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《钢铁冶炼》2013,40(3):173-180
AbstractThe performance of a 12?t, delta shaped, four‐strand, billet casting tundish was investigated using a full scale (1∶1) isothermal model using water as the simulating fluid for steel. Three different modelling experiments were carried out. Quantifiable parameters like ‘number of slag beads’ in transient physical modelling of slag entrainment, or ‘residual ratio of inclusions’ (RRI %), in steady state mathematical modelling of inclusion removal and ‘mean residence time’, ‘dead volume fraction’, etc., in steady state mathematical computation of residence time distributions, were used as the performance indicators. Results for three different flow modifying dam arrangements were considered and compared with those of a bare tundish. Computational fluid dynamic analysis showed that different flow modifying dam arrangements significantly alters the flow pattern within the tundish. On the basis of these performance indicators, the best arrangement was identified. The assumption in this paper that similar conclusions can be drawn from experiments carried out either in transient or in steady state conditions was verified. It was shown that both transient physical modelling experiments and the steady state mathematical predictions, point to the same conclusion. 相似文献
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The tundish plays a major role in the continuous casting process. The flow in a tundish has a very substantial effect on the quality of the final product and on efficient casting conditions. Efforts are being made worldwide to obtain the most favourable shape of tundish interior by using dams, weirs and gas curtains. The aim of these flow control devices is to reduce the dead zone areas and improve the conditions for the separation of non‐metallic inclusions. Numerous model studies are being carried out to explain the effect of the tundish working space shape and steel flow conditions on the inclusions floating processes. The presented article shows the results of investigations performed to obtain the mass exchange characteristics in the investigated tundish. The measurements were done directly at the steel plant during normal working conditions. By controlling the changing content of manganese in steel, the residence time distribution (RTD) characteristics were acquired. The RTD characteristics are also obtained with a water model of the tundish with dimensional scale of 1:3. Parallel to the water model, numerical simulation based on mathematical modelling of fluid flow, relying on the system of differential equations, is employed in the research work. Numerical simulations were carried out with the finite‐volume commercial code FLUENT using the standard k‐ε turbulence model. The primary purpose of the investigations carried out is to present the characteristics describing the transitory zone in a six‐strand tundish. It is shown that the F‐curve, describing the transitory zone, can be obtained by using different measurement techniques. Tracer concentration characteristics for the model of tundish obtained from both modelling techniques ‐ physical as well as numerical ‐ are very similar. 相似文献
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Swirling flow tundish is a new kind of tundish which has shown good effects on flotation of inclusion and reduction of inclusion content. In this paper, studies have been carried out on the flow fields in a one‐strand slab tundish. A full scale model of the flow patterns in the water model tundish was developed using a self‐developed code. RTD curves under different experimental conditions were obtained from both physical and numerical simulations. The effects of the swirling flow chamber geometry and the flowrate on flow patters in the tundish were discussed and compared with results from the numerical simulation. Validation of the self‐developed codes was achieved by comparing the physical and numerical results of the RTD curves and the mean rotational velocities in swirling flow tundish. As a result, significant rotational flow in the swirling flow chamber and asymmetrical flow pattern in the whole tundish were confirmed and the effects of these parameters on dead zone and mean residence time were also obtained. Further and more comprehensive studies are needed to optimize the design and application of such tundishes. 相似文献
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《钢铁研究学报(英文版)》2014
Fields of fluid flow and temperature, and residence time distribution (RTD) curves were investigated by mathematical simulation in a one-strand tundish for continuous casting. It was known from the investigation that a big “spring uprush” formed on surface around the long shroud when molten steel flowed into a turbulence inhibitor (TI) with extending lips and rushed up reversely out of the TI, while four small “spring uprushes” existed on surface when a TI without extending lips because the liquid steel flowed mainly out of the 4 corners of the TI. The flow of liquid steel in the former tundish configuration was not reasonable and the height of an area where temperature was less than 1819 K was about half of liquid surface height on the right side of the stopper, which meant that big dead zone existed in the former tundish configuration. In the optimal one, the height of such area was only seventh of the liquid surface height. The RTD curves obtained from the mathematical simulation basically agreed with those from the physical modeling and the flow characteristics obtained from these two methods agreed with each other. 相似文献
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Alexander Braun Marek Warzecha Herbert Pfeifer 《Metallurgical and Materials Transactions B》2010,41(3):549-559
This article presents computational and water model studies of the three-dimensional turbulent fluid flow in a two-strand
tundish for steady-state and transient casting conditions. First, it presents the flow field measurements obtained at a 1:3-scale
water model of the tundish with the particle-image velocimetry (PIV) method during steady-state casting. The PIV measurements
were performed using the Reynolds-similarity criterion. Thereafter, numerical simulation is carried out with the computational
