Additional Information on “Fluid Flow Characterization in Asymmetric Tundish” by Cui, Liu and Li

Abstract

Cui et al. 1) proposed a methodology for the fluid flow characterization of asymmetric tundishes that does not rely on any idealized flow model. First, the E curves of each tundish strand is obtained through the pulse input experiment. Subsequently, the E curves are converted into F curves by integration. Then, the dead volume fraction of the entire tundish (V d ⁄V) is calculated so as to evaluate the overall tundish performance. Finally, the flow uniformity among tundish strands is assessed through quantities obtained from the strand F curves (i.e. maximum difference between strand F curves for two-strand tundishes or maximum standard deviation among strand F curves for multi-strand tundishes). In the present work, the calculation procedure for the methodology of Cui et al. 1) is discussed in detail. It was identified a problem in the obtention of F curve by Cui et al. 1) that modified the actual formulas of V d ⁄V. In addition, this work presents new equations that facilitate the calculation of V d ⁄V when physical and mathematical models are employed. Moreover, the most convenient definition of the dead volume fraction is studied. It was found that V d ⁄V can distinguish different flows more effectively if it is based on one dimensionless residence time rather than two. Furthermore, some parameters for assessing the flow uniformity among tundish strands were compared. The area metric described by Oberkampf and Roy 11) is the recommended one.

Effect of Uniform and Non-Uniform Increasing Casting Flow Rate on Dispersion and Outflow Percentage of Tracers in Four Strand Tundishes under Strand Blockage Conditions

“…Some researchers [29][30][31] assessed the uniformity of strands in the tundish through the characteristic parameters of the RTD curve of each strand, such as the integral area of the RTD curve, the average residence time of each strand, the response time of each strand, the time for each strand to reach the concentration peak, the full width at half maxima of the RTD curve of each strand, etc. The uniformity of each strand by calculating the standard deviation of the F-curve of each strand was proposed [32,33].…”

“…curve of each strand, such as the integral area of the RTD curve, the average residence time of each strand, the response time of each strand, the time for each strand to reach the concentration peak, the full width at half maxima of the RTD curve of each strand, etc. The uniformity of each strand by calculating the standard deviation of the F-curve of each strand was proposed [32,33]. In this study, the flow field, tracer dispersion and uniformity of strands in two designs of four-strand tundish under normal conditions and single-strand blockage conditions will be studied by numerical simulation.…”