Numerical Simulation of Particulates in Multistage Axial Compressors

Aircraft engines ingest airborne particulate matter, such as sand, dirt, and volcanic ash, into their core. The ingested particulate is transported by the secondary flow circuits via compressor bleeds to the high pressure turbine and may deposit resulting in turbine fouling and loss of cooling effectiveness. Prior publications focused on particulate deposition and sand erosion patterns in a single stage of a compressor or turbine. This work addresses the migration of ingested particulate through the high pressure compressor (HPC) and bleed systems. This paper describes a 3D CFD methodology for tracking particles along a multistage axial compressor and presents particulate ingestion analysis for a high pressure compressor section. The commercial CFD multiphase solver ANSYS CFX® has been used for flow and particulate simulations. Particle diameters of 20, 40, and 60 μm are analyzed. Particle trajectories and radial particulate profiles are compared for these particle diameters. The analysis demonstrates how the compressor centrifuges the particles radially toward the compressor case as they travel through the compressor; the larger diameter particles being more significantly affected. Nonspherical particles experience more drag as compared to spherical particles, and hence a qualitative comparison between spherical and nonspherical particles is shown.