Fabric filter performance of helicopter inlet barrier filters

An inlet barrier filter system is integrated into the intake of a helicopter to perform the task of removing potentially harmful particles from engine-bound air. While performing a vital duty in the prolonging of engine life, their use may incur a loss of engine performance as a result of the pressure loss that is synonymous with air passing through a porous barrier. Furthermore, as particles collect on the filter they pose additional restriction to the flow of air, causing the pressure drop to increase over time. It is the objective of the present work to propose a low-order model to predict this transient pressure loss, in order that the performance of helicopters operating with inlet barrier filters may be analyzed. The contribution includes a model to predict the temporal separation efficiency of a woven fabric filter and the temporal change in pressure drop due to the buildup of particles on the filter. © 2012 The American Helicopter Society.