Experimental investigations for the effect of fine powders on size-induced segregation in binary granular mixtures

This paper presents experimental investigations on the size-induced segregation behavior of binary granular mixtures in a rotating drum by adding a small amount of fine powders. Four different fine powder contents were selected, and three different rotation speeds were adopted. Experimental results reveal that the flowability of granular mixtures can be enhanced by a lubrication effect induced by a proper amount of fine powders. The segregation index and rate increase with the increasing fine powder content and rotation speed. The local-ensemble average velocity and granular temperature for large main particles also increase with the increase of fine powder content and rotation speed. The increase of fine powder content provides stronger lubrication effects, and the increase of rotation speed offers more energy into the granular mixtures. The dynamic properties proposed herein can characterize the size-induced granular segregation behavior. The increasing fine powder content and rotation speed facilitate size-induced granular segregation.