Effect of Scale on Slab Heat Transfer in a Walking Beam Type Reheating Furnace

Authors: Man Young Kim

Abstract:

In this work, the effects of scale on thermal behavior of the slab in a walking-beam type reheating furnace is studied by considering scale formation and growth in a furnace environment. Also, mathematical heat transfer model to predict the thermal radiation in a complex shaped reheating furnace with slab and skid buttons is developed with combined nongray WSGGM and blocked-off solution procedure. The model can attack the heat flux distribution within the furnace and the temperature distribution in the slab throughout the reheating furnace process by considering the heat exchange between the slab and its surroundings, including the radiant heat transfer among the slabs, the skids, the hot combustion gases and the furnace wall as well as the gas convective heat transfer in the furnace. With the introduction of the mathematical formulations validation of the present numerical model is conducted by calculating two example problems of blocked-off and nongray gas radiative heat transfer. After discussing the formation and growth of the scale on the slab surface, slab heating characteristics with scale is investigated in terms of temperature rise with time. 

Keywords: Reheating Furnace, Scale, Steel Slab, Radiative Heat Transfer, WSGGM.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1086899

References:

[1] M. Y. Kim, “A heat transfer model for the analysis of transient heating of the slab in a direct-fired walking beam type reheating furnace,”International Journal of Heat and Mass Transfer, vol. 50, 2007, pp. 3740-3748.
[2] D. Wild, T. Meurer, and A.Kugi, “Modelling and experimental model validation for a pusher-type reheating furnace,”Mathematical and Computer Modelling of Dynamical Systems, vol.15, 2009, pp. 209-232.
[3] J. G. Kim, K. Y. Huh, and I. T. Kim, “Three-dimensional analysis of the walking-beam-type slab reheating furnace in hot strip mills,”Numerical Heat Transfer, PartA, vol. 38, 2000, pp. 589-609.
[4] S. H. Han, D. Chang, and C. Y. Kim, “A numerical analysis of slab heating characteristics in a walking beam type reheating furnace,”International Journal of Heat and Mass Transfer, vol. 53, 2010, pp. 3855-3861.
[5] C.-T. Hsieh, M.-J. Huang, S.-T. Lee,and C.-H. Wang, “Numerical modeling of a walking-beam-type slab reheating furnace,”Numerical Heat Transfer, Part A, vol. 53, 2008, pp. 966-981.
[6] K. S. Chapman, S. Ramadhyani, and R. Viskanta, “Modeling and parametric studies of heat transfer in a direct-fired continuous reheating furnace,”Metallurgical Transactions, vol. 22B, 1991, pp. 513-521.
[7] S. H. Han, D. Chang, and C. Huh, “Efficiency analysis of radiative slab heating in a walking-beam-type reheating furnace,”Energy, vol. 36, 2011, pp. 1265-1272.
[8] A. Jaklic, T. Kolenko, and B. Zupancic, “The influence of the space between the billets on the productivity of a continuous walking-beam furnace,”Applied Thermal Engineering, vol. 25, 2005, pp. 783-795.
[9] J. H. Jang, D. E. Lee, C. Kim, and M. Y. Kim, “Prediction of furnace heat transfer and its influence on the steel slab heating and skid mark formation in a reheating furnace,”ISIJ International, vol. 48, 2008, pp. 1325-1330.
[10] J. H. Jang, D. E. Lee, M. Y. Kim, and H. G. Kim, “Investigation of the slab heating characteristics in a reheating furnace with the formation and growth of scale on the slab surface,”International Journal of Heat and Mass Transfer, vol. 53, 2010, pp. 4326-4332.
[11] T. F. Smith, Z. F. Shen, and J. N. Friedman, “Evaluation of coefficients for the weighted sum of gray gases model,”Journal of Heat Transfer, vol. 104, 1982, pp. 602-608.
[12] M. F. Modest, “The weighted-sum-of-gray-gases model for arbitrary solution methods in radiative transfer,”Journal of Heat Transfer, vol. 113, 1991, pp. 650-656.
[13] K. Sachs and C. W. Tuck, “Surface oxidation of steel in industrial furnaces,”Iron and Steel Institute, vol. 111, 1968, pp. 1-17.
[14] J. Tominaga, K. Wakimoto, T. Mori, M. Murakami, and T. Yoshimura, “Manufacture of wire rods with good descaling property,”Trans. ISIJ, vol. 22, 1982, pp. 646-656.
[15] M. Torres and R. Colas, “A model for heat conduction through the oxide layer of steel during hot rolling,”Journal of Materials Processing Technology,vol. 105, 2000, pp. 258-263.
[16] R.Y. ChenandW. Y. D. Yuen, “Review of the high-temperature oxidation of iron and carbon steels in air or oxygen,”Oxidation of Metals, vol. 59, 2003, pp. 433-468.
[17] S. V. Patankar, Numerical Heat Transfer and Fluid Flow, Mc-Graw Hill, New York, 1980.
[18] E. H. Chui and R. D. Raithby, “Computation of radiant heat transfer on a nonorthogonal mesh using the finite-volume method,”Numerical Heat Transfer, Part B, vol. 23, 1993, pp. 269-288.
[19] J. C. Chai, H. S. Lee, and S. V. Patankar, “Treatment of irregular geometries using a Cartesian coordinates finite-volume radiation heat transfer procedure,”Numerical Heat Transfer, Part B, vol. 26, 1994, pp. 225-235.
[20] S. W. Baek, M. Y. Kim, and J. S. Kim, “Nonorthogonalfinte-volume solutions of radiative heat transfer in a three-dimensional enclosure,”Numerical Heat Transfer, Part B, vol. 34, 1998, pp. 419-437.
[21] M. K. Denison and B. W. Webb, “A spectral line-based weighted-sum-of-gray-gases model for arbitrary RTE solvers,”Journal of Heat Transfer,vol. 115, 1993, pp. 1004-1012.
[22] T. K. Kim, J. A. Menart, and H. S. Lee, “Nongrayradiativegas analyses using the S-N discrete ordinates method,” Journal of Heat Transfer, vol. 113, 1991, pp. 946-952.
[23] T. H. Song, “Comparison of engineering models of nongray behavior of combustion products,”International Journal of Heat and Mass Transfer,vol. 36, 1993, pp. 3975-3982.