Navegando por Autor "Mateus, Felipe Leonardo Barcelos"

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Evaluation of species transfer models in the cfd simulation of fixed bed soybean drying
(Editora UFLA, 2021) Mateus, Felipe Leonardo Barcelos; Faria, Mauro Magalhães Leite; Petri Junior, Irineu
The drying is fundamental to the preservation of materials, particularly food, which is sensible to damaging related to moisture because of its hygroscopic nature. The drying increases the shelf life of these products and reduces their overall weight, which facilitates the logistics and aggregates value to the product. Computational Fluid Dynamics is a potentially facilitating tool for the analysis of drying variables, such as velocity, air temperature, and particle temperature, which have great influence on the drying rate. This work aimed at studying different numeric models for the simulation of a fixed bed drying operation, analyzing the influence of the equilibrium ratio and water diffusivity in the solid on the results. The computations were made in the software FLUENT 19.2, using the Multiphase Eulerian Granular Model with packed bed configuration and different mass transfer models: Constant, Species-Con stant, Species-Sherwood, Ranz-Marshall, and Hughmark, as well as heat transfer models: Constant Heat Transfer Coefficient, Constant Nusselt Number, Ranz-Marshall, and Hughmark. The mass transfer models with the best performance were the Ranz-Marshall and Hughmark models. A strong influence of the equilibrium ratio was observed for both models, and a moderate influence of the water diffusivity. The influence of equilibrium ratio and water diffu sivity was not observed for the other models. The heat transfer models did not present expressive difference, and the system reached thermal equilibrium quickly. The overall study of the models and the influence of different parameters was effective, and was able to document the obtained results for future optimization and further investigation of the numeric model.
Modeling effectiveness analysis of momentum and heat transfer in a fixed bed silo-dryer through computational fluid-dynamics
(Editora UFLA, 2021) Mateus, Felipe Leonardo Barcelos; Petri Júnior, Irineu
The drying procedure is of great use in the industry, being capable of increasing the shelf life of many products, in addition to facilitate its transport and storage. The operation is essential for coffee beans to remove their excessive moisture content. The silo-drier has potential to ensure sensorial qualities through the intermittent drying, as well as with optimizations in the energy consumption. The objective of this work was to study the optimization of the numeric representation of a silo-dryer system, comparing the results of three different models available in the software FLUENT® 19.2: Eulerian Multi phase Model for Granular flow with packed bed configuration disabled, the same model but with the packed bed configuration enabled, and the porous zone single-phase modelling. The convergence efficiency of these models was also analyzed through the results of the numeric residue, and the influence of the relaxation factor in the simulation results. The behavior of solid volumetric fraction, air velocity and bed temperature were qualitatively examined with hot air at the inlet. It was found that the momentum relaxation factor influenced the results. Moderately lower factors allowed for faster convergence without significant particle behavior change. Monitoring the mass residue, the enabled packed bed modelling presented lower residuals, while the porous zone modelling presented higher residuals. The packed bed and porous zone modelling reported lower air velocities in comparison to the disabled packed bed modelling, and presented satisfactory heat transfer through the temperature profiles.