Aerodynamic and structural numerical investigation of unsteady flow effects on last stage blades

Tadashi Tanuma, Hiroshi Okuda, Gaku Hashimoto, Satoru Yamamoto, Naoki Shibukawa, Kenichi Okuno, Hiroshi Saeki, Tomohiko Tsukuda

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

8 Citations (Scopus)

Abstract

The aim of this paper is to present some of research results of our current collaborative program to increase steam turbine efficiency with the development of high-performance blade and exhaust hood design methodology using large-scale aerodynamic and structural interaction analysis. Aerodynamic optimum designs of stator blades are already introduced in many designs of actual operating commercial steam turbine units. However, aerodynamic optimum designs of rotating blades are still difficult due to high centrifugal force and vibration stress on rotating blades. This paper focuses on rotating blades and exhaust diffusers that affect the flow field just downstream of last stage long blades. The large-scale highaccuracy CFD analysis of unsteady wet steam flows has been successfully introduced for simulations of low pressure exhaust diffuser using the Earth Simulator of Japan Agency for Marine- Earth Science and Technology. This result shows that the diffuser domain analysis can provide static pressure recovery coefficients and its circumferential deviations with enough accuracy for design use except correct location predictions of separations. The unsteady flow analyses of the typical designed last stage with the measured and calculated downstream static pressure distribution as the outlet boundary condition were conducted. The unsteady flow analyses of the typical designed low pressure exhaust diffuser with the measured and calculated upstream flow conditions as the inlet boundary condition were also conducted. Some of the calculated results were compared with measured data. The large-scale parallel computing Finite Element Analysis of turbine blades with inter-connection parts has been also successfully introduced on the Earth Simulator. The calculation result shows that the eigen frequencies of the present group of loosely-connected rotating blades correspond well to the existing measured data. For the next step, the unsteady structural analysis is being conducted with the calculated unsteady forces on the rotating blades as the FEA boundary conditions. Some of the FEA results are also presented in this paper.

Original languageEnglish
Title of host publicationMicroturbines, Turbochargers and Small Turbomachines; Steam Turbines
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791856796
DOIs
Publication statusPublished - 2015 Jan 1
EventASME Turbo Expo 2015: Turbine Technical Conference and Exposition, GT 2015 - Montreal, Canada
Duration: 2015 Jun 152015 Jun 19

Publication series

NameProceedings of the ASME Turbo Expo
Volume8

Other

OtherASME Turbo Expo 2015: Turbine Technical Conference and Exposition, GT 2015
CountryCanada
CityMontreal
Period15/6/1515/6/19

ASJC Scopus subject areas

  • Engineering(all)

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    Tanuma, T., Okuda, H., Hashimoto, G., Yamamoto, S., Shibukawa, N., Okuno, K., Saeki, H., & Tsukuda, T. (2015). Aerodynamic and structural numerical investigation of unsteady flow effects on last stage blades. In Microturbines, Turbochargers and Small Turbomachines; Steam Turbines (Proceedings of the ASME Turbo Expo; Vol. 8). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/GT2015-43848