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arc has been developed and used to predict heat transfer from the arc to the molten bath in ferrosilicon AC submerged-arc furnace. In this model the time-dependent conservation equations for mass, momentum and energy in the specified domain of plasma zone have been solved numerically coupled with the Maxwell and Laplace equations for magnetic filed and electric potential respectively. A control volume based finite difference method was used to solve the governing equations in cylindrical coordinates. The reliability of the developed model was tested by comparison with the data available in the literature. The present model showed a better consistency with the data given in the literature because of solving the Maxwell and Laplace equations simultaneously for calculation of current density. Parametric studies were carried out to evaluate the effect of electrical current and arc length on flow field and temperature distribution within the arc. According to computed results, a lower power input lead to the higher arc efficiency. 相似文献
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A two dimensional axisymmetric model was developed to predict the heat flux in a steelmaking ladle during the teeming process. The model predicts dynamically the flow fields in both liquid phase and gas phase along with the movement of the liquid upper surface. The model also predicts the temperature distributions in the liquid metal, gas phase and all layers in the ladle wall. Industrial measurements using infrared radiation camera inside the ladle after teeming and at the wall outside the ladle during the whole process were carried out. The model predictions were found to be in agreement with the measured data. It was found that the heat transfer to the surrounding atmosphere and the conductivity of the highly insulating layer were the most important factors for the heat loss. The decrease of the thickness of the working lining was found to have limited effect on the total heat flux. 相似文献
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The transport phenomena based heat transfer and fluid flow calculations in weld pool require a number of input parameters.
Arc efficiency, effective thermal conductivity, and viscosity in weld pool are some of these parameters, values of which are
rarely known and difficult to assign a priori based on the scientific principles alone. The present work reports a bi-directional three-dimensional (3-D) heat transfer
and fluid flow model, which is integrated with a real number based genetic algorithm. The bi-directional feature of the integrated
model allows the identification of the values of a required set of uncertain model input parameters and, next, the design
of process parameters to achieve a target weld pool dimension. The computed values are validated with measured results in
linear gas-tungsten-arc (GTA) weld samples. Furthermore, a novel methodology to estimate the overall reliability of the computed
solutions is also presented. 相似文献
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本文针对Cz法晶体生长特点,通过数值模拟的方法,对Cz法生长砷化镓单晶时从引晶、放肩、等径至收尾这一完整工艺过程中晶体的温度场、熔体的温度场和速度场进行了计算,从中分析籽晶和坩埚的转向、转速等因素对流动和传热的影响,并与实际的砷化镓单晶生长过程进行比较,从比较结果看,二者基本吻合。 相似文献
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《Canadian Metallurgical Quarterly》2013,52(3-4):265-273
AbstractHeat and momentum transfer in a submerged electric smelting furnace were investigated in a physical model, using oil and an aqueous calcium chloride solution to simulate the slag and matte phases, respectively. Gas evolution at the electrode was simulated by the injection of gas through the electrode in the model. A mathematical model for fluid flow and heat transfer in the model was also developed. The measured temperature distributions near the oil/solution interface could only be reproduced in the mathematical model by the imposition of a no-slip boundary condition at the interface. This condition impedes the transfer of heat and momentum into the lower phase; the implications for smelting are discussed. © 1998 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved. Résumé On a étudié avec un modèle physique, le transfert de chaleur et de movement dans un four à fusion électrique submergé, en utilisant de l'huile et une solution aqueuse de chlorure de calcium pour simuler les phases de laitier et de matte, respectivement. Dans le modèle, l'évolution de gaz à l'électrode était simulée par l'injection de gaz à travers l'électrode. On a aussi développe un modèle mathematique de l'écoulement de fluide et de transfert de chaleur dans le modèle (physique). Dans le modele mathématique, on pouvait reproduire les distributions de temperature mesurée pres de l'interface huile/solution seulement si on imposait une condition limite de non-glissant à l'interface. Cette condition empeche le transfert de chaleur et de movement vers la phase inferieure; on discute des implications pour le traitement en fonderie. © 1998 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved. 相似文献
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The physical models of the outer and inner half coil jackets were simplified to two types of coiled ducts.The mathematic models of incompressible fluid at the condition of laminar flow and heat transfer in the two types of jackets for cooling process reactor were set up and solved by the semi-implicit method for pressure linked equations consistent (SIMPLEC) algorithm based on a control volume method. The flow and temperature fields were given and the effects of Dean and Prandtl numbers on flow and heat transfer were studied. The results show that flow in the inner half coil jacket is found to exhibit transition of secondary flow pattern from two vortices to fourvortices when the Dean number increases, but that in the outer half coil jacket is not found. The critical Dean number is about 96. The inner half coil jacket has stronger heat transfer ability than the outer half coil jacket and this superiority is more evident with larger Prandtl number. However, as the Dean number is greater than 105, the flow resistance enhances more severely in the inner jacket than the outer jacket. For both jackets, the centers of the heated wall are the poorest for heat transfer. 相似文献
