Purge-Mainstream Interactions in a Turbine Stage With Rotor Endwall Contouring

Research output: Chapter or section in a book/report/conference proceedingChapter in a published conference proceeding


Purge flows are prevalent in modern gas turbine design allowing for increased turbine entry temperatures. The purge flow passes through a rim seal and interacts with the mainstream flow, modifying the blade secondary flow structures and reducing stage efficiency. These structures may be controlled using End Wall Contouring (EWC), though experimental demonstration of their benefit is seldom reported in the literature. The optically accessible turbine at the University of Bath was designed to directly measure and visualize the flow field within the blade passage for a rotor with EWC.

The single-stage turbine enables phase-locked flow field measurements with volumetric Particle Image Velocimetry (PIV). Purge flow was supplied to investigate a range of operating conditions in which the secondary flow structures were modified. The modular turbine rotor allowed for expedient change of a bladed ring, or bling, featuring non-axisymmetric EWC.

The identified secondary flow structures were the Pressure-Side leg of the Horse Shoe Vortex (PS-HSV) and an Egress Vortex (EV) of concurrent rotational direction. An increase in purge flow rate monotonically shifted the EV toward the suction-side (SS) of the adjacent blade. The migration of the PS-HSV towards the SS caused the two aforementioned vortices to merge.

The EWC rotor design included a Leading-Edge (LE) feature to alter the PS-HSV, and a trough to guide the EV low spanwise in the passage and maintain displacement from the adjacent suction side. The EWC rotor was found to be effective at altering the formation and positioning of the secondary flow structures at a range of purge flow conditions.
Original languageEnglish
Title of host publicationTurbomachinery - Axial Flow Turbine Aerodynamics
Subtitle of host publicationAxial Flow Turbine Aerodynamics
Number of pages13
ISBN (Electronic)9780791887097
Publication statusPublished - 28 Sept 2023
EventASME Turbo Expo 2023: Turbomachinery Technical Conference and Exposition - Boston, Massachusetts, USA
Duration: 26 Jun 202330 Jun 2023

Publication series

NameProceedings of the ASME Turbo Expo


ConferenceASME Turbo Expo 2023: Turbomachinery Technical Conference and Exposition

Bibliographical note

Publisher Copyright:
Copyright © 2023 by ASME.


  • Axial Turbine
  • Endwall Contouring
  • Purge
  • Secondary Flows
  • Volumetric Velocimetry

ASJC Scopus subject areas

  • General Engineering


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