Avaliação numérica da influência de modelos de turbulência e qualidade de malha sobre o transporte pneumático de biomassa

Abstract

Pneumatic conveying, a unitary operation widely applied in industry, refers to the movement of bulk particulate materials through pipes by means of a gaseous fluid, which can occur in both horizontal and vertical directions. The process is based on the creation of a pressure gradient generated by equipment such as fans, blowers or compressors, which drives the solid phase along the transport line. This system is particularly common in chemical, energy and food industries, being used to transport biomass and other materials to storage silos, reactors, gasifiers or boilers. The choice of transport fluid generally falls on atmospheric air, due to its availability, reduced cost and safe handling characteristics. The present study aims to evaluate the influence of topological factors of the computational mesh and the performance of different turbulence models on the accuracy of pneumatic transport simulations. The complexity of flows, especially in dense and dilute phase regimes, requires a careful analysis of the independence and quality of the mesh, in addition to a correct choice of turbulence models. To this end, numerical simulations were carried out using the Computational Fluid Dynamics (CFD) technique, implemented in the SALOME software. The analysis of the results was conducted with the aid of the Paraview software, focusing on qualitative and quantitative parameters, aiming for a detailed interpretation of flow patterns and interactions between the fluid and particulate phases. During the work, mesh independence tests were carried out, which allowed the definition of an intermediate hexahedral mesh as the most suitable, both in terms of precision and computational efficiency. Choosing a quality mesh is critical to adequately capture physical phenomena, especially in pneumatic flows that present complex transitions between dilute and dense phases. Furthermore, the study compared two widely used turbulence models, k-ε and k-ω, whose intrinsic characteristics make them suitable for different flow regimes. The analysis revealed that the k-ω model presented better performance, especially in the dense phase, due to its ability to deal with highly non-linear and complex flows, a characteristic present in pneumatic transport systems. The relevance of this study lies in the optimization of mesh parameters and the careful choice of turbulence models, contributing significantly to the advancement of understanding of the behavior of flows in pneumatic transport.