Analysis model of internal residence time distribution for fluid flow in a multi-strand continuous casting tundish

• Published in: Journal of iron and steel research, international Vol. 31; no. 9; pp. 2186 - 2195
• Main Authors: Yue, Qiang, Li, Yue, Wang, Zi-ming, Sun, Ben-chen, Wang, Xiu-zhen
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01-09-2024
• Subjects: Applied and Technical Physics; Engineering; Machines; Manufacturing; Materials Engineering; Materials Science; Metallic Materials; Original Paper; Physical Chemistry; Processes; Tundish; Dead volume; Mathematical modelling; Internal residence time distribution; Critical velocity
• ISSN: 1006-706X; 2210-3988
• DOI: 10.1007/s42243-024-01189-3

The external residence time distribution (RTD) curve is extensively used to characterise fluid flow within the single-strand continuous casting tundish. Dead volume fraction determination typically relies on the external RTD curve to reveal macroscopic fluid flow behaviour. Based on the external RTD to effectively assess dead volume fractions and other fluid characteristics under conditions of internal non-uniform flow, an internal RTD was introduced. In a smooth pipe under laminar flow conditions, the dead region occupies 25% of the total volume, which is defined as the space between the pipe wall and a radius of 0.866
R
0
(where
R
0
is the radius of pipe). Under turbulent flow conditions, the dead region only occupies 0.38% of the reactor’s internal volume, spanning from the pipe wall to a radius of 0.00189
R
0
. The results obtained using the external RTD method are consistent with the theoretical analysis. Experimental trials involving water were conducted to examine the flow of molten steel within a five-strand tundish. Subsequently, an analysis approach employing internal RTD was employed to evaluate fluid mixing within a multi-flow continuous casting tundish. Using the internal RTD method, the analysis revealed that the whole dead zone volume fraction of the intermediate package decreased from 26.9% to 18.9% after the addition of the flow control device. The dead volume fraction can be accurately depicted by utilising the internal mean RTD function. The association between the internal RTD function and the external average RTD can be effectively employed to scrutinise the response curve of the tracer within a system exhibiting uneven flow distribution.