The Use of an Enhanced Eulerian Deposition Model to Investigate Nozzle Clogging During Continuous Casting of Steel
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NOZZLE clogging caused by the build-up of nonmetallic inclusions on ceramic walls is a serious industrial problem in continuous casting of steel, especially for the production of Al-killed steel, Ca-treated steel, rare earth metal-alloyed steel, and Ti-killed steel. Specifically, it can lead to an uneven distributed steel flow and temperature field in a mold as well as an interruption of the steel flow during a continuous casting process. These non-metallic inclusions in molten steel normally have a size of a micro level, and their volume fraction in molten steel is very low. Since these nonmetallic inclusions, i.e., Al2O3, and the refractory wall of a SEN normally are not wetted by molten steel, they tend to stick to the ceramic refractory wall. This is driven by the decreased interfacial energy, when they come close to the wall.[1–3] During the last decades, nozzle clogging problems have represented reoccurring problems. The probable reasons for the clogging and the probable countermeasures to prevent clogging have been discussed extensively.[4–11] Although much effort has been invested, clogging is still a common problem in steel production. A large number of mathematical simulations, summaPEIYUAN NI, Ph.D. Student, MIKAEL ERSSON, Docent, and PA¨R GO¨RAN JO¨NSSON, Professor, are with the Division of Applied Process Metallurgy, Department of Material Science and Engineering, KTH-Royal Institute of Technology, Brinellva¨gen 23, 100 44 Stockholm, Sweden. Contact email: [email protected] LAGE TORD INGEMAR JONSSON, Professor, is with the Division of Applied Process Metallurgy, Department of Material Science and Engineering, KTH-Royal Institute of Technology, and also with the Division of CBRN Defence and Security, FOI, Swedish Defence Research Agency, 901 82 Umea˚, Sweden. Manuscript submitted May 23, 2014. Article published online August 12, 2014. 2414—VOLUME 45B, DECEMBER 2014
rized 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. Among these previous simulations, especially a Lagrangian scheme has been used extensively. This approach gives a great amount of information with respect to the motion of an individual particle. Since one kilogram of a typical low carbon aluminum-killed steel contains 107 to 109 non-metallic inclusions,[13] a Lagrangian scheme may need to track an extremely large number of inclusions in a steel flow to obtain sufficient statistical meanings with respect to the inclusion behavior, e.g., deposition rate of inclusions on the SEN walls. Therefore, it is really time-consuming and thus difficult to obtain a prediction of the deposition rate of inclusions in a SEN in complex steel flows. A new and enhanced Eulerian deposition model suitable for predicting the deposition rate of nonmetallic particles to ceramic walls in liquid metal flows was recently reported.[14] This Eule
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