Investigations about the detrimental effects of   inlet distortions on compressor performance and stability;

Four distortion types were considered:   circumferential total pressure distortion, radial total pressure distortion,   swirl distortion and rotating distortion;

Distortion generators for all distortion types   have been constructed combined with the existing facilities;

The inlet flow fields for different distorted   conditions were measured and depicted;

Assessment for the effects of inlet distortions   has been carried out.

Casing treatment

The stall precursor-suppressed (SPS) casing   treatment has been developed and well validated on both subsonic compressor   rig and transonic compressor rig with uniform inlet and distorted inlet;

The mechanism of SPS casing treatment was also   investigated by measuring the pressure perturbation energy.

Stall Warning

A stall warning approach based on the   aeroacoustic theory was developed;

This method is an on-line data processing used   the dynamic pressure trace detected by only one sensor mounted on the inner   casing wall;

The correlation analysis and probability distribution   analysis were engaged in this approach which can accurately indicate the   instability phenomena far before the stall inceptions.

Compressor stability control

An adaptive control method for compressor stability   was established;

The geometrically adjustable SPS casing treatment   can be used as an adaptive controller with the instruction of the computer   system;

The stall warning approach can monitor the   stability state of compressor and make the control system be as a feedback   loop;

Effectiveness of this adaptive control method has   been validated on a low-speed compressor rig.