Numerical investigation of rub-induced composite fan blade vibrations and abradable coating removals

2019 ◽  
Vol 226 ◽  
pp. 111274 ◽  
Author(s):  
Jia-Guang-Yi Xiao ◽  
Yong Chen ◽  
Jie Tian ◽  
Hua Ou-Yang ◽  
Anjenq Wang
Keyword(s):  
Numerical Investigation ◽  
Abradable Coating ◽  
Blade Vibrations ◽  
Fan Blade

Experimental Reduction of Transonic Fan Forced Response by IGV Flow Control

2004 ◽  
Author(s):  
S. Todd Bailie ◽  
Wing F. Ng ◽  
William W. Copenhaver
Keyword(s):  
Flow Control ◽  
Forced Response ◽  
Resonant Response ◽  
Compressor Blades ◽  
Resonant Amplitude ◽  
Engine Order ◽  
Blade Vibrations ◽  
Fan Blade ◽  
Transonic Fan ◽  
Bending Response

The main contributor to the high-cycle fatigue of compressor blades is the response to aerodynamic forcing functions generated by an upstream row of stators or inlet guide vanes. Resonant response to engine order excitation at certain rotor speeds can be especially damaging. Studies have shown that flow control by trailing edge blowing (TEB) can reduce stator wake strength and the amplitude of the downstream rotor blade vibrations generated by the unsteady stator-rotor interaction. In the present study, the effectiveness of TEB to reduce forced fan blade vibrations was evaluated in a modern single-stage transonic fan rig. Data was collected for multiple uniform full-span TEB conditions over a range of rotor speed including multiple modal resonance crossings. Resonant response sensitivity was generally characterized by a robust region of strong attenuation. The baseline resonant amplitude of the first torsion mode, which exceeded the endurance limit on the critical blade, was reduced by more than 80% with TEB at 1.0% of the total rig flow. The technique was also found to be modally robust; similar reductions were achieved for all tested modal crossings, including more than 90% reduction of the second LE bending response using 0.7% of the rig flow.

scholarly journals Wavelet Analysis of Experimental Blade Vibrations During Interaction With an Abradable Coating

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Romain Mandard ◽  
Jean-François Witz ◽  
Yannick Desplanques ◽  
Jacky Fabis ◽  
Jean Meriaux
Keyword(s):  
Wavelet Transform ◽  
Continuous Wavelet Transform ◽  
High Speed ◽  
Continuous Wavelet ◽  
High Speed Imaging ◽  
Blade Vibration ◽  
Time Frequency ◽  
Abradable Coating ◽  
Blade Vibrations ◽  
Blade Tip

Minimizing the clearance between turbofan blades and the surrounding casing is a key factor to achieving compressor efficiency. The deposition of an abradable coating on casings is one of the technologies used to reduce this blade-casing clearance and ensure blade integrity in the event of blade-casing contact. Aircraft in-service conditions may lead to interactions between the blade tip and the coated casing, during which wear of the abradable coating, blade dynamics, and interacting force are critical yet little-understood issues. In order to study blade/abradable-coating interactions of a few tens of milliseconds, experiments were conducted on a dedicated test rig. The experimental data were analyzed with the aim of determining the friction-induced vibrational modes of the blade. This involved a time-frequency analysis of the experimental blade strain using continuous wavelet transform (CWT) combined with a modal analysis of the blade. The latter was carried out with two kinds of kinematic boundary conditions at the blade tip: free and modified, by imposing contact with the abradable coating. The interaction data show that the blade vibration modes identified during interactions correspond to the free boundary condition due to the transitional nature of the phenomena and the very short duration of contacts. The properties of the continuous wavelet transform were then used to identify the occurrence of blade-coating contact. Two kinds of blade/abradable-coating interactions were identified: bouncing of the blade over short time periods associated with loss of abradable material and isolated contacts capable of amplifying the blade vibrations without causing significant wear of the abradable coating. The results obtained were corroborated by high-speed imaging of the interactions.

Numerical Investigation of Discharge Current Path in a Hydrogen MPD Thruster

2016 ◽  
Vol 136 (3) ◽  
pp. 141-146 ◽  
Author(s):  
Akira Kawasaki ◽  
Kenichi Kubota ◽  
Ikkoh Funaki ◽  
Yoshihiro Okuno
Keyword(s):  
Numerical Investigation ◽  
Discharge Current ◽  
Current Path

Numerical Investigation of the Correlation between Electrode Structure and Number of Captured Particles in a Dielectrophoretic Device

2014 ◽  
Vol 134 (7) ◽  
pp. 235-240
Author(s):  
Ryoto Aoki ◽  
Naoki Shirai ◽  
Satoshi Uchida ◽  
Fumiyoshi Tochikubo
Keyword(s):  
Numerical Investigation ◽  
Electrode Structure
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