-In previous work, it was observed that the covering of soybean seeds with bacteria and micronutrients enhances vigorous growth of the plant thereby avoiding use of ammoniacal fertilizers. In the spouted bed covering can be done by pulverization of the coater slurry on the soybean seeds using a pneumatic atomizer. The optimum thickness of the cover allows the fundamental gaseous interchanges for germination and provides the ideal conditions for bacterium activity. The objective of this work was to study the influence of the process variables on thickness of the cover. A simulation of the mass distribution of seeds was obtained using a population balance model. Through the results obtained the operational conditions under which the coating layer distribution were determined has the greatest uniformity.
Turbulent flows in concentric and eccentric annuli with and without rotating inner cylinder were investigated by numerical simulations. Similar flows occur in drilling operations of oil wells. Several turbulence models with Reynolds Average Navier-Stokes approach were used in the simulations and the respective models predictions were compared with experimental data from the literature. The simulated results of axial and tangential velocities show a good agreement with the experimental data. As compared with another turbulence models, the simulations with the standard Reynolds Stress model presented a slightly better prediction for most of the responses studied.On a analysé des turbulences en espaces annulaires concentriques et excentriques avec ou sans cylindre interne tournantà l'aide de simulations numériques. Desécoulements semblables se produisent lors d'activités de forage de puits de pétrole. Plusieurs modèles de turbulence avec l'approche de Navier-Stokes en moyenne de Reynolds ontété utilisés dans les simulations et les prédictions respectives des modèles ontété comparées aux données expérimentales de la littérature. Les résultats simulés des vélocités axiales et tangentielles cadrent bien avec les données expérimentales. Comparativementà d'autres modèles de turbulence, les simulations avec le modèle de tension de Reynolds standard ont présenté une prédiction légèrement supérieure pour la plupart des réponsesétudiées.
Facing the challenges to develop more efficient solar dryers, this work used the Computational fluid dynamics (CFD) to test different configurations of lateral air feeding in a fixed bed solar dryer. Through the simulations, it was found the best configuration of air inlet that provided a better fluid-particle contact. It was made a fixed bed solar dryer, which was tested using soybeans seeds and Moringa oleifera LAM leaves to evaluate the drying rate using two bed configurations: fully opened and partially opened inlets. The CFD results indicated that the air flow rate was more pronounced at the bed top, near the exhaust fan. This can explain the poor drying near the bottom for the experiments performed with all lateral inlets opened. According to the simulation results, the air velocity profile was more homogeneous when the air was fed only near the bottom. So, the use of a partially opened configuration led to a more homogenous solar drying, with a drying rate about 300% higher than the one using the fully opened inlets.
-Helical flow in an annular space occurs during oil drilling operations. The correct prediction of flow of drilling fluid in an annular space between the wellbore wall and the drill pipe is essential to determine the variation in fluid pressure within the wellbore. This paper presents experimental and CFD simulation results of the pressure drop in the flow of non-Newtonian fluids through a concentric annular section and another section with fixed eccentricity (E = 0.75), using aqueous solutions of two distinct polymers (Xanthan Gum and Carboxymethylcellulose). The hydrodynamic behavior in this annular system was analyzed based on the experimental and CFD results, providing important information such as the formation of zones with preferential flows and stagnation regions.
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