共查询到20条相似文献,搜索用时 15 毫秒
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Rodolfo D. Morales Manuela Díaz‐Cruz Jorge Palfox‐Ramos Simn Lpez‐Ramírez Jos de Jesús Barreto‐Sandoval 《国际钢铁研究》2001,72(1):11-16
A three‐strand tundish belonging to a billet caster was water modelled and plant trials were performed to compare the performance of a pouring box and a turbulence inhibitor in terms of melt flow parameters and steel cleanliness. A tailor made turbulence inhibitor for this tundish is useful to accomplish with flow control of fluid turbulence and even melt redirection to all strands. The turbulence inhibitor helps to decrease nitrogen pickup during ladle changes and to float out inclusions towards the covering slag. As a consequence, rod operations to take of alumina deposits from nozzle walls are considerably decreased using a turbulence inhibitor. 相似文献
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Aaron Espino-Zárate Rodolfo D. Morales Alfonso Nájera-Bastida Manuel J. Macías-Hernández Alejandro Sandoval-Ramos 《Metallurgical and Materials Transactions B》2010,41(5):962-975
Flow in a six-strand billet tundish, using turbulence inhibitors (TIs), was characterized using inputs of a pulsed tracer
and mathematical simulations. It was found that to control turbulence attaining high fluid fractions under plug flow patterns,
the key parameter for designing TIs is the dissipation rate of kinetic energy. TI designs that induce steep dissipation gradients
are less efficient as flow controllers than those designs that yield more prolonged dissipation gradients from the inhibitor
bottom to the bulk flow. A direct relationship between the dissipation of kinetic energy and the linear acceleration of the
smallest turbulent eddies in the flow was established through dimensional analysis. The inhibitor with the highest linear
accelerations of eddies in the viscous sublayer at the Kolmogorov scale, for a given liquid flow rate, yields the better flow
control. 相似文献
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R. D. Morales J. Palafox-Ramos J. de J. Barreto S. Lopez-Ramirez D. Zacharias 《Metallurgical and Materials Transactions B》2000,31(6):1505-1515
Water modeling and mathematical simulation techniques were used to study the melt flow under the influence of turbulence inhibitors
in a multistrand bloom caster tundish. Three different cases were studied: a bare tundish (BT), a tundish with two pairs of
baffles and a waved impact pad (BWIP), and a tundish equipped with turbulence inhibitor and a pair of dams (TI&D). Chemical
mixing of tracer turbulence diffusion was also simulated and compared with actual experimental results. The TI&D arrangement
showed an improvement of the fluid flow characteristics, yielding better tracer distribution among the outlets, lower values
of back mixing flow, and higher values of plug flow. A mass transfer model coupled with k-ɛ turbulence model predicted acceptably well the experimental chemical mixing of the tracer in the water model. The water modeling
and the numerical simulation indicated that the TI&D arrangement retains the tracer inside the vessel for longer times, increasing
the minimum residence time. These results encourage the use of turbulence-inhibiting devices in bloom and billet casters,
which pursue excellence in product quality. 相似文献
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Water Modeling of Optimizing Tundish Flow Field 总被引:2,自引:1,他引:2
In the water modeling experiments, three cases were considered, ie, a bare tundish, a tundish equipped with a turbulence inhibitor, and a rectangular tundish equipped with weirs (dams) and a turbulence inhibitor. Comparing the RTD curves, inclusion separation, and the result of the streamline experiment, it can be found that the tundish equipped with weirs (dams) and a turbulence inhibitor has a great effect on the flow field and the inclusion separation when compared with the sole use or no use of the turbulent inhibitor or weirs (dams). In addition, the enlargement of the distance between the weir and dam will result in a better effect when the tundish equipped with weirs (dam) and a turbulence inhibitor was used. 相似文献
