MODELAGEM FÍSICA DA FORMAÇÃO DE VÓRTICE DURANTE O VAZAMENTO DO AÇO DE UMA PANELA
PHYSICAL MODELING OF VORTEX FORMATION DURING LADLE DRAINAGE
Santos, Sandro de Souza; Furtado, Henrique Silva; Silva, Carlos Antonio da; Silva, Itavahn Alves da; Seshadri, Varadarajan
http://dx.doi.org/10.4322/tmm.00501003
Tecnol. Metal. Mater., vol.5, n1, p.12-16, 2008
Resumo
Um modelo em acrílico de uma panela (315 toneladas, ArcelorMittal Tubarão), escala 1:7, foi utilizado para simular as condições de vazamento do aço, e avaliar as condições de surgimento do vórtice. O momento da inserção do vórtice no canal de vazamento foi determinado através de sensores foto-elétricos e o material residual foi pesado de modo a se avaliar o rendimento metálico. A influência do tipo de fluxo residual imposto pelas rotas normais de processamento, tais como RH e IRUT, da vazão de drenagem, além de dispositivos antivórtice foi avaliada. O fluxo residual devido ao processamento em RH e IRUT, bem como o nível inicial de aço na panela não afetaram os resultados. O Volume Residual se mostrou função apenas da vazão. Verificou-se que o fluxo de aço era interrompido pela capacidade de abastecimento radial do canal de saída. Como tal, a utilização de quebradores de vórtice se mostrou contra producente. Simulações realizadas induzindo um fluxo rotacional no fluido de forma a aumentar a propensão ao vórtice permitiram confirmar que a injeção de gás pelo fundo da panela e a utilização de barreiras próximas à região de vazamento contribuem para aumentar o rendimento.
Palavras-chave
Lingotamento contínuo, Vórtice, Panelas, Simulação física
Abstract
A 1:7 scale plexiglas model of a steelmaking ladle (315 tons, ArcelorMittalTubarão) was built in order to assess the conditions of vortex formation during the final stages of draining. The vortex was detected by a photo-electric sensor and the mass of residual liquid inside the ladle was evaluated after weighing. The influence of the type of residual flow, as dictated by routes of processing such as: RH degasser, IRUT reactor, as well as the drainage flow rate, in addition to anti-vortex devices, was assessed Residual flow due to RH or IRUT processing as well as the initial level of liquid did not affect the results. The mass of residual liquid at vortex onset was influenced by the flow rate only. At the final stages of drainage, the liquid surface collapse was dictated by the bottom ladle capacity of supplying liquid in the radial direction to the outlet. As a consequence vortex breakers were found deleterious under these set of conditions. A rotational flow was induced in order to increase the likelyhood of vortex formation. In this case gas injection through the pouring nozzle, vortex breakers, slopped bottoms have been found effective.
Keywords
Continuous casting, Ladle, Simulation, Vortex
References
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2 CHIAPPAROLI, W.; SYLVESTRE, S.; MADÍAS, J. First experiences with a steel ladle water model. In: SEMINARIO DE ACERIA OF THE INSTITUTO ARGENTINO DE SIDERURGIA, 13.; SEMINARIO DE REDUCCIÓN,3.; ENCUENTRO DE LA SECCIÓN ARGENTINA DE LA ISS, 3., 2001, Buenos Aires, Argentina. Buenos Aires, IAS, 2001. p. 689-96.
3 PIMENTA, H.P.; VALADARES, C.A.; BELLIGOLI, G.C.D. Estudo da passagem de escória na etapa de vazamento de aço panela/distribuidor. In: IAS STEELMAKING SEMINAR, 17., 1997, Buenos Aires, Argentina. Buenos Aires: IAS, [199-?]. p. 199-207.
4 SANKARANARAYANAN, R.; GUTHRIE, R.I.L. Slag entrainment through a “funnel” vortex during ladle teeming operations. In: STEELMAKING CONFERENCE, 1992, Ontario, Canada. Proceedings… Montreal: The Metallurgical Society of the Canadian Institute of Mining and Metallurgy, [s.d.]. p. 655-64.
5 PIVA, M.; IGLESIAS, M.; BISSIO, P.; CALVO, A . Experiments on vortex funnel formation during drainage. Physica A, v. 329, n. 1-2, p.1-6, Nov. 2003.
6 HAMMERSCHMID, P.; TACKE, K.H.; POPPER, H.; WEBER, L.; DUBKE, M.; SCHWERDTFERGER, K., Vortex formation during drainage of metallurgical vessels. Ironmaking and Steelmaking, v. 11, n. 6, p. 332-9, Aug. 1984.
7 AJMANI, S.K.; CHOUDHARY, S.K. Cold model study of vortexing in ladle and Tundish. TATA Search, p. 103-9, 2002.
8 HEASLIP, L.J.; DORRICOTT, J.D.; RICHAUD, J.; ROGLER, J.P.; ALVES, W.A. Yield Improvement through enhanced ladle bottom design (ELBY). In: SEMINÁRIO DE ACIARIA – INTERNACIONAL, 37., 2006, Porto Alegre, RS. Anais… São Paulo: ABM, 2006. p. 515-24.
9 DAVILA, O.; FERRO, L.; MORALES, R.D.; DEMEDICES, G.L.; PEREZ, P.R. Physical model and mathematical simulations of ladle draining operations. In: AISTECH CONFERENCE PROCEEDINGS, 2005, Charlotte, NC. Warrendale, PA: Association for Iron & Steel Technology, 2005. v. 1, p. 873-99.
10 SZEKELY, J.; THEMELIS, N.J. Rate phenomena in process metallurgy. New York: John Wiley & Sons, 197. p. 784.
11 LANGE, M.; CLAES, J.; JOLY, A. Clean steel block – new developments towards clean steel. Revue de Metallurgie. Cahiers D’Informations Techniques, v. 100, n. 6, p. 577-82, June 2003.
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