6 kA稀土钕电解槽多相流动数值模拟

Numerical simulation of multiphase flow in 6 kA neodymium electrolytic cell

  • 摘要: 稀土电解槽中气泡和电解质的流动决定离子浓度分布、温度分布以及氧化物颗粒的溶解,进而决定产品的质量。文中以6 kA圆柱形钕电解槽为原型,建立了二维、三维电解槽数学模型,用ANSYS-FLUENT软件对模型进行求解。模拟结果表明,二维模型无法模拟阳极空隙处及阳极外侧的流动过程,三维模型能更准确地反映实际电解槽内的流动特性。根据实际工况建立了非均一极距几何模型并对其流动过程进行了模拟,结果表明,随着极距增大,主旋涡向着阴极和电解槽底部偏斜;尽管流速改变较小,但由于电解质内漩涡的旋流强度不同,导致稀土金属产生偏斜,偏斜程度随阳极极距比增大而增大;阳极气泡穿透深度随极距增大而减小。

     

    Abstract: The flow field of air bubbles and electrolytes in the rare earth electrolytic cells is of great significance to ion concentration distribution, temperature distribution and the dissolution of oxide particles, and determines the quantity of products. In this paper, a cylindrical neodymium electrolysis cell with an anodic current density of 6 kA was taken as the prototype, and two-dimensional and three-dimensional mathematical models were established, respectively. The ANSYS-FLUENT software was used to solve the models. The results show that the flow process at the anodal gap and outboard of the carbon anode not be simulated by the two-dimensional model, while the three-dimensional model can accurately reflect the flow characteristic in the actual electrolytic cell. A nonuniform polar distance geometric model was built based on the real rare earth electrolyzer and the flow process was also simulated. The results show that the main vortices between the cathode and anode deviate toward the cathode and the bottom of the electrolytic cell with the increase of polar distance. Although the change in velocity is tiny, differences in swirl intensity within the electrolyte will lead to the deviation of rare earth metals. the degree of which increases with the anode distance ratio. The penetration depth of the anode bubble flow decreases with increasing polar distance.

     

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