Fig.1

Contra-rotating compressor test bench

Fig.2

Distortion generator installation schematic

Fig.3

Dynamic pressure sensor layout schemes

Table 1

Stall disturbance characteristics of contra-rotating compressor under different inlet conditions

Fig.4

Curve of compressor discharge blockage ratio to the axial position of the throttle cone

Fig.5

Characteristic curves of contra-rotating compressor for different working conditions

Table 2

SMV results for different working conditions

Fig.6

Stall disturbance propagation along the circumferential direction at stall initiation process for undistorted conditions （n1=2 400 r/min，n2=2 400 r/min）

Fig.7

FFT spectrum of the dynamic pressure stall sequence

Fig.8

Stall disturbance propagation along the circumferential direction at stall initiation process for undistorted conditions （n1=1 600 r/min，n2=1 142 r/min）

Fig.9

Stall disturbance propagation along the circumferential direction at stall initiation process for undistorted conditions （n1=1 600 r/min，n2=1 050 r/min）

Fig.10

FFT spectrum of inter-stage at stall condition

Fig.11

Proportion of the front rotor BPF in the inter-stage flow field for different speed configurations

Fig.12

Stall disturbance propagation along the circumferential direction at stall initiation process with 120° circumferential distortion （n1=2 400 r/min， n2=2 400 r/min）

Fig.13

Stall disturbance propagation along the circumferential direction at stall initiation process with 120° circumferential distortion （n1=1 600 r/min， n2=1 142 r/min）

Fig.14

Stall disturbance propagation along the circumferential direction at stall initiation process with 120° circumferential distortion （n1 = 1 600 r/min， n2 = 1 050 r/min）

Fig.15

Time-frequency-energy structure of the joint EMD-LMD method for pressure sequence at stall condition