Contributions to the study of the aerodynamics of damaged turbine blades.

Klein, Wendy A.

doi:10.22215/etd/1993-02522

Cited by 2 publications

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“…Previous literature on the forced response induced by damaged stator vanes, on the other hand, is limited. Carleton University first [ 21 , 22 , 23 , 24 ] studied a single turbine vane damaged at the mid-span of the trailing edge. Experimental and numerical simulations showed that a swept leakage from the pressure surface to the suction surface like the tip leakage flow is formed at the edge of the notch.…”

Section: Introductionmentioning

confidence: 99%

Low-Engine-Order Forced Response Analysis of a Turbine Stage with Damaged Stator Vane

Zheng,

Jin,

Yang

2023

Entropy

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A damaged stator vane can disrupt the circumferential symmetry of the design flow for turbine assemblies, which can lead to a low-engine-order (LEO) forced response of rotor blades. To help engineers be able to better address sudden vane damage failures, this paper conducts a mechanism analysis of the LEO forced response of rotor blades induced by a single damaged vane using an in-house computational fluid dynamic code (Hybrid Grid Aeroelasticity Environment). Firstly, it is found that the damaged vane introduces a family of LEO aerodynamic excitations with high amplitudes by full-annulus unsteady aeroelastic simulations of a single-stage turbine. In particular, the LEO forced response of the rotor blades excited by 3EO is 2.01 times higher than the resonance response excited by vane passing frequency, and the LEO resonance risk of the rotor blades is greatly increased. Then, by analyzing the flow characteristics of the wake and potential field of the stator row with a damaged vane, the localized high transient pressure in the notch cavity and the radial redistribution of the secondary vortex at the stator exit are the main sources of the low-order harmonic components in the flow field. Importantly, the interaction mechanisms in two regions with high LEO excitation amplitude on the rotor blade surface are revealed separately. Finally, an evaluation and comparison of a single damaged vane in terms of aerodynamic performance and LEO forced response was carried out. The results of this paper provide a good theoretical basis for engineers to effectively control the resonance response of rotor blades caused by a damaged stator vane in turbine design.

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Section: Introductionmentioning

confidence: 99%

Low-Engine-Order Forced Response Analysis of a Turbine Stage with Damaged Stator Vane

Zheng,

Jin,

Yang

2023

Entropy

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“…From the perspective of damage modelling, the 2D analysis also allows damage effects to be concentrated at a specific span location, as opposed to the present approach where the damage effects are averaged across the span. Such a 2D-based "concentrated" damage modelling approach has been successfully demonstrated by Klein in simulating the tip-clearance damage effects, which resulted in more realistic predictions of the spanwise temperature distributions and the overall efficiency penalties caused by the damage [57]. Klein's work shows promise in incorporating such an approach of damage effects predictions into the framework.…”

Section: Recommendationsmentioning

confidence: 99%

Physics-Based Online Assessment of Surface Roughness Severity for High-Pressure Turbines

Li¹

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Surface roughness is a critical indicator of the health of turbine blades, due to its implications on blade surface heat transfer and structural integrity. The present work proposes a physics-based online assessment framework for industrial gas turbine engines (GTE), in order to assess the blade surface roughness in a high-pressure turbine without engine shutdown. The framework consolidates gas path analysis (GPA) based performance monitoring models and meanline turbomachinery analysis using a novel GPA-meanline matching process. This extracts meaningful performance deviation trends from GPA, while resolving the uncertainties associated with the measurements and modeling. To relate efficiency loss to surface roughness severity, a meanline-based system-identification process has been developed to establish the meanline representation of the turbine stage and to incorporate an empirical surface roughness loss correlation system. The roughness loss correlations have been evaluated against recent transonic test data in the literature. A modification to the compressibility correction factor has been made according to the evaluation outcome, which yielded improved loss predictions compared to the experimental measurements.The successful application of the framework on three-year operational data of a cogenerative GTE validated the framework's potential as an effective online surface roughness monitoring tool. The estimated surface roughness index achieved magnitudelevel and trend agreement with the measurements reported in the literature.iii "No, in all these things we are more than conquerors through him who loved us." -Romans 8:37, ESV iv Acknowledgements I wish to thank my supervisor, Professor Jie Liu, for providing me the opportunity to work on this research project. This work could not have been accomplished without his encouragement and sound advice. I would also like to gratefully acknowledge my supervisor from my fourth-year capstone project, Professor Steen A. Sjolander, for introducing me to the field of turbomachinery. I am also truly grateful for his intermittent, but invaluable, guidance and encouragement over the course of this work.

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Contributions to the study of the aerodynamics of damaged turbine blades.

Cited by 2 publications

References 0 publications

Low-Engine-Order Forced Response Analysis of a Turbine Stage with Damaged Stator Vane

Low-Engine-Order Forced Response Analysis of a Turbine Stage with Damaged Stator Vane

Physics-Based Online Assessment of Surface Roughness Severity for High-Pressure Turbines

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