Numerical investigation of exhaust diffuser performances in low pressure turbine casings

Tadashi Tanuma, Yasuhiro Sasao, Satoru Yamamoto, Shinji Takada, Yoshiki Niizeki, Naoki Shibukawa, Hiroshi Saeki

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

13 Citations (Scopus)

Abstract

Low pressure (LP) exhaust hoods are an important component of steam turbines. The aerodynamic loss of LP exhaust hoods is almost the same as those of the stator and rotor blading in LP steam turbines. Designing high performance LP exhaust hoods should lead further enhancement of steam turbine efficiency. This paper presents the results of exhaust hood computational fluid dynamics (CFD) analyses using last stage exit velocity distributions measured in a full-scale development steam turbine as the inlet boundary condition to improve the accuracy of the CFD analysis. One of the main difficulties in predicting the aerodynamic performance of the exhaust hoods is the unsteady boundary layer separation of exhaust hood diffusers. A highly accurate unsteady numerical analysis is introduced in order to simulate the diffuser flows in LP exhaust hoods. Compressible Navier- Stokes equations and mathematical models for non-equilibrium condensation are solved using the high-order high-resolution finite-difference method based on the fourth-order compact MUSCL TVD scheme, Roe's approximate Riemann solver, and the LU-SGS scheme. The SST turbulence model is also solved for evaluating the eddy viscosity. The computational results were validated using the measurement data, and the present CFD method was proven to be suitable as a useful tool for determining optimum three dimensional designs of LP turbine exhaust diffusers.

Original languageEnglish
Title of host publicationASME 2011 Turbo Expo
Subtitle of host publicationTurbine Technical Conference and Exposition, GT2011
Pages2347-2357
Number of pages11
EditionPARTS A, B, AND C
DOIs
Publication statusPublished - 2011 Dec 1
EventASME 2011 Turbo Expo: Turbine Technical Conference and Exposition, GT2011 - Vancouver, BC, Canada
Duration: 2011 Jun 62011 Jun 10

Publication series

NameProceedings of the ASME Turbo Expo
NumberPARTS A, B, AND C
Volume7

Other

OtherASME 2011 Turbo Expo: Turbine Technical Conference and Exposition, GT2011
CountryCanada
CityVancouver, BC
Period11/6/611/6/10

ASJC Scopus subject areas

  • Engineering(all)

Fingerprint Dive into the research topics of 'Numerical investigation of exhaust diffuser performances in low pressure turbine casings'. Together they form a unique fingerprint.

Cite this