Comparisons of Pins/Dimples/Protrusions Cooling Concepts for a Turbine Blade Tip-Wall at High Reynolds Numbers

Forskningsoutput: Kapitel i bok/rapport/Conference proceedingKonferenspaper i proceeding

Abstract

The blade tip region encounters high thermal loads because of the hot gas leakage flows, and it must therefore be cooled to ensure a long durability and safe operation. A common way to cool a blade tip is to design serpentine passages with a 180 deg turns under the blade tip-cap inside the turbine blade. Improved internal convective cooling is therefore required to increase blade tip lifetime. Pins, dimples, and protrusions are well recognized as effective devices to augment heat transfer in various applications. In this paper, enhanced heat transfer of an internal blade tip-wall has been predicted numerically. The computational models consist of a two-pass channel with 180 deg turn and arrays of circular pins, hemispherical dimples, or protrusions internally mounted on the tip-wall. Inlet Reynolds numbers are ranging from 100,000 to 600,000. The overall performance of the two-pass channels is evaluated. Numerical results show that the heat transfer enhancement of the pinned-tip is up to a factor of 3.0 higher than that of a smooth tip while the dimpled-tip and protruded-tip provide about 2.0 times higher heat transfer. These augmentations are achieved at the cost of an increase of pressure drop by less than 10%. By comparing the present cooling concepts with pins, dimples, and protrusions, it is shown that the pinned-tip exhibits best performance to improve the blade tip cooling. However, when disregarding the added active area and considering the added mechanical stress, it is suggested that the usage of dimples is more suitable to enhance blade tip cooling, especially at low Reynolds numbers. [DOI: 10.1115/1.4003558]

Detaljer

Författare
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Energiteknik

Nyckelord

Originalspråkengelska
Titel på värdpublikationJournal of Heat Transfer-Transactions of The Asme
FörlagAmerican Society Of Mechanical Engineers (ASME)
Volym133
StatusPublished - 2011
PublikationskategoriForskning
Peer review utfördJa
Evenemang2nd International Conference on Thermal Issues in Emerging Technologies - Cairo, Egypten
Varaktighet: 2008 dec 172008 dec 20

Publikationsserier

Namn
Nummer6
Volym133
ISSN (tryckt)0022-1481

Konferens

Konferens2nd International Conference on Thermal Issues in Emerging Technologies
LandEgypten
OrtCairo
Period2008/12/172008/12/20