Clogging of fibrous filters by liquid aerosol particles: Experimental and phenomenological modelling study

Fibrous filters are the most common means used to separate liquid aerosol particles from an industrial gas stream. The pressure drop and penetration (=1-efficiency) are the most important performance criteria of the filter. In this study, experimental and modelling results describing the pressure drop and penetration evolution of a glass microfibre HEPA filter are presented. For the experimental part, the pressure drop and penetration evolutions of a HEPA filter are described as well as the influence of the filtration velocity on those evolutions. For the modelling part, the physical collection mechanisms taken into account and their mathematical expressions which are the basis of the phenomenological model are described in a first step. After that the experimental values are compared to their modelled counterparts. Different efficiency models from the literature have been tested in order to determine the one closest to the experimental values. The influence of the filtration velocity on the model is studied in the last part. The model presented here is capable of describing the pressure drop and penetration evolution of a HEPA filter over the whole filtration period.     

On the drag coefficient of flat and non-flat solid particles of irregular shapes: An experimental validation study

The very wide varieties of geometries of irregular particles makes it difficult to study their motion also propose a simple and general equation to estimate their drag coefficient (C_D). The goal of this research is to (1) experimentally validate the general C_D correlation previously proposed by the authors of this article as a simple tool to estimate the C_D of spherical to highly irregular particles over a wide ranges of Re from 0.001 to 300,000, and (2) examine and expand the reference model particles proposed by the authors to represent a wide range of irregular shapes (60 non-flat and 36 flat). A comparison between the C_D experimentally measured using reference model particles over a range of Re from 9 to 2481 and the C_D estimated using general C_D correlation, also comparing with C_D correlations by others, demonstrated the accuracy and simplicity of the proposed general C_D correlation.