Avaliação numérica do fenômeno de mistura granular no interior de tambores rotatórios

Abstract

Processes involving granular materials are common in chemical industries, whether in drying, heat exchange or mixing operations, and require a deep understanding to design optimized projects and equipment. In this context, rotating drums are extremely important equipment because they have simple geometry, consisting of a cylinder rotating around its own axis, low operating cost and simplified maintenance. Due to these factors, rotating drums are being increasingly used in chemical processes, however, the chaotic nature of particle movement and the complexity of the systems make it difficult to optimize and understand the phenomenon of granular mixing within these equipments. The present study aimed to deepen the knowledge of the degrees of mixing inside rotating drums through imulations using the discrete element method, which calculates the properties of each individual particle in addition to their interactions with neighboring particles and with the system. Numerical tests were performed based on a central composite design where the variables studied were the Particle Size Ratio, varying between 0.2172 and 0.7828 and the Density Ratio, also varying between 0.2172 and 0.7828, based on a particle of radius 0.003 m and density of 2450 kg/m³. The simulations were carried out with the numerical solver LIGGGHTS, software developed for simulations with the discrete element method. Tthe results were visualized with the aid of the PARAVIEW software, in addition the data generated in the simulations were treated with scripts developed in the Python programming language and the results analyzed with the help of Origin and Statistica software. In this way, it was possible to analyze the variation of the standard deviation during the operation of the equipment and analyze that this parameter is linearly influenced by the density ratio and by the combination of factors of the density ratio and the size ratio and calculate the decay coefficient exponential rate of this mixture, finding that it is linearly influenced by the particle size ratio, making it possible to deepen the knowledge about rotating drums.