Rotating drums have been studied in the pharmaceutical industry for a long time. Flows in rotating drums are divided into distinct regimes:

• Rolling regime: Powder on the surface cascades down the incline and powder at the bottom rotates with the drum.
• Slumping regime: Back and forth rocking motion of the bed is observed.
• Cataracting regime: Powder may avalanche periodically at higher rotation speeds.
• Centrifugal regime: At very high rotation speeds, powder is plastered to the outer edge of the drum, with no relative motion.

The flow regime is a strong function of the Froude number (dimensionless rotation speed, scaled with gravity and drum diameter) and the friction between the powder and the drum wall.

A rotating drum is one of the major systems studied in granular regimes, since it serves as a good characterizatin system for powders. Discrete Element Models (DEM) are able to accurately reproduce experimental results in all the flow regimes.

Visualization and Animation of Rotating Drum Output

The Rotating Drum tool generates a state file describing the particle positions in the drum over time. Screenshot #3 above shows a portion of the state file generated by the tool for the default parameters (click thumbnail to enlarge). The BenchmarkDrumMovie attached under Supporting Documents was produced by the ParticleVis visualization software using the generated state file as input.

Any state file produced by the Rotating Drum 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.

Professor Carl Wassgren
Avik Sarkar
Mechanical Engineering, Purdue University

If you reference this work in a publication, please cite as follows:

• Sarkar, Avik; Wassgren, Carl;   , dsk (2008), "Rotating Drum," http://pharmahub.org/resources/rotatingdrum?v=76.

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