A Numerical Study of Sand Particle Distribution, Density, and Shape Effects on the Scavenge Efficiency of Engine Inlet Particle Separator Systems

Sand size and shape factor, engine inlet angle to the approaching flow, splitter position, inlet wall rebound characteristics, inlet and scavenge vanes, and struts have pronounced effects on the scavenge efficiency. A numerical study is conducted on the effects of particle shape, density, and distribution at the engine inlet on the scavenge efficiency. Three‐dimensional Navier‐Stokes equations for air and the conservation equations in the Lagrangian framework for particles were solved simultaneously. Sand distribution, density, and shape factor for four engine inlet geometries were varied, and results were compared. Nonuniform distributions with small (large) particles concentrated at the inlet inner radius have the highest (lowest) scavenge efficiency. For random distributions, scavenge efficiency increases with inlet tilt angle, particularly for angles above 10°. Particles smaller than 20 μm are the most problematic as they follow the flowpath to the engine core. Sand density and size have similar influences on the scavenge efficiency, i.e., higher (lower) density particles behave like larger (smaller) particles. However, this effect is noticeable only for particle sizes less than 10 μm. Variations in particle shape factor are only noticeable for particle sizes less than 20 μm. Scavenge efficiencies for particle sizes less than 5 μm are influenced by both increasing and decreasing shape factors, whereas scavenge efficiency for 10‐μm particles is influenced only by shape factors below that for spherical particles.