Experimental and simulation of torque values of large and small particle size powders in Anton Paar Powder Cell using a commercial DEM simulation Software

The flow properties of fine powders at very low consolidation levels are relevant to small scale industrial applications of powder flow, such as in small process hoppers and mixers of pharmaceutical powders, or in everyday applications such as toner flow in cartridges. In addition, many process applications of powder technology involve gas-solids systems, which require the knowledge of flow properties of aerated powders for proper handling. The equipment used in this research project is the state of the art powder cell purposely developed by Anton Paar Company to fit on an Anton Paar rheometer and carry out torque measurements on both aerated and fluidized powders. In this instrument, the state of consolidation of the powder can be adjusted by changing the impeller depth and the aeration rate and different impeller shape and size provided by the company. Two different size of impeller, 10 and 5 mm, were used to measure the torque values of sand, dbp3.2 225 µm, and Alumina dbp3.2 75 µm, at different powder depth. The same conditions were used for the simulation of torque values with EDEM software. Simulation are carried out to understand if the main hypotheses made in the model developed by Bruni et al. are reasonable in this apparatus under the conditions tested and if limiting conditions occur, for example on the relative dimension between 1) the gap available between the impeller and the container wall and 2) the particle size. Test are carried out and compared with different particle sizes, air flow rates and impeller speeds.