Porosity distribution in random packed columns by gamma ray tomography

Gamma ray tomography experiments have been carried out to detect any spatia l patterns in the porosity in a 0.6 m diameter packed column. Three differe nt sizes of stainless steel Pall rings (16, 25 and 38 mm) have been examine d. The primary objective is to detect spatial patterns and statistical info rmation on porosity variation in packed distillation columns. Such data are needed in the computational fluid dynamics simulators based on volume aver aged equations. Horizontal scans, at different vertical positions of the pa cked bed, were made for each size of Pall rings. A tomographic reconstructi on algorithm has been used to calculate the spatial variation over the colu mn cross section. Radial porosity variation within the packed bed has been determined. The variation of the circumferentially averaged porosity in the radial direction indicates that the porosity in the column wall region is a somewhat higher than that in the bulk region, due to the effect of the co lumn wall. The probability density function for porosity variation has been constructed from the experimental data and it can be represented by a norm al distribution. (C) 2001 Elsevier Science B.V. All rights reserved.