| Popis: |
Foam-metal casing treatment (FMCT) installed over the rotor tip has been proved to affect the performance of compressors. To develop a design strategy for FMCTs, different parameters of surface geometries (SGs), including the shape, staggering, and denseness, based on a 2mm-depth groove were designed to model the FM surface morphology, which dominates the transverse flow resistance near the end wall region. Eight axial installation locations of the casing treatment were set on the tested low-speed compressor, among which the optimum stall margin improvement (SMI) up to 11.5% with 1% efficiency loss was achieved by a brush-type SG at a near mid-chord axial location. But the acoustic measurements of all the SGs showed nearly no benefit of broadband noise reduction. Accompanied by the investigations into the flow field and pressure unsteadiness, the mechanism of FMCT on compressor stability and noise attenuation were discussed and the design strategy was obtained. |
