DESIGN, NUMERICAL SIMULATION AND EXPERIMENTAL EVALUATION OF AN INERTIAL IMPACTOR USED TO COLLECT ATMOSPHERIC AEROSOLS / PROJETO, SIMULAÇÃO NUMÉRICA E TESTE EXPERIMENTAL DE UM IMPACTADOR INERCIAL EM CASCATA PARA AMOSTRAGEM DE AEROSSÓIS ATMOSFÉRICOS

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Impactors are simple devices in which a sample flows of air and pollutants flow around an obstacle, called impaction plate. Particles with sufficient inertia will slip across the flow streamlines and impact on the obstacle. Particles with less inertia will follow the airflow away from the impaction surface. Inertial cascade impactors have more than one impaction area. Each one has an impaction plate and a nozzle plate. From one stage to the other, the nozzle diameters become smaller and, consequently, the velocities are higher. This allows for the collection of smaller particles. The challenge is to design an instrument with the higher collection efficiency as possible, reducing wall losses, recirculation regions and other effects. In this study a 3-stages inertial cascade impactor was designed and tested. The cut-point aerodynamic diameters for each stage were 10, 2.5 and 1 (mi)m, respectively, when operating with a flow rate of 30 l/min at atmospheric pressure. To evaluate the instrument, some numerical simulations were performed. They provided results for the flow field, particle trajectories and the collection efficiency curves. Experimental tests were also done to allow for the determination of the real efficiency curves. The numerical and experimental data were compared. Finally, the conclusions of the work and recommendations for future studies are presented.

ASSUNTO(S)

simulacao numerica impactor numerical simulation impactador testes experimentais aerosol aerossol experimental tests

ACESSO AO ARTIGO

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