Instability and Periodicity of Asymmetrical Flow in a Funnel Thin Slab Continuous Casting Mold

摘要

Characteristics of the transient turbulent flow in a funnel thin slab continuous casting mold are studied using a large eddy simulation (LES) computational approach. Validations were done through comparison with previous experimental data of the mean velocities and the instantaneous velocities, and good qualitative and quantitative agreements are obtained. The turbulence flow inside the mold consists of various scales vortices; many pronounced large scale vortex structures were clear found inside the mold, containing various small scale vortices between them. The boundary shear flow can separate from the narrow wall and transport vorticity into the interior flow, and then possibly develop into a vortex. The intermittent chaotic vortex formation on both sides of the SEN is found at the meniscus. Three types of vortex phenomena are identified: one big vortex, two vortices and three small vortices. The positions and sizes are different, and the vortexes are located at the low velocity sides adjacent to the SEN. Significant asymmetry is seen in the instantaneous flow in the two halves of the thin slab mold cavity, especially in the lower recirculation zone. The periodical behavior of asymmetric flow inside the liquid pool was identified and characterized. The spectrum of velocities shows that the mean time interval for periodical changeover is 14.28 seconds.