Analysis of Filter Performance as function of Particle Diameter, Filter Internal Surface and Filter Pore Size Distribution

Abstract

It is well known that filter performance drops to a minimum corresponding to a particle diameter that is a characteristic of each filter. We analyse this behaviour in light of two competing trends: adhesion of particles onto the internal surface and particle trapping at the interstices. The calculations show that particle adhesion to the internal surface decreases with particle diameter while particle trapping becomes less effective as particle diameter decreases. Therefore, the filter efficiency is found to have a minimum corresponding to a specific particle diameter that depends on the filter internal surface area and on the filter pore size distribution. Filter efficiency is found to drop significantly at a time corresponding to filter half lifetime.