WO2015147821A1

WO2015147821A1 - Stator vane support system within a gas turbine engine

Info

Publication number: WO2015147821A1
Application number: PCT/US2014/031934
Authority: WO
Inventors: Elliot Griffin
Original assignee: Siemens Aktiengesellschaft; Siemens Energy, Inc.
Priority date: 2014-03-27
Filing date: 2014-03-27
Publication date: 2015-10-01
Also published as: EP3123002B1; JP2017509831A; US20170146026A1; CN106471218A; JP6461305B2; EP3123002A1

Abstract

A stator vane segment (10) including a connection system (12) that enables stator vane (14) alignment while enabling an individual stator vane (14) to be replaced is disclosed. The stator vane connection system (12) may include a radially extending inner support (26) extending from a stator vane (14), whereby the inner support (26) is secured to forward and aft inner rings via a removable, inner axial bolt (22). The stator vane connection system (12) may include one or more first inner pins (24) that aligns the stator vane (14) and is positioned within the portion of the inner support (26) of the stator vane (14) to which one or more inner axial bolts (22) are attached. The stator vane connection system (12) may include one or more first outer alignment pins (28) that aligns the stator vane (14) and is positioned within a portion of the outer diameter platform (48) of the stator vane (14), whereby the first outer alignment pin (28) aligns the stator vane (14).

Description

STATOR VANE SUPPORT SYSTEM WITHIN A GAS TURBINE ENGINE

FIELD OF THE INVENTION

This invention is directed generally to stator vane airfoils within gas turbine engines, and more particularly to support systems for stator vane airfoils.

BACKGROUND

Turbine engines typically include a plurality of rows of stationary compressor stator vanes extending radially inward from a shell and include plurality of rows of rotatable compressor blades attached to a rotor assembly for turning the rotor.

Conventional turbine engines often include a segment with multiple stationary airfoils collectively referred to as a stator. Stator segments deflect in the upstream direction under steady gas pressure loading, and the deflection varies around the

circumference dependent upon how the segment is constrained to the casing. The unconstrained ends of the segment deflect more and have less axial clearance to the upstream rotor disk. Thus, a need exists to control deflection and alignment of the stator vane airfoils forming the stator.

SUMMARY OF THE INVENTION

A compressor stator vane segment including a connection system that enables stator vane alignment while enabling an individual stator vane to be replaced is disclosed. The stator vane connection system may include a radially extending inner support extending from a stator vane, whereby the inner support is secured to forward and aft inner rings via a removable, inner axial bolt. The stator vane connection system may include one or more first inner pins that aligns the stator vane and is positioned within the portion of the inner support of the stator vane to which one or more inner axial bolts are attached. The stator vane connection system may include one or more first outer alignment pins that aligns the stator vane and is positioned within the portion of the outer diameter platform of the stator vane, whereby the first outer alignment pin aligns the stator vane.

The compressor stator vane segment may be formed from a stator vane including an airfoil formed from an outer wall, and having a leading edge, a trailing edge, a pressure side, a suction side, an inner diameter platform at a first end of the airfoil, and an outer diameter platform at a second end of the airfoil. The compressor stator vane segment may include a stator vane connection system. The stator vane connection system may be formed from one or more inner axial bolts extending through a first inner ring, through at least a portion of an inner support of the stator vane positioned inward of the airfoil, and into a second inner ring to secure the stator vane. At least one first inner pin may be positioned within the portion of the inner support of the stator vane to which the inner axial bolt is attached. The first inner pin may align the stator vane relative to an adjacent stator vane. One or more first outer alignment pins may be positioned within the portion of the outer diameter platform of the stator vane, whereby the first outer pin aligns the stator vane relative to an adjacent stator vane.

The stator vane connection system may also include an outer tie bar coupled to the outer diameter platform. The outer tie bar may be secured to the outer diameter platform via a removable connection system, such as, but not limited to, a dovetail connection and one or more radially extending bolts between the outer tie bar and the outer diameter platform. In at least one embodiment, the first inner ring may be a forward inner ring. One or more seals may extend radially inward from a radially inner surface of the forward inner ring. The seal extending radially inward from a radially inner surface of the forward inner ring may be a honeycomb seal. The forward inner ring may be sized to fit radially inward of a forward extending portion of the inner diameter platform and within a recess in the inner diameter platform. In at least one embodiment, the second inner ring may be an aft inner ring. One or more seals may extend radially inward from a radially inner surface of the aft inner ring. The seal extending radially inward from a radially inner surface of the aft inner ring may be a honeycomb seal.

