MATHEMATICAL AND PHYSICAL MODELING STUDIES OF MOLTEN ALUMINUM FLOW INA TUNDISH

Quantitative velocity and turbulence measurements that were obtained u sing laser Doppler velocimetry during the course of the physical model ing of the molten aluminum now in a tundish are presented. Laser sheet and surface powder visualization techniques were also used to provide qualitative understanding of the complex three-dimensional (3-D) flow regimes encountered in the tundish. The experimental findings are com pared to the results obtained by the finite-element computational simu lation of the flow, showing favorable agreement between the two approa ches. Nonintrusive laser Doppler measurements revealed asymmetric velo city and nonisotropic turbulence field near the nozzle exit. In the vi cinity of the nozzle, the interaction of the impinging jet and the inc lined walls gives rise to vortex structures. Downstream of the nozzle, two counter-rotating secondary cells diminish in strength. The experi ments indicate that the turbulence structure near the bottom of the tu ndish is isotropic, whereas nonisotropy dominates near the free surfac e. As flow turns through the bend, a separation region is created. The flow heading into the closed duct is observed to be nonsymmetric.