1. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China; 2. School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, Hebei, China; 3. School of Mechanical and Materials Engineering, North China University of Technology, Beijing 100144, China
Abstract:A three-dimensional numerical model coupled with the large eddy simulation (LES) turbulence model and VOF multiphase model, was established based on an actual slab continuous casting mold to investigate the influence of clogging degree and misalignment distribution of submerged entry nozzle (SEN) on the transient multiphase flow field and slag entrainment. The quantitative prediction of number, size, and spatial distribution of the entrained slag droplet in the mold under different conditions were successfully realized using a user defined function,and the distribution of the probability of the slag entrainment at the meniscus was proposed. The results indicate that under the misalignment distribution of the SEN rotating 5° clockwise, the liquid steel jet hit the wide surface more, resulting in a slight decrease in the liquid level distribution near the narrow surface of the meniscus, and the liquid level fluctuation also decreases from the ±(6-7) mm to within ±5 mm compared with the normal conditions. The SEN clogging had a significant effect on the liquid level fluctuation. The liquid level fluctuation was increased to about ±11 mm when the SEN was completely clogging on the left side-without clogging on the right side, and the liquid level fluctuation was increased to ±15 mm when the SEN was 2/3 clogging on the left side-1/3 clogging on the right side. With the normal conditions, the net slag entrainment rate was 0.0130 kg/s and the slag entrainment was mainly occurred around the meniscus and where the stream collides. The net slag entrainment rate was slightly decreased to 0.009 3 kg/s and the probability of slag entrapment near the wide surface was increased under the SEN misalignment condition. The net slag entrainment rate was increased to 0.045 5 kg/s and 0.067 kg/s respectively when the SEN was completely clogging on the left side-without clogging on the right side and 2/3 clogging on the left side-1/3 clogging on the right side. The slag entrainment rate was mainly caused by the shearing effect of the excessive flow velocity of molten steel on the meniscus. The slag entrainment was mainly located within the range of the SEN to 1/4 the width of the mold. The vortex caused by the asymmetric flow was increased after the SEN was clogged, and the slag entrainment also increased accordingly.
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