Experimental investigation of the blade/seal interaction

Baiz, Sarah; Fabis, Jacky; Boidin, Xavier; Desplanques, Yannick

doi:10.1177/1350650112472853

Cited by 20 publications

(22 citation statements)

References 15 publications

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“…Overall though, the data set was relatively small, and measured forces were not linked to wear, meaning little insight into the behaviour of abradable materials was attained. Baiz et al [13] also analysed the dynamic contact between a flexible blade and abradable coating. During that study, a number of different parameters (incursion speed, number of blade contacts, seal geometry and material removal, normal contact force and blade displacement) were monitored using high-speed videography and force transducers in order to monitor the interaction between the blade and abradable seal.…”

Section: Introductionmentioning

confidence: 99%

An investigation of the relationship between wear and contact force for abradable materials

Fois

Watson

Stringer

et al. 2014

Proceedings of the Institution of Mechanical Engineers, Part J:

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Abradable linings are frequently used on the inside of aero-engine casings. During the operation of engine, the rotating blades may strike the lining of the casing. The wear mechanisms present during these incursions have been re-produced on a scaled test rig platform. Previously, characterisation of the wear has been performed using a stroboscopic imaging technique in order to identify the different wear mechanisms at the incursion conditions investigated. In the present study a dynamometer has been included in the test arrangement allowing the measurement of the contact force. This approach has then been combined with sectioning of the abradable test samples, in order to investigate the material response to the different incursion conditions. The wear results, the cutting force and material structure post-incursion show a high degree of correlation. At low incursion rates, significant consolidation and solidification of abradable material was observed, whilst at the same time adhesive transfer to the blade was recorded along with a low tangential to normal force ratio.At high incursion rates, little solidification and consolidation was observed, together with negligible adhesion and a higher tangential force, suggesting a cutting mechanism.Transitions in material behaviour, wear mechanism, and force ratio were observed at the same incursion condition, further highlighting the link between the different experimental measurements.

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Section: Introductionmentioning

confidence: 99%

An investigation of the relationship between wear and contact force for abradable materials

Fois

Watson

Stringer

et al. 2014

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…The characterization of abradable wear also tends to be performed after either a few [7] or many [5] blade rubs. In terms of abradable-wear mechanisms, the quoted studies are clearly more representative of the full-scale situation than the short-duration interactions reported by Baïz et al in [10]. The present paper provides a complementary approach to that, with the aim of understanding how blades are excited and abradable coatings are worn by a single rub.…”

Section: Introductionmentioning

confidence: 62%

“…The present work is based on an experimental approach initiated by Baïz et al [10], in which a test rig was developed to reproduce blade-coating interactions of a few tens of milliseconds. The rig was designed to allow blade displacement measurement, strain measurement and high-speed imaging for the analysis of couplings between blade vibration and abradable coating wear.…”

Section: Introductionmentioning

confidence: 99%

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

Mandard

Witz

Desplanques

et al. 2014

Journal of Tribology

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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.

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“…Numerical studies based on finite element models were used to predict the vibratory behaviors associated with contacts on axial [4,5] and centrifugal compressors [6]. Given the complexity of the phenomena, experimental setups were developed to get a better understanding on the physics involved during contacts [7][8][9][10]. To our knowledge, blade-casing contact experiments were only studied with axial compressors.…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of Dynamic Interaction Between a Centrifugal Compressor and its Casing

Almeida

Gibert

Thouverez

et al. 2014

Volume 7B: Structures and Dynamics

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In turbomachinery, one way to improve aerodynamic performance and reduce fuel consumption consists of minimizing the clearance between rotor and casing. Yet the probability of contact is increased and this may lead in some specific conditions to a large and even unstable excitation on the impeller and stator. To achieve better understanding of the dynamic behavior occurring during the blade-to-casing contact, many numerical studies have been conducted but only a few experiments have been reported in the literature thus far. The interaction experiment reported in this paper involves a low-pressure, rotating centrifugal compressor and its casing tested in a vacuum chamber. Contact is initiated by introducing a gap near zero, and certain events with significant dynamic levels are observed during the run-up. Measurements are performed using strain gauges on both the rotating and stationary parts and a Scanning Laser Doppler Vibrometer on the stator. This research focuses on an analysis of the recorded data. Time series data are also analyzed by means of standard signal processing and a full spectrum analysis in order to identify the direction of traveling wave propagation on the two structures as well as nodal diameters and frequencies. The dynamic response of structures is accompanied by variations in other physical parameters such as temperature, static deformed shapes, speed and torque. A wearing pattern is evaluated following the contact experiments. The spectral content of response is dominated by frequency modes excited by engine orders as well as by sidebands due to inherent system non-linearity.

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Experimental investigation of the blade/seal interaction

Cited by 20 publications

References 15 publications

An investigation of the relationship between wear and contact force for abradable materials

An investigation of the relationship between wear and contact force for abradable materials

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

Experimental Analysis of Dynamic Interaction Between a Centrifugal Compressor and its Casing

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