Early warning method for rotating stall of axial-flow air compressor based on frequency domain hump identification

Abstract

The invention discloses an early warning method for rotating stall of an axial-flow air compressor based on frequency domain hump identification. The method comprises the following steps: continuously and dynamically acquiring a pressure signal; continuously calculating the frequency spectrum of the pressure signal within one air compressor rotation period by utilizing fast Fourier transform; calculating a characteristic hump distinguish factor Ch corresponding to the frequency spectrum; and judging whether the air compressor is close to the rotating stall boundary by comparing the characteristic hump distinguish factor Ch with a detection threshold value Chsta11. The characteristic hump distinguish factor Ch defined by the early warning method for rotating stall of the axial-flow air compressor has definite physical significations and is used for implementing real-time on-line detection on a frequency domain hump appearing earlier than rotating stall so as to give an early warning when the work situation of the air compressor is close to the rotating stall boundary, and the early warning method is reliable. By requiring a simplex signal sensor only and adopting fast Fourier transform, the early warning method for rotating stall of the axial-flow air compressor has few middle procedures, realizes high calculation speed and provides sufficient response time for active control.

Description

technical field [0001] The invention relates to the technical field of turbomachinery stability expansion, in particular to a method for early warning of rotational stall of an axial flow compressor based on hump identification in the frequency domain. Background technique [0002] Rotating stall is a common aerodynamic instability phenomenon in compressors, which can lead to a sharp deterioration in compressor performance, or lead to blade breakage and damage to the entire compressor. The traditional stall control method is a passive control technology, and its core is to ensure that there is sufficient margin between the operating point of the compressor and the stall boundary, so that the compressor can work far away from the stall boundary point. However, the stall boundary is often affected by factors such as the working state and the distortion of the inlet flow field, so it is difficult to determine accurately. The stall point often appears near the highest pressure r...

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Problems solved by technology

This situation makes it difficult for the actuation system to have enough time to respond, making it difficult for the stability active control technology based on the prediction of stall precursors to be practically applied in aero-engines

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