AbstractA drum of 12 inch diameter and 3 inch width containing two kinds of spherical balls was rotated and the segregation of balls along the cross-section of the drum was investigated. Plastic, glass and steel balls of 6.0, 12.5 and 15.3 mm diameter were used.In order to measure the segregation of balls quantitatively, a segregation parameter, S, was defined.Under the conditions of identical density but different diameters, the smaller balls were found to segregate. In the case of different densities but same diameter, the heavier balls tended to concentrate inside the bed. When the heavier, larger size balls and the lighter, smaller size balls were mixed, better mixing was observed. S was also found to change with the volume fraction of the heavier balls.Empirical equations which represent the relationship between S and the experimental conditions, such as diameter ratio, density ratio and volume fraction of the heavier balls were derived. Resume Les auteurs utilisent un tambour rotatif de 12 po. de di...