Contoured endwall flow and heat transfer experiments with combustor coolant and gap leakage flows for a turbine nozzle guide vane

Reema Saxena, Mahmood H. Alqefl, Zhao Liu, Hee Koo Moon, Luzeng Zhang, Terrence W. Simon

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

6 Scopus citations

Abstract

Flow in a high pressure gas turbine passage is complex, involving systems of secondary vortex flows and strong transverse pressure gradients. This complexity causes difficulty in providing film cooling coverage to the hub endwall region, which is subjected to high thermal loading due to combustor exit hot core gases. Therefore, an improved understanding of these flow features and their effects on endwall film cooling is needed to assist designers in developing efficient cooling schemes. The experimental study presented in this paper is performed on a linear, stationary, two-passage cascade representing the first stage nozzle guide vane of a high-pressure gas turbine. The sources of film cooling flows are the upstream combustor liner coolant and the leakage flow from the combustor-nozzle guide vane interfacial gap. Measurements are performed on an axisymmetrically-contoured endwall passage under conditions of various leakage mass flow rates to mainstream flow ratios (MFR= 0.5%, 1.0%, 1.5%). Flow migration and mixing are documented by measuring passage thermal fields and adiabatic effectiveness values over the endwall. It is found that, compared to our previous studies with a rotor inlet leakage slot geometry, the thin slot geometry of the nozzle leakage path gives a more uniform coolant spread over the endwall with significant coverage reaching the downstream and pressure-side regions of the passage. Interestingly, the coverage is seen to be only weakly dependent on the leakage mass low ratio and even reduce slightly with an increase in mass flow ratio above 1%, as indicated by lowered endwall adiabatic effectiveness values.

Original languageEnglish (US)
Title of host publicationHeat Transfer
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791849804
DOIs
StatePublished - Jan 1 2016
EventASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition, GT 2016 - Seoul, Korea, Republic of
Duration: Jun 13 2016Jun 17 2016

Publication series

NameProceedings of the ASME Turbo Expo
Volume5C-2016

Other

OtherASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition, GT 2016
CountryKorea, Republic of
CitySeoul
Period6/13/166/17/16

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