Estudo experimental e numérico de um alimentador Venturi aplicado ao transporte pneumático de sólidos

Abstract

The Venturi feeder has its function based on the Venturi effect, which consists of the suction of solids, caused by the pressure difference between the external environment and the interior of the equipment. In view of the importance of this device for the industry, it is necessary to understand the behavior of the gas-solid flow inside it. The experimental study of different geometric configurations and mass flows, generally requires a lot of financial resources and does not present a high level of detail. Therefore, numerical techniques, such as computational fluid dynamics, known as CFD (Computational Fluid Dynamics), have been widely used in order to predict better operating conditions and optimum geometric configurations for the best solid-gas flow inside. Therefore, this work aimed to evaluate the angle of divergence in a Venturi feeder using the CFD tools. Air flow and velocity fields were determined by the commercial package Ansys CFX®. In the simulations, a uniform distribution of the gas velocity in the feed and absence of particulate solids was considered. In the particle feed section, an input speed of 0.0055346 m / s was defined. The results showed that the velocity profiles of the gas phase, simulated and experimental, had good agreement between them, validating the computational technique applied. Reverse flow was observed in the upper half of the tube downstream from the Venturi. When evaluating the influence of the angle in the divergent channel, it was possible to infer that by increasing the angle of divergence, the reflux of particles in the feeder decreased. For this air reflux to cease to exist, a very long channel length would be necessary. In this context, the use of CFD proved to be useful to understand the flow inside the Venturi feeder at various angles of divergence, thus ensuring an improvement in its operation.