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采用了一种新的混合LES-RANS(大涡模拟-雷诺平均模型)湍流模型模拟结晶器中钢液的流场.模型通过修正湍流黏度系数对水口和结晶器内湍流进行过滤,对大尺度的湍流直接采用Navier-Stokes方程求解计算,对小尺度的脉动采用标准k-ε模型进行计算.该模型能避免RANS的过分耗散并且能捕捉到更多的瞬态湍流信息.模型通过对连铸结晶器内液态金属GaInSn模型速度进行测量验证,速度测量方法为超声波多普勒测速仪(UDV)测速法.新模型与实验测量值吻合程度明显好于RANS模拟的结果,能更准确地预测结晶器和水口内的湍流行为.结晶器内瞬态流动特征表明,水口两侧流体呈周期性的偏流,周期约为5s.
A new mixed LES-RANS turbulence model was used to simulate the flow field of the molten steel in the mold.The model filtered the turbulent flow in the nozzle and the crystallizer by modifying the turbulent viscosity coefficient, Of the turbulence directly by Navier-Stokes equations for solving the calculation of small-scale pulsations using standard k-ε model to calculate the model to avoid excessive dissipation of RANS and capture more transient turbulence information. The velocity of liquid metal GaInSn model in the mold was tested and the velocity was measured by UDV velocimetry.The new model was in good agreement with the experimental data and better predicted by the RANS simulation Turbulent behavior in the mold and in the nozzle The transient flow characteristics in the mold indicate that the fluid on both sides of the nozzle exhibits a periodic bias current of about 5 s.