(238d) Discrete Element Simulation of Particle Mixing and Segregation In a Saddle Blender

Tumbling blenders are widely used for granular mixing operations in many industries such as pharmaceutical, cosmetics and food. These blenders exist in different sizes, are easy to operate and can handle materials with various properties. In particular, the V-blender has been one of the most common tumbling blenders used to mix granular materials in the pharmaceutical industry. One aspect that must be addressed when designing such mixing systems is the axial mixing efficiency, which can lead to nonhomogeneous mixtures, especially when the physical and flow properties of the particles that are brought into play vary.

We recently got interested in the so-called tetrapodal mixing device, patented in 1964 (U.S.A. Patent Office, 3134578), which consists of a container with one axis of rotation going through its center of gravity, one leg extending from it in one direction and three other legs organized as in a tripod and extending in the opposite direction. In other words, it can be thought of as a blender with two V-shaped pairs of legs. Compared to the V-blender, this geometry then has an increased ability to pour, split and recombine powder materials in one cycle, and eventually lead to better (axial and radial) mixing efficiency. The objective of this work is to investigate using the discrete element method (DEM) particle mixing and segregation in both the V- blender and the tetrapodal mixing device, which we have dubbed “saddle” blender. The results obtained will be compared on the basis of mixing time and mixing uniformity, both axial and radial, for different loading patterns, fill levels and rotational speeds.