反向凝固器内伴随固液相变的湍流流动与传热的数值分析

Mathematical Model and Numerical Simulation of Turbulent Flow, Heat Transfer and Solidification in a Crystallizor of Inverse Casting

  • 摘要: 针对 Fe-C二元合金,建立了描述反向凝固器内伴随相变的湍流流动和传热过程的二维稳态数学模型.应用连续统一方程模拟固液相变过程,并假设两相区为疏松介质,对其中的流动应用Darcy法则.湍流现象则通过Launder-Sharma的к-ε双方程低雷诺数修正模型描述.采用Simple算法对凝固器内的速度场和温度场进行了模拟计算,并讨论了母带的厚度、入口温度和补充钢液的过热度等操作参数对相变过程的影响.分析表明母带停留时间是影响新生相生长的关键参数,即反向凝固器高度与母带拉速的比值应控制在一定的范围内.

     

    Abstract: A steady state, two-dimensional numerical model is undertaken to describe coupled liquid steel's turbulent flow and heat transfer with solidification for the Fe-C binary alloy in a crystallizor of inverse casting. The solid-liquid phase change phenomena are modeled by using the continuum formulations and considering the mush zone as porous media. The turbulence flow in the crystallizor is accounted for, using a modified version of the low-Reynolds-number κ-ε turbulence model. The flow pattern in liquid zones and the temperature distribution in solid, mushy and liquid regions are predicted. The numerical analysis indicates that the residence time of the mother sheet in the crystallizor is one of the key parameters. The effects of some other main parameters on the solidification behavior are also studied, such as the thickness and the initial temperature of the mother sheet, the superheat degree of liquid steel, etc.

     

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