To fully understand the instability process and reveal the occurrence

development and essence of the unstable flow phenomena of one-stage transonic axial compressor with high loading

test investigation was carried out with both steady and dynamic measurements. The analysis was performed by the original signal

the low pass filtering and the FFT (fast Fourier transform) method. The results show that the large amplitude

low frequency axisymmetric axial disturbance appears firstly at the stator hub during the instability process. At that time

there is a decrease in the performance below 50% span of the compressor. But the compressor can still be operated. Meanwhile

considering the features of this disturbance such as low frequency

axisymmetricity

large amplitude

this kind of unstable flow phenomena

named as partial surge

is identified. Then

this disturbance spreads axially and radially with the further decrease of the mass flow. Next

this disturbance extend to the full span. Finally

it leads to the rotating stall cells at the rotor tip region

and the indicating the compressor reached the instability boundary.