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Step-down turbine platform

Imported: 24 Feb '17 | Published: 06 Jan '04

Leslie Eugene Leeke, Sean Robert Keith, Lawrence Paul Timko

USPTO - Utility Patents

Abstract

A turbine includes a row of blades each having an integral airfoil, platform, and dovetail. Each platform has opposite first and second side edges corresponding with the opposite pressure and suction sides of the airfoil. The platform first side edge is radially higher than the platform second side edge continuously between opposite forward and aft edges of the platform. In this way, adjacent platforms define a down step therebetween for preventing obstruction of combustion gases flowable downstream thereover.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, in accordance with preferred and exemplary embodiments, together with further objects and advantages thereof, is more particularly described in the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is an axial sectional view of a portion of a turbofan aircraft gas turbine engine including a combustor discharging combustion gases through a high pressure turbine nozzle and turbine in accordance with an exemplary embodiment of the present invention.

FIG. 2 is an isometric view of two adjacent turbine blades in accordance with the exemplary embodiment illustrated in FIG.

1.

FIG. 3 is a radial sectional view through the vanes and blades of the turbine illustrated in FIG.

1 and taken along line

3

3.

Claims

1. A turbine comprising:

2. A turbine according to claim 1 wherein said platform first and second edges are oblique to said forward and aft edges, with said first edge being spaced from said airfoil leading edge greater than from said airfoil trailing edge, and said down step faces said airfoil suction side of an adjacent platform between said leading and trailing edges.

3. A turbine according to claim 2 wherein said platform first and second edges and down step are straight.

4. A turbine according to claim 3 wherein said airfoil is disposed diagonally in section atop said platform for channeling said combustion gases downstream over said down step from said platform forward edge to said aft edge.

5. A turbine according to claim 4 wherein said down step is substantially uniform in height between said platform forward and aft edges.

6. A turbine according to claim 4 wherein said platform first edge is radially higher than said platform inboard therefrom by about half said down step, and said platform second edge is radially lower than said platform inboard therefrom by about half said down step.

7. A turbine according to claim 4 further comprising a turbine nozzle disposed upstream from said row of turbine blades, and including a row of nozzle vanes configured for directing said combustion gases downstream between said turbine blades in streamlines directed obliquely across said platform first side edges for step-down over adjacent platform second side edges from said forward to aft edges.

8. A turbine comprising:

9. A turbine according to claim 8 wherein said airfoil is disposed diagonally in section atop said platform for channeling said combustion gases downstream over said down step from said platform forward edge to said aft edge.

10. A turbine according to claim 9 wherein said platform first and second edges and down step are straight.

11. A turbine according to claim 10 wherein said platform first and second edges are oblique to said forward and aft edges, with said first edge being spaced from said airfoil leading edge greater than from said airfoil trailing edge, and said down step faces said airfoil suction side of an adjacent platform between said leading and trailing edges.

12. A turbine according to claim 11 wherein said platform first edge is radially higher than said platform inboard therefrom by about half said down step, and said platform second edge is radially lower than said platform inboard therefrom by about half said down step.

13. A turbine according to claim 12 wherein said down step is substantially uniform in height between said platform forward and aft edges.

14. A turbine blade comprising:

15. A blade according to claim 14 wherein said platform first and second edges are oblique to said forward and aft edges, with said first edge being spaced from said airfoil leading edge greater than from said airfoil trailing edge.

16. A blade according to claim 15 wherein said platform first and second edges are straight.

17. A blade according to claim 16 wherein said airfoil is disposed diagonally in section atop said platform for channeling combustion gases downstream over said platform first side edge from said forward edge to said aft edge.

18. A blade according to claim 17 wherein said platform first edge is radially higher than said platform inboard therefrom by about half said down step, and said platform second edge is radially lower said platform inboard therefrom by about half said down step.