连铸板坯滑动水口三维流场湍流计算模型比较

Comparison of Turbulent Models on 3-D Flow in the SEN of Slab Continuous Casting Controlled by Slide Gate

分别采用标准k-ε模型、雷诺应力模型(RSM)和超声波多普勒测速(UDV)方法对滑板控制浇注流量浸入式水口内部和出口流动特征进行对比分析,并探讨湍流模型对滑板浇注系统数值模拟的适用性.结果表明,由于滑板的节流作用,在滑板下方的水口内出现高度约为80mm的二次流,在滑板下方100mm处出现高度为50mm的分离流,并在水口出口出现旋转出流,其方向由滑板堵塞侧、经水口底部向滑板开启侧旋转.标准k-ε模型计算的水口出流的旋转方向与UDV测量的旋转方向相反,RSM计算结果与实验测量结果比较吻合,具有更好的适用性.并从分子动力理论角度、各向同性假设和历史效应等方面,分析了标准k-ε模型存在的理论缺陷.

The fluid flow in the SEN and its outflow characteristics at nozzle port,after introduction of slide gate system to control molten steel flow rate,are investigated by mathematical simulation using standard k-ε model,RSM and experimental measurement by ultrasonic Doppler velocimeter （UDV）,and the adaptability of turbulence models is also examined. The research results indicate that due to the throttling action of slide gate,a secondary flow,with 80 mm length in vertical direction,appears under the slide gate,and a separated flow,located at 100 mm under the slide gate,forms with the length of 50 mm. At nozzle port,a swirl flow is generated with the swirling direction from the clogging side via nozzle bottom to the opening side of slide gate. The swirling direction of fluid at the nozzle port calculated by standard k-ε model is contrary to the measurement result by UDV,but the calculated result obtained by RSM is close to the UDV data. Based on molecular dynamic theory,isotropy hypothesis and history effect,theoretical deficiencies of the standard k-ε model are discussed.