Cold model study of raceway under mixed particle conditions

The raceway phenomenon has been studied using mixed particle systems in a two-dimensional cold model. No study is available in the existing literature for the raceway under the mixed particle conditions that prevail in operating blast furnaces. Two types of material, quartz and polypropylene, in different shapes and sizes have been considered. These particles are mixed in various proportions to study the effect of mixed particles on void and raceway formation and raceway breaking. The effects of particle diameter, density, and gas flowrate have been studied. The results obtained from the mixed particles have been compared with the results obtained from particles of uniform size. Experiments have been carried out using models made of glass and Perspex in order to study the effect of fabricating materials on the results. Some interesting results have been obtained in the study and are reported here. Correlations have been proposed to predict void and raceway formation, raceway growth, and raceway breaking under mixed particle conditions.