Theoretical modeling of filtration by nonuniform fibrous filters

Modeling commercial filter media using classical theories results in incorr ect filter pressure drop and efficiencies and this is attributed to media i nhomogeneity. The use of an arbitrary inhomogeneity factor is seen to be in adequate in accounting for the effect of operating conditions on the perfor mance of inhomogeneous filter media. A simplistic theoretical modeling appr oach is described here to account for the variations in filter packing dens ities and to estimate their effect on the media particle capture characteri stics, The theoretical modeling results are used in obtaining an equivalent filter packing density distribution from media local efficiency measuremen ts, Considering this variation in the theoretical models is seen to result in better prediction of media performance over a wide range of operating co nditions. The observed deviation of experimental efficiencies from the theo ry at smaller Peclet numbers can be explained from the results of the theor etical analysis.