ZHU Qingtian
,
CHENG Shusen
钢铁研究学报(英文版)
The gas flow from tuyere to raceway zone by blasting involves three distributional zones, such as dripping, cohesive, and lumpy zone. The gas flow distribution in lumpy zone directly affects the gas utilization ration and smooth operation in the blast furnace. However, the furnace closeness brings about great difficulty in the study of hightemperature gas flow. The charging and blasting system affecting the gas flow and whether the top gas flow distribution could reflect its inner condition as well as the furnace state, such as hanging or scaffolding, which have become the main problems for the research on gas flow. Recently, several researches overseas studied gas flow distribution using the numerical simulation method; however, such a research was rare amongst the natives. In this study, the flow model of gas in cohesive and lumpy zone was established using the numerical simulation software and the gas flow distributions with uniform distribution of burden permeability, scaffolding of wall, and nonuniform charge level were analyzed. As a result, the effects of cohesive zone and lower parts on the gas flow are very limited and the charge level largely affects the distribution of top gas flow. Therefore, it was found that the distribution of top gas flow could hardly reflect the inner gas flow. The process is called “redistribution” effect, which means that the gas flow after passing through the raceway, dripping, and cohesive zone is distributed when it flows into the lumpy zone.
关键词:
blast furnace;gas flow;lumpy zone;numerical simulation
ZHAO Hongbo
,
CHENG Shusen
,
ZHAO Minge
钢铁研究学报(英文版)
One of the bottlenecks of the blast furnace (BF) campaign is the life length of hearth bottom. The basic reason for the erosion of hearth bottom is its direct contact with hot metal. According to the theory of heat transfer, models of BF hearth bottom are built based on the actual examples using software and VC language, and the calculated results are in good agreement with the data of BF dissection after blowing out. The temperature distribution and the capability of the resistance to erosion for different structures of hearth bottom are analyzed, especially the two prevalent kinds of hearth bottom arrangements called “the method of heat transfer” for allcarbon brick bottom and “the method of heat isolation” for ceramic synthetic hearth bottom. Features of the two kinds of hearth bottoms are analyzed. Also the different ways of protecting the hearth bottom are clarified, according to some actual examples. After that, the same essence of prolonging life, and the fact that the existence of a “protective skull” with low thermal conductivity between the hot metal and brick layers is of utmost importance are shown.
关键词:
hearth bottom;heat transfer method;heat isolation method;long life
BAI Yongqiang
,
CHENG Shusen
,
BAI Yanming
钢铁研究学报(英文版)
Many problems appear in the sintering process of vanadiumbearing titanomagnetite, such as high energy consumption and low productivity; sinter quality is also very poor for its low tumble strength and high reduction degradation. Sinter productivity and quality are dominated by bed permeability and mineralogy structure, which are highly influenced by the thermal state of sintering bed, so the sintering process of titanomagnetite is researched by bed dissection in this work. Temperature evolution curves of sinter materials were measured, and the results show that melting duration, peak temperature duration and sintering temperature of different layers differ greatly from each other; flame front speed and vertical sintering speed of bed lower region are much smaller than those of bed upper region. Simultaneously, sinter samples were collected from different layers, and their mineralogy characteristics are analyzed; sinters from bed lower region have poor mineralogy structure, and the amounts of perovskite and dicalcium silicate increase intensively, which are bad for sinter strength and reduction degradation property. Measures are proposed to improve the quality and productivity of titanomagnetite sinter.
关键词:
sintering
,
vanadiumbearing titanomagnetite
,
thermal state
,
bed dissection
,
mineralogy characteristic
WU Su-zhou
,
ZHANG Jiong-ming
,
LI ZHi-zheng
钢铁研究学报(英文版)
The SEN clogging is a long term issue for all the steelmakers. In the current study, the kinetics of SEN clogging during steel continuous casting was established. The dynamic build-up of alumina inclusions to the lining refractory of SEN was analyzed. The fluid flow and inclusions motion are calculated by means of mathematic model. Effect of diameters of inclusions, roughness of nozzle, diameter of nozzle and casting speed on the entrapment probability are estimated.
