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International Journal of Rotating Machinery
Volume 4 (1998), Issue 3, Pages 163-174

Effect of Film Injection Location on Local Heat Transfer Coefficient on a Gas Turbine Blade

Turbine Heat Transfer Laboratory, Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA

Received 10 March 1997; Revised 24 March 1997

Copyright © 1998 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Experiments were performed to study the effect of film hole location on local heat transfer coefficient distribution of a turbine blade model with air or CO2 film injection to simulate coolant density effect. Tests were performed on a five blade linear cascade at the chord Reynolds number of 3×105 at cascade inlet. The test blade had three rows of film holes in the leading edge region and two rows each on the pressure and suction surfaces. Film hole locations were varied by leaving the desired ones open and plugging the rest. A combination of turbulence grid and unsteady wake was used to generate upstream high turbulence condition. Results indicate that film injection by itself causes a substantial increase in Nusselt numbers over a blade model without film holes. An increase in mainstream turbulence intensity causes an increase in Nusselt numbers over most of the blade surface, for both coolants, and at all blowing ratios. Film injection promotes an earlier boundary layer transition on the suction surface and the onset of transition depends on the film injection location; but at high turbulence levels, transition location is almost independent of film injection location.