Effect of EMBr on Multiphase Flow and Bubble Entrapment in Steel Continuous Casting
作者单位：Dept.of Mechanical Science and Engineering University of Illinois at Urbana–Champaign Steelmaking Research Department Research Institute Baoshan Iron & Steel Co. Ltd.
会议名称：《第十届中国钢铁年会暨第六届宝钢学术年会》
会议日期：2015年
学科分类：080602[工学-钢铁冶金] 08[工学] 0806[工学-冶金工程]
基 金：Baosteel, Shanghai, PRC, the National Science Foundation (Grant CMMI 11-30882) the Continuous Casting Consortium, University of Illinois, for support of this project
关 键 词：continuous casting bubble entrapment computational model model validation EMBr
摘 要：In steel continuous casting, double-ruler electromagnetic braking（EMBr） is often applied to control the flow pattern in the mold. In addition, argon gas is usually injected to prevent clogging, but the bubbles also affect the flow pattern, and may become entrapped to form defects in the final product. To investigate the combined behaviors, plant measurements were conducted and a computational model was applied to simulate turbulent flow of the molten steel and the transport and capture of argon gas bubbles into the solidifying shell in a continuous slab caster, including EMBr. An Eulerian k-ε model of the steel flow was two-way coupled with a Lagrangian model of the large bubbles using a Discrete Random Walk method to simulate their turbulent dispersion. The top surface velocities agreed well with nailboard measurements, and indicated strong cross flow caused by biased flow of Argas due to the slide-gate orientation. Then, the trajectories and capture of over two million bubbles（25 μm to 5 mm diameter range） were simulated using an advanced capture criterion. The number, locations, and sizes of captured bubbles agreed well with measurements, especially for larger bubbles. The relative capture fraction of 0.3% was close to the measured 0.2% for 1mm bubbles, and occurred mainly near the top surface. About 85% of smaller bubbles were captured, mostly deeper down in the caster. EMBr produced similar behavior with slightly lower capture rates.