Effect of Rotating Cylinder on Mixing Performance in a Cylindrical Double-Ribbon Mixer

Abstract

Uniform mixing is highly essential in the food manufacturing, pharmaceutical, chemical, and cement industries. However, based on the various process requirements, these industries use different mixers to achieve their commercial outputs. Most of these industries rely on sample-based verification of the mixing index, which may not produce accurate results. Adopting a non-sampling mixing index method is more accurate. In this study, we used the discrete element method (DEM) to simulate the mixing of multiple components contained in a typical commercial whey protein mixture. An effective non-sampling mixing index, the subdomain-based mixing index (SMI), was incorporated to assess the mixing levels. The main motivation for this study was to acquire a high mixing index in the least possible mixing time to boost the manufacturing rate. For this purpose, a half-filled cylindrical double ribbon mixer was simulated, and the SMI outputs are presented for the following four cases: (1) rotating ribbon, (2) rotating cylinder, (3) rotating cylinder with a static ribbon, and (4) rotating cylinder and ribbon. For the given simulation conditions, the SMI values ranged from 0 (segregation condition) to 0.91–0.94 (fully randomly mixed condition) within a time range of 0–60 s.