Effects of High Freestream Turbulence and Conduction on Film Cooling Effectiveness of Shaped Holes
Technical Report,01 Sep 2018,01 Mar 2020
AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH WRIGHT-PATTERSON AFB United States
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This investigation studied overall effectiveness for a cylindrical hole and a laidback fan-shaped hole over a range of coolant flow rates and freestream turbulence intensities. Increasing the turbulence intensity resulted in lower overall effectiveness values due to increased heat transfer coefficients. Increasing Reynolds number also decreased the overall effectiveness due to the increased external heat transfer coefficient. Increasing the internal heat transfer coefficient resulted in increased overall effectiveness due to lower temperatures in the coolant channel drawing heat from the external surface. Increasing the coolant flow rate resulted in lower airfoil temperatures upstream and downstream of the channel due to an increase in conductive heat flux through the airfoil. Conduction in the rig caused the temperature of the coolant to dramatically increase within a short distance. This implies that in a turbine engine, the density of the coolant entering the cooling holes is significantly lower than the density in the coolant line.