Measurement of particle adhesion force and effective contact radius via centrifuge equipped with horizontal and vertical substrates

A comprehensive review of characterization techniques for particle adhesion and powder flowability

The study of the flow properties of particles is crucial because it directly impacts the efficiency and product quality of various industrial particulate processes, such as continuous manufacturing of solid oral dosages. However, challenges arise due to the flow behavior of cohesive particles, which tend to adhere to surfaces or other particles, necessitating careful process design. The importance of selecting appropriate measurement pathways for accurate characterization has been overlooked. In response, an overview of measurement technologies for surface energy and cohesive/adhesive forces is provided in this work, aiming to establish a practical guide. Understanding these forces is crucial for optimizing continuous manufacturing processes to effectively mitigate flow-related issues such as obstructions, segregation, irregular flow, and flooding. Furthermore, various methods characterization experiments were conducted and compared to illuminate the methodological disparities. This analysis provides valuable insights into particle adhesion, cohesion, and powder flowability, potentially enhancing industrial particulate processes development.

Kinetic adhesion test to determine particle surface energy

A new hardware is described to quantify the particle surface energy by assuming that the Johnson Kendall and Roberts theory of elastic-adhesive contacts is applicable. The setup is used in the active section of the measurement, where newly designed elements provide the sharp impact needed to detach the particles under the action of their own kinetic energy. It employs a selection of sensors to provide the necessary measurements in a streamlined procedure, which lets the user complete one test in less than one minute. The temporal resolution is 1μs for the contact time measurement and the velocity has a repeatability of 1%. The surface energy is a significant parameter for the characterisation of particulate materials and is widely used in Discrete Element simulations of the bulk behaviour.