Suscripción a Biblioteca: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

EFFECTS OF ROTATION ANGLE OF TEARDROP-SHAPED DIMPLES ON HEAT TRANSFER ENHANCEMENT OF AIRFOIL INTERNAL COOLING INVESTIGATED BY TRANSIENT TECHNIQUE

Get access (open in a dialog) DOI: 10.1615/IHTC16.hte.023228
pages 5537-5542

Sinopsis

Sophisticated cooling technologies are essential to cool gas turbine airfoils, as the hot gas temperature in gas turbines is far above the permissible metal temperatures to maximize the thermal efficiency. Internal cooling is widely used in modern gas turbine airfoils for the high cooling performance. Among different internal cooling techniques, teardrop-shaped dimple surface is a prominent method for high heat transfer performance and low pressure drop. In the present study, in order to investigate the effects of rotation-angle of teardrop-shaped dimples on heat transfer enhancement, experiments were performed by transient technique with compensation of three-dimensional heat conduction analysis. Three-dimensional thermal conductivity analysis was performed by finite volume method in OpenFOAM. The vertical direction temperature gradient on the dimpled surface was calculated for the Reynolds number in a range of 16,000 to 36,000. Five different rotation angles were examined in the present study, where whole 0 deg dimpled surface was rotated by 15, 30, 45, and 60 deg. The experimental results revealed that the highest heat transfer occurred at 30 deg rotated dimpled surface at the Reynolds number of 16,000 to 36,000. The highest friction factor was found at 30 deg dimpled surface and lowest friction factor found for 0 deg dimpled surface. The overall heat transfer performance of the airfoil internal cooling was evaluated in terms of heat transfer efficiency index and the maximum value was found for 30 deg rotated dimpled surface.