Effects of Nozzle Radial Position, Separation Angle, and Gas Flow Partitioning on the Mixing, Eye Area, and Wall Shear S
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Metallurgical and Ecological Engineering, University of Science and Technology Beijing (USTB), 30 Xueyuan Road, Haidian District, Beijing, 100083, People’s Republic of China, and also with the Ferrous Metallurgy Research Institute (FeMRI), Morelia, Mexico. Contact e-mail: aconejonava@hot mail.com RISHIKESH MISHRA and D. MAZUMDAR are with the Department of Materials Science and Engineering, Indian Institute of Technology Kanpur (IITK), Kanpur, UP 208016, India. Manuscript submitted November 13, 2018.
METALLURGICAL AND MATERIALS TRANSACTIONS B
INTRODUCTION
THE chemical efficiency of the ladle refining operation has been customarily quantified in terms of mixing times. To this end, numerous water modeling and computational studies on ladles fitted with single or dual plugs have been carried out, and the influence of various operating variables (i.e., gas flow rate, ladle size, plug position, presence of a slag layer, etc.) on mixing time has been assessed. Nevertheless, in addition to chemical efficiency, reoxidation of steel, refractory–metal interaction, etc. are often important because these tend to influence the quality of steel produced and the associated process economics. In such a context, the exposed slag eye area and shear stress on the vessel wall in refining ladles are important and have been given considerable emphasis in recent years due to market
demand. It is therefore desirable that the processing efficiency of a steelmaking ladle be examined from a broader perspective, considering two or more objectives rather than mixing time alone. However, a search of relevant literature indicates that efforts in this direction, so far, have been rather limited.[1] More comprehensive studies are needed to understand and quantify the concurrent influence of operating variables on various decision-making process performance parameters, such as mixing time, slag eye area, and refractory degradation. Mixing phenomena in gas stirred ladle systems fitted with single as well as twin porous plugs have been extensively investigated and reported in the literature.[2–20] The large volume of literature has clearly indicated that principal operating variables, such as inert gas flow rate,[10,12] ladle diameter, and bath depth,[17,18] thickness, and physical properties of slag[6,7] and the radial position of the nozzle,[6,7] considerably influence mixing time. It has also been generally acknowledged that the radial position of each nozzle and the separation angle between two nozzles, particularly in ladles fitted with dual plugs, also influence mixing time to some extent.[6,7] In contrast, views on the influence of injection nozzle diameter on mixing time have been divergent.[4] As far as experimental measurements of mixing time are concerned, the tracer amount,[19] tracer saturation concentration,[19] location of tracer addition,[20] sensor position,[20] sensor dimensions, and degree of mixing have been shown to influence results. As a consequence, comparison of results among studies is sometimes difficult because the experimental conditions are e
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