Performance Prediction of Inlet Barrier Filter Systems for Rotorcraft

This contribution addresses the performance of Inlet Barrier Filter Systems (IBF) for rotorcraft with respect to IBF Design. IBF are fitted to rotorcraft to extract potentially harmful particles from engine-bound air. However, whilst protecting the engine from erosion and other damage, installation of an IBF incurs a loss in static pressure that is of detriment to the engine’s performance. The inherent pressure drop across an IBF can be curtailed somewhat by pleating of the filter surface, but phenomenological effects that arise in the flow at high pleat density limit the extent of this action. The result is an optimum pleat shape for a given filter medium in a given flow. This contribution investigates the optimisation process for IBF with respect to IBF performance, which is assessed through three identified factors: pressure drop, capture efficiency and filter holding capacity; and makes provision for IBF Design in order that the IBF may be of maximum benefit to the engine.