Investigation of Mold Flux Entrainment in CC Molds Due to Shear Layer Instability

Mechanisms for mold flux entrainment in continuous casting molds include vortexing and suction down the SEN due to asymmetric fluid flow, excessive upward flow impingement on the meniscus, surface level fluctuations, argon bubble effects, and shear-layer instability. The latter mechanism, also called Kelvin-Helmholtz instability, is a crucial phenomenon which has been investigated previously only with over-simplified theoretical models and room-temperature physical models using surrogate fluids, both of which behave very differently from steel casters. This paper critically reviews previous literature on entrainment mechanisms. It then presents a realistic numerical model to investigate the Kelvin-Helmholtz entrainment mechanism in steel continuous casters and validates it with a simplified analytical solution of this phenomenon. Finally, the critical meniscus velocity to avoid mold flux entrainment via this mechanism is briefly discussed