The study aims to analyze the causes of blade trailing edge fracture in a centrifugal impeller and propose effective improvement measures to enhance its high-cycle fatigue (HCF) life.
Methods
2
Firstly
unsteady flow field analysis was employed to identify the radial diffuser as the primary excitation source based on the relation between flow excitation and blade resonance. Secondly
dangerous high-order modes within the excitation frequency range were determined through modal analysis and subsequently confirmed by dynamic stress measurement tests. Finally
improvement measures
including reducing blade outlet height
optimizing blade profiles
and adjusting diffuser blade angles
were implemented to mitigate vibration stress.
Results
2
The results of dynamic stress measurements and long-term engine tests show that the HCF reserve of the improved impeller meets the service requirements. The peak vibration stress was reduced from 120 MPa to 70 MPa. The proposed method provides a valuable reference for the vibration design of aero-engine impellers.
LIU Meiru , TENG Guangrong , XIAO Xiao , et al . Vibration measurement of turbine rotor blades of aero-engine based on blade tip-timing [J]. Journal of Aerospace Power , 2020 , 35 ( 9 ): 1954 - 1963 . (In Chinese)
ZHOU Jinman , XUE Qiang , YANG Shuo , et al . A systematic review on effect of FOD on HCF strength of compressor blades [J]. Aeroengine , 2023 , 49 ( 1 ): 27 - 33 . (In Chinese)
SHI Lizhong , DONG Shuo , LIU Xuefeng , et al . Research on the law of engine compressor blade crack propagation based on operation data [J]. Journal of Mechanical Strength , 2024 , 46 ( 3 ): 602 - 610 . (In Chinese)
CHOI Y S , LEE K H . Investigation of blade failure in a gas turbine [J]. Journal of Mechanical Science and Technology , 2010 , 24 ( 10 ): 1969 - 1974 .
HONG Jie , ZHANG Dayi , CHEN Lulu . Review on investigation of high cycle fatigue failures for the aero engine blade [J]. Journal of Aerospace Power , 2009 , 24 ( 3 ): 652 - 661 . (In Chinese)
WANG Jing , WANG Deyou , HAN Qingkai . Mechanism analysis and treatment on loss corner faults of compressor blades [J]. China Mechanical Engineering , 2008 , 19 ( 9 ): 1048 - 1050 . (In Chinese)
LEI Mozhi , HU Guoan , WANG Yuehua , et al . High order mode vibration failure of an aero-engine centrifugal impeller [J]. Journal of Vibration and Shock , 2019 , 38 ( 22 ): 244 - 250 . (In Chinese)
WANG Yi , LU Xingen , ZHAO Shengfeng , et al . Effects of diffuser blade geometry at leading edge on a highly-loaded centrifugal compressor [J]. Journal of Propulsion Technology , 2011 , 32 ( 2 ): 175 - 181 . (In Chinese)
ZHAO Yujie , LI Lei , SUN Shouyi , et al . 20 kHz air jet excitation technology and high-order vibration characteristics of turbine blade [J]. Journal of Propulsion Technology , 2025 , 46 ( 6 ): 286 - 297 . (In Chinese)
HU Minghui , LIU Shaopeng , WANG Hao , et al . Characterization and identification of gas turbine blade fracture faults based on broadband vibration [J]. Acta Aeronautica et Astronautica Sinica , 2024 , 45 ( 20 ): 311 - 328 . (In Chinese)
DANG Wei , HU Minghui , JIANG Zhinong , et al . Vibration features and diagnosis methods for rotor blade fracture in a gas turbine's compressor [J]. Journal of Vibration and Shock , 2021 , 40 ( 10 ): 7 - 19 . (In Chinese)
SONG Kailiang . Research on dynamic characteristics of centrifugal impeller under airflow excitation [D]. Beijing : Beijing University of Chemical Technology , 2017 : 26 - 28 . (In Chinese)