Paper Number
AR21 

Session
Applied Rheology and Rheology Methods

Title
Defluidization of cohesive particles on an air-bearing rheometer for estimation of particle-level cohesion

Presentation Date and Time
October 12, 2021 (Tuesday) 1:55

Track / Room
Track 2 / Ballroom 7

Authors (Click on name to view author profile)

1. Shetty, Abhishek (Anton Paar USA, Rheology)
2. Mishra, Ipsita (University of Colorado Boulder, Chemical Engineering)
3. Hrenya, Christine (University of Colorado Boulder, Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Abhishek Shetty¹, Ipsita Mishra² and Christine Hrenya^2
1Rheology, Anton Paar USA, Ashland, VA 23005; ²Chemical Engineering, University of Colorado Boulder, Boulder, CO

Speaker / Presenter 
Shetty, Abhishek

Keywords
experimental methods; granular materials; rheology methods

Text of Abstract
Granular media which includes cohesive powders and bulk solids have to be handled on a regular basis in a variety of industrial applications. Characterization of the flow properties of these powders are of paramount importance when it comes to efficient design and optimization of many industrial operations. Given the abundance of cohesive particles in various industrial applications, accurate prediction of inter-particle cohesion is very important. Inter-particle cohesion plays an important role in various industrial unit operations. However, predicting particle-level cohesion is non-trivial at best. An attractive alternative is bulk measurements from which cohesion can be easily estimated. Recently, particle defluidization was identified as a bulk measurement that can be used to extract inter-particle cohesion (Liu et al., 2018). This method requires direct-coupling of experimental, ‘‘standard” defluidization curves (pressure-drop vs. gas velocity) with discrete-element-method (DEM) simulations; ‘‘standard” refers to defluidization without channeling. Hence, the method is not readily applicable to highly-cohesive (Group C) particles that exhibit channeling. In this work, we obtain standard-defluidization-curves for Group C particles using a rheometer with a rotating impeller. Then, we confirm that the measurements from the rheometer are system-size-independent, thereby ensuring the feasibility of direct-coupling of the experiments with smaller DEM simulations. Furthermore, we show that the torque required to rotate the impeller may provide an alternative to the pressure-drop to characterize particle defluidization. Finally, we show that the extracted characteristic-velocities from these experiments may provide a relative-gauge for particle-level cohesion.