Granular mixing remains an art rather than a science and is a hot research topic in adademia as well as in industry. Granular materials display wide range of behaviour ranging from poor mixing to segregation based on mixer characteristics and operating regimes. Understanding how the materials in these systems mix or separate in response to external forcing is important for designing efficient processing and handling equipment.

Simulations offer several advantages for studying granular flows. Perhaps the most significant is that the state of the particulate system is known at all times in a simulation. Hence, the interior of a flow can be examined and measurements can be made that may be difficult to make in experiments. The insights that these simulations can provide are valuable for understanding how granluar materials behave. Most granular flow computer simulations use discrete element models (DEM). The term "discrete element" refers to the fact that the simulation models the granular material as a system of individual particles.

A horizontal cylinder with rotating blades at the bottoom is one of the most common equipment designs encountered in pharmaceutical manufacturing processes. Such configurations have been employed as mixers as well as granulators. Since such devices operate at much higher RPMs or Froude numbers than some other designs (e.g. tumbling blenders), they are often categorized as high shear devices. This simulation mimics a high shear mixer with dry non-cohesive particulate material (approximated as frictional spheres). Shearing action is provided by a pair of blades at the bottom of the cylinder, oriented at 180 degrees to each other.

Visualization and Animation of High Shear Mixer Output

The High Shear Mixer tool generates a state file describing the particle positions in the mixer over time. Screenshot #4 above shows a portion of the state file generated by the tool for the default parameters (click thumbnail to enlarge). The BenchmarkMixerMovie attached under Supporting Documents was produced by the ParticleVis visualization software using the generated state file as input.

Any state file produced by the High Shear Mixer tool can be be downloaded to your machine from the output screen of the tool following tool execution. The ParticleVis software can be downloaded to your machine from the pharmaHUB resources page.

Researchers should cite this work as follows:

• dsk  ; Avik Sarkar; Carl Wassgren (2014), "High Shear Mixer," https://pharmahub.org/resources/highshrmix.

  BibTex | EndNote

1. Discrete element model (DEM)
2. High shear mixer
3. Particle-based computations
4. Process modeling