An Early Warning Method for Aerodynamic Instability of Turbine

Abstract

The invention relates to an early warning method for pneumatic stability loss of turbines. The method comprises the following steps of: setting a dynamic pressure sensor at the wall surface of a case of a turbine to acquire wall surface static pressures generated by blades and record a dynamic pressure signal; carrying out real-time calculation through sapling points in the current rotor period and in the previous rotor period to obtain a periodic coefficient Rc of the current sampling point; obtaining a periodic coefficient Rc before the current sampling point through the sampling point in the previous rotor period and in the one before the previous rotor period, and doing the rest I the same manner to continuously obtain periodic coefficients Rc; setting a threshold value Rcth, and calculating the probability F (Rcth) that the periodic coefficient Rc in the previous statistical window before the current sampling point is less than or equal to Rctch; presetting an early warning value of a working margin, comparing the probability F (Rcth) with the early warning value, and when the probability F (Rcth) is greater than the early warning value, generating an early warning signal. The early warning method for pneumatic stability loss of turbines, stall early warning signals can be given earlier.

Description

technical field [0001] The invention relates to an early warning method for aerodynamic instability of a turbomachine, in particular to an early warning method for aerodynamic instability of a high-speed turbomachine based on the principle of aeroacoustics, and belongs to the technical field of turbomachines. Background technique [0002] In the prior art, the common stall early warning technology usually adopts the way of compressor stall precursor detection (including modal waves and spikes). Existing results show that it takes only 0.03-1 second from the detection of stall precursors such as modal waves or spikes to compressor stall. In this case, the various active / passive control systems usually do not have enough time to activate. [0003] In engineering practice, the changing factors leading to the stall initiation of high-speed turbines are complex and diverse. Any change in working conditions will lead to changes in the location of the stall precursor. How to achie...

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Problems solved by technology

At the same time, the time from the discovery of the stall warning signal to the occurrence of aerodynamic instability is very short. It is extremely difficult to capture and identify the stall warning signal, and it is easy to generate false alarms.

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