Transpiration Cooling: Contribution of Film Cooling to the Overall Cooling Effectiveness
Abstract
The overall cooling effectiveness of a plane 152 mm square transpiration wall was measured on a simulated gas turbine combustion chamber. Boundary layer temperature traverses were used to determine the film temperature adjacent to the wall, and a pseudo 'adiabatic' film cooling effectiveness. The ratio of this to the overall cooling effectiveness was used as a measure of the proportion of the overall cooling attributable to film cooling. Rigid mesh porous walls were used with three different porosities and film cooling was found to be of major importance at all coolant flow rates and dominant at high flows. Comparison of the equivalent data for full coverage discrete hole wall cooling showed that at low coolant flow rate these designs could match the film cooling effectiveness of the transpiration wall but their inferior internal wall cooling resulted in a reduced overall cooling performance.
- Publication:
-
International Journal of Turbo and Jet Engines
- Pub Date:
- September 1986
- DOI:
- 10.1515/TJJ.1986.3.2-3.245
- Bibcode:
- 1986IJTJE...3..245A
- Keywords:
-
- Combustion Chambers;
- Cooling;
- Film Cooling;
- Gas Turbine Engines;
- Sweat Cooling;
- Transpiration;
- Film Thickness;
- Temperature Profiles;
- Test Equipment;
- Thermal Boundary Layer;
- Fluid Mechanics and Heat Transfer