대와류모사를 이용한 축류압축기의 익렬 유동 및 공력소음 계산

초록

The losses at off-design points from a cascade occur due to the deviation from a design incidence angle at the inlet of compressor cascade. The self-noise from blade cascade at off-design points mainly comes from separated boundary layer and vortex sheddings, and is also dependent on blade shape. If the incidence angle to the cascade increases, the stalling in blades may occur and the noise level increases significantly. This study applied Large-Eddy Simulation using a subgrid-scale model to low Mach-number compressible flow with each incidence angle to the cascade to compare numerical predictions with flow-visualized data. Aero-acoustics from the cascade of compressor is summarized as sound generated a by structure interacting with turbulent flows. The hybrid method using acoustic analogy was employed to compute the far-field noise spectra and directivity patterns from the separated vortex shedding at off-design points of the cascade of impeller.