In at least one embodiment, an outer surface of the aft inner ring may be flush with a radially outer surface of the inner diameter platform of the airfoil. The aft inner ring may include a portion that is sized to extend axially forward into an aft recess in the inner diameter platform. The aft inner ring may also include two aft extending arms separated from each other via an aft recess. A radially inner surface of the inner support of the stator vane may be flush with a radially inner surface of the first inner ring and a radially inner surface of the second inner ring. In at least one embodiment, the first inner pin may be positioned within the portion of the inner support of the stator vane and may extend in a circumferential direction, and one or more second inner pins may be positioned within the portion of the second inner ring and may extend in a circumferential direction. The inner axial bolt may include threads that engage threads within the second inner ring. The inner axial bolt may include a head that is larger than a shaft of the axial bolt, and the first inner ring may include a head receiving cavity in which the head of the inner axial bolt resides.

The compressor stator vane segment may be assembled in a number of ways. In at least one embodiment, the compressor stator vane segment may be assembled by milling the airfoil, coating the airfoil flow path surfaces, turning the outer ring from a rolled ring, turning the forward inner ring from a custom forging, turning the aft inner ring from a custom forging, drilling holes in the outer ring, drilling holes in the inner forward ring, drilling holes in the aft inner ring, brazing a forward honeycomb seal to the forward inner ring, brazing an aft honeycomb seal to the aft inner ring, turning the forward honeycomb inner diameter, turning the aft honeycomb inner diameter, sawing the outer ring in half, sawing the forward inner ring in half, sawing the aft inner ring in half, and assembling the stator vanes and rings with bolts and pins and stake the fasteners. Formation of the compressor vane segment in this manner, reduces the number of manufacturing steps by seven steps in comparison to conventional systems.

An advantage of the compressor stator vane segment is that the compressor stator vane segment enables individual airfoil replacement without cutting or welding during outages or other times.

Another advantage of the compressor stator vane segment is that fewer custom made parts, such as in one embodiment, three fewer custom made parts, are needed than in conventional systems.

Yet another advantage of the compressor stator vane segment is that the compressor stator vane segment may be formed with fewer manufacturing steps, such as in one embodiment, seven fewer steps, are needed than in conventional systems. Still another advantage of the compressor stator vane segment is that welding and stress relieving are not required.

Another advantage of the compressor stator vane segment is that machining of the entire assembly is not required, which reduces lifting time and equipment costs.

Yet another advantage of the compressor stator vane segment is that coating of the entire assembly is not required, which reduces lifting time, shipping and equipment costs.

Still another advantage of the compressor stator vane segment is that inner rings may be formed from a lower cost material, such as, but not limited to, low carbon steel, than conventional systems.

Another advantage of the compressor stator vane segment is that a cover half and a base half may be interchangeable between engines, which reduces service inventory and handling costs.

Yet another advantage of the compressor stator vane segment is that the segment could be formed in 90 degree segments to further reduce service inventory and handling costs and for ease of assembly and disassembly.

Still another advantage of the compressor stator vane segment is that mechanical dampening may be achieved through use of the bolted assembly.

These and other embodiments are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention.

Figure 1 is a perspective view of compressor stator vane segment within a gas turbine engine.

Figure 2 is a cross-sectional view of a compressor stator vane segment within a gas turbine engine taken at section line 2-2 in Figure 1 .

Figure 3 is a detail view of a portion of the compressor stator vane segment within a gas turbine engine taken at detail line 3-3 in Figure 2. Figure 4 is an end view of two compressor stator vane segments forming a single stage stator assembly.

Figure 5 is an end view of another embodiment of compressor stator vane segments forming a single stage stator assembly, whereby four stator vane segments are used.

DETAILED DESCRIPTION OF THE INVENTION

As shown in Figures 1 -5, a compressor stator vane segment 10 including a connection system 12 that enables stator vane alignment while enabling an individual stator vane 14 to be replaced is disclosed. The stator vane connection system 12 may include a radially extending inner support 16 extending from a stator vane 14, whereby the inner support 16 is secured to forward and aft inner rings 18, 20 via a removable, inner axial bolt 22. The stator vane connection system 12 may include one or more first inner pins 24 that aligns the stator vane 14 and is

positioned within the portion of the inner support 16 of the stator vane 14 to which one or more inner axial bolts 22 are attached. The stator vane connection system 12 may include one or more first outer alignment pins 28 that aligns the stator vane 14 and is positioned within the portion of the outer diameter platform 30 of the stator vane 14, whereby the first outer alignment pin 28 aligns the stator vane 14.

