The applicability of kinetic energy for granular materials at the beginning of the instability process in a rotating drum by means of Particle Image Velocimetry (PIV)

Abstract

This article presents a study of the behavior of granular materials that are subject to a process of instability in a rotating drum. By employing an original procedure, the applicability of kinetic energy as a parameter to measure processes of instability and their relationships with the granulometry of materials and rotating drum’s velocities are evaluated. Certain granulometries are tested in various set-ups in order to capture consecutive images of the process in which the present materials flow into the rotating drum. Image processing is carried out by using the Particle Image Velocimetry (PIV) technique in order to be able to determine the particles’ displacement vectors and velocity fields by using Pivlab, the Matlab toolbox. Subsequently, the kinetic energy is calculated and its applicability is determined through analyzing the variation of this parameter in the processes of instability and its relationship with the granulometry of materials and the velocities of the rotating drum. The trials undertaken as part of this study have determined that there are two types of particle flow: falling and rolling. Moreover, the dependence of the material type on the threshold value of kinetic energy at the beginning of the process of instability was discovered as well as the independence of this parameter from the angle of inclination of the material inside the rotating drum. The results from this research allow for an analysis of the processes of instability in granular materials by means of non-conventional methodologies