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Glossary

What are transonic airfoils, and what is the active clearance control? Check out our technical dictionary and find out more about engine technology terms – from active clearance control to velocity triangle.
Scanning electron microscopy Shaped holes Shot peening Silver-plating Single-crystal turbine blades Skeleton line Slurry coatings Soft annealing Solid-film lubricants Specific work of a stage Stage Steel shot peening STEM drilling Straight cascade Stress-relieving Sulphuric acid DC anodizing Supersonic aircraft

Shaped holes

High-pressure turbine blades and vanes must be cooled to be able to withstand the high turbine inlet temperatures. The cooling air required is taken from the compressor, i.e. this air volume is no longer available for combustion and thrust generation. This calls for an efficient use of the cooling air. In new engine designs, therefore, shaped holes are provided in addition to the cylindrical cooling air holes. Their thermo-dynamically optimized flared geometry increases the cooling effectiveness with the air volume remaining the same.
 
 
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