连铸结晶器内湍流大涡模拟

采用大涡模拟研究连铸钢水非定常湍流特性，比较了雷诺平均数学模型与大涡模拟数学模型对预测结晶器内钢水湍流运动的影响.模型采用一种低温液态金属模型的超声波多普勒速度仪（UDV）的测量结果进行验证，表明大涡模拟比雷诺平均模拟与实验测量结果更加吻合.瞬态湍流研究表明，大涡模拟优于雷诺平均数学模型，能够捕捉到水口附近高频率的湍流脉动现象.水口出流钢水区域内小尺度湍流结构起支配作用，射流以阶梯状上下摆动向结晶器内扩散.受湍流大尺度作用，结晶器内流场偏流现象始终存在，并且呈周期性变化，随着对流场时间平均的增加，结晶器内的不对称现象逐渐消除.

Large eddy simulation of turbulent flow in a continuous casting mold

Large eddy simulation(LES) computational model was applied to investigate the transient turbulent flow in a continuous casting mold. Reynolds-averaged Navier-Stokes equations(RANS) model was also compared with LES to predict the turbulent flow features. The computation models were validated by ultrasonic doppler velocimetry(UDV) measurement in a liquid metal model,which indicates that the LES model predict much more accurate than RANS model. LES model can capture the large turbulent fluctuation near the jet region. A wobbling stair-step downward jet was simulated,which indicates that the small scale flow dominants this region. Due to the large scale flow structure in the lower velocity region,the asymmetrical flow pattern behavior always exists; the asymmetrical flow disappears with more time averaging.