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本文利用大涡模拟模型分析薄板坯连铸钢液非稳态湍流特性,其中非稳态湍流流动N-S方程采用盒式函数进行滤波处理,亚格子模型采用Smagorinsky-Lilly模型.将大涡模拟结果与粒子图像测速及超声探伤结果进行分析比较来校正模型.通过对薄板坯连铸过程进行数值分析,获得了结晶器内非稳态钢液湍流的流动特征,包括流场的漩涡分布及大涡拟序结构的形成、发展、脱落和破碎过程,并发现即使水口和结晶器在几何上完全对中,结晶器内湍流分布也不对称,偏流产生是必然的,同时导致弯月面较强的波动.随着非稳态时间的延长,结晶器内钢液偏流在两侧呈现周期性变化,周期约为40 s.
In this paper, the large-eddy simulation model is used to analyze the unsteady turbulent characteristics of thin slab continuous casting fluid, in which unsteady turbulent flow Navier-Stokes equations are filtered using a box function, and the subgrid model is Smagorinsky-Lilly model. Particle image velocimetry and ultrasonic flaw detection were used to calibrate the model.The flow characteristics of turbulent flow in unsteady liquid steel in the mold were obtained by numerical analysis of thin slab continuous casting process including swirling distribution of flow field and large eddy simulation Formation, development, shedding and fragmentation of the ordered structure, and found that the turbulent flow distribution in the crystallizer is not symmetrical even though the nozzle and the crystallizer are perfectly centered. The generation of the bias current is inevitable and at the same time leads to the strong fluctuation of the meniscus With the prolonging of unsteady time, the flow of molten steel in the mold periodically changes on both sides, with a period of about 40 s.