ISSN -
11th International Rolling Conference (IRC 2019) — vol. 11, num.11 (2019)
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Resumo
Impinging water jets promote high heat flux extraction rate. Steel industry widely employs the process for accurate temperature control to improve the microstructure and to ensure adequate mechanical properties. The range of surface temperatures, heat fluxes and cooling rates are very large, which makes it important to obtain an accurate value of the heat transfer coefficient. This paper presents an experimental and numerical study of the heat transfer behavior of a high temperature (450°C - 900°C) steel plate cooled by a water jet at 20°C to 70°C. High-speed imaging (up to 20,000 fps) within water jet impingement zone allowed the characterization of the boiling regimes in the early stages of cooling. The effects of initial temperature, water jet temperature and velocity and on the heat transfer coefficient were analyzed by inverse heat conduction method that predicts the heat flux and temperature on the top surface from temperatures measured with thermocouples inserted in test plate. Heat transfer is strongly affected by the initial temperature of the hot steel, water jet temperature and, less intensely, by jet velocity. High cooling rates start when liquid water is in direct contact with surface temperatures above 700°C.The results will contribute to the enhancement of the temperature cooling control on the runout table and cooling model employed at Usiminas Hot Strip Mill.
Palavras-chave
heat transfer; water jet cooling; hot strip mill; temperature cooling control
Como citar
Leocadio, Hormando;
Geld, CWM van der;
Passos, Julio Cesar.
HEAT TRANSFER COEFFICIENT DURING WATER JET COOLING OF HIGH-TEMPERATURE STEEL
,
p. 763-773.
In: 11th International Rolling Conference (IRC 2019),
São Paulo,
2019.
ISSN: -
, DOI 10.5151/9785-9785-32400
