Flow migration and mixing in a high pressure turbine rotor passage with axisymmetrically contoured endwall and leakage flow

Reema Saxena, Arya Ayaskanta, Terrence W Simon, Hee Koo Moon, Luzeng J. Zhang

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

2 Scopus citations

Abstract

The flow field in the passage of a high pressure gas turbine is quite complex, involving strong secondary flows, transverse pressure gradients and strong streamwise acceleration. This complexity may have an adverse effect on cooling of the hub endwall, which is subjected to high thermal loading due to the flat combustor exit temperature profile of modern low-NOx systems. Therefore, given material limitations, better cooling management techniques that can be included with certainty in new gas turbine designs are needed. In the present study, film cooling has been investigated experimentally in a stationary linear cascade. The flow is representative of a high pressure gas turbine rotor with combustor liner coolant introduced to the approach flow. Focus is on the endwall axisymmetric contouring and the cooling effect of leakage flow bled from the compressor through the stator-rotor disc cavity. Two endwall contours, 'shark nose' (gradual slope over a larger distance) and 'dolphin nose' (steep slope over a shorter distance), are considered and comparison is made under conditions of three mass flow rates (MFR) of leakage, 0.5%, 1.0% and 1.5% of the approach flow rate. The performance of both endwall contours is compared at different streamwise locations in terms of adiabatic effectiveness values over the endwall. This study gives enhanced insight into the physics of coolant flow mixing, migration and subsequent coverage over the endwall. The results show the cooling effects of the contoured shapes over a range of leakage flow rates in the strong secondary flow environment. It is found that the leakage flow plays a crucial role in enhancing coolant coverage over the endwall. To add to our knowledge of mixing effects, detailed thermal field data are taken in the leakage flow discharge region. Doing so helps explain the behavior of the flow as it is ejected into the passage and interacts with the mainstream flow.

Original languageEnglish (US)
Title of host publicationHeat Transfer
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791856727, 9780791856727
DOIs
StatePublished - Jan 1 2015
EventASME Turbo Expo 2015: Turbine Technical Conference and Exposition, GT 2015 - Montreal, Canada
Duration: Jun 15 2015Jun 19 2015

Publication series

NameProceedings of the ASME Turbo Expo
Volume5B

Other

OtherASME Turbo Expo 2015: Turbine Technical Conference and Exposition, GT 2015
CountryCanada
CityMontreal
Period6/15/156/19/15

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