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Blade tip timing to determine turbine blade fatigue in high backpressure conditions
Dissertation (MEng)--University of Pretoria, 2020.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2020
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| _version_ | 1867613635850797056 |
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| access_status_str | Open Access |
| author2 | Heyns, P.S. (Philippus Stephanus) |
| author_browse | Heyns, P.S. (Philippus Stephanus) |
| author_facet | Heyns, P.S. (Philippus Stephanus) |
| collection | Thesis |
| dc_rights_str_mv | © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng)--University of Pretoria, 2020. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/75831 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:39:17.410Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/75831 Blade tip timing to determine turbine blade fatigue in high backpressure conditions Heyns, P.S. (Philippus Stephanus) wjvisagie@gmail.com Visagie, Willem Johannes Steam turbine Blade tip timing Finite elements High cycle fatigue Residual stress UCTD Engineering, built environment and information technology theses SDG-07 SDG-07: Affordable and clean energy Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Dissertation (MEng)--University of Pretoria, 2020. This dissertation presents an approach to use blade tip timing measurements with finite element analysis to predict the fatigue life of a low pressure steam turbine last stage blade under high backpressure and low flow conditions. Material fatigue properties were determined through the extended universal material law for FV566 material, along with different temper scenarios. A finite element model of a blade with damping pins was developed, using the principle of cyclic symmetry for a perfectly tuned model. Pre-stress modal analysis was conducted, incorporating damping via friction and plasticity for initial 20% overspeed test. The finite element model was verified by two experimental tests: the first being a blade impact test and the second a telemetry strain gauge test in a balance pit. Fatigue life analysis was conducted under the assumption that non-synchronous vibration is experienced by the blade and that only one mode is dominant in the vibration. The results from the fatigue analysis corresponded to the location of the cracks experienced on the blades. The results show twelve orders of magnitude lower life at low load, high backpressure conditions, compared to high load high pressure conditions. The research was further extended to check the same vibratory response on the first three modes, up to their tenth nodal diameters. This was done to analyse fatigue life in a case that a different mode was excited. Eskom Rotek Industries mi2025 Mechanical and Aeronautical Engineering MEng Unrestricted SDG-07: Affordable and clean energy SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production 2020-08-21T08:22:50Z 2020-08-21T08:22:50Z 2020-08 2020 Dissertation Visagie, WJ 2020, Blade tip timing to determine turbine blade fatigue in high backpressure conditions, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/75831> http://hdl.handle.net/2263/75831 en © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Steam turbine Blade tip timing Finite elements High cycle fatigue Residual stress UCTD Engineering, built environment and information technology theses SDG-07 SDG-07: Affordable and clean energy Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Blade tip timing to determine turbine blade fatigue in high backpressure conditions |
| title | Blade tip timing to determine turbine blade fatigue in high backpressure conditions |
| title_full | Blade tip timing to determine turbine blade fatigue in high backpressure conditions |
| title_fullStr | Blade tip timing to determine turbine blade fatigue in high backpressure conditions |
| title_full_unstemmed | Blade tip timing to determine turbine blade fatigue in high backpressure conditions |
| title_short | Blade tip timing to determine turbine blade fatigue in high backpressure conditions |
| title_sort | blade tip timing to determine turbine blade fatigue in high backpressure conditions |
| topic | Steam turbine Blade tip timing Finite elements High cycle fatigue Residual stress UCTD Engineering, built environment and information technology theses SDG-07 SDG-07: Affordable and clean energy Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production |
| url | http://hdl.handle.net/2263/75831 |