Avaliação da dinâmica granular no interior de tambores rotatórios com suspensores

Abstract

Rotary drums are widely used in industry due to their geometric simplicity and operational versatility, being applied in processes such as mixing, drying, and granulation. However, these systems present limitations associated with particle segregation, influenced by properties such as size, density, and shape. In this context, the use of internal flights emerges as an alternative to intensify particle interaction and promote greater homogenization, especially in the active region of the drum. Despite this, the effects of flight geometry on granular dynamics are not yet fully understood. Thus, this study aimed to experimentally and numerically evaluate the influence of the angles (α1 and α2) and segment lengths (l1 and l2) of the flights on particle loading and distribution. A Central Composite Design (CCD) was employed, considering as response variables the last unloading angle (LUF), solids holdup in the flights (SH), mass in the active phase (MAP), and the coefficient of variation of particle distribution (DSH), obtained through image analysis. The mixing index (IM) was evaluated based on simulations using the Discrete Element Method (DEM). The results showed that flight geometry directly influences system behavior. Increasing α1 reduced SH, while α2 showed an opposite trend. Segment lengths affected the formation of the particle curtain and the homogeneity of particle distribution, reflected in MAP and DSH. LUF showed lower sensitivity to geometric variations, occurring within a characteristic angular range. Particle physical properties also influenced the results, affecting both loading and dispersion. The comparison between experimental and numerical results showed good agreement, demonstrating the ability of the DEM model to represent the system behavior, acting as a digital twin. In addition, the mixing index analysis showed that the presence of flights enhances homogenization, promoting greater particle interaction and reducing segregation effects. Thus, this study contributes to the understanding of granular dynamics in rotary drums with flights and provides support for the optimization of these systems in industrial applications.