TY - GEN
T1 - Aerodynamic loss characteristics of a turbine blade with trailing edge coolant ejection
T2 - ASME Turbo Expo 2000: Power for Land, Sea, and Air, GT 2000
AU - Uzol, Oʇuz
AU - Camci, Cengiz
AU - Glezer, Boris
N1 - Publisher Copyright:
Copyright © 2000 by ASME.
PY - 2000
Y1 - 2000
N2 - The internal fluid mechanics losses generated between the blade plenum chamber and a reference point located just downstream of the trailing edge are investigated for a turbine blade trailing edge cooling system. The discharge coefficient Cd is presented as a function of the free stream Reynolds number, cut-back length, spanwise rib spacing and chordwise rib length. The results are presented in a wide range of coolant to free stream mass flow rate ratios. The losses from the cooling system show strong free stream Reynolds number dependency especially at low ejection rates when they are correlated against the coolant to free stream pressure ratio. However, when Cd is correlated against a coolant to free stream mass flow rate ratio, the Reynolds number dependency is eliminated. The current data clearly shows that internal viscous losses due to varying rib lengths do not differ significantly. The interaction of the external wall jet in the cutback region with the free stream fluid is also a strong contributor to the losses. Since the discharge coefficients do not have Reynolds number dependency at high ejection rates, Cd experiments can be performed at a low free stream Reynolds number. Running a discharge coefficient experiment at low Reynolds number (or even in still air) will sufficiently define the high blowing rate portion of the curve. This approach is extremely time efficient and economical in finding worst possible Cd value for a given trailing edge coolant system.
AB - The internal fluid mechanics losses generated between the blade plenum chamber and a reference point located just downstream of the trailing edge are investigated for a turbine blade trailing edge cooling system. The discharge coefficient Cd is presented as a function of the free stream Reynolds number, cut-back length, spanwise rib spacing and chordwise rib length. The results are presented in a wide range of coolant to free stream mass flow rate ratios. The losses from the cooling system show strong free stream Reynolds number dependency especially at low ejection rates when they are correlated against the coolant to free stream pressure ratio. However, when Cd is correlated against a coolant to free stream mass flow rate ratio, the Reynolds number dependency is eliminated. The current data clearly shows that internal viscous losses due to varying rib lengths do not differ significantly. The interaction of the external wall jet in the cutback region with the free stream fluid is also a strong contributor to the losses. Since the discharge coefficients do not have Reynolds number dependency at high ejection rates, Cd experiments can be performed at a low free stream Reynolds number. Running a discharge coefficient experiment at low Reynolds number (or even in still air) will sufficiently define the high blowing rate portion of the curve. This approach is extremely time efficient and economical in finding worst possible Cd value for a given trailing edge coolant system.
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U2 - 10.1115/2000-GT-0258
DO - 10.1115/2000-GT-0258
M3 - Conference contribution
AN - SCOPUS:84955278526
T3 - Proceedings of the ASME Turbo Expo
BT - Heat Transfer; Electric Power; Industrial and Cogeneration
PB - American Society of Mechanical Engineers (ASME)
Y2 - 8 May 2000 through 11 May 2000
ER -