A Fluid Dynamic Study in a Rotating Disk Applied in Granulation of Fertilizers

In fertilizers industries the granulation is an essential operation to form pellets with good quality. The granular product has improved handling, hardness, solubility, resistance to segregation and meets requirements such as the size, shape and particle size distribution through appropriate manipulation of the process variables. There are several types of granulators, however, this work is intended to study a granulator known as rotating disk, which promotes agitation of the particles by rotating around its axis. Although these devices are used industrially, cannot be found in the literature many details about the fluid dynamics in these operations. To study the fluid dynamics behavior of these particles on a rotation disk was analyzed the variables: rotation axis and filling degree. It was verified the existence of flow regimes which depends on these variables: rolling, cascading and centrifugation. Also, it was evaluated the dynamic angle of repose, that characterizes the rolling regime. This work aimed to obtain results of fluid dynamics that describe the behavior of solids flowing in a rotating disk. Thus, to meet the objectives of this work, simulations was carried out through the techniques of Computational Fluid Dynamics (CFD) and Discrete Element (DEM) to evaluate different parameter values: restitution coefficient (η), friction coefficient (μ) and the coefficient of elasticity (k) of the linear model "spring-dashpot" to find a good set of parameters that characterizes this system.