Aero-thermal aspects of film cooled nozzle guide vane endwalls: Part 1 - Aerodynamics

Mahmood H. Alqefl, Kedar P. Nawathe, Pingting Chen, Rui Zhu, Yong W. Kim, Terrence W. Simon

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

Abstract

The first stage turbine of a modern gas turbine is subjected to high thermal loads which lead to a need for aggressive cooling schemes to protect its components from melting. Endwalls are particularly challenging to cool due to the complex system of secondary flows near them that wash the protective film coolants into the mainstream. This paper shows that without including combustor cooling, the complex secondary flow physics are not representative of modern engines. Aggressive injection of all cooling flows upstream of the passage is expected to interact and change passage aerodynamics and, subsequently, mixing and transport of coolants. This study describes, experimentally, the aero-thermal interaction of cooling flows near the endwall of a first stage nozzle guide vane passage. The test section involves an engine-representative combustor-turbine interface geometry, combustor coolant flow and endwall film cooling flow injected upstream of a linear cascade. The approach flow conditions represent flow exiting a cooled, low-NOx combustor. This first part of this two-part study aims to understand the complex aerodynamics near the endwall through detailed measurements of passage three-dimensional velocity fields with and without endwall film cooling. The aerodynamic measurements reveal a dominant vortex in the passage, named here as the Impingement Vortex, that opposes the passage vortex formed at the airfoil leading edge plane. This Impingement Vortex completely changes our description of flow over a modern film cooled endwall.

Original languageEnglish (US)
Title of host publicationHeat Transfer
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791884171
DOIs
StatePublished - 2020
EventASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition, GT 2020 - Virtual, Online
Duration: Sep 21 2020Sep 25 2020

Publication series

NameProceedings of the ASME Turbo Expo
Volume7B-2020

Conference

ConferenceASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition, GT 2020
CityVirtual, Online
Period9/21/209/25/20

Bibliographical note

Funding Information:
The authors would like to acknowledge Solar Turbines Incorporated for their financial support and would like to thank Alex Li for his assistance in the laboratory.

Publisher Copyright:
Copyright © 2020 Solar Turbines Incorporated

Keywords

  • Film Cooling
  • Impingement Vortex
  • Passage Vortex
  • Secondary Flows
  • Turbine Aerodynamics

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