| 1. |
- Chen, Chao, 1989-, et al.
(författare)
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Mathematical modelling of molten alloy mixing in a continuous casting tundish - A hydrodynamic study
- 2015
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Ingår i: Proceedings of the 6th International Congress on the Science and Technology of Steelmaking, ICS 2015. - : Chinese Society for Metals. ; , s. 407-411
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Konferensbidrag (refereegranskat)abstract
- The emergence of the nozzle clogging have inspired steelmakers to optimize the alloying routine from alloying in ladle to alloying in tundish or in continuous casting mould. Meanwhile, wire injection in tundish has been shown to be successful for postalloying and tundish temperature adjustment. However, there is limited information on the continuous feeding of alloy in tundishes. There are three aspects to be considered: a) "alloy melting", b) "alloy particle dispersion" and c) "liquid alloy mixing". In the present paper, the "liquid alloy mixing" process is studied using CFD (Computational Fluid Dynamics) from a hydrodynamic perspective. In the simulation, the molten alloy is described by the density coupled mixed composition fluid model, which has been verified and validated by water modelling experiments using black ink and KCl tracer mixing in water as a priori. In the present model, the density of the liquid alloy is assumed to be 1.15 or 0.85 times of that of the liquid steel. Thereafter, the denser alloy injection at two positions has been studied, i.e. near the inlet (L1) and at the centre of the tundish (L2). The results indicate that the breakthrough time for the mass fraction of alloy at the outlet are about 100s for both locations. The difference is when the alloy was injected at the center (L2), there is a bypassing flow above the dam. As a result, the mass fraction of alloy at the outlet increases rapidly but the homogeneity in the tundish bath is reduced. Moreover, the denser alloy injection with different velocities was studied. The result shows that the mixing is slightly enhanced during the initial injection stage for the big velocity case. Besides, a test simulation on the mixing of a lighter alloy indicates that the alloy is floating to the top surface.
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| 3. |
- Saffari Pour, Mohsen, 1987-, et al.
(författare)
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The behavior of impurities during producer gas implementation as alternative fuel in steel reheating furnaces : A CFD and thermochemical study
- 2016
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Ingår i: ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE). - USA : American Society of Mechanical Engineers (ASME). - 9780791850589
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Konferensbidrag (refereegranskat)abstract
- The use of available and cheap industrial producer gases as alternative fuels for the steel reheating furnaces is an attractive topic for steel industry. The application of producer gases for such furnaces introduces not only the complicated combustion system of Low Calorific Value (LCV) gases, but also several impurities that could be problematic for the quality of final steel products. The quality of steel can be highly affected by the interaction of impurities with iron-oxides at hot slab surfaces. In this research, the combustion of producer gases and the behavior of impurities at the steel slab surface are studied by aid of a novel coupled computational fluid dynamics (CFD) and thermodynamics approach. The impurities are introduced as mineral ash particles with the particle size distributions of 15-100 νm. The CFD predicted data regarding the accumulation of ash particles are extracted from an interface layer at the flaring gas media around the steel slab surface. Later on, these predicted data are used for the thermo-chemical calculations regarding the formation of sticky solutions and stable phases at the steel slab surface. The results show that the particles are more likely follow the flow due to the high injection velocity of fuel (70 m/s) and the dominant inertial forces. More than 90 percent of particles have been evacuated through the exhaust pipes. The only 10 percent of remaining particles due to the high recirculation zones at the middle of furnace and the impinging effect of front walls tend to stick to the side wall of slab in the heating zone more than the soaking zone.
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