Physical and Mathematical Models of Steel Flow and Heat Transfer in a Tundish Heated by Plasma

Temperature control of liquid steel by plasma heating is physically and mathematically modeled. A dimensionless plasma heating number is employed for scaling up of heating operations between a steam jet for water model and a plasma prototype. Overall responses of step-input temperatures in steel are fairly well predicted by the physical model. Fluid-flow structure and thermal fields, in terms of dimensionless temperatures, of steel are different from those of water. Two positions of plasma in a tundish were studied, centered and off-centered. The second position decreased the heating response of a plasma, although a more homogeneous thermal field was obtained in regard to the first position. Consequently, a centered position offered a faster thermal response than the off-centered one. Flow controllers decreased the efficiency of plasma due to the formation of stagnant zones located in their proximity, which were not active enough to exchange momentum and heat with the bulk flow.