关键词:
nozzle clogging;mathematic model;inclusion motion
B.W. Li
,
X.Y. Tian
,
E.G. Wang
,
J.C. He
,
null
,
null
,
null
,
null
金属学报(英文版)
In recent years, thin slab continuous casting technology has been widely used to improve the quality of the product and to reduce
the cost. One of the challenges faced by this technology is to design reasonable flow patterns, which strongly affect the surface
and inner properties of the final slab in the mold. With the fixed scales and complex geometrical structures of nozzle and funnel
type mold, a series of numerical simulations are made to analyze the flow patterns in melt steel using finite volume method based
on structured body fitted coordinate grids. The CFD (computational fluid dynamics) package is validated first using one typical case described in previously published studies, and then it is developed to study the effect of operational parameters on fluid
flow in thin slab caster. Two operational parameters, casting speed and SEN depth (submerged entry nozzle), are mainly
considered for numerical analysis. On the basis of present simulations, the reasonable SEN submergence depths corresponding to different casting speeds are suggested according to fluid flow characteristics like, flow jet impingement on the narrow side of
the mold, flow speed of the melt steel beneath the meniscus and the recirculation region. This is the first stage of study on the numerical analysis of the whole thin slab casting process with electromagnetic brake.
关键词:
continuous casting
,
null
,
null
王翠娜 温良英 陈登福 张大江 彭政 靳星
钢铁
针对某钢厂板坯连铸结晶器及浸入式水口(SEN)的结构参数，建立了描述结晶器内钢液流动的三维数学模型，用FLUENT软件对结晶器内钢液的流场和温度场进行耦合计算，分析SEN底部形状对结晶器内流场和温度场的影响。结果表明：凸底水口出口附近钢液的速度较大，对结晶器窄面的冲击深度较大，使结晶器内高温区下移，不利于凝固坯壳的生长；平底水口自由面速度较大、温度较高，有利于保护渣的熔化，但易产生液面裸露现象；凹底自由面速度较小、温度较低，有利于液面稳定。
关键词:
浸入式水口（SEN）;底部形状;结晶器;流场;温度场
王翠娜
,
温良英
,
陈登福
,
张大江
,
彭政
,
靳星
钢铁
针对某钢厂板坯连铸结晶器及浸入式水口(SEN)的结构参数,建立了描述结晶器内钢液流动的三维数学模型,应用FLUENT软件对结晶器内钢液的流场和温度场进行耦合计算,分析SEN底部形状对结晶器内流场和温度场的影响,并利用水模试验对钢液的流动行为进行了验证.结果表明:凸底水口出口附近钢液的速度较大,流股的冲击深度较大,使结晶器内高温区下移,不利于凝固坯壳的生长;平底水口自由面速度较大、温度较高,有利于保护渣的熔化,但易产生液面裸露现象;凹底自由面速度较小、温度较低,有利于液面稳定.
关键词:
浸入式水口
,
底部形状
,
结晶器
,
流场
,
温度场
Y.P.Du
金属学报(英文版)
According to turbulent theory and characteristics of beam blank continuous casting, 3-D model to represent the flow of beam blank mould is established. The predicted results indicate that the exit obliquity of up 15°(+15°) should be adopted, which will benefit the floatation of non-metallic inclusion and purification of the molten steel. When the nozzle angle is 120°, the flow pattern is reasonable. Proper nozzle depth can be 200ram. Turbulent kinetic of meniscus can be reduced by adopting the square nozzle and suitable area of side outlet when casting speed increases. The results are consistent with those of water model experiment, so the model is exact and reasonable. The model can provide important information for design of SEN and defining of immersion depth.
关键词:
SEN parameter
,
null
,
null
