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DYNAMIC MODEL AND SIMULATION OF EAF STEELMAKING PROCESS

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Acta Metallurgica Sinica(English Letters) 2003年第3期16卷 197-203页

作者： q.li X.Hong Shanghai Enhanced Laboratory of Ferrometallurgy Shanghai University Shanghai 200072 ChinaShanghai Enhanced Laboratory of Ferrometallurgy Shanghai University Shanghai 200072 China

Based on mass and energy balances and theories of thermodynamics and kinetics, a dynamic model in conjunction with relative operation parameters was derived. With this model, the EAF process in later stage of scarp melting was dynamically described, including time dependent variations of bath temperature, slag quantity, compositions of steel, slag and off-gas, etc. Steelmaking process in a domestic 100 ton UHP AC EAF was chosen as a computational example, and the simulated variations of temperature of hot metal and element contents was shown consistent with the actual process measurements within average error scopes of |△T| <15K, |[△A%C]| ≤ 0.036, |[△%Si]|≤0.00027, |[△%Mn]|≤0.002, |[△%P]|≤0.00089 and |[△%S]|≤0.001 respectively at the test points. The model will be extended to predict the whole production process including scrap melting procedure and evaluate its energy and material consumption, the production efficiency, etc., which will provide assistance for the improvement of EAF operation and control.

关键词： EAF dynamic model simulation

Strain Growth in Containment Vessels

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Transactions of Tianjin University 2006年第B9期12卷 193-198页

作者： DONG q li q M ZHENG J Y School of Mechanical Aerospace and Civil Engineering The University of Manchester PO Box 88 Manchester M60 1QD UK Institute of Chemical Machinery Zhejiang University Hangzhou 310027 China

Strain growth is a phenomenon observed in containment vessels subjected to internal blast loading. The elastic response of the vessel may become larger in a later stage compared to its response during the initial stage. The dynamic responses of infinitely long cylindrical containment vessels subjected to uniformly-distributed internal blast loading are studied using LS-DYNA. The development of bending modes and the interaction between the breathing mode and bending modes are observed. The methodology developed for dynamic elastic buckling analysis is employed to study the strain growth phenomenon in explosion containment vessels. It is shown that the dynamic instable vibration of a containment vessel is the basic mechanism of strain growth.

关键词： strain growth containment vessel dynamic response impulsive loading

Effects of the Reversely Rotating Assisted Shoulder on Microstructures During the Reverse Dual-rotation Friction Stir Welding

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Journal of Materials Science & Technology 2015年第4期31卷 375-383页

作者： J.q.li H.J.liu State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Capital Aerospace Machinery Company

The reverse dual-rotation friction stir welding(RDR-FSW) has the capability to adjust the heat generation because of the separately designed tool shoulder and tool *** welding torque exerted on the workpiece by the reversely rotating shoulder is opposite to that exerted by the rotating tool pin,so the total welding torque is reduced,which is beneficial to reducing the clamping requirement of *** the present paper,a RDR-FSW joint was welded in a condition similar to the optimal welding condition of conventional FSW,and microstructures in various zones were investigated by comparison,aiming to highlight effects of the reversely rotating assisted *** to the heat conduction of the middle cylinder and the bottom end cover on which the assisted shoulder was machined,the thermal effect of RDR-FSW was smaller than that of the conventional ***,the effect of assisted shoulder on the plastic flow or deformation of material or was constrained in a thin layer near the weld top surface,and thus the flow of material especially along the thickness direction was clearly decreased in the *** the heat-affected zone(HAZ),the precipitate coarsening was the main evolution and was completed through the dissolution of small precipitates and the continuous growth of large *** contrast,the dissolution degree of precipitates increased significantly in the thermomechanically affected zone(TMAZ),and a small amount of original meta-stable precipitates transformed to block-shaped stable *** evolutions in the shoulder affected zone(SAZ)and the weld nugget zone were similar,*** majority of original meta-stable precipitates dissolved into the matrix and the remainder transformed to stable precipitates,though the dissolution degree was greater in the *** with the conventional FSW joint,the coarsening degrees of precipitates in the HAZ and TMAZ of RDR-FSW joint were much smaller,as well as the dissolution degrees of p

关键词： Friction stir welding Reverse dual-rotation fricti

COUPLED SIMULATION OF 3D ELECTRO-MAGNETO-FLOW FIELD IN HALL-HEROULT CELLS USING FINITE ELEMENT METHOD

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Acta Metallurgica Sinica(English Letters) 2006年第2期19卷 105-116页

