A surge early warning method and device for an axial flow fan with adjustable moving blades

Abstract

The invention discloses a surge early warning method and device for a movable blade adjustable axial flow fan, and relates to the field of state monitoring and fault early warning of the axial flow fan. According to the method, vibration signals and angles of movable blades of the movable blade adjustable axial flow fan are monitored, surge judgment and early warning are carried out according to characteristics of the vibration signals of the movable blades of the movable blade adjustable axial flow fan, early warning information is taken as an input signal of a movable blade angle adjusting module, and the real-time monitored movable blade angle is taken as a feedback signal of the movable blade angle adjusting module, so that real-time early warning and dynamic regulation of surge in therunning process of the movable blade adjustable axial flow fan are realized. The method can also convert the vibration signals of the movable blades into dynamic stress data for fatigue analysis andevaluation of the movable blades, so as to prevent the movable blades from being subjected to a fatigue failure in the operation process of the axial flow fan and ensure the safe and reliable operation of the axial flow fan.

Description

technical field [0001] The invention relates to the field of state monitoring and fault early warning of an axial flow fan, in particular to a surge early warning method and device for an axial flow fan with adjustable moving blades. Background technique [0002] Axial flow fans are widely used in electric power, petrochemical and other industries due to their large flow, high efficiency, and good cost performance. The structure of axial flow fans is complex. When the working conditions of the units change or the parallel operation is unbalanced, the fans may surge . The strong periodic back and forth flow of the airflow during surge will lead to increased noise and increased stress on the blades, which will generate a large impulsive force on the impeller, bearing and its connecting parts. When these forces increase to a certain extent, it will cause the fan to rotate Fracture with stationary parts, or even destroy the entire fan. According to the theoretical and practica...

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Problems solved by technology

[0003] After research, it is found that the current surge warning system for axial fans is to monitor the operating parameters of the axial fans such as air volume and pressure head in real time, combined with the performance curve of the axial fans and the installation angle of the moving blades to judge whether the current working point is in the surge stall alarm This method requires a large amount of information and a lot of monitoring equipment, and the accuracy of any parameter will directly affect the accuracy of judging the early warning, which will adversely affect the efficient and stable operation of the unit. During the operation of time, the rotor blades are prone to fatigue failure. Obtaining the dynamic stress of the fan rotor blades and performing fatigue analysis and evaluation is of great significance for the safe and reliable operation of the fan.

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