Numerical analysis of similarities of particle flow behavior in stirred chambers
Granular shear flows in chambers with rotating shafts are ubiquitous in manufacturing processes for numerous industries such as pharmaceuticals, food, and cereal processing, wherein flow homogeneity is critical to maintain product quality. In this work, Discrete Element Modeling (DEM) was used to study flow behaviors of rice particles using the special stirred chambers. The non-geometric similar chambers equipped with a regular polygon sieve and a roller shaft are used as simulated stirred chambers. This work’s goal was to establish a similarity rule of the particle flow behaviors among these chambers. The gap between the shaft and the sieve periodically varies from maximum to minimum when the chamber is in work, which forms the gap curve. The kinematic flow behavior evaluated in this work were normalised velocity, normalised tangential velocity, radial velocity and radial distance distribution of particles. The dynamic flow behavior evaluated in this work was the particle collision energy. The DEM results were used to compare the kinematic and dynamic flow behaviors for the different chambers. The results indicated that both kinematic and dynamic flow behaviors were similar among chambers with the same gap curve. From these results and analysis, an empirical similarity rule of particle flow behavior, that is, the constant gap curve, was developed. Meanwhile, the effectiveness of the proposed similarity rule is experimentally confirmed. These findings are useful to understand and control the operational performance of the similar stirred chambers.
Keywords: Discrete element method, Stirred chamber, Kinematic similarity, Dynamic similarity,