WO2018128599A1

WO2018128599A1 - Combustor basket with two piece resonator

Info

Publication number: WO2018128599A1
Application number: PCT/US2017/012097
Authority: WO
Inventors: Miguel Bascones; Rituparna BASU; Erick J. DEANE; James M. Hurney; Clifford E. Johnson; Abhijeet TIWARY
Original assignee: Siemens Aktiengesellschaft
Priority date: 2017-01-04
Filing date: 2017-01-04
Publication date: 2018-07-12

Abstract

A gas turbine engine (10) has a combustor basket (15) that has resonators (25). Resonator bases (26) are attached directly to the outer surface (22) of a combustor liner (20). A thermal barrier coating (23) is applied to the internal surface (21) of the combustor liner (20) and holes (29) are drilled through the combustor liner (20) at the location of the resonator base (26). After the application of the thermal barrier coating (23) and the drilling of holes (29) a resonator cap (24) is attached to the resonator base (26). Variations of the method are used in servicing existing gas turbine engines.

Description

COMBUSTOR BASKET WITH TWO PIECE RESONATOR

BACKGROUND

[0001] 1. Field

[0002] Disclosed embodiments are generally related to gas turbine engines and, more particularly to the resonators used in gas turbine engines.

[0003] 2. Description of the Related Art

[0004] A gas turbine engine typically has a compressor section, a combustion section having a number of combustors and a turbine section. Ambient air is compressed in the compressor section and conveyed to the combustors in the combustion section. The combustors combine the compressed air with a fuel and ignite the mixture creating combustion products. The combustion products flow in a turbulent manner and at a high velocity. The combustion products are routed to the turbine section via transition ducts. Within the turbine section are rows of vane assemblies. Rotating blade assemblies are coupled to a turbine rotor. As the combustion product expands through the turbine section, the combustion product causes the blade assemblies and turbine rotor to rotate. The turbine rotor may be linked to an electric generator and used to generate electricity.

[0005] During the operation of gas turbine engines strong forces are generated that can impact the structure of the gas turbine engine. High frequency pressure oscillations may be generated from the heat release from the combustion process and the acoustics of the combustion chamber. If these high frequency pressure oscillations reach certain amplitudes they may cause nearby structures to vibrate and ultimately break. A particularly undesired situation is when a combustion generated acoustic wave has a frequency at or near the natural frequency of a component of the gas turbine engine. Such adverse synchronicity may result in sympathetic vibration and ultimate breakage or other failure of such a component.

[0006] Resonators for the combustion section of a gas turbine engine have been developed to damp such undesired acoustics and reduce the risk of undesired frequencies. SUMMARY

[0007] Briefly described, aspects of the present disclosure relate to resonators used with combustor baskets.

[0008] An aspect of the disclosure may be a method of fabricating and assembling a combustor basket for a gas turbine engine. The method comprises forming a resonator base for direct attachment to an outer surface of a combustor basket liner; attaching the resonator base directly onto the outer surface of the combustor basket liner; applying a thermal barrier coating to an inner surface of the combustor basket liner; drilling holes through the combustor basket liner at the location of the resonator base; and attaching a resonator cap to the resonator base thereby forming a resonator for the combustor basket directly on the combustor basket liner.

[0009] Another aspect of the present disclosure may be a method of servicing an existing combustor basket of a gas turbine engine. The method may involve removing the existing combustor basket on a gas turbine engine; installing a new combustor basket for the gas turbine engine; wherein the new combustor basket is made by forming a plurality of resonator bases for direct attachment to an outer surface of a combustor basket liner; attaching the plurality of resonator bases directly onto the outer surface of the combustor basket liner; applying a thermal barrier coating to an inner surface of the combustor basket liner; drilling holes through the combustor basket liner at the location of each of the plurality of resonator bases; and attaching a resonator cap to each of the plurality of resonator bases thereby forming a plurality of resonators for the combustor basket directly on the combustor basket liner.

