Improving Efficiency of a High Work Turbine Using Non-Axisymmetric Endwalls: Part I—Endwall Design and Performance
METADATA ONLY
Author / Producer
Date
2008
Publication Type
Conference Paper
ETH Bibliography
yes
Citations
Altmetric
METADATA ONLY
Data
Rights / License
Abstract
This paper is the first part of a two part paper reporting the improvement of efficiency of a one-and-half stage high work axial flow turbine by non-axisymmetric endwall contouring. In this first paper the design of the endwall contours is described and the CFD flow predictions are compared to five-hole-probe measurements. The endwalls have been designed using automatic numerical optimization by means of an Sequential Quadratic Programming (SQP) algorithm, the flow being computed with the 3D RANS solver TRACE. The aim of the design was to reduce the secondary kinetic energy and secondary losses. The experimental results confirm the improvement of turbine efficiency, showing a stage efficiency benefit of 1%±0.4%, revealing that the improvement is underestimated by CFD. The secondary flow and loss have been significantly reduced in the vane, but improvement of the midspan flow is also observed. Mainly this loss reduction in the first row and the more homogeneous flow is responsible for the overall improvement. Numerical investigations indicate that the transition modeling on the airfoil strongly influences the secondary loss predictions. The results confirm that non-axisymmetric endwall profiling is an effective method to improve turbine efficiency, but that further modeling work is needed to achieve a good predictability.
Permanent link
Publication status
published
External links
Editor
Book title
Proceedings of ASME Turbo Expo 2008
Journal / series
Volume
6 Part B
Pages / Article No.
1109 - 1119
Publisher
American Society of Mechanical Engineers
Event
53rd ASME Turbo Expo (GT 2008)
Edition / version
Methods
Software
Geographic location
Date collected
Date created
Subject
Organisational unit
03548 - Abhari, Reza S. / Abhari, Reza S.
Notes
GT2008-50469