibrations(VIV).The FIV suppression methods are mainly extended to the multiple cylinders from the vibration control of the isolated *** to the mutual interference between the multiple cylinders,the FIV mechanism is more complex than the VIV mechanism,which makes a great challenge for the FIV *** efforts have been devoted to vibration suppression of multiple cylinder systems undergoing FIV over the past two *** control methods,such as helical strakes,splitter plates,control rods and flexible sheets,are not always effective,depending on many influence factors,such as the spacing ratio,the arrangement geometrical shape,the flow velocity and the parameters of the vibration control *** FIV response,hydrodynamic features and wake patterns of the multiple cylinders equipped with vibration control devices are reviewed and *** FIV suppression efficiency of the vibration control methods are analyzed and compared considering different influence *** research on the FIV suppression of multiple cylinders is suggested to provide insight for the development of FIV control methods and promote engineering applications of FIV control methods.

关键词： flow-induced vibration vibration control multiple cylinders tandem side-by-side staggered

Experimental evaluation on well pattern adaptability of ultra-low permeability reservoir using sandstone flat model

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Journal of Central South University 2014年第6期21卷 2334-2340页

作者：肖前华魏国齐杨正明徐轩田文博张亚蒲 institute of porous flow and fluid mechanics China Academy of Sciences Langfang Branch Petro China Exploration and Development Research Institute

As for ultra-low permeability reservoir,the adaptability of common nine-spot well pattern is studied through large-scale flat models made by micro-fractured natural sandstone *** with non-linear porous flow characteristics,the concept of dimensionless pressure sweep efficiency and deliverability index are put forward to evaluate the physical models' well pattern *** experiments,the models' pressure distribution is measured and on which basis,the pressure gradient fields are drawn and the porous flow regions of these models are divided into dead oil region,non-linear porous flow region,and quasi-linear porous flow region with the help of twin-core non-linear porous flow *** results indicate that rectangular well pattern in fracture reservoirs has the best adaptability,while the worst is inverted nine-spot equilateral well *** the increase of drawdown pressure,dead oil region decreases,pressure sweep efficiency and deliverability index increase; meantime,the deliverability index of rectangular well pattern has much more rational *** the same drawdown pressure,the rectangular well pattern has the largest pressure sweep efficiency.

关键词： micro-fractured development sandstone flat model adaptability of well pattern pressure sweep efficiency deliverability index

An overview on nonlinear porous flow in low permeability porous media

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Theoretical & Applied mechanics Letters 2013年第2期3卷 1-8页

作者： Yanzhang Huang Zhengming Yang Ying He Xuewu Wang The institute of porous flow and fluid mechanics Chinese Academy of Sciences

This paper gives an overview on nonlinear porous flow in low permeability porous media, reveals the microscopic mechanisms of flows, and clarifies properties of porous flow fluids. It shows that, deviating from Darcy＇s linear law, the porous flow characteristics obey a nonlinear law in a low-permeability porous medium, and the viscosity of the porous flow fluid and the permeability values of water and oil are not constants. Based on these characters, a new porous flow model, which can better describe low permeability reservoir~ is established. This model can describe various patterns of porous flow, as Darcy＇s linear law does. All the parameters involved in the model, having definite physical meanings, can be obtained directly from the experiments.

关键词： low permeability porous media nonlinear porous flow porous flow equation porous flowfluid