Dynamic testing provides a range of empirical measurements that entail measuring the energy expended when rotating a blade through a column of powder, to assess cohesive behaviours and flowability. The rate and direction of rotational and axial movement of the blade are chosen depending on the requirements of the test.
Basic flow energy is the energy required to drive the blade down through a conditioned column of powder in a confined situation.
Specific energy is the energy required to lift a rotating blade through a column of powder in an unconfined situation.
The ability to easily perform cycled dynamic measurements on a single sample make it possible to identify changes in flow energies that can provide indications of either particle attrition, caking or segregation behaviour.
Measuring powders in this way has additional unique benefits in enabling the characterisation of powder behaviour in more complex situations, such as during aeration.
In an aeration test, jets of air are passed through a powder column at increasing flow rates as the powder's flow energy is measured.
As the air attempts to find the path of least resistance through the powder, it can disrupt weak cohesive forces thereby reducing the measurable flow energy, giving an indication of the strength of these cohesive forces, and the powder's sensitivity to aeration.
If you would like to learn more about these methods, please feel welcome to contact us at lab@rheologylab.com
[ Ссылка ]
A big thank you to Freeman Technology for giving us permission to borrow a few copyrighted clips from their video “Mechanisms that Contribute to Powder Flow”.
