New experimental studies to directly measure aspiration efficiencies of aerosol samplers in calm air

摘要: Abstract Typical air movements in many indoor living and working places are as low as, or less than, 0.1 m / s , so conditions might best be described terms of calm, opposed to moving air—or perhaps some combination the two. However, history aerosol sampling science has been dominated by studies aspiration efficiencies devices air, there have very few definitive calm sampling, even for simple systems. With this mind, paper sets out basis development a larger body experimental work, describes an method which unambiguous measurements may made range systems (i.e., shape orientation). The method, referred “direct method”, owes much ‘thread-of-droplets’ approach proposed Lipatov et al. (J. Aerosol Sci. 17 (1986) 763) efficiency air. In new monodisperse large droplets olive oil with aerodynamic diameter from 40 70 μm were generated using vibrating orifice generator controlled carefully that well-defined, vertically-falling droplet stream was obtained. By application appropriate tracking apparatus, visual observation used map pattern particle trajectories near given inlet identify limiting order calculate efficiency. initial carried upwards-facing thin-walled tubes, results found satisfying agreement numerical Agarwal Liu (1980, Am. Ind. Hyg. Assoc. J. 41 (1980) 191) Yoshida (Kagaku Kogaku Ronbunshu 4 (1978) 123). study provide confidence now applied wider