Parameters Identification of Blade Synchronous Vibration Based on Whole Domain Transient Response Fitting Method

Abstract

Vibration monitoring and health assessment of rotor blades using the blade tip-timing (BTT) method has gained increasing attention in turbine machinery. Identifying synchronous vibration parameters identification of rotor blades can help prevent high-cycle fatigue failure and can also evaluate blade status, such as vibration stress reconstruction and modal identification. However, during acceleration and deceleration, rotor blades passing through synchronous are affected by transient response. This leads to significant errors in the blade vibration parameters identified based on the steady-state response fitting method. To improve the accuracy of blade vibration parameters identification under transient response conditions, the transient vibration displacement response equation of rotor blades during synchronous vibration is derived based on the BTT method monitoring. A whole domain transient response fitting method is proposed by replacing the Faddeeva function with the imaginary error function. To reduce computation time and improve the identification efficiency, an improved whole domain transient response fitting (IWDTRF) method is developed by combining the advantages of Algorithm 916. The IWDTRF method enables engine order analysis by monitoring blade vibration displacement with only a single sensor based on the BTT method. Simulations and experiments demonstrate that the blade synchronous vibration parameters identified by the proposed method are more accurate and stable, and further confirm its effectiveness for transient vibration parameter identification under variable acceleration conditions, making it suitable for identifying synchronous vibration parameters of rotor blades under actual engine operation conditions.