Unsteady flow simulation through stator-rotor blade rows in intermediate-pressure steam turbines with cutback blades

Hironori Miyazawa, Akihiro Uemura, Takashi Furusawa, Satoru Yamamoto, Koichi Yonezawa, Shuichi Umezawa, Shuichi Ohmori, Takeshi Suzuki

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

Stator and rotor blades in intermediate-pressure steam turbines gradually deteriorate during operation because of solid particle erosion. In addition to that, turbine blades unexpectedly crack because of metal fatigue or thermal stress deformation. As eroded blades increase the aerodynamic losses and cracked blades may induce rupture of the blade, the periodic maintenance, repair, and overhaul of steam turbines is essential. Eroded or cracked blades should be replaced with new ones or repaired for further use. Cutback treatment is one of the repair methods wherein the deteriorated trailing edge on a turbine blade is removed to avoid further cracking and blade fracturing. The use of cutback blades can reduce the replacement cost; however, that may affect the steam flow and the turbine’s performance. In this study, we numerically investigated the effect of the blade deterioration on the performance of a three-stage intermediate-pressure steam turbine using a numerical method that was developed at Tohoku University. Further various cutback lengths were considered for the deteriorated first-stage stator-blade trailing edge. The obtained numerical results indicate that the cutback first-stage stator blades certainly affected the steam flow in the turbine, resulting in a negative influence on the torque obtained from the adjacent rotor blades, which depends on the cutback length. However, the torque decrement can be mitigated by arranging the cutback and non-cutback stator blades alternately in a row.

Original languageEnglish
Title of host publicationTurbomachinery
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791884102
DOIs
Publication statusPublished - 2020
EventASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition, GT 2020 - Virtual, Online
Duration: 2020 Sep 212020 Sep 25

Publication series

NameProceedings of the ASME Turbo Expo
Volume2E-2020

Conference

ConferenceASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition, GT 2020
CityVirtual, Online
Period20/9/2120/9/25

ASJC Scopus subject areas

  • Engineering(all)

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