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A. Nájera‐Bastida L. Garcia‐Demedices P. Ramírez‐López E. Torres‐Alonso R.D. Morales 《国际钢铁研究》2007,78(4):318-326
Turbulent flow of liquid steel and its control is studied using different geometries of turbulence inhibitors. Four designs of turbulence inhibitors were characterized through experiments of tracer injection in a water model and mathematical simulations using the Reynolds Stress Model (RSM) of turbulence. Inhibitor geometries included octagonal‐regular, octagonal‐irregular, pentagonal and squared. A layer of silicon oil was used to model the behaviour of tundish flux during steel flow. Fluid flows in a tundish using these geometries were compared with that in a bare tundish. Experimental and simulation results indicate that the flow in a bare tundish and a tundish using turbulence inhibitors open large areas of oil close to the ladle shroud due to strong shear stresses at the water‐oil interface with the exception of the squared inhibitor. Oil layer opening phenomena are explained by the high gradient of the dissipation rate of turbulent kinetic energy. Using the squared inhibitor the kinetic energy reports a high gradient from the tundish floor to the free bath surface as compared with other geometries. 相似文献
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S. Chatterjee 《钢铁冶炼》2017,44(6):403-412
A numerical model based on computational fluid dynamics was used to simulate the effect of non-isothermal conditions on melt flows in a multi-strand billet caster tundish. To start with, water was used as the operating fluid in a one-third scale tundish to calculate the fluid flow and temperature fields under isothermal and non-isothermal conditions. The model was then extended to the full-scale tundish with molten steel as the operating liquid in order to simulate the conditions in a real plant. It was observed that using step inputs of 10° and 23° for water and steel cases, respectively, changed the fluid flow patterns significantly, more so at locations far from the inlet, due to stronger buoyancy-driven natural convective flows. The temperature distribution and inclusion trajectories within the tundish were also affected due to the presence of non-isothermal conditions. 相似文献
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镁质料涂抹中间包技术的应用 总被引:1,自引:0,他引:1
济钢第一炼钢厂以涂抹料中间包替代绝热板中间包,经合理设计涂抹工艺及烘烤制度,中间包的平均寿命达到19.98炉。与使用绝热板中间包相比,平均连浇炉数由47.64炉提高到51.16炉,钢水收得率提高0.35%,耐材消耗降低0.15元/t钢,并提高了钢水纯净度。 相似文献
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Physical and mathematical determination of the influence of input temperature changes on the molten steel flow characteristics in slab tundishes 总被引:1,自引:0,他引:1
S. López-Ramírez J. De Barreto P. Vite-Martínez J. A. Romero Serrano C. Duran-Valencia 《Metallurgical and Materials Transactions B》2004,35(5):957-966
Transient fluid flow behavior in a tundish with two different arrangements, a bare tundish and a tundish using flow control
devices, was studied using physical modeling and a mathematical model. The study places special emphasis on buoyancy effects,
particularly transient buoyancy effects due to step change in inlet temperature. For the bare tundish case, the inertial forces
are strongly dominant, while in the arrangement using flow control devices, tundish with turbulence inhibitor and low dams,
the buoyancy forces are dominant. The results were compared to those representing the real behavior, considering temperature
variations, for each tundish arrangement. This comparison made possible the determination of the probable implicit error that
could be present in the estimation of the fluid flow characteristic behavior used for the design of the tundish geometry and
flow control devices when the temperature variations are not considered. 相似文献
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以某钢厂的八流连铸中间包为研究对象,采用数值模拟方法对不同控流结构中间包内钢液流场进行了研究,并通过水模型实验和工业生产进行验证。模拟结果表明:ASF中间包内的挡墙和湍流器能够明显改善钢液的流动状态和温度分布,加上双坝后效果更佳,钢液的流动存在4个环流区,不仅增加了钢液的混合程度,而且中间包内钢液的温度分布更均匀且低温区较少。水模试验表明在空包中加入湍流器和挡墙能明显改善各流流动特性的一致性,且在其基础上加入双坝能进一步改善钢液的流动特性,与数值模拟结果一致,此外,工业生产也完全达到预期效果。 相似文献
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Adam Cwudziński 《钢铁冶炼》2018,45(6):528-536
