利用水模型与数值模拟相结合的方法,对Ruhrstahl-Heraeus (RH)精炼过程中的多相流体流动及混匀现象进行模拟研究。根据相似原理建立与实际210 t RH精炼装置几何相似比为1：5的水模型,采用粒子图像测速(PIV)技术获取水模型中心截面处流场分布。数值模拟采用多相流模型(VOF)和离散相模型(DPM)相耦合的计算方法,湍流模型分别选用k-ε模型和大涡模拟(LES)模型。对比测量值与计算值,结果表明2种湍流模型均能较好地预测RH内流场分布;而采用LES模拟能够获得RH内瞬态的速度分布及漩涡的产生和耗散过程。测量并计算了水模型钢包内整体的混匀时间分布,结果表明上升管附近区域的混匀时间大于下降管附近区域的混匀时间。开发了气泡膨胀的数学模型,并将其用于钢液-氩气体系的模拟计算,结果表明气泡膨胀过程对钢液流动的影响显著。

The Ruhrstahl-Heraeus (RH) vacuum system is vitally important in the secondary refining process since it is highly effective on decarburization and degassing, which involves complex multiphase flow and transport phenomena. Many investigations on the flow field in the RH refining process have been reported. However, only several investigations are focused on the bubble expansion in the up-leg snorkel. In this work, the combined mathematical model and physical model were employed to simulate the fluid flow and mixing phenomena in the RH reactor. A water model for a practical 210 t RH reactor was established according to similitude principle, and the flow field on the center section of the physical model was captured by PIV (particle image velocimetry) system. The coupled VOF (volume of fluid) model and DPM (discrete phase model) were used to simulate the multiphase fluid flow in the RH reactor. Both the k-ε model and LES (large eddy simulation) model were performed to describe the turbulent characteristics during the RH refining process. The mathematical model was validated by the water model with the same experimental conditions. It suggests that the calculated results show a good agreement with the measured one. Based on the LES model, the instantaneous velocity distribution and the generate and the dissipate of vortex were computed. Also, the mixing time of different position in the ladle was measured and calculated. The results show that the mixing time near the up-leg snorkel is larger than that near the down-leg snorkel. A model for bubble expansion was developed and used to simulate the bubble behavior in the steel-argon system. The results show that the bubble expansion has a strong impact on the flow field in the RH reactor.