Influence of Nozzle Design on Flow Characteristic in the Continuous Casting Machinery

Abstract

In the process of continuous casting, the submerged nozzle will affect the flow of the liquid steel and the quality of the slab. In this paper, three nozzle structures are investigated to compare the influence of the nozzle structure on the flow and solidification of steel. In addition, the flow field, flow velocity, recirculation zone, free-surface turbulent kinetic energy and heat transfer of fluid steel are calculated. The results demonstrate that among the three nozzles, the structure of the B nozzle is the best. The fluid steel flows out from the nozzle at a certain angle. The flow rate and momentum of the fluid steel gradually decrease, and two split streams are formed when the main stream approaches the narrow surface. The spherical area at the bottom of the nozzle can reduce the flow rate of the fluid steel at the outlet of the nozzle, leading to a stable liquid level. The turbulent kinetic energy of the free liquid surface of nozzle A is the largest, reaching 0.00204 m2·s−2. The turbulent kinetic energy of nozzle C is slightly lower (0.00193 m2·s−2), and the free-liquid-surface turbulent kinetic energy of nozzle B (0.00154 m2·s−2) is the smallest. The surface velocity of nozzle B is also lower than that of A and C because the vortex center of the upper recirculation zone of nozzle B is closer to the narrow surface. The results show that the B nozzle is optimal, and this model can provide theoretical guidance for the design of a nozzle during the continuous casting.