Aircraft Propulsor Modeling and Design for Boundary Layer
David K. Hall
Massachusetts Institute of Technology
Propulsion with Boundary Layer Ingestion (BLI), where a craft's boundary layer or wake fluid is ingested and re-accelerated by the propulsor, has long been recognized to provide a theoretical propulsive efficiency benefit. A major challenge associated with aircraft BLI is non-uniform flow at the engine inlet, which can lead to decreased engine efficiency, decreased engine stall margin, and increased unsteady force on rotating turbomachinery. This presentation describes a new conceptual framework for three-dimensional turbomachinery flow analysis and its use to assess fan stage attributes for mitigating the adverse effects of BLI. The turbomachinery is modeled in CFD calculations using momentum and energy source distributions that are determined as a function of local flow conditions and an approximate blade geometry. Comparison with higher-fidelity computational and experimental results shows the analysis captures the principal flow redistribution and distortion transfer effects associated with BLI fans, which differ from established models for compressor distortion response. The distortion response is assessed for a range of fan stage design parameters, and the results indicate that circumferential variations in the design of the downstream fan exit guide vanes yield the greatest reductions in flow non-uniformities in the rotor, and may offer the most potential for improved performance with BLI inlet distortion.
Wednesday, January 11, 2017
Seaver Science Library, Room 150 (SSL 150)
Refreshments will be served at 3:15 pm.