Impinging jets are often employed within the leading edge of turbine blades and vanes to combat the tremendous heat loads incurred as the hot exhaust gases stagnate along the exterior of the airfoil. Relative to traditional cylindrical jets, racetrack shaped impinging jets have been shown to produce favorable cooling characteristics within the turbine airfoil. This investigation experimentally and numerically quantifies the cooling characteristics associated with a row of racetrack shaped jets impinging on a concave, cylindrical surface. Detailed Nusselt number distributions are obtained using both a transient liquid crystal technique and commercially available CFD software (Star CCM+ from CD-Adapco). Three geometrical jet inlet and exit conditions are experimentally investigated: a square edge, a partially filleted edge (r/dH,Jet = 0.25), and a fully filleted edge (r/dH,Jet = 0.667). Additionally, to investigate the effect of high crossflow velocities at the inlet of the jet, a portion of the flow supplied to the test apparatus radially bypasses the impingement section. Thus, the mass flow rate into the test section is varied to achieve the desired inlet crossflow conditions and jet Reynolds numbers. As a result, jet Reynolds numbers (ReJet) of 11500 and 23000 are investigated at supply duct Reynolds numbers (ReDuct) of 20000 and 30000. The results are compared to baseline cases where no mass bypasses the test section. Additionally, the relative jet – to – jet spacing (s/dH,Jet) is maintained at 8, the relative jet – to – target surface spacing (z/dH,Jet) is 4, the target surface curvature – to – jet hydraulic diameter (D/dH,Jet) is 5.33, and the relative thickness of the jet plate (t/dH,Jet) is 1.33. Measurements indicate that the addition of fillets at the edges of the jet orifice and the introduction of significant crossflow velocity at the inlet of the jet can significantly degrade the cooling characteristics on the leading edge of the turbine blade. The magnitude of such degradation generally increases with increasing fillet size and inlet crossflow velocity. The V2F model is adequate for predicting the flow field and target surface heat transfer in the absence of inlet crossflow; however, it is believed the turbulence within the jet is overpredicted by the CFD leading to elevated heat transfer coefficients (compared to the experimental results).
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ASME Turbo Expo 2013: Turbine Technical Conference and Exposition
June 3–7, 2013
San Antonio, Texas, USA
Conference Sponsors:
- International Gas Turbine Institute
ISBN:
978-0-7918-5514-0
PROCEEDINGS PAPER
Leading Edge Impingement With Racetrack Shaped Jets and Varying Inlet Supply Conditions
C. Neil Jordan,
C. Neil Jordan
Baylor University, Waco, TX
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Cassius A. Elston,
Cassius A. Elston
Baylor University, Waco, TX
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Lesley M. Wright,
Lesley M. Wright
Baylor University, Waco, TX
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Daniel C. Crites
Daniel C. Crites
Honeywell Aerospace, Phoenix, AZ
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C. Neil Jordan
Baylor University, Waco, TX
Cassius A. Elston
Baylor University, Waco, TX
Lesley M. Wright
Baylor University, Waco, TX
Daniel C. Crites
Honeywell Aerospace, Phoenix, AZ
Paper No:
GT2013-94611, V03AT12A020; 13 pages
Published Online:
November 14, 2013
Citation
Jordan, CN, Elston, CA, Wright, LM, & Crites, DC. "Leading Edge Impingement With Racetrack Shaped Jets and Varying Inlet Supply Conditions." Proceedings of the ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. Volume 3A: Heat Transfer. San Antonio, Texas, USA. June 3–7, 2013. V03AT12A020. ASME. https://doi.org/10.1115/GT2013-94611
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