초록 ▼

An improved cooling design and method for cooling airfoils within a gas turbine engine is provided which includes a plenum longitudinally located within the leading edge of the airfoils. Within the plenum are positioned a plurality of turbulence promoters to provide enhance heat transfer within the

An improved cooling design and method for cooling airfoils within a gas turbine engine is provided which includes a plenum longitudinally located within the leading edge of the airfoils. Within the plenum are positioned a plurality of turbulence promoters to provide enhance heat transfer within the leading edge. Also, the cooling design includes a plurality of inlets to receive cooling air from an internal cavity of the airfoil as well as a plurality of outlets located within a trench on the exterior surface of the leading edge through which the cooling air exits to film cool leading edge.

대표청구항 ▼

1. A hollow airfoil, comprising:an internal cavity into which cooling air is flowable from an end of the airfoil; an external wall which includes suction and pressure sidewalls joined together at leading and trailing edges and extending from a first end at a platform to a second end; a stagnation li

1. A hollow airfoil, comprising:an internal cavity into which cooling air is flowable from an end of the airfoil; an external wall which includes suction and pressure sidewalls joined together at leading and trailing edges and extending from a first end at a platform to a second end; a stagnation line, said stagnation line extends spanwise along said leading edge; a longitudinally extending first plenum disposed proximate to said leading edge and said pressure sidewall; a plurality of first inlets in flow communication with said first plenum and cooling air within said cavity; a plurality of discrete first pedestals, said pedestals extend in the spanwise direction within said first plenum; a trench disposed in said external wall centered on said stagnation line, said trench extends in a spanwise direction and includes a first half and a second half, said first and second halves separated by said stagnation line; and a plurality of first exit apertures disposed adjacent said stagnation line and within said first half of said trench adjacent said pressure sidewall, said first apertures in flow communication with said first plenum; wherein cooling air enters said first plenum through said first inlets, impinges onto said first pedestals and is directed into said first apertures, said first apertures direct cooling air exiting therefrom over said stagnation line and onto said suction sidewall to film cool the airfoil. 2. The airfoil of claim 1, further including:a longitudinally extending second plenum disposed proximate to said leading edge and said suction sidewall; a plurality of second inlets in flow communication with said second plenum and cooling air within said cavity; a plurality of discrete second pedestals, said pedestals extend in the spanwise direction within said second plenum; and a plurality of second exit apertures disposed adjacent said stagnation line and within said second half of said trench adjacent said suction sidewall, said second apertures in flow communication with said second plenum; wherein cooling air enters said second plenum through said second inlets, impinges onto said second pedestals and is directed into said second exit apertures, said second exit apertures direct cooling air exiting therefrom over said stagnation line and onto said pressure sidewall to film cool the airfoil. 3. The airfoil of claim 2, further including:a plurality of third inlets in flow communication with said first plenum and cooling air within said cavity; and a plurality of third exit apertures disposed adjacent to said first exit apertures and within said pressure sidewall, said third exit apertures in flow communication with said first plenum; wherein cooling air enters said first plenum through said third inlets, impinges onto said first pedestals and is directed into said third exit apertures, said third exit apertures direct cooling air exiting therefrom onto said pressure sidewall to film cool the airfoil. 4. The airfoil of claim 3, further including:a plurality of fourth inlets in flow communication with said second plenum and cooling air within said cavity; and a plurality of fourth exit apertures disposed adjacent to said second exit apertures and within said suction sidewall, said fourth exit apertures in flow communication with said second plenum; wherein cooling air enters said second plenum through said fourth inlets, impinges onto said second pedestals and is directed into said fourth exit apertures, said fourth exit apertures direct cooling air exiting therefrom onto said suction sidewall to film cool the airfoil. 