Mathematical And Physical Simulation On Optimization And Inclusion Removal Of Gas Bubbling Curtains In The Tundish

With the increasing demand worldwide for high quality metal products, the important function of tundish on refining of steel has been emphasized. In recent years, because of the efficiency of argon bubble enhancing the removal of the small inclusions less than 50 μ m in diameter, the important role of the gas bubbling curtains on the production of superior clean steel has been gamed considerable attention. The gas blowing parameters is the key factor for gas curtain tundish performing its metallurgical operations. While the gas blowing parameters have closed relevance with the properties and microstructures of the porous refractory through which gas blowing. But the porous refractory was more simplified in the previously mathematical and physical modeling. And the simplified model has great difference with the practical porous refractory.According to the practical production conditions, the factors affecting properties of the porous plugs were studied at first. Then porous refractory models which properties and microstructures were similar as the practical porous refractories were prepared. Using the porous refractory models made in the lab as gas blowing elements, adopting porous media model for the gas flow through the porous refractory, effect on steel flow in the tundish of different porous refractories were studied by mathematical and physical simulation. Considering inclusions collision and rising, absorption of refractory wall, Stokes floating and bubble flotation, inclusion trajectories and removal in the gas curtain tundish were simulated using Lagrangian random particle tracking approach. The factors affecting particle moving and removal were analyzed and the mathematical model for calculating inclusion removal in the gas curtain tundish were more accurate. Based on the above studies, the two-strand tundish of some plant equipped with bottom gas blowing were mathematical and physical simulated. And the gas blowing parameters were optimized. Some conclusions were drawn as below:1. The properties and microstructure of the corundum-mullite system porous refractory were studied from the particle size distribution, powder content, additive content. The resistant coefficients of gas flowing through the porous refractory were analyzed using dimensionless analysis. The results indicate when the powder content was about 15%, adding some expansive additives and dispersant, adopting oscillating and casting technology, the porosity of the samples can be above 30% as well as the higher strengths, favorable permeability, uniform distribution small size pores can be acquired for the samples. The resistant coefficients of gas flowing through the porous refractory can be expressed by the follow equations:...