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Mathematical modeling of heat transfer in the meniscus region of the continuous slab casting mould

University of British Columbia

The objective of this investigation was to characteristize the heat transfer phenomena related to the Submerged Entry Nozzle (SEN) and its role on the heat transfer of the liquid steel in the meniscus region of the mould broad face. The investigation has been conducted based on a previous plant trial at Stelco’s Lake Erie. A mathematical model, which includes the SEN and the liquid steel, was formulated. The heat transfer in the SEN was examined by performing a two - dimensional finite difference model with the Alternating Direction Implicit (ADI) method. The influences of the SEN on the steel heat transfer in the meniscus region was studied under various conditions. The heat transfer of the liquid steel was investigated (i) by a plug flow model for the liquid steel flowing through the SEN tube and (ii) by a one-dimensional finite difference model for the liquid steel in the meniscus region. The modeling results revealed that the SEN absorbs heat from the liquid steel both inside the SEN tube and in the meniscus region, and loses heat to the atmosphere through its exposed surface above the meniscus; the liquid steel falling through the SEN tube has a temperature drop of about 2.4°C from the SEN entrance to exit for a SEN length of 0.7 m; about 30% of the superheat extracted of the liquid steel in the meniscus region is absorbed by the SEN. Many factors, such as the thermal properties of the SEN sleeve and body materials and the mould flux insulation depth and performance, have influences on the heat transfer of the SEN and then on the heat transfer of the liquid steel in the meniscus. The distance between the mould broad face and the SEN is also an important factor which influences the severity of the cooling effect of the liquid steel in the meniscus caused by the SEN heat transfer. With the shorter distance between the mould broad face and the SEN, the cooling effect of the liquid steel is more pronounced. The SEN tube length, especially the length above the meniscus, has an effect on the temperature drop of the liquid steel inside the SEN. The results of this work showed the importance of the heat transfer of the SEN regarding to the casting process and provided guidelines for improvements on slab surface quality and operating practice.

Thesis/Dissertation

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2009-02-24

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http://hdl.handle.net/2429/5012

Materials Engineering

University of British Columbia

UBCV

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