5. The airfoil of claim 2, wherein said first inlets and said second inlets alternate to form a longitudinally extending row.6. The airfoil of claim 2, wherein said first and second apertures extend in separate longitudinal rows, said first and second apertures are offset from each other.7. The airfoil of claim 4, wherein said third apertures extend in a longitudinal row, said third apertures parallel to said first apertures and said fourth apertures extend in a longitudinal row, said fourth apertures parallel to said second apertures.8. The airfoil of claim 1, wherein said first pedestals within said first plenum are shaped to promote turbulence of cooling air within said first plenum and increase the heat conduction within said leading edge.9. The airfoil of claim 2, wherein said second pedestals within said second plenum are shaped to promote turbulence of cooling air within said second plenum and increase the heat conduction within said leading edge.10. The airfoil of claim 2, wherein said first and second pedestals include a center portion and first and second segments that flare outward from said center portion, and said first and second segments of each of said first and second pedestals are aligned to form a longitudinal extending row.11. The airfoil of claim 2, wherein said first and second apertures are shaped as slots and have dimensions no greater than about 0.200 inches.12. The airfoil of claim 4, wherein said third and fourth apertures are shaped as slots.13. The airfoil of claim 1, wherein said second end is a free tip.14. The airfoil of claim 4, wherein said first and second pedestals are propeller shaped.15. The airfoil of claim 2, wherein said first and second inlets are shaped as slots.16. The airfoil of claim 4, wherein said third and fourth inlets are shaped as slots.17. The airfoil of claim 5, wherein said first and second inlets extend longitudinally along a mean camber line of the airfoil.18. A hollow airfoil, comprising:an internal cavity into which cooling air is flowable from an end of the airfoil; an external wall which includes pressure and suction sidewalls joined together at leading and trailing edges and extending from a root to a tip; a stagnation line, said stagnation line extends spanwise along said leading edge; a trench disposed in said external wall, said trench extends in a spanwise direction and includes a first half and a second half, said first and second halves separated by said stagnation line; a first cooling flow passage having a first inlet in flow communication with said internal cavity, a first outlet disposed within said first portion of said trench between said pressure sidewall and said stagnation line, and a first pedestal extending within said first cooling passage such that cooling air enters said first cooling passage through said first inlet, impinges onto said first pedestal and is directed to exit the airfoil through said first outlet to film cool the suction sidewall; and a second cooling flow passage having a first inlet in flow communication with said internal cavity, a first outlet disposed within said second portion of said trench between said suction sidewall and said stagnation line, and a second pedestal extending within said second cooling passage such that cooling air enters said second cooling passage through said first inlet of said second cooling passage, impinges onto said second pedestal and is directed to exit the airfoil through said first outlet of said second cooling passage disposed in said second portion to film cool the pressure sidewall. 19. The airfoil of claim 18, wherein said first outlet of said first cooling passage is staggered relative to said first outlet of said second cooling passage.20. The airfoil of claim 18, wherein said first cooling passage further includes:a second inlet in flow communication with said internal cavity; and a second outlet disposed within said pressure sidewall and adjacent to said leading edge; wherein cooling air enters said second inlet of said first cooling passage and impinges onto said first pedestal such that cooling air is directed to exit the airfoil through said second outlet of said first cooling passage to film cool the pressure sidewall; and said second cooling passage further includes: a second inlet in flow communication with said internal cavity; and a second outlet disposed within said suction sidewall and adjacent to said leading edge; wherein cooling air enters through said second inlet of said second cooling passage and impinges onto said second pedestal such that cooling air is directed to exit the airfoil through said second outlet of said second cooling passage to film cool the suction sidewall. 21. The airfoil of claim 20, wherein said first and second pedestals are bow-tie shaped having a center portion and first and second segments longitudinally extending from said center portion, said first cooling passage further includes:a third outlet disposed within said first portion of said trench between said pressure sidewall and said stagnation line, wherein cooling air enters said first inlet of said first cooling passage, impinges onto said center portion of said first pedestal and is directed by said first and second segments of said first pedestal to exit the airfoil through said first and third outlets of said first cooling passage to film cool the suction sidewall; and said second cooling passage further includes: a third outlet disposed within said second portion of said trench between said suction sidewall and said stagnation line, wherein cooling air enters said first inlet of said second cooling passage, impinges onto said center portion of said second pedestal and is directed by said first and second segments of said second pedestal to exit the airfoil through said first and third outlets of said second cooling passage to film cool the pressure sidewall. 