Characterisation of particle suspensions by spectral extinction: A numerical study

A numerical investigation has demonstrated the feasibility of using optical density measurements at several wavelengths to characterise particle size distributions. The technique can be applied to particle size distributions having a mean size parameter in the range 2<µ<16 and standard deviation s<2. Using wavelengths in and near the visible spectrum, this covers particles having diameters in the range 0.05 µm to 25 µm. In this method, the solution does not assume a form for the shape of the particle size distribution, but a log normal size distribution is assumed initially to estimate the range of particle sizes present and to supply an initial estimate of the shape of the particle size distribution. Monomodal distributions and other distributions of large particles were reproduced accurately. Bimodal distributions of small particles were reproduced less precisely but, in terms of particle volume, reasonable accuracy was obtained. © 1991.