In at least one embodiment, the compressor stator vane segment 10 may include a stator vane 14 formed from an airfoil 32 formed from an outer wall 34, and having a leading edge 36, a trailing edge 38, a pressure side 40, a suction side 42, and an inner diameter platform 44 at a first end 46 of the airfoil 32 and an outer diameter platform 30 at a second end 50 of the airfoil 32. The stator vane 14 may be secured with the turbine engine 54 via a stator vane connection system 12. The stator vane connection system 12 may be formed from one or more inner axial bolts 22 extending through a first inner ring 18, through at least a portion of an inner support 16 of the stator vane 14 positioned inward of the airfoil 32, and into a second inner ring 20 to secure the stator vane 14. In at least one embodiment, the first inner ring 18 is a forward inner ring 18, and the second inner ring 20 is an aft inner ring 20. One or more first inner pins 24 may be positioned within the portion of the inner support 16 of the stator vane 14 to which the inner axial bolt 22 is attached. The first inner pin 24 may align the stator vane 14 relative to an adjacent stator vane 14. The stator vane connection system 12 may also include on or more first outer alignment pins 28 positioned within the portion of the outer diameter platform 30 of the stator vane 14. The first outer pin 24 aligns the stator vane 14 relative to an adjacent stator vane 14.

The stator vane connection system 12 may also include an outer tie bar 56 coupled to the outer diameter platform 30. The outer tie bar 56 may be secured to the outer diameter platform 30 via a removable connection system 58, such as, but not limited to, a dovetail connection 58. The outer tie bar 56 may be configured to have a dovetail shape extending in a circumferential direction such that it includes an linear outer surface 70 with inwardly sloped sidewalls 72, 74. In addition, the outer diameter platform 30 may have a dovetail shaped receiver 62 with a linear base surface 64 and inward sloped sidewalls 66 and 68. The outer tie bar 56 may also be coupled to the stator vane 14 via one or more radially extending bolts 60 between the outer tie bar 56 and the outer diameter platform 30.

The stator vane connection system 12 may also include one or more forward seals 76 extending radially inward from a radially inner surface 78 of the forward inner ring 18. In at least one embodiment, the forward seal 76 may be, but is not limited to being, a honeycomb seal or a knife seal. The forward inner ring 18 may be is sized to fit radially inward of a forward extending portion 80 of the inner diameter platform 44 and within a recess 82 in the inner diameter platform 44. The forward surface 84 of the forward inner ring 18 may be flush with a forward surface 86 of the inner diameter platform 44.

The stator vane connection system 12 may also include one or more aft seals 88 extending radially inward from a radially inner surface 90 of the aft inner ring 20. In at least one embodiment, the aft seal 88 may be, but is not limited to being, a honeycomb seal or a knife seal. In at least one embodiment, an outer surface 92 of the aft inner ring 20 may be flush with a radially outer surface 94 of the inner diameter platform 44 of the airfoil 32. The aft inner ring 20 may include a forward portion 96 that is sized to extend axially forward into an aft recess 98 in the inner diameter platform 44. The aft inner ring 20 may also include two aft extending arms 100, 102 and separated from each other via an aft recess 104. In at least one embodiment, a radially inner surface 106 of the inner support 16 of the stator vane 14 may be flush with a radially inner surface 108 of the first inner ring 18 and a radially inner surface 1 10 of the second inner ring 20.

On or more first inner pins 24 positioned within the portion of the inner support 16 of the stator vane 14 extends in a circumferential direction. One or more second inner pins 1 12 may be positioned within the portion of the second inner ring 20 and may extend in a circumferential direction. The first inner pin 24 or the second inner pin 1 12 or both may be positioned generally orthogonal to a longitudinal axis 1 14 of a turbine engine 54. The first inner pin 24 and the second inner pin 1 12 may have any appropriate shape and length. In at least one embodiment, the first inner pin 24 or the second inner pin 1 12, or both may be generally cylindrical. The first inner pin 24 and the second inner pin 1 12 may be formed from any appropriate material. The

The inner axial bolt 22 may include threads 1 16 that engage threads 1 18 within the second inner ring 20. The inner axial bolt 22 may also include a head 120 that is larger than a shaft 122 of the axial bolt 22. The first inner ring 18 may include a head receiving cavity 124 in which the head 120 of the inner axial bolt 22 resides.