作者： J. li W. liu Y.q. Lai q.Y. li Y.X. liu School of Metallurgy Science and Engineering Central South University Changsha 410083 China Chemistry Department Guangxi Normal University Guilin 531400 China

Two full 3D steady mathematical models are developed by finite element method （FEM） to calcalate coupled physics fields. the electro-magnetic model is built and solved first and so is the fluid motion model with the acquired electromagnetic force as source body forces in Navier-Stokes equations. Effects caused by the ferromagnetic shell, busbar system around, and open boundary problem as well as inside induced current were considered in terms of the magnetic field. Furthermore, a new modeling method is found to set up solid models and then mesh them entirely with so-called structuralized grids, namely hex-mesh. Examples of 75kA prebaked cell with two kinds of busbar arrangements are presented. Results agree with those disclosed in the literature and confirm that the coupled simulation is valid. It is also concluded that the usage of these models facilitates the consistent analysis of the electric field to magnetic field and then flow motion to the greater extent, local distributions of current density and magnetic flux density are very much dependent on the cell structure, the steel shell is a shield to reduce the magnetic field and flow pattern is two dimensional in the main body of the metal pad.

关键词： coupled simulation electromagnetic field flow field aluminum reduction cell finite element analysis

Characterization of face-centered cubic structure and deformation mechanisms in high energy shot peening process of TC17

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Journal of Materials Science & Technology 2022年第15期110卷 136-151页

作者： C.Yang M.q.li Y.G.liu School of Materials Science and Engineering Northwestern Polytechnical UniversityXi’an 710072China

The face-centered cubic structure(fcc)and its deformation behaviors,as well as the distinctive role of fcc-Ti in nanocrystallization in TC17 subjected to high energy shot peening(HESP),were investigated by using comprehensive high-resolution transmission electron microscopy(HRTEM).The results showed that there was a stress-induced fcc-Ti in TC17 with a lattice constant of 0.420–0.433 nm and the B-type orientation relationship between the hcp-Ti and the fcc-Ti as[2-1-10]_(hcp)//[-110]_(fcc)and(0001)_(hcp)//(111)_(fcc),which was accomplished by the gliding of Shockley partial dislocations with Burgers vector of 1/3[01-10]on the basal *** deformation twinning dominated the subsequent deformation of fcc-Ti,producing two types of{111}twins with different *** them,the I-type twin with complete structure was generated by successive gliding of Shockley partial dislocations with the same Burgers vector of 1/6[11-2].In contrast,the cooperative slip of three Shockley partials,whose sum of Burgers vectors was equal to zero,produced the II-type twin with zero net macroscopic *** then,the emission of Shockley partial with the Burgers vector of 1/6[11-2]on every three(111)fccplanes resulted in the formation of a 9R *** to the dissociation effect of lamellar fcc-Ti and the superior deformation ability of fcc structure,the occurrence of fcc-Ti effectively promoted surface nanocrystallization of TC17.

关键词： TC17 Severe plastic deformation Stress-induced phase transformation Deformation twinning Nanocrystallization

A brief review：experimental investigation of zonal flows and geodesic acoustic modes in fusion plasmas

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Plasma Science and Technology 2018年第9期20卷 72-84页

作者： K J ZHAO J q DONG J q li L W YAN Southwestern Institution of Physics Chengdu 610041People＇s Republic of China

Zonal flows self-generated by turbulence play an important role in regulating turbulence,reducing transport level,and thus improve plasma confinement in fusion *** zonal flows and geodesic acoustic modes have been identified in various *** related issues,such as the poloidal and toroidal symmetries,coupling to turbulence,effects on turbulence and transport,nonlinear energy transfer between turbulence and zonal flows,dependence of the plasma parameters,roles in the confinement regime transitions etc are overviewed briefly in this *** interaction between zonal flows and magnetic islands is emphasized.

