초록 ▼

A turbine blade is provided comprising: an airfoil including an airfoil outer wall extending radially outwardly from a blade root, a squealer tip section located at an end of the airfoil distal from the root, and cooling structure. The squealer tip section comprises a blade tip surface including pre

A turbine blade is provided comprising: an airfoil including an airfoil outer wall extending radially outwardly from a blade root, a squealer tip section located at an end of the airfoil distal from the root, and cooling structure. The squealer tip section comprises a blade tip surface including pressure and suction edges joined together at chordally spaced-apart leading and trailing edges of the airfoil, and a squealer tip rail. At least a substantial portion of the squealer tip rail is located near the blade tip surface suction edge. The cooling structure directs cooling fluid toward the squealer tip rail to effect impingement cooling of the rail after the cooling fluid has convectively cooled at least a portion of the airfoil outer wall. Cooling fluid is also deflected by the squealer tip rail so as to yield a very small effective flow area above the squealer tip section through which hot working gases may flow.

대표청구항 ▼

1. A turbine blade comprising: an airfoil including an airfoil outer wall extending radially outwardly from a blade root;a squealer tip section located at an end of said airfoil distal from said root, said squealer tip section comprising a blade tip surface including pressure and suction edges joine

1. A turbine blade comprising: an airfoil including an airfoil outer wall extending radially outwardly from a blade root;a squealer tip section located at an end of said airfoil distal from said root, said squealer tip section comprising a blade tip surface including pressure and suction edges joined together at chordally spaced-apart leading and trailing edges of said airfoil and a squealer tip rail, wherein at least a substantial portion of said squealer tip rail is located near said blade tip surface suction edge; andcooling structure directing cooling fluid toward said squealer tip rail to effect impingement cooling of said rail after said cooling fluid has convectively cooled at least a portion of said airfoil outer wall. 2. The turbine blade as set out in claim 1, wherein said squealer tip rail comprises a sole rail associated with said blade tip surface. 3. The turbine blade as set out in claim 1, wherein said cooling structure comprises pressure-side cooling holes in communication with a cooling fluid circuit within said airfoil, said pressure-side cooling holes extending toward said squealer tip rail to effect impingement cooling of said tip rail. 4. The turbine blade as set out in claim 3, wherein said squealer tip rail comprises a deflector portion including a curved and concaved side surface substantially facing said blade tip surface pressure edge. 5. The turbine blade as set out in claim 4, wherein said pressure-side cooling holes are located such that said cooling fluid exiting said pressure-side cooling holes contacts said concave side surface of said squealer tip rail deflector portion and deflects toward said blade tip surface pressure edge to push hot gas away from said squealer tip rail. 6. The turbine blade as set out in claim 5, wherein said pressure-side cooling holes extend substantially parallel to said blade tip surface. 7. The turbine blade as set out in claim 6, wherein said cooling structure further comprises suction-side cooling holes in communication with said cooling fluid circuit within said airfoil, said suction-side cooling holes extending toward said squealer tip rail to effect further impingement cooling of said tip rail. 8. The turbine blade as set out in claim 7, wherein said squealer tip rail further comprises an intermediate portion and an aft portion substantially facing said blade tip surface suction edge, said aft portion including a curved lower part. 9. The turbine blade as set out in claim 8, wherein cooling fluid emitted from said suction-side cooling holes strikes said curved lower part and flows towards a stationary outer air seal so as to reduce an amount of hot gases flowing through a gap located between said tip section and said stationary outer air seal. 10. The turbine blade as set out in claim 7, wherein said cooling fluid circuit comprises: first cooling channels located near said airfoil outer wall suction sidewall to convectively cool the suction sidewall; andsecond cooling channels located near said airfoil outer wall pressure sidewall to convectively cool the pressure sidewall. 11. A turbine blade comprising: an airfoil including an airfoil outer wall extending radially outwardly from a blade root, said outer wall having pressure and suction sidewalls;a squealer tip section located at an end of said airfoil distal from said root, said squealer tip section comprising a blade tip surface including pressure and suction edges joined together at chordally spaced-apart leading and trailing edges of said airfoil and a squealer tip rail, wherein at least a substantial portion of said squealer tip rail is located near said blade tip surface suction edge; andcooling structure directing cooling fluid through forward and back portions of said squealer tip section toward said squealer tip rail. 12. The turbine blade as set out in claim 11, wherein said squealer tip rail comprises a sole rail associated with said blade tip surface. 13. The turbine blade as set out in claim 12, wherein at least a substantial portion of said squealer tip rail is spaced away from said blade tip surface pressure edge. 14. The turbine blade as set out in claim 13, wherein said squealer tip rail comprises a deflector portion comprising a curved and concaved side-surface substantially facing said blade tip surface pressure edge. 15. The turbine blade as set out in claim 14, wherein said squealer tip rail further comprises an intermediate portion and an aft portion. 16. The turbine blade as set out in claim 15, wherein said cooling structure comprises pressure-side cooling holes in communication with a cooling fluid circuit within said airfoil, said pressure-side cooling holes extending toward said squealer tip rail deflector portion, wherein cooling fluid passing through said pressure-side cooling holes serves to convectively cool said forward portion of said squealer tip section. 17. The turbine blade as set out in claim 16, wherein said cooling fluid exiting said pressure-side cooling holes contacts said concave side surface of said squealer tip rail deflector portion and deflects toward said blade tip surface pressure edge to push hot gas away from said squealer tip rail. 18. The turbine blade as set out in claim 17, wherein said cooling structure further comprises suction-side cooling holes in communication with said cooling fluid circuit within said airfoil, said suction-side cooling holes extending toward said squealer tip rail, wherein cooling fluid passing through said suction-side cooling holes serves to convectively cool said back portion of said blade tip section. 19. The turbine blade as set out in claim 18, wherein said cooling fluid circuit comprises first cooling channels located near said airfoil outer wall suction sidewall, said suction-side cooling holes communicating with said first cooling channels. 20. The turbine blade as set out in claim 19, wherein said cooling fluid circuit comprises second cooling channels located near said airfoil outer wall pressure sidewall, said pressure-side cooling holes communicating with said second cooling channels.