Estudo numérico dos regimes de escoamento no interior de tambores rotatórios

Abstract

Rotary drums are widely used in industries, especially in the pharmaceutical, fertilizer and food sector, and in unit operations such as drying and mixing. These equipments are known for having relatively simple geometry, being composed of a cylindrical structure that rotates around its own axis, moving the particles inside it. However, the behavior of these particles is not simple, requiring a study of their flow regimes in order to understand the most suitable conditions for each application, verifying the influence of variables such as drum rotation speed, particle diameter and density, drum diameter and length and degree of filling. To understand the operation of the equipment, simulations were performed applying the Discrete Element Method (DEM) using the numerical solver LIGGGHTS 3.8, a free software for modeling granular material, from a cylindrical geometry built using Gmsh 4.9. The results were analyzed qualitatively using the free software for interactive scientific visualization ParaView 5.8.1, and quantitatively using the Python 3.8.6 programming language, for graphics customization, and statistical analysis through the Statistica 7.0 software. With the results obtained, it was possible to understand the behavior of five flow regimes (avalanche, sliding, cascading, cataracting and centrifugation) as a function of rotation speed. Furthermore, it was found that properties such as particle diameter, drum diameter and degree of filling influence the flow regimes through the critical centrifugation speed. It was possible to verify that changes in particle density and changes in drum length do not present significant changes in flow regimes.