Compressor variable vane assembly

Patent metadata

Field	Value
Publication number	US-9533485-B2
Application number	US-201414228616-A
Country	US
Kind code	B2
Filing date	Mar 28, 2014
Priority date	Mar 28, 2014
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

A variable vane assembly for a gas turbine engine compressor and method of manufacturing same is described. A plurality of projections the inner and/or outer shroud which protruded into the annular gas path such as to ensure that a radial clearance gap, defined between the projections and a vane airfoil overhang portion, remains substantially constant throughout a substantial portion of the vane pivot arc of the variable vane. The method includes forming one cavities within the shroud, the cavities isolated from the annular gas path and disposed radially beneath at least each of the projections, and providing one or more structural reinforcing elements within the cavities.

First claim

The invention claimed is:

1. A method of manufacturing a variable vane assembly for a compressor of a gas turbine engine, the variable vane assembly including an inner shroud and an outer shroud radially spaced apart from each other to define therebetween an annular gas path through which a plurality of variable vanes radially extend between the inner and outer shrouds, each of the variable vanes is pivotable through a vane pivot arc about a respective span-wise vane axis and has a vane airfoil with an overhang portion disposed at a trailing edge thereof, the method comprising:
forming a plurality of projections on at least one of the inner and outer shrouds, the projections protruding from an annular boundary surface into the annular gas path, each of the projections being at least partially circumferentially disposed between two of said variable vanes and located adjacent the overhang portion of each of said vane airfoils, including:
forming one or more enclosed cavities within said at least one of the inner and outer shrouds, the cavities being isolated from the annular gas path and disposed radially beneath at least each of the projections;
providing one or more structural reinforcing elements within said one or more cavities; and
forming the projections over said one or more structural reinforcing elements to have at least one angled planar surface that is substantially parallel to a plane defined by a terminal edge of the overhang portion of the variable vanes when pivoted through said vane pivot arc, and ensuring that a radial clearance gap, defined between the angled planar surface of the projection and the terminal edge of the vane airfoil overhang portion, remains substantially constant throughout a substantial portion of the vane pivot arc of the variable vane.

2. The method of claim 1 , further comprising separately forming the structural reinforcing elements as inserts, and inserting the inserts into said one or more cavities.

3. The method of claim 2 , wherein a body of the inner and outer shrouds is formed from a first material, further comprising forming the inserts to be lighter in weight than a corresponding solid filling said one or more cavities and made of said first material.

4. The method of claim 3 , further comprising forming the inserts from a second material different from and lighter than the first material.

5. The method of claim 3 , further comprising forming the inserts to be porous.

6. The method of claim 5 , further comprising forming the inserts from a mesh lattice structure.

7. The method of claim 1 , further comprising integrally forming the structural reinforcing elements with a body of said at least one of the inner and outer shrouds as one-piece composed of a single material.

8. The method of claim 7 , further comprising forming the structural reinforcing elements having a mesh lattice structure.

9. The method of claim 7 , further comprising using additive manufacturing to form said at least one of the inner and outer shrouds and the structural reinforcing elements.

10. The method of claim 9 , wherein the additive manufacturing includes performing direct metal laser sintering (DMLS) or electron beam melting (EBM).

11. The method of claim 1 , further comprising integrally forming the projections and the structural reinforcing elements as inserts which are received within the cavities of said at least one of the inner and outer shrouds.

12. The method of claim 11 , further comprising using additive manufacturing to form said inserts.

13. A method of manufacturing a variable vane assembly for a compressor of a gas turbine engine, the variable vane assembly including an inner shroud and an outer shroud radially spaced apart from each other and each having an annular boundary surface thereon defining therebetween an annular gas path through which a plurality of variable vanes radially extend between the inner and outer shrouds, each of the variable vanes is pivotable through a vane pivot arc about a respective span-wise vane axis and has a vane airfoil with an overhang portion disposed at a trailing edge thereof, the method comprising:
forming at least one of the inner and outer shrouds with one or more enclosed cavities defined within a body thereof, the cavities being isolated from the annular gas path and disposed radially beneath said annular boundary surface; and
forming said at least one of the inner and outer shrouds to have a plurality of projections thereon protruding from the annular boundary surface into the annular gas path, each of the projections being at least partially circumferentially aligned with said cavities and disposed between two of said variable vanes and located adjacent the overhang portion of each of said vane airfoils, the projections having at least one angled planar surface that is substantially parallel to a plane defined by a terminal edge of the overhang portion of the variable vanes when pivoted through said vane pivot arc; and
ensuring that a radial clearance gap, defined between the angled planar surface of the projection and the terminal edge of the vane airfoil overhang portion, remains substantially constant throughout a substantial portion of the vane pivot arc of the variable vane.

14. The method of claim 13 , further comprising providing one or more structural reinforcing elements within said one or more cavities.

15. The method of claim 14 , further comprising separately forming the structural reinforcing elements as inserts, and inserting the inserts into said one or more cavities.

16. The method of claim 14 , further comprising integrally forming the structural reinforcing elements with the body of said at least one of the inner and outer shrouds as one-piece composed of a single material.

17. The method of claim 16 , further comprising using additive manufacturing to form said at least one of the inner and outer shrouds.

18. The method of claim 17 , wherein the additive manufacturing includes performing direct metal laser sintering (DMLS) or electron beam melting (EBM).

19. The method of claim 14 , further comprising forming the structural reinforcing elements having a lattice structure.

20. A variable vane assembly for a compressor of a gas turbine engine, the variable vane assembly comprising:
a plurality of radially extending variable vanes, each pivotable through a vane pivot arc about a respective span-wise vane axis and having a vane airfoil with an overhang portion disposed at a trailing edge thereof; and
inner and outer shrouds radially spaced apart and each having a gas path facing annular boundary surface defining therebetween an annular gas path through which the variable vanes extend, and at least one of the inner and outer shrouds including:
a plurality of projections protruding from the annular boundary surface into the annular gas path, each of the projections being at least partially circumferentially disposed between two of said variable vanes and located adjacent the overhang portion of each of said vane airfoils, the projections having at least one angled planar surface that is substantially parallel to a plane defined by a terminal edge of the overhang portion of the variable vanes when pivoted through said vane pivot arc, such that a radial clearance gap, defined between the angled planar surface of the projection and the terminal edge of the vane airfoil overhang portion, remains substantially constant throughout a substantial portion of the vane pivot arc of the variable vane;
one or more cavities within a body of said a

Assignees

• Pratt & Whitney Canada

Inventors

• Marshall Andrew R
• Menheere David

Classifications

• B22F10/28

  Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] · CPC title

• B33Y10/00 Primary

  Processes of additive manufacturing · CPC title

• F05D2300/608

  Microstructure · CPC title

• F04D29/023

  especially adapted for elastic fluid pumps · CPC title

• F05D2230/31

  Layer deposition · CPC title