检索结果-南通市图书馆

A novel method for modeling the phase change of iron ore particles in the cohesive zone of a blast furnace

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第3期86卷 252-261页

作者： Dianyu E Yingming Wen Jiayun Dan Youyuan Jiang Guangchao Wei Jiaxin Cui Jiangxi Provincial Key Laboratory for Simulation and Modelling of Particulate Systems Jiangxi University of Science and TechnologyNanchang330013China International Institute for Innovation Jiangxi University of Science and TechnologyNanchang330013China Ironmaking Plant Xiangtan Iron and Steel Corporation of Hunan HualingXiangtan411101China Schoolof Transportation and Vehicle Enginering Shandong University of TechnologyZibo255000China

cohesive zone plays a vital role in the stable operation of a blast furnace(BF),yet the complex phase change process of iron ore particles in this zone is still not well understood.In this study,a novel one-dimensional(1D)unsteady phase change model was developed to elucidate the heat transfer and melting mechanisms of iron ore particles.After model validation,the effects of several key operating parameters(e.g.,particle diameter,gas velocity,initial temperature)on the phase change behavior of iron ore particles were analyzed,and the joint effect of multiple parameters was discussed.The results show that larger-sized iron ore particles possess lower specific surface areas,which in turn reduces their convective heat absorption capacity.Consequently,the distance from the solid-liquid phase interface to the particle surface increases,thereby slowing down the movement of the phase interface and pro-longing the melting duration of the particles.Increasing the gas velocity and the initial temperature does not have a significant impact on reducing the duration of the complete melting process.Under the specified conditions,it is observed that increasing the gas velocity by 3-fold and 9-fold results in a reduction of the melting duration by 2.4%and 8.3%,respectively.Elevating the initial temperature of iron ore particles results in a decrease in the core-to-surface temperature difference,a slower heating rate,and a shorter duration to achieve melting.Among the factors affecting the melting process,the particle diameter is found to be the most significant in terms of the liquid phase precipitation,mushy zone thickness,and core-to-surface temperature difference of iron ore particles.

关键词： Blast furnace Iron ore melting cohesive zone Heat transfer Phase change

Softening and melting behaviors of ferrous burden in hydrogen-rich blast furnace cohesive zone

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2023年第12期30卷 2366-2377页

作者： Bin-bin Lyu Guang Wang Fan Yang Hai-bin Zuo Qing-guo Xue Jing-song Wang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China

The changes in the softening and melting behaviors of ferrous burden in the cohesive zone and the characteristics of the slag–iron–coke interface in a blast furnace were investigated by simulating an actual blast furnace under hydrogen-rich conditions.According to the variation in the transient shrinkage of the burden under different atmospheres,the shrinkage start temperature of the sinter was higher than that of the pellets.The negative shrinkage rate of the pellets was greater than that of the sinter.Additionally,the softening start temperature in the blast furnace decreased under hydrogen-rich conditions,giving the blast furnace a broader range of softening zones.The softening start temperatures of the pellets and sinter decreased from 1102 to 949℃ and 1152 to 1080℃,respectively.The hydrogen-rich traditional blast furnace conditions narrowed the melting zone temperature range and shifted it toward the high-temperature zone,significantly improving the burden layer permeability.However,under the hydrogen-rich oxygen blast furnace conditions,there were a decrease in the melting start temperature,a shift of the melting zone location to the low-temperature zone,and an increase in the burden layer permeability and pressure difference.A comparison of the slag–iron–coke interface characteristics under different atmospheric conditions showed that the carbon content in metallic iron decreased under hydrogen-rich traditional blast furnace conditions compared with traditional blast furnace conditions.Contrastingly,under hydrogen-rich oxygen blast furnace conditions,the carbon content in metallic iron increased compared with oxygen blast furnace conditions.These findings provide guidance for the development of low-carbon ironmaking processes in blast furnaces.