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Effects of tundish size,tundish design and casting flow rate on fluid flow phenomena of liquid steel
S. Lpez-Ramírez J. Palafox-Ramos Rodolfo D. Morales M. A. Barrn-Meza Miguel Velzquez Toledo 《国际钢铁研究》1998,69(10-11):423-428
Fluid dynamics of liquid steel in continuous casting tundishes is closely related to tundish volume and geometry, existence of flow control devices and steel flow rate. To study this complex interaction physical and mathematical models were used in the present work. The first one was based in a 1/3 scale water model with injection of tracers and the second one on the solution to the steady state-turbulent Navier-Stokes equations using the K-ε [1] approximation for the turbulent viscosity. When the tundish size is increased from 30 t to 50 t the tracer indicates a strong bypassing in the second case. The mathematical predictions indicate very high fluid velocities along the tundish bottom in agreement with the experimental findings. The employment of turbulence inhibitors promotes a counter-flow that surrounds the incoming stream jet of liquid from the inlet nozzle with steel displacing itself, after leaving this zone, along the upper free surface of the liquid. The addition of well designed baffles complements the action of the turbulence inhibitor to obtain a higher volume fraction under a plug flow pattern giving a softer flow of liquid steel. Besides, the positioning of baffles inside a tundish should be performed according to the steel flow rate. 相似文献
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Numerical Investigation of the Fluid Flow in Continuous Casting Tundish Using Analysis of RTD Curves 总被引:2,自引:1,他引:1
A detailed mathematical procedure of the optimization of the fluid flow in a tundish water model with and without flow control devices (weir and dam) was carried out using the commercial CFD code FLUENT 60. The (k ε) two equation model was used to model turbulence. The residence time distribution (RTD) curves were used to analyze the behavior of the flow in tundish. The location of flow control devices in the tundish was studied. The results show that the flow modifiers play an important role in promoting the floatation of nonmetallic inclusions in steel. Comparing the three geometric configurations that are considered (bare tundish, weir, weir+dam), the tundish equipped with the arrangement (weir+dam) is a best and optimal geometric configuration of tundish. 相似文献
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薄板坯连铸中间包内抑湍器的模拟研究 总被引:3,自引:0,他引:3
控制中间包内钢液的合理流动对夹杂物的排除有重要影响,为此建立了模拟薄板坯连铸中间包流动情况的水模型。通过测定停留时间分布(RTD)曲线,研究了不同组合控流装置对中间包流体流动特性的影响。结果表明,结构及尺寸合理的抑湍器能延长水口响应时间及平均停留时间、提高活塞流区体积分数及降低死区体积分数;抑湍器与单坝组合的控流装置在控制流体流动方面效果极佳,而抑湍器与单墙单坝、单墙双坝组合的控流装置的控流效果不太理想。 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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板坯连铸中间包内夹杂物去除的数值模拟 总被引:1,自引:0,他引:1
以某厂50tT型2流中间包为研究对象,利用大型商业软件ANSYS CFX10.0建立了三维有限体积模型,采用多相流模型对中间包内钢液的流动特性、温度分布与夹杂物去除规律进行了数值模拟,重点研究了不同堰-坝组合方式、湍流抑制器形状、拉速、夹杂物粒径等工艺参数对中间包内钢水平均停留时间、夹杂物上浮率的影响。结果表明:湍流抑制器对夹杂物的上浮去除影响不大;随着夹杂物粒径的增大,夹杂物的上浮率迅速增大;20μm以下的夹杂物则很难在中间包内上浮去除;随着拉速的增大,夹杂物的上浮率是不断减小的;采用堰A=300cm、坝B=400cm、方形瓦楞湍流抑制器、过滤器组合式控流装置时夹杂物的上浮去除效果最好。 相似文献
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Liangcai Zhong Liying Li Bao Wang Maofang Jiang Lixing Zhu Li Zhang Rongrong Chen 《国际钢铁研究》2006,77(2):103-106
