Análise da influência de injeção de água sobre o escoamento de ar em um lavador Venturi utilizando Ansys Fluent

Abstract

Computational Fluid Dynamics (CFD) is a tool that simulates internal and external flows by solving models through numerical methods until reaching a predetermined value for convergence, with the advantage of reducing costs and time in data collection. The equipment that was studied was a Venturi scrubber with circular section because it is traditionally used in industries due to its high efficiency in gas scrubbing. Due to the fact that the atomization of the water jet occurs due to the high velocity of the air in relation to that of the liquid and that the fluids flow perpendicularly, the scrubber performance is influenced by factors such as the liquidgas ratio, the pressure drop and the configuration of the water injection holes. The main goal of this work was to check the influence of the liquid inlet on the air flow in a vertical Venturi scrubber with circular section and, for that, simulations were performed using the Fluent software contained in the Ansys Student 2021 R1 package. In the simulations, the gas inlet velocity and the water inlet diameter were kept constant, while the number of holes were varied from 1 to 4 and the liquid inlet velocity values were 4.5; 6.5 and 8.5 m/s; in addition, results were obtained for cases in which there was no water injection, in order to compare the scenarios obtained. Considering the data collected for the same mesh, the greater the number of holes, the bigger the pressure drop obtained and, the higher the water inlet velocity, the greater the pressure drop and the longer the penetration of water. As for the quality of the meshes, their refinement resulted in more accurate results and smoother curves with lower computational cost; thus, better results were obtained in the same range of number of iterations. In view of the results obtained, the scenario indicated would be of 4 holes with water inlet at 6.5 m/s due to better distribution of liquid within the equipment, absence of vortices and higher velocity in the central region of the equipment.