[0010] Still another aspect of the present disclosure may be a method of servicing combustor baskets of a gas turbine engine. The method may comprise stripping an existing thermal barrier coating; removing a top portion of a resonator attached to a combustor basket liner and leaving a bottom portion of the resonator, wherein the top portion of the resonator had been integrally formed with the bottom portion of the resonator; applying a new thermal barrier coating to an inner surface of the combustor basket liner; cleaning holes formed in the combustor basket liner at the location of the bottom portion of the resonator; and attaching a resonator cap to the bottom portion of the resonator attached to the combustor basket liner. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Fig. 1 shows a cross sectional view through a portion of a gas turbine engine.

[0012] Fig. 2 shows a close up partial view of a combustor basket.

[0013] Fig. 3 is a flow chart of the method for making a resonator in accordance with the present disclosure.

[0014] Fig. 4 is a view of a resonator base.

[0015] Fig. 5 is a view of a resonator cap.

[0016] Fig. 6 is a view of the resonator base welded to the combustor basket liner.

[0017] Fig. 7 is a view of the thermal barrier coating applied to the inner surface of the combustor basket liner.

[0018] Fig. 8 shows the resonator base welded to the combustor basket liner and liner holes formed though the combustor basket liner and thermal barrier coating.

[0019] Fig. 9 is a view of the resonator base with the resonator cap welded to the resonator base.

[0020] Fig. 10 is a flow chart of a method of servicing an existing gas turbine engine.

[0021] Fig. 11 is a view of a unitary resonator cap.

[0022] Fig. 12 is a view of the resonator shown in Fig. 11 with the top portion removed and a thermal barrier coating applied.

[0023] Fig. 13 is a view of the resonator shown in Fig. 12 with the liner holes cleaned.

[0024] Fig. 14 is a view of the resonator shown in Fig. 13 with the resonator cap attached.

DETAILED DESCRIPTION [0025] To facilitate an understanding of embodiments, principles, and features of the present disclosure, they are explained hereinafter with reference to implementation in illustrative embodiments. Embodiments of the present disclosure, however, are not limited to use in the described systems or methods.

[0026] The components and materials described hereinafter as making up the various embodiments are intended to be illustrative and not restrictive. Many suitable components and materials that would perform the same or a similar function as the materials described herein are intended to be embraced within the scope of embodiments of the present disclosure.

[0027] With increasing firing temperatures during the operation of gas turbine engines the use of thermal barrier coating (TBC) in the combustor basket has become more important. Without the usage of TBC in the inner liner area under the resonators in the combustor basket, failures may occur.

[0028] TBC can be applied under resonators through the use of a machined resonator ring that is a separate component from the rest of the combustor basket. An example of using a resonator ring can be found in U.S. Patent No. 9,395,082. In employing the resonator ring, the resonator ring is machined by rolling and welding plate and then milling the resonator boxes. The machined resonator ring is then assembled together with the combustor liner components to form the combustor basket. Spring clips are assembled to the liner assembly and then a thermal barrier coating is applied. Resonator holes are then drilled and resonator caps are attached. This process can be costly.

[0029] The inventor recognized that instead of using a resonator ring, a resonator base can be welded directly onto an uncoated liner of a combustor basket and then the uncoated liner can be coated with a thermal barrier coating, resonator holes can be drilled through the liner and then resonator caps can be welded on the resonator bases to seal the resonator base. By forming the resonators in this manner the cost of manufacturing can be reduced. Also the risk of TBC spallation caused by welding an already capped resonator onto the liner of the combustor basket after it has already been sprayed with TBC can be avoided. Variations of this method can be used in servicing and refurbishing existing combustor baskets as well.

[0030] In order to provide context for the implementation of the ideas in the present disclosure, Fig. 1 shows a cross sectional view through a portion of a gas turbine engine 10. The cross sectional view shows a combustion section 11, a transition system 14 and a turbine section 13. Compressed ambient air is supplied to the combustors located in the combustion section 11. The combustors combine the compressed air with fuel and ignite the mixture to create combustion products forming a hot working gas flow from each of the combustors. The hot working gas flows from the combustion section 11 to and through the transition system 14 and then to the turbine section 13.

