Turbine airfoil trailing edge with micro cooling channels

Abstract

The present invention provides active convection cooling through micro channels within or adjacent to a bond coat layer applied to the trailing edge of a turbine engine high pressure airfoil. When placed adjacent to or within a porous TBC, the micro channels additionally provide transpiration cooling through the porous TBC. The micro channels communicate directly with at least one cooling circuit contained within the airfoil from which they receive cooling air, thereby providing direct and efficient cooling for the bond coat layer. Because the substrate includes an actively cooled flow path surface region that can reduce the cooling requirement for the substrate, the engine can run at a higher firing temperature without the need for additional cooling air, achieving a better, more efficient engine performance. In one embodiment, a metallic bond coat is added to an airfoil with pressure side bleed film cooling slots. The bond coat is grooved such that the grooves are structured, with at least one structured micro groove communicating with at least one cooling fluid supply contained within the airfoil. A TBC layer is applied, using a shadowing technique, over the structured grooves, resulting in the formation of hollow micro channels for the transport of the cooling fluid. In different embodiments, the location of the structured grooves, hence, the resulting micro channels are placed within the airfoil substrate at the substrate/bond coat interface or within the TBC layer.

Dependencies are inferred from the claim text.