22. The airfoil of claim 21, wherein said first cooling passage further includes:a fourth outlet disposed within said pressure sidewall and adjacent to said leading edge; wherein cooling air enters said second inlet of said first cooling passage, impinges onto said center portion of said first pedestal and is directed by said first and second segments of said first pedestal to exit the airfoil through said second and fourth outlets of said first cooling passage to film cool the pressure sidewall; and said second cooling passage further includes: a fourth outlet disposed within said suction sidewall and adjacent to said leading edge; wherein cooling air enters said second inlet of said second cooling passage, impinges onto said center portion of said second pedestal and is directed by said first and second segments of said second pedestal to exit the airfoil through said second and fourth outlets of said second cooling passage to film cool the suction sidewall. 23. The airfoil of claim 21, wherein said first cooling passage further includes:a third inlet in flow communication with said cavity; and a third pedestal extending within said first cooling passage, said third pedestal is bow-tie shaped having a center portion and first and second segments longitudinally extending from said center portion; wherein cooling air enters said first inlet of said first cooling passage and impinges onto said center portion of said first pedestal and is directed by said first segment of said first pedestal to exit the airfoil through said first outlet of said first cooling passage to film cool the suction sidewall and cooling air enters said third inlet of said first cooling passage and impinges onto said center portion of said third pedestal, and is directed by said second segment of said third pedestal to exit the airfoil through said first outlet of said first cooling passage to film cool the suction sidewall; and said second cooling passage further includes: a third inlet in flow communication with said cavity; and a fourth pedestal extending within said first cooling passage, said fourth pedestal is bow-tie shaped having a center portion and first and second segments longitudinally extending from said center portion; wherein cooling air enters said first inlet of said second cooling passage and impinges onto said center portion of said second pedestal and is directed by said first segment of said second pedestal to exit the airfoil through said first outlet of said second cooling passage to film cool the pressure sidewall and cooling air enters said third inlet of said second cooling passage and impinges onto said center portion of said fourth pedestal, and is directed by said second segment of said fourth pedestal to exit the airfoil through said first outlet of said second cooling passage to film cool the pressure sidewall. 24. The airfoil of claim 18, wherein said first inlets are shaped as slots and have a length no greater than 0.030 inches and said first outlets are shaped as slots and have a length no greater than about 0.2 inches.25. The airfoil of claim 23, wherein said first inlets and said third inlets of said first and second cooling passages alternate to form a longitudinally extending row.26. The airfoil of claim 18, wherein said first and second pedestals are shaped to promote turbulence of cooling air and increase the heat conduction within said leading edge.27. The airfoil of claim 20, wherein said second inlets are shaped as slots and have a length no greater than 0.030 inches and said second outlets are shaped as slots and have a length no greater than about 0.2 inches.28. The airfoil of claim 18, wherein said second end is a free tip.29. A method for cooling a leading edge of a hollow airfoil suitable for use in gas turbine, comprising the steps of:providing cooling flow from a cooling fluid source to flow into the inlet; and fabricating a microcircuit within the leading edge, the microcircuit comprising: a longitudinally extending plenum disposed proximate to the leading edge: a plurality of inlets in flow communication with the plenum through which cooling flow may enter; a plurality of discrete pedestals, the pedestals extend in the spanwise direction within the plenum; a trench disposed in the leading edge, the trench extends in a spanwise direction; and a plurality of first exit apertures disposed within the trench, the first exit apertures in flow communication with the plenum, the first exit apertures transitions the cooling flow from the plenum to a region exterior to the leading edge of the airfoil to film cool the leading edge. 30. The method of claim 29, wherein the fabricating the microcircuit comprises the steps of:fashion a refractory metal into the form of the plenum and the discrete pedestals; inserting the refractory metal into a mold for casting the airfoil; and removing the refractory metal from the airfoil after casting. 31. The method of claim 30, wherein the airfoil is fabricated from a metal selected from the group consisting of nickel based alloys and cobalt based alloys.32. The method of claim 30, wherein the pedestal has a length no greater than about 0.150 inches and the inlets have a dimension no greater than 0.030 inches and the exit apertures have a dimension no greater than about 0.200 inches.