Experimental Deduction of Restitution Coefficients of Different Sand Sizes in an Inertial Particle Separator System

Abstract Rotorcraft engines frequently operate in harsh environments, ingesting contaminants like sand, dust, rain, and hail, which degrade performance and reduce lifespan. Inertial Particle Separator (IPS) systems are commonly utilized in gas turbine engines, which force particles separated by their inertia. Separated sand value is influenced by various factors, including airflow rate, particle features, surface profile and properties. The current study focuses on the deduction of the Coefficient of Restitution (COR) and its impact on target surfaces under various condition to understand the particle-wall interaction in detail. The tangential and normal components of COR are key determinants of IPS efficiency. A previous study validated aerodynamics and measured separation efficiency in an enginelike test rig. Therefore, the current study aims to experimentally investigate the trajectories of sand particle of varying sizes within an IPS system and estimate their respective COR values. The obtained COR values are intended to be used as input for modelling wall interactions in numerical analyses. The article provides a detailed description of the experimental setup, methodology for COR calculation, and the wall interactions of particles of different sizes. Results indicate that smaller particles, accelerated by airflow, impact the IPS outer dome at farther points, while larger particles experience multiple collisions near the inlet, losing momentum. Smaller particles follow airflow due to aerodynamic forces, whereas larger particles, dominated by inertia, deviate from the flow.