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

[摘要] 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 of3×105at cascade inlet. The test blade had three rows of film holes inthe leading edge region and two rows each on the pressure and suction surfaces. Film holelocations were varied by leaving the desired ones open and plugging the rest. A combinationof turbulence grid and unsteady wake was used to generate upstream high turbulencecondition. Results indicate that film injection by itself causes a substantial increase inNusselt numbers over a blade model without film holes. An increase in mainstreamturbulence 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 boundarylayer transition on the suction surface and the onset of transition depends on the filminjection location; but at high turbulence levels, transition location is almost independent offilm injection location.

[学科分类] 力学，机械学