A model of turbulent multiphase flow, heat transfer, and particle entrapment during continuous casting of steel is presented. The model includes 7m of the vertical and curved strand, and considers the effects of argon gas injection and thermal buoyancy. RANS results are compared with LES. The models feature advanced particle capture criteria, including capture by solidified hooks at the meniscus, entrapment between dendrites, and engulfment by the surrounding of large particles. The fluid flow and bubble/inclusion capture results are validated with plant measurements, including nail board dipping tests and ultrasonic tests of particle locations, and good agreement is seen. The superheat has negligible effect on flow in the mold region but causes complex flow in the lower strand by creating multiple recirculation zones due to the thermal buoyancy. With high (30K) superheat, this leads to less penetration, fewer and shallower capture of particles. Lower (10K) superheat may enable significant top surface freezing, leading to very large internal defect clusters. Lower superheat also leads to deeper meniscus hooks, and more surface capture. Capture bands occur near the transition from vertical to curved, where downward velocity balances the particle terminal velocity.

Moderated by: Brian Thomas / Laurentiue Nastac