Modeling and Measurements of Intermixing Time in a Water Model of a Four Strand Steelmaking Tundish System

Abstract Intermixing of two different grades of steel in a
17 tonne, 4 strand bloom casting has been investigated in a
*0.3 scale, geometrically and dynamically similar, isothermal water model tundish system. In this, intermixing phenomena were studied by simulating mixing of flowing water
in the tundish, having different dissolved tracer (electrolyte) concentrations. Electrical conductivity measurement technique was employed to monitor concentration of dissolved electrolyte near the strands as a function of time and thereby determine intermixing time. For each experimental condition, three measurements were made and based on such an average intermixing timewas estimated. Reproducibility was found to be always within±15 %. Influence of key operating variables such as, inflow rate fromladle, net outflow rate from tundish, residual liquid volume left over from the previous grade etc. on the duration over which intermixing occurs (referred to as in the text as the intermixing time) was investigated. It was found that any increase in residual volume as well as inflow rate tends to prolong intermixing time.In contrast, influence of outflow rate was quite the opposite. Furthermore, while variation of intermixing time among