INERTIAL IMPACTION OF AEROSOL-PARTICLES ON SINGLE AND MULTIPLE SPHERICAL TARGETS

Inertial deposition of aerosol droplets (diameter: 1 - 14 mum) on stee l spheres (diameter: 3 - 9 mm) was investigated. Air velocity was vari ed between 7 and 28 m/s (corresponding sphere Reynolds numbers: 1400 - 17 000). The impaction on single spheres as well as that on linear ar rays of eight spheres was measured. Theoretical results, based on pote ntial flow investigations were verified by single sphere experiments. Of special interest was the range of lower Stokes numbers, where the t heoretically predicted limit of deposition cannot be verified. The exp eriments on sphere arrays were for the first time performed in the low Stokes number range. Deposition on the leading sphere, relative to th at on the shielded spheres, exhibits a maximum in the high Stokes numb er range, but this changes drastically in the low Stokes number range. Here, maximum deposition can be found on the shielded spheres while t he leading sphere shows a markedly lower deposition.