[0031] Fig. 2 shows a close-up partial view of a combustor basket 15, which is located at the combustion section 11. The combustor basket 15 has a plurality of resonators 25 that are attached directly to the outer surface 22 of the combustor basket liner 20. The resonator 25 is formed with a resonator base 26 and a resonator cap 24. The resonator cap 24 has cap holes 28 formed therein in order to facilitate a flow of air through the resonators 25 and into liner holes 29. The flow of air facilitates cooling of the combustor basket 15.

[0032] The resonators 25 shown in Fig. 2 are rectangular in shape and are spaced circumferentially around the combustor basket 15. It should be understood that while rectangular shaped resonators 25 are shown other shapes are possible, such as triangular, trapezoidal, and/or other polygonal shapes. The shape and size of the resonators 25 are selected in order to dampen the frequencies that may occur during operation of the gas turbine engine. This can change based on the type of gas turbine engine. Additionally, each of the resonators 25 need not be the same shape or size and individual resonators 25 may vary in size and shape. Furthermore, while the resonator 25 shown in Fig. 2 is spaced circumferentially around the combustor basket 15 in a single row, more than one row of resonators 25 may be used, i.e. two, three, etc.

[0033] Turning to Figs. 3-9 the method of forming the resonators 25 for the combustor basket 15 is now discussed in detail. By using the method shown and discussed in Figs. 3-9, a resonator ring does not have to be employed. Furthermore, a thermal barrier coating can be employed to the area where the resonators 25 are located and liner holes 29 formed in the combustor basket liner 20 without spallation. It should be understood that while the method and figures are discussed below in reference to one resonator 25 for ease of explanation, the method and figures are applicable to the formation of a plurality of resonators 25 of the same or various shapes and sizes.

[0034] In step 100, illustrated in Fig. 4, a resonator base 26 is formed. The resonator base 26 may be formed from a single sheet of metal and shaped into a rectangular shape. The resonator base 26 may be made of the same material as the combustor basket liner 20 or may be made of a different material. The formed rectangle is open at the top and at the bottom. It should be noted that while a rectangle shape is shown for the resonator base 26, other shapes and/or sizes may be employed depending upon the ultimate shape and size of the resonator 25. Furthermore, in addition to the formed rectangle, side holes 27 may also be drilled into the resonator base 26 after the formation of the resonator base 26.

[0035] Fig. S shows a resonator cap 24 that will ultimately be attached to the resonator base 26. The resonator cap 24 may have cap holes 28 formed therein. The formation of the resonator cap 24 with cap holes 28 may occur prior to, simultaneously with or after the formation of the resonator base 26. The resonator cap 24 is placed on the resonator base 26 at a different stage in the process.

[0036] In step 102, as illustrated in Fig. 6, the resonator base 26 is attached to the outer surface 22 of the combustor basket liner 20. The resonator base 26 may be attached to the outer surface 22 via welding, brazing or another art recognized manner. The resonator base 26 is attached directly to the combustor basket liner 20 and is not part of separate gas turbine engine component, such as the resonator ring mentioned above. Connecting directly to the combustor basket liner 20 reduces the cost of construction of the combustor basket 15 while facilitating the application of a thermal barrier coating.

[0037] In step 104, shown in Fig. 7, a thermal barrier coating 23 is applied to the inner surface 21 of the combustor basket liner 20. Application of the thermal barrier coating 23 may occur in any art recognized manner. The thermal barrier coating 23 protects the combustor basket liner 20 from damage that may be caused from exposure to high temperatures. By applying the thermal barrier coating 23 the life span of the combustor basket 15 may be extended. Additionally the application of the thermal barrier coating 23 during this stage of the process avoids "shadowing" that can occur if the thermal barrier coating 23 is applied at a different stage. Shadowing occurs due to the use of a masking agent which can prevent areas from being coated. Shadowing results in reduced amount of protection that can be provided by the thermal barrier coating 23. This can result in a reduced life span for the combustor basket 15 or more frequent maintenance of the combustor basket 15.