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Mathematical modelling was used to study the effect of a changed aspect ratio of a continuous casting mould on the resulting flow field in the upper part of the mould when using a swirl flow in the nozzle. Model predictions were initially compared to physical modelling data. More specifically, the predicted axial velocities were found to differ only at the most ~3 mm/s from the measured data. Thus, the model was concluded to be sound. By changing the aspect ratio of a billet mould from 1 to 3 systematically, a numerical analysis of the mould region of a billet continuous caster was performed with a novel injection concept using swirling flow in the immersion nozzle in order to control the heat and mass transfer in the continuous casting mould. The predictions showed that the aspect ratio of the mould has a large influence on the flow field in the upper part of the mould. The meniscus temperature was found to increase with an increasing aspect ratio from 1 to 2, but the maximum temperature was found to decrease when the aspect ratio was increased above 2. 相似文献
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Fluid Flow and Heat Transfer in a Continuous Casting Tundish With the Channel Type Induction Heating
A coupled mathematical model was developed to describe the flow field,temperature distribution of molten steel in the tundish with the channel type induction heating.The molten steel motion was dominated under the combined effect of the thermal buoyancy and the electro-magnetic forces(EMFs)due to the channel type induction heating.The results indicate that the thermal loss of molten steel in the tundish can be compensated effectively by the channel type induction heating.In addition,the molten steel would flow upward under the thermal buoyancy which can reduce the erosion of refractory.Moreover,the upward flow would increase the residence time of the molten steel in the tundish which provide more opportunities for the inclusion to reach the top surface of the tundish. 相似文献
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Understanding the complex phenomena in the BF hearth is essential to increasing furnace productivity and to extending furnace campaign. Numerical modeling provides a cost‐effective tool to obtain such knowledge. We have developed several continuum‐based mathematical/numerical models to simulate the flow, heat transfer and mass transfer in the lower part of BF and in the hearth. These models have generated an improved insight into the mechanisms for liquid drainage efficiency, lining erosion and wall protection in BF hearth under operational conditions. The current paper provides an overview of these studies, as well as dealing with three specific aspects: (a) Gas flow and pressure on the liquid surface, and its effect on the drainage characteristics; (b) Flow and temperature distributions of liquid iron in the hearth, and the temperature distribution in the refractories; and (c), Titania injection to form Ti(C,N)‐rich scaffolds on the hearth refractory surface, to protect the hearth from erosion. 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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薄板坯连铸结晶器内流动传热行为的研究 总被引:2,自引:0,他引:2
基于珠钢CSP薄板坯连铸机设备工艺条件和所采用扁平浸入式水口结构,结合铜板测温导出的热流密度分布进行了漏斗形结晶器内钢水流动、自由液面以及传热凝固等冶金现象的综合描述和数值分析.结晶器熔池中以两个上旋涡为主的钢水循环流动局限在漏斗形结晶器内,上旋涡流股冲击和离开熔池液面分别对液面起伏波动有所贡献,弯月面下距窄边100 mm范围内有二次涡形成.除水口下方两侧存在两个具有明显过热的高温区外,熔池中绝大部分钢水的温度在液相线附近保持恒定,铸坯表面温度分布和坯壳发育过程均反映出水口高温射流的影响,铸坯表面最高温区位于熔池液面下方靠近结晶器窄边的地方. 相似文献
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Three-dimensional mathematical model coupling of the molten steel flow and heat transfer in the slab continuous casting mold and secondary cooling zone is established to describe molten steel flow and heat transfer phenomena in the slab continuous casting mold with EMBR.The computational model is applied to investigate the flow field and temperature field in slab mold contrast with and without a constant EMBR,which strength measured at a steel plant.The study shows that The EMBR has not changed the mold steel flow field characteristic.But it has reduced the intensity of the upper and downer recirculation in the mold,reduced the speed of the upper recirculation zone,increase the free surface temperature which is compared to the state without EMBR. 相似文献
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ZHU Miao-yong WANG Jun ZHANG Ying 《钢铁研究学报(英文版)》2005,12(6):14-19
SymbolList Ab,An———Surfaceareaofbroadfaceandnarrowfaceof moldrespectively,m2;Cp———Effectiveheatcapacity,J·kg-1·K-1;Cp,s———Heatcapacityofsolidphase,J·kg-1·K-1;Cp,l———Heatcapacityofliquidphase,J·kg-1·K-1;Cw———Waterheatcapacity,J·kg-1· 相似文献
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Zeng Jianhua Gan Meijuan Yan Xiaobo Wang Qiangqiang He Shengping 《Metallurgical and Materials Transactions B》2020,51(1):213-221
Metallurgical and Materials Transactions B - The deformation of a bloom tube mold was investigated using an in-house-developed complex model considering the flow, heat transfer, and solidification... 相似文献