Single stage centrifugal air sampler: a theoretical and experimental approach for cut-off size (d50) evaluation

This work focuses on the study of the particle sampling efficiency of a small single stage centrifugal air sampler under different air sampling flow rates and particles diameters. The centrifugal force perpendicular to the mean airflow motion within the circular cavity is opposed to the viscous one, which depends on the particle aerodynamic diameter. The particles hitting the outer surface of the sampler stick on it and are trapped. Experimental tests have been done for the lowest particle size sampled by the instrument, usually called d 50 or cut-off size, at different air sampling flow rates. Experimental results for particle´s diameters higher than 2 µm agree quite well with those obtained by the theoretical model and by computational fluid dynamics simulations. Furthermore, it has been shown how the particles sampling efficiency of the instrument increases with the airflow rate.