Abstract
An approximate expression for single-sphere collection efficiency due to diffusion and interception was obtained theoretically by using the Tomotika-Aoi flow field around an isolated sphere for viscous flow (NRe<<1).
The coefficients of the expression were experimentally modified to obtain a semi-empirical formula for granular-bed gas filtration, as a function of Peclet number Npe and interception parameter NR. Another empirical expression which took account of Reynolds number NRe as well as Npe and NR was also proposed.
Both expressions not only well described the present experimental data in the range of filtration velocity Us=0.2-20cm/s, aerosol particle diameterDp=0.31-2.0μm and packed granule diameterDc=88-4300μm, but also agreed fairly well with the data reported by several investigators in the diffusion-predominant region.