Continuous casting of steel ensures the flexible production of different grades of slabs intended for the Rolling Mill departments. Therefore, it seems justifiable to search new solutions for tundish metallurgy. This study puts forward a new gas-permeable barrier’s design solution with two circular porous plugs, whose purpose is to punctually agitate the liquid steel in tundish. Two argon injection system locations were tested. The results for the hydrodynamic pattern of liquid steel and bubbles’ behaviour in the tundish were obtained from laboratory experiments with water glass model and computer simulations. Within the framework of the investigation, three argon flow rates, i.e. 5, 10 and 15?NL?min?1, were considered. The designed gas-permeable barriers effectively stimulate active flow in the tundish for isothermal and non-isothermal conditions, while reducing the stagnant flow share and the transient zone extent. 相似文献
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Ken Morales-Higa R. I. L. Guthrie M. Isac R. D. Morales 《Metallurgical and Materials Transactions B》2013,44(1):63-79
The performance characteristics of a tundish, such as the flotation of inclusions and slag entrainment, are largely influenced by the fluid-flow phenomena. Physical modeling in water is widely used to understand the fluid flows in a tundish and as a tool to improve, control, and design procedures for high-quality steel processing operations. These approaches were used to study the performance of fluid flow for a new design of ladle shroud. The new design for a dissipative ladle shroud (DLS) was studied, using a one-third scale, delta shaped, four-strand tundish. The results were compared with those achieved with the conventional ladle shroud. Different cases have been analyzed, including a conventional ladle shroud (LS) with a bare tundish and a tundish furnished with an impact pad. Similarly, the new design of the shroud (DLS) was studied under equivalent conditions. The physical experiments included the use of particle image velocimetry (PIV) and conductivity tracer techniques. The PIV measured the instantaneous velocities at the outlet of the DLS and the LS at different flow rates, showing the detailed jetting characteristics of water leaving the two types of ladle shroud. Residence time distribution (RTD) curves were also obtained for the different flow arrangements previously mentioned, and the dispersion of a colored dye tracer was observed at different intervals of time during tundish operation and analyzed using the video visualization technique. 相似文献
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攀钢连铸中间包水力模型实验 总被引:1,自引:0,他引:1
参照攀钢提钒炼钢玫连铸中间包尺寸及其连铸工艺参数。用有机玻璃制作一个与实物之比为1:4的物理模型。通过测定中间包内钢液仪时间分布曲线,计算其平均停留时间及死区,活塞区和混合区占中间包容积的百分比。 相似文献
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Uxia Dieguez Salgado Christian Weiß Susanne K. Michelic Christian Bernhard 《Metallurgical and Materials Transactions B》2018,49(4):1632-1643
Since nonmetallic inclusions (NMIs) in steel cannot be completely avoided, a greater understanding of their development and evolution during the steelmaking process is required. In particular, this includes the adhesion of microinclusions to the refractory/steel interface in the flow control system between the tundish and the mold. This phenomenon, commonly referred to as clogging, causes losses in productivity and product quality. Inclusions transported from the bulk melt to the boundary layer may adhere to the refractory/steel interface due to formation of a fluid cavity. A detailed model was derived for the detachment of NMIs adhering to a nozzle wall and is based on the local hydrodynamic conditions combined with the specific interfacial properties in the system consisting of the inclusions, the refractories, and the steel. The model is evaluated for three different application-oriented cases. This study has been focused on providing a better understanding of fluid flow in the near-wall region in order to reduce clogging during steelmaking. 相似文献
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Rüdiger Schwarze Frank Obermeier Jan Hantusch Armin Franke Dieter Janke 《国际钢铁研究》2001,72(5-6):215-220
In steelmaking processes, various efforts are made in order to enhance steel cleanness. Among other approaches, the volume of the tundish has been increased and flow‐controlling devices are used. The extended mean residence time of steel in the tundish leads to an improved inclusion separation. In the present study, the degree of inclusion separation in different tundish configurations is determined through numerical modelling. Flows in the tundish has been calculated under isothermal and non‐isothermal conditions. The numerical model is based on a Euler Lagrange approach. The flow and the temperature field are described through Reynolds averaged transport equations in conjunction with a turbulence model. 相似文献
