Novel Inlet Protection System for Auxiliary Power Units using Boundary-Layer Momentum Transfer Technology

Ingested particulates, especially sand, severely degrade performance and increase wear in small gas turbine engines used in helicopter auxiliary and secodary power units. Existig Inlet Particle Separator (IPS) systems based on Bortex tube designs have two major limitations: their efficiency decreases with the size of particulate matter, and they are difficult and expensive to retrofit in existing APU/SPUs. The objectives of this project are to develop and assess a novel IPS system based on a boundary-layer momentum transfer concept that will greatly improve the efficiency of particle removal while operating within the performance and spatial parameters of existing APU/SPus. Prior research has shown this technique to be very efficient at removing particulates from unconstrained gaseous streams. The thrust of Phase I research is to use computer simulation modelling to analyze the trade-offs between particle removal efficiency, pressure loss, airflow, size and weight of an IPS that can be adapted to existing APU/SPUs. The resulting criteria will be used to evaluate production/retrofit costs and to create a preliminary IPS design emphasizing the higest efficiency for the lowest cost and size. Subsequent development, fabrication and testing of a prototype in phase II will confirm the efficiency and airworthiness of the novel IPS. thrust of Phase I research is to use computer simulation modelling to anal