[0038] In step 106, shown in Fig. 8, liner holes 29 are drilled through the thermal barrier coating 23, the inner surface 21 and the upper surface 22. The liner holes 29 may be formed by laser drilling or through the use of water jets. The liner holes 29 are formed by drilling first through the inner surface 21 in order to avoid incomplete coverage of the inner surface 21 of the combustor basket liner 20 with the thermal barrier coating 23. The drilling may also avoid sharp edges in the thermal barrier coating 23 on the liner holes 29 and possible chipping of the thermal barrier coating around the liner holes 29. Alternatively, the liner holes 29 may be formed by drilling first through the upper surface 22. The formation of the liner holes 29 prior to the attachment of the resonator cap 24 prevents damage to the resonator cap 24 that can occur if the resonator cap 24 was already attached. This is why the use of the resonator cap 24 is preferable to a resonator that is formed as a unitary component as opposed to being formed as a resonator base 26 and a resonator cap 24. Furthermore, if it is formed as a unitary component holes have to be formed first, then the unitary component welded and then the thermal barrier coating 23 applied, which can cause shadowing.

[0039] The liner holes 29 are thereby formed in the area on the combustor basket liner 20 that is surrounded by the walls of resonator base 26. These liner holes 29 enable a flow of air to pass through the fully formed resonator 25. The flow of air helps in cooling the combustor basket 15.

[0040] In step 108, shown in Fig. 9, the resonator cap 24 is attached to the resonator base 26 forming the resonator 25. The resonator cap 24 is attached via welding. However, it should be understood that the resonator cap 24 can be attached via brazing or other art recognized methods of attachment. The resonator cap 24 is preferably made of the same material as the resonator base 26. Furthermore, the resonator cap 24 and the resonator base 26 may be made of the same material as the combustor basket liner 20. [0041] The method of making the resonators 25 discussed above provides a more durable resonator configuration than resonators formed by other methods. Additionally, variations of the method discussed above can be used in refurbishing and/or servicing gas turbine engines that are already out in the field.

[0042] One such method of servicing an existing gas turbine engine 10 would involve the removal of an existing combustor basket that employs unitary resonators or removing a combustor basket 15 that had already been made in accordance with the method discussed above. After the removal of the existing combustor basket a combustor basket 15 made in accordance with the method set forth in Fig. 3 can be installed on the gas turbine engine 10. Replacing existing combustor baskets with combustor baskets 15 can add extended life and operational capability to the gas turbine engine 10.

[0043] Another method of servicing an existing gas turbine engine 10 is set forth and shown in Figs. 10-14. Referring to steps 200, 202 and Fig. 11, an existing thermal barrier coating may be first stripped from the combustor basket liner 20. Resonator 35 is a unitary piece resonator 35 that had been welded to the outer surface 22 of a combustor basket liner 20. Formed within the walls of the resonator 35 through the outer surface 22 to the inner surface 21 are liner holes 29. A top portion 34 of a resonator 35 is removed from a bottom portion 36 of a resonator 35. The combustor basket liner 20 may be repaired as needed when servicing. The top portion 34 may be cut from the bottom portion 36 using any art acceptable method, such as through the use of a blade, grinding, laser cut water jet, etc. The location of the cut is illustrated by the dashed line shown in Fig. 11. It should be understood that the location of the cut may vary depending on the size and shape of the resonator cap to be installed and whether additional improvement may be obtained by damping the acoustic frequencies using a certain size or shape of the resonator.

[0044] Referring now to step 204 and Fig. 12, after the removal of the top portion 34 of the resonator 35 a thermal barrier coating 23 is applied to the inner surface 21 of the combustor basket liner 20. The application of the thermal barrier coating 23 provides added protection and may add time to the lifespan of the combustor basket 15.

[0045] Referring now to step 206 and Fig. 13, after the application of the thermal barrier coating 23 to the inner surface 21 of the combustor basket liner 20 the liner holes 29 are cleaned using a laser, water jet, or other art acceptable means. The cleaning of the liner holes 29 occurs prior to the attachment of the resonator cap 24 so as not to damage the resonator cap 24.

[0046] Referring now to step 208 and Fig. 14, after the cleaning of the liner holes 29, resonator cap 24 is attached to the bottom portion 36 of the resonator 35. The resonator cap 24 may be the same as the resonator cap 24 discussed above. The resonator cap 24 is attached via welding, brazing or other art acceptable means for attachment. While refurbishment is discussed in terms of modification of an existing resonator it should be understood that an entire resonator including both the top portion and the bottom portion may be replaced as well.

