REALISTIC MODELING OF THE BEHAVIOR OF FIBROUS FILTERS THROUGH CONSIDERATION OF FILTER STRUCTURE

A new model is proposed to describe the effects of structural inhomoge neities in fibrous filters on pressure drop and particle collection. T he filter is subdivided into a series of elements with different struc tural characteristics, defined by local directionally-dependent permea bilities, and the resulting three-dimensional flow field is calculated . Using published relationships, local particle collection is calculat ed. Spatially nonhomogeneous fibre distribution is shown to play a dom inant role. The difference in fibre collection efficiency between a re al and a homogeneous filter depends on the dominant mechanism transpor ting particles to the fibres. In the interception-inertia range, the p redictions are verified quantitatively by measurements on industrial f ilters with characterised structure.