Turbulent Flow Phenomena and Ce2O3 Behavior during a Steel Teeming Process

Abstract

Steel flow phenomena and Ce2O3 inclusion behavior are presented in this paper. A three-dimensional model was developed to describe the steel flow phenomena and the inclusion behavior during a teeming process. The Kim-Chen modified k-ε turbulent model was used to simulate the turbulence properties and the Height-of-Liquid model was used to capture the interface between gas and steel. A Lagrangian method was then used to track the inclusions and to compare the behaviors of different-size inclusions in the steel flow. In addition, a statistical analysis was carried out by the use of a stochastic turbulence model to investigate the behaviors of different-size inclusions at different nozzle regions. The results show that the steel flow was the most turbulent at the connection region of the straight pipe part and the expanding part of the nozzle. All inclusions with a diameter smaller than 20 μ m were found to have a similar trajectory and velocity distribution in the nozzle. However, inertia force and buoyancy force were found to play an important role for the behaviors of large-size inclusions/clusters. The statistical analysis results indicate that the regions close to the connection region between different angled nozzle parts seem to be very sensitive with respect to deposition of inclusions.

Decrease of Nozzle Clogging through Fluid Flow Control

“…Based on the previous discussion, the distribution and percentages of the inclusions touching the nozzle wall have support through the analysis of the flow velocity and turbulent kinetic energy, underlining that the touching inclusion percentage should not be taken as the attachment inclusion percentage, as reported in several works [3,50,51]. Experimental results [26][27][28][29] indicate that the proportion of the largest inclusions yield low attachment rates while the numerical results reported here yield no influence of the particle size.…”

Transport and Deposition of Non‐Metallic Inclusions in Steel Flows‐ A Comparison of Different Model Predictions to Pilot Plant Experiment Data

“…The previous pilot plant experiments show that the REM alloyed steel has a very serious nozzle clogging problem during teeming . Figure shows the pictures of a clogged nozzle from a pilot plant experiment . It can be seen that regions 3 and 4 have a serious clogging problem.…”

“…The molten steel flow is normally very complex and it is very difficult to get the real observation or measurement on some phenomena in steel flows at such high temperature around 1773 K. The interface phenomena are even more complex compared to an air flow since some other forces may exist like the interfacial tension gradient force, which is related to the content of some surface active elements in molten steel . Therefore, a “stick” boundary is commonly assumed when investigating inclusion depositions in steel flows …”

“…Zhang et al tracked the trajectories and entrapment locations of inclusions in a slide‐gate nozzle, based on the flow field solved by k ‐ ϵ turbulence model. Ni et al investigated different sizes and densities of inclusions touching the nozzle wall in the flow field solved by realizable k ‐ ϵ turbulence model and compared predictions to pilot plant experiment data. In addition, the inclusions deposition in a swirling flow SEN was investigated …”

The Use of an Enhanced Eulerian Deposition Model to Investigate Nozzle Clogging During Continuous Casting of Steel

“…[4][5][6][7][8][9][10][11] Although much effort has been invested, clogging is still a common problem in steel production. A large number of mathematical simulations, summarized by Ni et al, [12] have been carried out aiming to get a good understanding of the inclusion transport. However, none of the previous simulations can even give an effective prediction on the deposition rate of inclusions, which is very important to help in judging the clogging situation.…”