The compressor stator vane segment 10 may be assembled in a number of ways. In at least one embodiment, the compressor stator vane segment 10 may be assembled by milling the airfoil 32, coating the airfoil flow path surfaces, turning the outer ring from a rolled ring, turning the forward inner ring 18 from a custom forging, turning the aft inner ring 20 from a custom forging, drilling holes in the outer ring, drilling holes in the inner forward ring 18, drilling holes in the aft inner ring 20, brazing a forward honeycomb seal 76 to the forward inner ring 18, brazing an aft honeycomb seal 88 to the aft inner ring 20, turning the forward honeycomb inner diameter, turning the aft honeycomb inner diameter, sawing the outer ring in half, sawing the forward inner ring 18 in half, sawing the aft inner ring 20 in half, and assembling the stator vanes 14 and rings 18, 20 with bolts 22, 60 and pins 24, 28, 1 12 and staking the fasteners.

The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.

Claims

CLAIMS We claim:

1 . A stator vane segment (10), characterized in that:

a stator vane (14) formed from an airfoil (32) formed from an outer wall (34), and having a leading edge (36), a trailing edge (38), a pressure side (40), a suction side (42), an inner diameter platform (44) at a first end (46) of the airfoil (32) and an outer diameter platform (48) at a second end (50) of the airfoil (32);

a stator vane connection system (12) comprising:

at least one inner axial bolt (22) extending through a first inner ring

(18), through at least a portion of an inner support (26) of the stator vane (14) positioned inward of the airfoil (32), and into a second inner ring (20) to secure the stator vane (14);

at least one first inner pin (24) positioned within the portion of the inner support (26) of the stator vane (14) to which the at least one inner axial bolt

(22) is attached, wherein the at least one first inner pin (24) aligns the stator vane (14); and

at least one first outer alignment pin (28) positioned within the portion of the outer diameter platform (48) of the stator vane (14), wherein the at least one first outer pin (28) aligns the stator vane (14).

2. The stator vane segment (10) of claim 1 , further characterized in that an outer tie bar (56) coupled to the outer diameter platform (48), wherein the outer tie bar (56) is secured to the outer diameter platform (48) via a dovetail connection (58) and at least one radially extending bolt between the outer tie bar (56) and the outer diameter platform (48).

3. The stator vane segment (10) of claim 1 , characterized in that the first inner ring (18) is a forward inner ring (18).

4. The stator vane segment (10) of claim 3, further characterized in that a seal (76) extending radially inward from a radially inner surface of the forward inner ring.

5. The stator vane segment (10) of claim 4, characterized in that the seal

(76) extending radially inward from a radially inner surface of the forward inner ring is a honeycomb seal (76).

6. The stator vane segment (10) of claim 3, characterized in that the forward inner ring is sized to fit radially inward of a forward extending portion of the inner diameter platform (44) and within a recess in the inner diameter platform (44).

7. The stator vane segment (10) of claim 1 , characterized in that the second inner ring (20) is an aft inner ring (20).

8. The stator vane segment (10) of claim 7, further characterized in that a seal (88) extending radially inward from a radially inner surface (90) of the aft inner ring (20).

9. The stator vane segment (10) of claim 8, characterized in that the seal

(88) extending radially inward from a radially inner surface (90) of the aft inner ring (20) is a honeycomb seal (88).

10. The stator vane segment (10) of claim 7, characterized in that an outer surface (92) of the aft inner ring (20) is flush with a radially outer surface (94) of the inner diameter platform (44) of the airfoil (32).

1 1 . The stator vane segment (10) of claim 7, characterized in that the aft inner ring (20) includes a portion that is sized to extend axially forward into an aft recess (98) in the inner diameter platform (44).

12. The stator vane segment (10) of claim 7, characterized in that the aft inner ring (20) includes two aft extending arms (100, 102) and separated from each other via an aft recess (104).

13. The stator vane segment (10) of claim 1 , characterized in that a radially inner surface (106) of the inner support (26) of the stator vane (14) is flush with a radially inner surface (108) of the first inner ring (18) and a radially inner surface

(1 10) of the second inner ring (20).

14. The stator vane segment (10) of claim 1 , characterized in that the at least one first inner pin (24) positioned within the portion of the inner support (26) of the stator vane (14) extends in a circumferential direction and at least one second inner pin (1 12) positioned within the portion of the second inner ring (20) and extending in a circumferential direction.

15. The stator vane segment (10) of claim 1 , characterized in that the at least one inner axial bolt (22) includes threads (1 16) that engage threads (1 18) within the second inner ring (20).

16. The stator vane segment (10) of claim 1 , characterized in that the at least one inner axial bolt (22) includes a head (120) that is larger than a shaft (122) of the axial bolt (22) and wherein the first inner ring (18) includes a head receiving cavity (124) in which the head 912) of the inner axial bolt (22) resides.