Effusion cooling holes
A turbine component includes a structure having hot and cold surfaces opposite each other; and a plurality of cooling holes extending between the cold and hot surfaces, each of the cooling holes including at least one projection or recess element to form part of a fluid path surface with enhanced in-hole heat convection.
1. A combustor liner of a gas turbine engine, comprising:
a structure having a hot surface for being exposed to a flow of hot combustion gases and a cold surface for being exposed to cooling air, the hot and cold surfaces being opposite each other; and
a plurality of cooling holes extending through a body of the structure from the cold surface to the hot surface, at least one of the cooling holes including a straight section substantially parallel to the hot surface, an inlet section extending from the straight section toward the cold surface to define an inlet opening on the cold surface, and a flared section extending and flaring from the straight section toward the hot surface to define an outlet opening on the hot surface, at least one of the cooling holes including at least one projection or recess element to form part of a fluid path surface to enhance in-hole heat convection, the at least one of the cooling holes extending from the inlet opening to the outlet opening generally in a same direction as that of the flow of hot combustion gases, the inlet opening upstream of the outlet opening relative to the direction of the flow of hot combustion gases, the at least one of the cooling holes having an inner surface on which the at least one projection or recess element is formed, a cross-sectional area of the at least one of the cooling holes at the inner surface decreasing within the straight section from the inlet opening to the flared section and increasing within the flared section to the outlet opening, the outlet opening being at the end of the flared section, wherein the at least one projection or recess is located upstream of the flared section.
2. The combustor liner as defined in claim 1 wherein a plurality of projections or recess elements including said at least one projection or recess element is provided in a form of a plurality of ribs projecting from the inner surface of the at least one of the cooling holes.
3. The combustor liner as defined in claim 2 wherein the plurality of ribs are spaced apart one from another along a length of the at least one of the cooling holes.
4. The combustor liner as defined in claim 1 wherein at least one of the cooling holes defines a central axis extending at an oblique angle with respect to the hot surface.
5. The combustor liner as defined in claim 1 wherein the at least one projection or recess element is located in the straight section.
6. The combustor liner as defined in claim 1 wherein the straight section comprises opposed inner surfaces substantially parallel to the hot surface, the at least one projection or recess element being positioned on one of the opposed inner surfaces that faces away from and is adjacent the hot surface.
7. The combustor liner as defined in claim 6 wherein a plurality of projection or recess elements including said at least one projection or recess element is provided in a form of a plurality of ribs projecting into a fluid path of the straight section and extending transverse with respect to the fluid path of the straight section.
8. The combustor liner as defined in claim 6 wherein a plurality of projection or recess elements including said at least one projection or recess element is provided in a form of a plurality of V shaped ribs projecting into a fluid path of the straight section and extending divergently toward the flared section.
9. A combustor liner comprising a hot surface for being exposed to hot combustion gases and a cold surface for being exposed to cooling air, the hot and cold surfaces being opposite each other, and a plurality of cooling holes extending between the cold and hot surfaces, at least one of the cooling holes including a straight section substantially parallel to the hot surface, an inlet section extending from the straight section toward the cold surface to define an inlet opening on the cold surface, and a flared section extending and flaring from the straight section toward the hot surface to define an outlet opening on the hot surface, wherein the inlet opening is disposed upstream of the outlet opening relative to a direction of flow of the hot combustion gases over the hot surface, and at least one projection or recess element being provided on an inner surface of the at least one of the cooling holes to enhance in-hole heat convection, the at least one of the cooling holes having the inner surface on which the at least one projection or recess element is formed, a cross-sectional area of the at least one of the cooling holes at the inner surface decreasing within the straight section from the inlet opening to the flared section and increasing within the flared section to the outlet opening, the outlet opening defined at an end of the flared section, wherein the at least one projection or recess is located upstream of the flared section.
10. The combustor liner as defined in claim 9 wherein the at least one projection or recess element comprises a plurality of ribs projecting from the inner surface of the respective cooling hole.
11. The combustor liner as defined in claim 9 wherein the at least one projection or recess element comprises a plurality of ribs located in the straight section.
12. The combustor liner as defined in claim 11 wherein the straight section comprises opposed inner surfaces substantially parallel to the hot surface, the plurality of ribs being positioned on one of the opposed inner surfaces that faces away from and adjacent the hot surface, and wherein said plurality of ribs comprise at least one V shaped rib extending divergently toward the flared section and being positioned closer to the flared section with respect to the remaining ribs.