Investigated was the aerodynamic instability problem of an axial-flow compressor during throttling tests.A nonlinear correlation-integral method was employed to analyze static pressure signals along the compressor casing-wall surface.The results of the analysis indicate that correlation-integral values of the static pressure signals at a given point of the compressor stator passage casing-wall surface will undergo regular changes,depending on the engine operating conditions,and reflect the flow separation conditions... Investigated was the aerodynamic instability problem of an axial-flow compressor during throttling tests.A nonlinear correlation-integral method was employed to analyze static pressure signals along the compressor casing-wall surface.The results of the analysis indicate that correlation-integral values of the static pressure signals at a given point of the compressor stator passage casing-wall surface will undergo regular changes,depending on the engine operating conditions,and reflect the flow separation conditions at corresponding locations.The correlation-integral values of static pressure at various-stage stator channel casing-wall surface along the compressor flow passage can reflect the flow matching status at the blade tip of the various compressor stages under different operating conditions.The correlation-integral values of the static pressure of the compressor first stage stator casing-wall surface reflect the impact of the bleed valve's switching state on the rotor end-wall flow regime at intermediate and low-speed operating conditions.The study conducted by the authors indicates that the correlation-integral analysis regarding the above-mentioned static pressure signals can serve as a kind of effective means for monitoring and diagnosing the compressor aerodynamic stability. |