关键词： zona flow tokamak turbulence fusion plasma

Laboratory study of fracture initiation and propagation in Barre granite under fluid pressure at stress state close to failure

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第3期15卷 538-550页

作者： Bing q.li Michela Casanova Herbert H.Einstein Department of Civil and Environmental Engineering Massachusetts Institute of TechnologyCambridgeUSA Department of Civil and Environmental Engineering Western UniversityLondonCanada School of Architecture Civil and Environmental EngineeringÉcole Polytechnique Fédérale de LausanneLausanneSwitzerland

Hydraulic fracturing is frequently used to increase the permeability of rock formations in energy extraction scenarios such as unconventional oil and gas extraction and enhanced geothermal systems(EGSs).The present study addresses uncertainties in the hydraulic fracturing process pertaining to EGSs in crystalline rock such as ***,there is debate in the literature on the mechanisms(*** and/or shear)by which these fractures initiate,propagate,and *** present experiments on Barre granite with pre-cut flaws where the material is loaded to high far-field stresses close to shear failure,and then the fluid pressure in the flaws is increased to move the Mohr’s circle to the left and observe the initiation and propagation of fractures using high-speed imaging and acoustic emissions(AEs).We find that the hydraulic fractures initiate as tensile microcracks at the flaw tips,and then propagate as a combination of tensile and shear *** focal mechanisms also show elevated levels of tensional microfracturing near the flaw tips during pressurization and final *** then consider a numerical model of the experimental setup,where we find that fractures are indeed likely to initiate at flaw tips in tension even at relatively high far-field stresses of 40 MPa where shear failure is generally expected.

关键词： Acoustic emission(AE) Hydraulic fracturing Enhanced geothermal system(EGS) Microseismicity

Numerical study on the resistance of rigid projectiles penetrating into semi-infinite concrete targets

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Acta Mechanica Sinica 2021年第3期37卷 482-493,I0003页

作者： Huawei Yang Jie Zhang Zhiyong Wang Zhihua Wang q.M.li College of Management Science and Engineering Shanxi University of Finance and EconomicsTaiyuan 030006China Institute of Applied Mechanics College of Mechanical and Vehicle EngineeringTaiyuan University of TechnologyTaiyuan 030024China Shanxi Key Laboratory of Material Strength and Structural Impact Taiyuan University of TechnologyTaiyuan 030024China Department of Mechanical Aerospace and Civil EngineeringSchool of EngineeringThe University of ManchesterManchester M139PLUK

A study on the resistance of rigid projectiles penetrating into semi-infinite concrete targets is performed in this *** data are analyzed to examine the penetration resistance during various stages of the penetration process.A numerical tool using AUTODYN hydrocode is applied in the *** numerical results on both deceleration-time history and depth of penetration of projectiles are in good agreement with experimental data,which demonstrate the feasibility of the numerical model in these *** on the numerical model with a two-staged pre-drilled hole,the rigid projectile penetration in tunneling stage is studied for concrete targets with different strengths in a wide range of impact *** results show that the penetration in tunnel stage can be divided into two different cases in terms of initial impact *** the first case,when the impact velocity is approximately less than 600 m/s,the deceleration depends on initial impact *** the second case,when the impact velocity is greater than 600 m/s,the effect of target inertia becomes apparent,which agrees with commonly used concrete penetration resistance equations based on cavity expansion model.

关键词： Rigid projectile Penetration resistance Entrance phase Inertial term Concrete target

Basic features of the multiscale interaction between tearing modes and slab ion-temperature-gradient modes

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Chinese Physics B 2019年第12期28卷 237-247页

作者： L Wei Z X Wang J q li Z q Hu Y Kishimoto Key Laboratory of Materials Modification by Laser Ionand Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024China Southwestern Institute of Physics Chengdu 610041China Graduate School of Energy Science Kyoto UniversityGokashoUjiKyoto 1-0011Japan

Nonlinear interaction between tearing modes(TM) and slab ion-temperature-gradient(ITG) modes is numerically investigated by using a Landau fluid model. It is observed that the energy spectra with respect to wavenumbers become broader during the transition phase from the ITG-dominated stage to TM-dominated stage. Accompanied with the fast growth of the magnetic island, the frequency of TM/ITG with long/short wavelength fluctuations in the electron/ion diamagnetic direction decreases/increases respectively. The decrease of TM frequency is identified to result from the effect of the profile flattening in the vicinity of the magnetic island, while the increase of the frequencies of ITG fluctuations is due to the eigenmode transition of ITG induced by the large scale zonal flow and zonal current related to TM. Roles of zonal current induced by the ITG fluctuations in the instability of TM are also analyzed. Finally, the electromagnetic transport features in the vicinity of the magnetic island are discussed.

关键词： magnetic reconnection tearing modes magnetohydrodynamics drift waves nonlinear phenomena