(598e) Measurement of the Axial Dispersion Coefficient in a Rotating Cylinder: Dependence On Material Properties

Rotating drums are encountered in numerous industrial applications, e.g. calciners, impregnators, coaters, cement mixers, etc.  In all of these devices, the rotation of drum is used to engender mixing of the granular material in the radial direction.  Axial mixing, despite its significantly lower rate, can also have an impact on the process performance, especially when residence time control is essential.  Typically, the particle dynamics in rotating drums are quantified as a function of process conditions, such as rotation speed, fill level, and cylinder size, as well as particle properties – usually limited to the characterization of particle size. 

In this work, the quantification of the axial particle dynamics has been expanded to include bulk flow properties.  Fick’s law is used to describe the axial dispersion behavior of the particles.  Therefore changes in behavior can be characterized using the axial dispersion coefficient.  A method has been developed to measure the axial dispersion coefficient and correlate it to bulk particle flow properties, such as cohesion.