Migration of Liquid Drops on Fibers in Nonwoven Fibrous Filters: Effect of Fibers, Fluid Flow and Orientation

The study of liquid drop migration on fibers is significant to many industrial applications (automotive, chemical, textile) and in particular to coalescence filtration of liquid aerosols. Liquid drop migration effects the saturation of liquid in a coalescing filter and determines pressure drop. It is important to design a self cleaning filter, whereby the liquid droplets are collected by the filter and drain out of the filter. An underlying need for all these applications is a reliable method to estimate the rate of liquid motion through the filter. This can be done by defining and determining a drag coefficient for movement of liquid drops on fiber surfaces. This book provides a summary of research results to determine drag coefficient correlations from experiments and models for axial and transverse air flow conditions. The experiments are conducted for different types of fibers and include the effects of an applied acoustic field. Correlations to predict the probability of the motion are also developed considering the effect of acoustic fields. These correlations are a unique approach to determine the velocities of the liquid drops on fibers for different fiber orientations.