Estimates of powder flow properties at low consolidations from the torque measured in a powder rheometer equipped with a cylindrical impeller

The equipment used in this research project is the Powder Cell unit purposely developed by Anton Paar to fit on Anton Paar Rheometers and to carry out torque measurements on aerated and not aerated powders. In this instrument, the state of consolidation of the powder can be adjusted by changing the impeller depth and the aeration rate. A cylindrical impeller geometry has been tested on a number of free flowing as well as slightly cohesive powders. A simple model was developed to relate the measured torque with the effective angle of internal friction in the powder measured with a standard powder shear tester. The results indicated a good match between the effective angle of internal friction measured with the instrument and those measured with the conventional shear cell in the range of consolidation tested.