CFD Performance Predictions of a Serpentine Diffuser Configuration in an Annular Cascade Facility

摘要

Modern serpentine diffusers are a key enabling technology for next generation aircraft. These diffusers are compact with highly curved surfaces that create distorted flowfields which are ingested by embedded propulsion systems. Fundamental research into the generation and content of such distortion patterns is necessary to better understand the full-scale inlet conditions for the engine. In this effort, CFD simulations were used to study the flowfield of a serpentine inlet diffuser configuration and support experiments performed in an Annular Cascade Facility. Qualitative flow analysis was completed on the steady, time-averaged, and unsteady flowfields using various flow visualization techniques to investigate the secondary structures produced by the diffuser. Comparisons were made with experiments at several measurement locations within the diffuser. Differences were shown in the prediction of the separation region and the impact of the separation on the flowfield. Simulation of the diffuser provided a number of insights for a complementary experimental program including PIV plane placement and seeding locations, necessary resolution of measurement, and expected operational range and conditions. Distortion-descriptor analysis at the Aerodynamic Interface Plane (AIP) provided better definition of some experimental requirements and sensitivities for capturing complex distortion patterns. This study expanded the ability to complete rapid CFD analysis of advanced inlet geometries and provided guidance to future CFD and experimental studies.