An improved single droplet collection efficiency for the intermediate flow regime

Abstract

An improved single droplet collection efficiency model for the intermediate flow regime is presented in this paper, taking into account both inertial impaction and interception mechanisms. This model uses the equations of motion that has been derived by performing a force balance on a particle interacting with the flow field of a spherical collector. The fluid flow field around the collector is assumed to be the approximate solution as developed by Hamielec and Johnson for Reynolds numbers ranging between 10 and 80 and Tomotika and Aoi for Reynolds numbers less than 1.0. The results of this work indicate that the collection efficiencies calculated by using potential flow conditions may have overestimated the overall collection of particulate matter. It was identified that the transition from intermediate to potential flow occurs when the Reynolds number is about 80. The interpolation scheme for the single droplet collection efficiency proposed in this work can be used from Stokes flow to potential flow conditions including intermediate flow regime.