Fluid flow characteristics in a two‐strand slab tundish with Ar bubbling curtain were studied in water modelling experiments. It was found that the Ar bubbling curtain can greatly improve the flow characteristics in the tundish with a weir, a dam and a turbulence inhibitor. It dramatically increased the peak concentration time and plug volume and greatly decreased the dead volume, but hardly influenced the minimum residence time. Therefore, the fluid flow characteristics in a tundish with Ar bubbling curtain were favourable to the flotation and separation of inclusions from molten steel. The flow characteristics with low gas flow rate and short distance of the Ar bubbling curtain from the tundish outlet were better than those with high gas flow rate and large distance of the curtain from the outlet. 相似文献
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The paper shows the results of the research obtained by physical and mathematical modeling of steel flow and mixing in the tundish. Two‐strand continuous casting tundish was under consideration. It has been working in one of polish steel plants. The change of concast slab assortment was caused by the changeable market terms. So, the tundish with the new system of steel flow controller was needed. Up to now baffles with the notch have played this role. Their placement cause the excessive consumption of the lining of the tundish front line. As a consequence the turbulence inhibitor (TI) was applied. Four different types of this inhibitor were designed. As a result of the experimental measurements and numerical simulations, the RTD curves of F‐type were obtained. Basing on these curves time constants for examined types were determined. Additionally, the research results were complemented by the E‐type curves. The percentage participations of dead volume flow, dispersed plug flow, and well‐mixed volume flow were calculated. The research gives possibility to estimate the designed TIs and their influence on the tundish work. 相似文献
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通过计算流体力学软件FLUENT建立的数学模型对钢厂200 mm×1 600 mm铸坯二流T型23 t中间包现挡墙和坝、湍流控制器和坝、湍流控制器和现挡墙以及新挡墙4种结构方案进行三维数值模拟,研究原中间包及安装不同控流装置后的钢水流动特性。结果表明,在所有的设计方案中安装有湍流控制器和坝的中间包能够达到最佳优化效果;中间包的死区体积分率由30.18%降到16.51%,活塞流区与死区的体积分率比RVp/Vd由55.80%增大到129.44%;中间包内流动稳定,有利于夹杂物的上浮。 相似文献
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采用1:3水模型实验对钢厂的八流150 mm×150 mm坯连铸不同控流结构80 t中间包内钢液流场进行了研究,并通过数值模拟进行验证。研究结果表明,中间包仅加湍流抑制器后对改善钢液的流动效果不明显,加上"V"型挡墙后能明显改善各流流动特性,湍流抑制器、"V"型挡墙和单坝组合能进一步提高各流的流动特性一致性,平均停留时间增大到505.22 s,在挡坝的两侧分别形成了明显的环流区。将单挡坝改为双挡坝后,Vp/Vd平均由原来1.77提高到2.63,死区比例平均也减少了6.0%,且各水口的稳定性最好,各流RTD曲线吻合度也最好,且存在3个大环流区和1个小环流区,水模型实验与数值模拟结果一致。 相似文献
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Lino García‐Demedices Rodolfo D. Morales Simon Lpez‐Ramírez Jos de J. Barreto‐Sandoval Jorge Palafox‐Ramos Manuela Díaz‐Cruz 《国际钢铁研究》2001,72(9):346-353
Simple changes on tundish geometry may lead to significant improvements of transport phenomena of liquid steel in tundishes. In the present case steel flow in a six‐strand billet trough type tundish is mathematically simulated. Numerical results indicate the existence of a high fluid turbulence in the pouring zone and recirculating flows. Steel temperatures in the strands are also different, which from practice it would mean different qualities of billet among the strands. A simple change of design by widening the pouring box improves all the steel flow characteristics. First the turbulence in the pouring box is decreased, the recirculating flows are eliminated and steel temperatures in the six strands become closer to each other. Using a computational technique known as volume of fluid, surface topography of bath including the covering slag was simulated for both types of tundishes. These simulations predicted an open eye of the slag layer for the first tundish while in the second this phenomena was avoided. Thus, it was demonstrated the original hypothesis that small changes in tundish design may lead to a more controlled steel flow. 相似文献