fluid dynamic software, FLUENT, using the realizable k-ε turbulence model. The numerical model is validated using the measurement results obtained with the water model. The results
of the numerical calculations are in good agreement with the PIV measurements. On this basis, the validated numerical model
is adapted to simulate the 1:1-scale steel flow with boundary conditions that are derived from the real casting process. The
nonisothermal, unsteady numerical calculations concerning the cooling process of steel melt inside the tundish are done for
a 1:1-scale industrial facility—a 69-t two-strand tundish with a 380-t ladle. The influence of transient boundary conditions
at the outlet of the tundish (one blocked strand) on the flow structure and mixing process of fluid during the casting process
are investigated. The evaluation of the flow structure is performed using a zonal method, which relates the fluid flow with
the mixing processes. 相似文献
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Lifeng Zhang 《国际钢铁研究》2005,76(11):784-796
Inclusions in the steel in a four‐strand continuous casting tundish, billet and wire products are firstly investigated with industrial trials, and the fraction of inclusions removed in terms of total oxygen in the tundish is measured. Then the 3‐dimenional fluid flow, heat transfer and inclusion motion in the tundish are numerically simulated. The κ‐? two‐equation model is used to model turbulence. Inclusion motion and trajectories are calculated by considering drag force and buoyancy force, coupling the effect of turbulent fluctuation (Random Walk Model). The effect of strands‐blocking on the fluid flow, heat transfer and inclusion removal is studied. A new design of tundish is proposed focusing on removing more inclusions from the molten steel. 相似文献
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Fluid flow and mixing of molten steel in a twin-slab-strand continuous casting tundish were investigated using a mixing model under non-isothermal conditions.This model led to a set of ordinary differential equations that were solved with a Runge-Kutta algorithm.Steady state water modeling was carried out under non-isothermal conditions.Experimental data obtained from the water model were used to calibrate the mixing model.Owing to the presence of a mixed convection in the non-isothermal conditions,a channelizing flow would be created in the fluid inside the tundish.A mixing model was designed that was capable of predicting RTD(residence time distribution)curves for different cases in non-isothermal conditions.The relationship between RTD parameters and the Tu(tundish Richardson number)was obtained for various cases under non-isothermal conditions.The results show that the RTD parameters were completely different under isothermal and non-isothermal conditions.The comparison of the RTD curves between the isothermal and non-isothermal conditions presents that the extent of mixing in the tundish in non-isothermal conditions is lower than the mixing extent in isothermal conditions. 相似文献
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《钢铁研究学报(英文版)》2016,(2):92-97
The flow characteristics and inclusion removal in a ten-strand continuous casting tundish were investigated with physical modelling and industrial trials.The results show that,among the strands,the strand with the mini-mum dimensionless time of the first appearance of tracer at the tundish exit appears to be the worst one for inclusion removal,while the strand with the maximum dimensionless mean residence time shows the best inclusion removal efficiency.The inclusion number decreases with increasing inclusion size for all strands.The inclusion number distri-bution among strands is the same for all inclusion sizes and the descending order of inclusion number is basically con-sistent with the ascending order of dimensionless mean residence time among individual strands.However,when the strand with the minimum dimensionless time of the first appearance of tracer at the tundish exit is not the same one with the minimum dimensionless mean residence time,the former seems to be inferior to the latter for inclusion re-moval. 相似文献
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通过计算得出在浇注过程中连铸中间包包壁瞬态热量损失作为边界条件的基础上,建立了连铸中间包内钢液流动与传热耦合数学模型,对连浇过程中中间包内非稳态的温度场和流场进行了数值模拟,考察了中间包连浇5个包次过程中钢液热量损失、温度分布以及流场情况,为现场操作和工艺优化提供依据和指导。 相似文献
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板坯连铸中间包内控流装置结构的优化 总被引:2,自引:2,他引:0
以国内某钢厂板坯连铸中间包为原型,进行控流装置的物理和数值模拟优化,提出优化方案.对比物理模拟和数值模拟结果发现,对于不使用抑湍器的控流方案,数值计算获得的结论与实验模拟结果较一致;而对于使用抑湍器的方案,数值模拟可以减少示踪剂和流体的分离流动对停留时间分布曲线的影响,更准确地反映实际流场. 相似文献
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The fluid flow in a continuous casting tundish is computed for an optimum parameter setting such that the stresses produced at the walls get minimized. This optimization task is carried out using a Genetic Algorithms based procedure that worked in tandem with a 3‐D transient Navier‐Stokes equation solver. The fluid flow equations are iteratively solved by using a pressure‐based finite volume method, according to the SIMPLER algorithm. The k‐ε model is used for achieving the turbulence closure. The numerical simulations reveal how the Genetic Algorithm can be effectively used for optimizing the fluidic design of the tundish. 相似文献
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Fluid Flow and Interfacial Phenomenon of Slag and Metal in Continuous Casting Tundish With Argon Blowing 总被引:1,自引:0,他引:1
The fluid flow and the interfacial phenomenon of slag and metal in tundish with gas blowing were studied with mathematical and physical modeling, and the effects of gas flowrate, the placement of porous beam for the generation of bubbles, and the combination of flow control devices on the flow and slag-metal interface were investigated. The results show that the position of gas bubbling has a significant effect on the flow in tundish, and the placement of porous beam and gas flowrate are the two main factors affecting the entrapment of slag in tundish. The closer the porous beam to the weir, the more reasonable is the flow, which is in favor of the control of slag entrapment in tundish. 相似文献
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