关键词： Ferrous burden-Hydrogen Softening Melting cohesive zone Slag-iron-coke interface

Effect of quaternary basicity on softening-melting behavior of primary slag based on magnesium flux pellet

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2022年第8期29卷 1185-1193页

作者： Kai-kai Bai Hai-bin Zuo Wen-guo Liu Jing-song Wang Jian-sheng Chen Qing-guo Xue State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

It is generally accepted that the softening-melting properties of ferrous burden play a vital role in optimizing the shape and position of cohesive zone.The effect of quaternary basicity and atmosphere on softening,melting and permeation temperatures of primary slag based on magnesium flux pellet was investigated by visualization method.The mechanisms were analyzed utilizing thermodynamic calculation,X-ray diffraction analysis and electron probe microanalysis.The results indicated that the softening and melting temperatures of oxide samples increased by approximately 120℃with increasing quaternary basicity from 0.3 to 1.2 owing to the formation of slag phases with high melting point and solid Fe.Meanwhile,the difference between softening and melting temperatures decreased from 21 to 11℃.The permeation temperature was not affected by the quaternary basicity and fluctuated around a level of 1250 C,given that the permeation temperature depends on the wettability between slag and coke bed.On the other hand,as the ratios of CO/CO_(2) varied from 3/7 to 7/3,there were no significant differences in either the softening or melting temperatures,whereas the permeation temperature was increased from 1239 to 1271℃ since the reduction of FeO-bearing phases to solid Fe could decrease the wettability between slag and coke bed.

关键词： Magnesium flux pellet Primary slag Quaternary basicity CO/CO_(2)ratio cohesive zone Softening-melting Behavior

Modeling and numerical investigation of slow crack growth and crack arrest in ceramic polycrystals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2013年第5期3卷 53-57页

作者： Bassem El Zoghbi Rafael Estevez Christian Olagnon Laboratoire SIMAP UMR CNRS 5266 Grenoble-INP UJF Universite' de Grenoble Laboratoire MATEIS UMR CNRS 5510 INSA Lyon Universite' de Lyon69621 France

ntergranular slow crack growth in zirconia polycrystal is described with a cohesive zone model that simulate mechanically the reaction-rupture mechanism underlying stress and environ- mentally assisted failure. A 2D polycrystal is considered with cohesive surfaces inserted along the grain boundaries. The anisotropic elastic modulus and grain-to-grain misorientation are accounted for together with an initial stress state related to the processing. A minimum load threshold is shown to originate from the onset of the reaction-rupture mechanism to proceed where a minimum traction is reached locally and from the magnitude of the initial compression stresses. This work aims at providing reliable predictions in long lasting applications of ceramics.

关键词： zirconia ceramic slow crack growth cohesive zone intergranular failure

fmax and fault zone property of Lushan earthquake of 20 April 2013,Sichuan,China

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Earthquake Science 2013年第3期26卷 179-183页

作者： Jian Wen Xiaofei Chen School of Earth & Space Science University of Science and Technology of China

In this study, we determined fnax from near- field accelerograms of the Lushan earthquake of April 20, 2013 through spectra analysis. The result shows that the values of fmax derived from five different seismography stations are very close though these stations roughly span about 100 km along the strike. This implies that the cause offmax is mainly the seismic source process rather than the site effect. Moreover, according to the source-cause model of Papageorgiou and Aki （Bull Seism Soc Am 73：693-722, 1983）, we infer that the cohesive zone width of the rupture of the Lushan earthquake is about 204 with an uncertainty of 13 m. We also find that there is a significant bulge between 30 and 45 Hz in the amplitude spectra of accel- erograms of stations 51YAL and 51QLY, and we confirm that it is due to seismic waves＇ reverberation of the sedi- mentary soil layer beneath these stations.

关键词： Lushan earthquake fmax Strongground motion Fault-zone width cohesive zone

A Dugdale model based geometrical amplifier enables the measurement of separation-to-failure for a cohesive interface

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2011年第1期1卷 25-29页

作者： Yu-Jie Wei~(a)) State Key Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences, Beijing 100190,China State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

Regardless of all kinds of different formulae used for the traction-separation relationship in cohesive zone modeling,the peak tractionσ_m and the separation-to-failureδ_0(or equivalently the work-to-separationΓ) are the primary parameters which control the interfacial fracture behaviors. Experimentally,it is hard to determine those quantities,especially forδ_0,which occurs in a very localized region with possibly complicated geometries by material failure.Based on the Dugdale model,we show that the separation-to-failure of an interface could be amplified by a factor of L/r_p in a typical peeling test,where L is the beam length and r_p is the cohesive zone size.Such an amplifier makesδ_0 feasible to be probed quantitatively from a simple peeling test. The method proposed here may be of importance to understanding interfacial fractures of layered structures,or in some nanoscale mechanical phenomena such as delamination of thin films and coatings.

关键词： cohesive zone dugdale model separation-to-failure thin film peeling test

Mechanisms Determining Softening/Melting and Reduction Properties of Lumps and Pellets

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mechanisms Determining Softening/Melting and Reduction Prope...