Flow in Two-Dimensional Model Filters

Abstract

Model filters consist of cylindrical collectors of diameter 2a spanning the gap 2s between parallel walls. This paper presents a theoretical flow model based on the unit cell approach of Kuwabara and Happel but accounts for the channel walls in an approximate way. When a/s » 1, as is the case for most model filters, the pressure drop significantly exceeds that due to the channel walls alone, or that due to the cylinders alone in fibrous media. The present calculation is in good agreement with Yoshida and Tien's measurements for filters with hexagonal arrangement of the cylinders of solids fraction 0.675 and a/s = 15.6. Channel walls may also influence capture efficiencies and penetrations for model filters.