Influence of Scavenge Leg Geometry on Inertial Particle Separator Performance

Abstract

An inertial particle separator (IPS) is a particulate removal device typically installed at the inlet of a gas turbine to mitigate effects of sand ingestion on the engine. This system can minimize particulate ingestion during helicopter landings in austere brownout conditions so as to increase engine life. Typically, IPS systems have lower engine power losses than alternative engine inlet filtration technologies. The present study investigates the effect of IPS particle removal and power losses as a function of scavenge leg geometry. Performance was evaluated based on particle separation efficiency, particle image velocimetry, and surface flow visualization, as well as power loss and mass flow rate variations. Of the various scavenge geometries considered, it was found that flow constriction with a hub-side ramp most improved separation efficiency, while also stabilizing mass flow rates and generally reducing power loss. This is attributed to a reduction in the level of flow separation by the addition of a favorable pressure gradient and geometry changes downstream of the attached flow region.