The Penetration of Aerosols Through Fine Capillaries

A practical procedure has not been developed and accepted internationally to quantify the leakage of aerosols in tests of radioactivity transport flasks. Hence it is necessary to understand how aerosols penetrate model pathways that have leakage rates close to the limits set by standards of flask integrity. A novel procedure has been developed to study the penetration of particles ranging from 0.5 to 15 μm volume equivalent diameter through capillaries varying from 20 to 80 μm bore and from 10 to 50 mm in length. The penetration of these particles was smaller than expected from a comparison of particle diameter with capillary bore, and showed a linear correlation with flow Reynolds number when both variables were plotted on a logarithmic scale. The lack of particle size dependent penetration was explained in terms of the capillary operating as an aerosol sampler in calm conditions.