Vol. 15, issue 08, article # 14

Medvedev A. A. Numerical study of aerosol particle sampling from a low-speed flow. // Atmospheric and oceanic optics. 2002. V. 15. No. 08. P. 663-666.    PDF
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Abstract:

Sampling of aerosol particles in a thin-walled tube opposite in direction to an external air flow is studied numerically using a solution of the Navier-Stokes equation, integration of equation of particle motion, and calculation of aspiration efficiency. Of primary concern is the case when the speed of a free air flow is much lower than the mean sampling velocity. It is shown that, when the velocity ratio tends to zero, the aspiration efficiency is determined by particle deposition on the tube walls and depends only on the Stokes number. Based on the calculation results, a semiempirical formula is derived for the aspiration efficiency as a function of the Stokes number and velocity ratio. The results of the calculations and the derived semiempirical formula can be used to choose the regimes of aerosol sampling from ambient air.