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In steelmaking and casting, transient operations are very critical for product quality and process regularity. This holds especially for the tundish. Typical drawbacks can occur at ladle change, where, for example, refilling high flow rates induce flow short‐circuits risky for dispersed oxides (“inclusions”) dragging towards the strands. At drainage, vortices formation can affect steel cleanliness via slag entrapment. Such topics were investigated for an industrial tundish with computational fluid dynamics validated tools. The focus was given on a multi‐strand layout more prone to unevenness features. As a matter of fact, the different steel path to reach different strands causes often too high temperature differences and different strand cleanliness levels. Strands closer to the tundish center, are generally hotter and less clean; the others, slightly colder but cleaner. Multiphase models, together with advanced meshing techniques and validated boundary conditions, were used to describe tundish refilling and drainage. Within the operating conditions of concern, a bath height of 300 mm was found as a best compromise between the need of avoiding slag entrapment through vortices and to have maximum yield. Once applied into operating practice, no rejection for cleanliness or customer claims were achieved. As refers to temperature loss from ladle to tundish, a drop at strands of about 2 and of 4°C from tundish inlet to strand, in agreement with plant data over about 700 heats and literature experiments under the same operating conditions, were found. 相似文献
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The water model experiments were carried out to study the bubble morphology in the tundish and mold with the process of annular argon blowing at tundish upper nozzle. The effects of the position of gas permeable brick, the casting speed and the argon flow rate on the bubble size distribution, the bubble migration behavior and the flow behavior of liquid steel near the liquid level in tundish were further investigated, coupled with the numerical simulation. The results show that with the process of annular argon blowing at tundish upper nozzle, a frustum cone shaped bubble plume can be formed around the stopper rod. The concentration of argon bubbles gradually decreases outward along the radial direction of the stopper rod. Owing to the wall attached effect, the bubble plumes float upward along the stopper rod, which can increase the collision probability between bubbles and the velocity of bubble plumes, causing a larger impact strength on the liquid level in tundish. In addition, a part of small bubbles are wrapped into the nozzle and the mold due to the drag force of liquid steel. With increasing argon flow rate, the number of bubbles in annular bubble plumes and the vertical velocity of liquid steel near the liquid level in tundish increase significantly. With increasing casting speed, the width and the bubble number of annular bubble plumes gradually decrease, leading to a decrease of the vertical velocity of liquid steel near the liquid level in tundish. Increasing the distance between the annular gas permeable brick and the center of tundish upper nozzle, the dispersion of bubbles and the width of bubble plumes increase, and the impact strength of bubbles acting on the liquid level in tundish becomes weaker. As the argon flow rate and the casting speed increase, and the distance between the gas permeable brick and the center of tundish upper nozzle decreases, the gas volume and bubble size in the mold increase. Under the experimental conditions, when the inner and outer diameters of the annular gas permeable brick are 110mm and 140mm, respectively, and the casting speed is 1.2m/min, the appropriate argon flow rate is 4L/min. 相似文献
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摘要:通过水模型实验研究了上水口环形吹氩工艺下中间包和结晶器内气泡形貌,并结合数值模拟分析了透气砖位置、拉坯速度和吹氩量对中间包和结晶器内气泡尺寸、气泡迁移和中间包近液面钢液流动的影响。结果表明:上水口环形吹氩形成以塞棒为中心的圆台状气泡羽流,气泡浓度沿径向向外逐渐减少;附壁效应使得气泡羽流偏向塞棒壁面流动,增大气泡的碰撞聚并概率和近塞棒壁面的羽流上升速度,对中间包液面产生较大冲击作用;同时,部分细小气泡会随钢液进入水口及结晶器内部;增大吹氩量,中间包内环形气泡羽流中气泡数目明显增多,中间包近液面钢液上升速度增大;增大拉坯速度,环形气泡羽流的宽度和气泡数量逐渐减小,近液面速度减小;增大透气环距水口中心距离,中间包内气泡弥散度增大,环形气泡羽流宽度也随之增大,气泡羽流对中间包液面冲击作用减弱;增大吹氩量和拉坯速度、减小透气环距水口中心距离,进入结晶器的气量和气泡尺寸逐渐增大。实验条件下,透气环内外径为110mm/140mm、拉坯速度为1.2m/min时,吹氩量为4L/min较为合适。 相似文献