Quantitative Analysis of Air Injection for Compressor Active Control

Aimed at analysing compressor stability with continual air injection quantitatively, the effect of injection air flow coefficient was investigated based on the Moore-Greitzer model with air injection. By changing the jet velocity for changing the quasi-steady state of the compressor, the influence of constant flow coefficient on the stability of the compressor was analysed theoretically. The results show that the compressor characteristic variation is the stability mechanism of compression system with air injection. Increasing the jet speed makes the compressor characteristic lineup, and the critical stall point shifts to left. There exists a corresponding minimum injection velocity for different throttle coefficients and the stability margin can be determined theoretically.