Modelling of transport phenomena in a delta-shaped, four-strand tundish

• Main Author: Kim, Hyoungbae
• Format: Others
• Language: en
• Published: McGill University 2003
• Subjects: Engineering - Metallurgy
• Online Access: http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19523

A full-scale physical model of a delta-shaped, four-strand tundish was constructed at McGill University to find optimal operating conditions for the tundish. The objective of this work was to determine how best to increase steel production rates by 14% over current tundish operating conditions, these being 12 tons/min with four 15.0 mm outlet nozzles for a 500 mm depth of liquid steel while maintaining steel quality levels. Two options were suggested: the normal head option uses 16.0 mm outlet nozzles and maintains the 500 mm tundish level, while the high head option uses 14.8 mm outlet nozzles and raises the depth of liquid steel within the tundish to 800 mm. The important effects of flow control devices on the hydrodynamic performance of the tundish were also tested, using two different types of flow modifiers: Impact Pad and Turbo-Stop. For a proper comparison between the two options, three aspects were investigated; vortex formation phenomena during tundish draining between ladle changes, Residence Time Distribution (RTD), and Inclusion Separation Ratios (ISR). Inclusion removal rates were studied experimentally with the aid of the aqueous" Liquid Metal Cleanliness Analyzer (LiMCA) system. Particle Image Velocimetry (PIV) was used to visualize the actual instantaneous, or momentary, flows, thereby providing the data needed for time averaged velocity fields and turbulent kinetic energies. A mathematical model based on METFLO was developed to simulate these tundish operations numerically. The Renormalization Group turbulence model (RNG) as well as the standard high Reynolds number k-s turbulence model (STD) was implemented in order to simulate the turbulent flows within the tundish. The validity of METFLO was confirmed by PIV measurements and the numerical predictions of the RTD, and RRI matched the results of physical modelling.