Library Subscription: Guest
Home Archives Officers Future meetings Assembly for International Heat Transfer Conferences
International Heat Transfer Conference 15

ISSN: 2377-424X (online)
ISSN: 2377-4371 (flashdrive)

Effect of Swirled Leakage Flow on Endwall Film-Cooling

DOI: 10.1615/IHTC15.gtb.009600
pages 3383-3398

Matthew Stinson
Heat Transfer Laboratory, Department of Mechanical Engineering, University of Minnesota, MN 55455

Richard J. Goldstein
Heat Transfer Laboratory, Department of Mechanical Engineering, University of Minnesota Twin Cities, 111 Church St SE, Minneapolis, MN-55455, USA

Terrence W. Simon
Department of Mechanical Engineering, University of Minnesota, 111 Church St. S.E., Minneapolis, Minnesota 55455, USA

Shu Fujimoto
IHI Corporation

Chiyuki Nakamata
IHI Corporation


KEY WORDS: Convection, Gas turbine, Film-Cooling, Mass Transfer, Naphthalene Sublimation

Abstract

Mass transfer measurements are performed on the endwall surface in a five-blade linear cascade to study the effect of swirled leakage flow on endwall film-cooling. A 45 deg inclined slot equipped with turning vanes upstream of the blades is used to model the leakage flow path between the stator and rotor. The turning vanes are used to impart swirl on the leakage flow, which simulates the relative motion between the stator and rotor walls found in a rotating cascade. For a Reynolds number of 6x10e5, based on blade chord and cascade exit velocity, a parametric study was conducted for three turning vane angles and three leakage flow blowing ratios. The effects on both mass transfer coefficient and film-cooling effectiveness were determined by injecting naphthalene-free and naphthalene-saturated air through the leakage flow slot upstream of the blade row. Endwall film-cooling coverage was found to improve with increased leakage flow rates and with decreased swirl angles (zero swirl defined as leakage flow aligned with axial direction, positive swirl defined as leakage flow angled towards suction surface). Endwall mass transfer coefficients were found to increase with increased leakage flow rates. The leakage flow path was found to be strongly influenced by the endwall secondary flows for the low leakage flow rates. At high leakage flow rates, the swirl angle was the primary determinant for where the leakage flow traveled. For realistic leakage flow rates and swirl angles, leakage flow alone was found to do a poor job at providing coolant coverage on the endwall surface. The downstream half and the pressure side of the endwall surface were found to be especially difficult to cool, so additional cooling sources, such as discrete film cooling holes, should be utilized to provide more complete coolant coverage.

Download article Publication Ethics and Malpractice Recommend to my Librarian Bookmark this Page