Coalescing filters are effective in removal of aerosols from gas and air streams in many industrial applications. Performance of filters is critically important to improve economy and reliability of process and to protect our environment and health. In coalescing filters captured liquid drains under the influence of gravity. The saturation or liquid hold-up in the filter constricts the flow, increases pressure drop, limits the filter life and increases cost of the process. Filter performance can be enhanced by improving liquid saturation and capture efficiency. To improve filter performance and study the effect of gravity; filter geometries are developed and tested in horizontal and vertical orientation by incorporating woven and nonwoven drainage structures with varying pore structures, basis weight, surface energy and material along with nanofibers in some cases. The drainage channels create a path of lower resistance by allowing maximum flow through the drainage channels which reduces saturation and pressure drop and improves filter performance and drainage. Experimental results, analysis and multiphase modeling of filter media with drainage channels are described in this book.