AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Characterization of Air Velocity Patterns Downstream of Pleated Filters Using Particle Image Velocimetry (PIV)
SEUNGKOO KANG, Noah Bock, David Y. H. Pui, Jacob Swanson, University of Minnesota
Abstract Number: 541 Working Group: Instrumentation and Methods
Abstract Air flow patterns across pleated filters are affected by a number of parameters such as filter media properties and pleat geometry. Research has been devoted to numerically examining the effects of different pleated filter properties and pleat geometries on airflow patterns in order to develop optimal conditions for pleated filters, minimizing pressure drop and increasing filtration efficiency. Experimental investigation of air flow patterns, however, has only been given a little attention.
Particle Image Velocimetry (PIV) is an experimental technique used to measure velocity fields within fluid flow. In PIV, a laser light sheet is pulsed to illuminate the seeding particles in order for them to be captured by the camera. The computer software tracks particle displacements during the time between two laser pulses, (~10 micro-seconds for this study), to produce instantaneous two dimensional velocity fields.
In this study, a method was developed for characterizing airflow patterns directly downstream of pleated filters using a PIV system consisting of a 200 mJ/pulse Nd:YAG laser, 11 MP digital camera, synchronizer, and computer software operating TSI’s INSIGHT 4G. Seeding particles, approximately equal to the most penetrating particle size of the filter media, were generated and flowed through a pleated filter. Velocity fields near the surface of pleated filters were measured to study the effects of pleat locks and pleat density at different flow rates. The velocity variation with time, as well as the time average of the velocity fields at selected planes along the filter, was determined. Also, the feasibility of using PIV to detect pinholes in filter media was evaluated. The design and experimental results of this study will be presented.