[0047] By servicing and refurbishing gas turbine engines 10 in the manners discussed above time may be added to the lifespans of the combustor baskets 10 thereby reducing future need maintenance and overall costs.

[0048] While embodiments of the present disclosure have been disclosed in exemplary forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions can be made therein without departing from the spirit and scope of the invention and its equivalents, as set forth in the following claims.

Claims

What is claimed is:

1. A method of making a combustor basket for a gas turbine engine comprising: forming a resonator base (26) for direct attachment to an outer surface (22) of a combustor basket liner (20);

attaching die resonator base (26) direcdy onto die outer surface (22) of the combustor basket liner (20);

applying a thermal barrier coating (23) to an inner surface (21) of the combustor basket liner (20);

drilling holes (29) through the combustor basket liner (20) at die location of the resonator base (26); and

attaching a resonator cap (24) to the resonator base (26) thereby forming a resonator (25) for the combustor basket (15) direcdy on die combustor basket liner (20).

2. The method of claim 1, wherein side holes (27) are drilled into the resonator base (26) during the step of forming the resonator base (26).

3. The method of claim 1 or 2, wherein the holes (29) formed in the combustor basket liner (20) are formed by drilling through the inner surface (21) of the combustor basket liner (20) to the outer surface (22) of the combustor basket liner (20).

4. The method of any one of claims 1 -3, wherein the resonator cap (24) has holes (28) formed prior to attachment to the resonator base (26).

5. The method of any one of claims 1-4, wherein the resonator base (26) is formed as a rectangle or trapezoid.

6. A method of servicing an existing combustor basket of a gas turbine engine comprising:

removing the existing combustor basket (15) on the gas turbine engine (10); installing a new combustor basket (15) for die gas turbine engine (10);

wherein the new combustor basket (15) is made by forming a plurality of resonator bases (26) for direct attachment to an outer surface (22) of a combustor basket liner (20);

attaching the plurality of resonator bases (26) directly onto the outer surface (22) of the combustor basket liner (20);

drilling holes (29) through the combustor basket liner (20) at the location of each of the plurality of resonator bases (26); and

attaching a resonator cap (24) to each of the plurality of resonator bases (26) thereby forming a plurality of resonators (25) for the combustor basket (15) directly on the combustor basket liner (20).

7. The method of claim 6, wherein side holes (27) are drilled into each of the plurality of resonator bases (26) during the step of forming the plurality of resonator bases (26).

8. The method of claim 6 or 7, wherein the holes (29) formed in the combustor basket liner (20) are formed by drilling through the inner surface (21) of the combustor basket liner (20) to the outer surface (22) of the combustor basket liner (20).

9. The method of any one of claims 6-8, wherein each of the plurality of resonator caps (24) has holes (28) prior to attachment.

10. The method of any one of claims 6-9, wherein each of the plurality of the resonator bases (26) is formed as a rectangle or trapezoid.

11. A method of servicing combustor baskets of a gas turbine engine comprising: stripping an existing thermal barrier coating (23);

removing a top portion (34) of a resonator (35) attached to a combustor basket liner (20) and leaving a bottom portion (36) of the resonator (35), wherein the top portion of the resonator (35) had been integrally formed with the bottom portion (36) of the resonator (35);

applying a new thermal barrier coating (23) to an inner surface (21) of the combustor basket liner (20);

cleaning holes (29) formed in the combustor basket liner (20) at the location of the bottom portion (36) of the resonator (35); and

attaching a resonator cap (24)to the bottom portion (36) of the resonator (35) attached to the combustor basket liner (20).

12. The method of claim 11 , wherein the cleaning of the holes (29) is performed by drilling through the inner surface (21) of the combustor basket liner (20) to the outer surface (22) of the combustor basket liner (20).

13. The method of claim 1 lor 12, wherein the resonator caps (24) has holes (28) formed thereon prior to attachment.

14. The method of any one of claims 11-13, wherein the resonator cap (24) is formed as a rectangle.