The subject matter disclosed herein relates to gas turbine systems, and more particularly to a combustor liner cooling assembly.
A combustor section of a gas turbine system typically includes a combustor chamber disposed relatively adjacent a transition piece, where a hot gas passes from the combustor chamber through the transition piece to a turbine section. As firing temperatures within the combustor chamber increase and NOx allowances are reduced, meeting combustor liner life requirements becomes increasingly challenging with currently employed cooling schemes.
One region of the combustor liner requiring effective cooling includes an aft end of the combustor liner, with one common cooling method including channel cooling. Channel cooling typically includes providing a cooling flow to a channel, then subsequently expelling the cooling flow to a region of the transition piece. Unfortunately, the useful length of the channel cooling is dependent on the temperature of the air in the cooling channel, thereby often rendering ineffective cooling of significant portions of the combustor liner due to increased firing temperatures and increased compressor discharge air temperatures. Alternatively, film cooling may be employed at various locations in the combustor chamber. Film cooling typically includes providing air from a plenum between a flow sleeve and the combustor liner to provide a barrier between the hot gas and the combustor liner. Unfortunately, the benefit of the barrier lasts for a finite length and is largely dependent on the flow in the film cooled region and not the temperature of the film gas. Therefore, either singular cooling scheme often does not achieve desired cooling performance of the aft end of the combustor liner.
According to one aspect of the invention, a combustor liner cooling assembly includes a combustor liner defining a combustor chamber. Also included is a cover sleeve spaced radially outwardly from and at least partially surrounding an aft end of the combustor liner, the cover sleeve and the combustor liner defining a cooling annulus. Further included is at least one aperture extending through the cover sleeve for routing a cooling flow to the cooling annulus. Yet further included is a perforated sleeve disposed between the cover sleeve and the combustor liner, wherein the perforated sleeve comprises a plurality of holes for impinging the cooling flow toward the combustor liner.
According to another aspect of the invention, a combustor liner cooling assembly includes a combustor liner defining a combustor chamber, wherein the combustor liner includes an outer surface and an inner surface. Also included is a cover sleeve spaced radially outwardly from and at least partially surrounding an aft end of the combustor liner, the cover sleeve and the outer surface of the combustor liner defining an annulus, wherein a cooling flow is routed to the annulus through an aperture extending through the cover sleeve. Further included is at least one protuberance extending radially outwardly from the outer surface of the combustor liner for increasing a surface area of the outer surface for increasing heat transfer proximate the aft end of the combustor liner and disrupting a boundary layer proximate the aft end of the combustor liner.
According to yet another aspect of the invention, a gas turbine system includes a combustor liner defining a combustor chamber, wherein the combustor liner includes an outer surface and an inner surface. Also included is a flow sleeve disposed radially outwardly of the outer surface of the combustor liner and having a first plurality of cooling apertures for directing compressor discharge air into a first flow annulus defined by the flow sleeve and the combustor liner. Further included is a transition piece operably connected to the combustor liner and configured to carry hot combustion gases to a turbine section of the gas turbine system. Yet further included is an impingement sleeve surrounding the transition piece and having a second plurality of cooling apertures for directing compressor discharge air into a second annulus defined by the transition piece and the impingement sleeve. The gas turbine system also includes a resilient seal structure disposed radially between an aft end of the combustor liner and a forward end of the transition piece. Further included is a cover sleeve spaced radially outwardly from and at least partially surrounding the end region of the combustor liner, the cover sleeve and the combustor liner defining a cooling annulus. Yet further included is a perforated sleeve disposed between the cover sleeve and the combustor liner, wherein the perforated sleeve comprises a plurality of holes for impinging a cooling flow toward the outer surface of the combustor liner.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
With reference to
Referring to
The combustor section 14 uses a combustible liquid and/or gas fuel, such as a natural gas or a hydrogen rich synthetic gas, to run the gas turbine system 10. The combustor chamber 30 is configured to receive and/or provide an air-fuel mixture, thereby causing a combustion that creates a hot pressurized exhaust gas flowing as a hot gas path 38. The combustor chamber 30 directs the hot pressurized gas through the transition piece 20 into the turbine section 16 (
Referring now to
In an exemplary embodiment, a resilient, compression-type seal 56, such as a hula seal, is mounted between the cover sleeve 58 and a portion of the forward sleeve 34 or alternatively the forward portion 26 of the impingement sleeve 24. The cover sleeve 58 is mounted on the combustor liner 28 to form a mounting surface for the resilient, compression-type seal 56.
The cooling annulus 52 also includes a forward region 60 and an aft region 62 that define the length L. It is to be appreciated that the cooling annulus 52 may be in the form of various dimensions and will be based on numerous parameters of the application employed in conjunction with. For example, the length L, the circumferential dimensional distance and the depth of the cooling annulus 52 may all vary. Irrespective of the precise dimensions, the cooling annulus 52 is configured to receive the cooling flow 42 through an aperture 64 disposed in the cover sleeve 58. The aperture 64 extends through the cover sleeve 58 and it is to be understood that the aperture 64 may be aligned relatively perpendicularly to the cooling flow 42 or at an angle thereto. Although it is contemplated that the aperture 64 may be disposed at numerous locations along the length L of the cooling annulus 52, typically the aperture 64 is located proximate the forward region 60 of the cooling annulus 52. At least a portion of the cooling flow 42 is routed into the aperture 64 and flows throughout the cooling annulus 52.
A perforated sleeve 68 is disposed within the cooling annulus 52 at a location radially inwardly of the cover sleeve 58 and radially outwardly of the combustor liner 28. The perforated sleeve 68 includes a plurality of axially spaced holes 70 extending therethrough for impinging the cooling flow 42 toward and onto the outer surface 54 of the combustor liner 28 for cooling of the aft end 40 as the cooling flow 42 is received into the cooling annulus 52. In combination with impingement of the cooling flow 42 onto the outer surface 54 of the combustor liner 28, the cooling flow 42 is routed along the outer surface 54 in a relatively axial direction to provide additional convective cooling.
At least one escape orifice 72 disposed proximate the aft region 62 extends from the cooling annulus 52 to an exterior region 74, relative to the cooling annulus 52. In the illustrated embodiment, the exterior region 74 corresponds to the second annulus 96 defined by the impingement sleeve 24 and the combustor liner 28 or the transition duct 22. The escape orifice 72 provides an exit for the cooling flow 42 flowing within the cooling annulus 52 and such a flow tendency is achieved based on the exterior region 74 being at a lower pressure than the cooling annulus 52. As is the case with the aperture 64 described above, it is also contemplated that the escape orifice 72 may be located at various axial locations along the length L of the cooling annulus 52, however, typically the escape orifice 72 is disposed proximate the aft region 62 of the cooling annulus 52, as illustrated and described above. Additionally, it is to be appreciated that the escape orifice 72 may be aligned at numerous angles, including parallel to the direction of flow of the cooling flow 42. It is also to be appreciated that the location of the exterior region 74 to which the cooling flow 42 is expelled may vary, as will be described in detail below with reference to alternative embodiments.
With respect to each of the escape orifices 72, it is contemplated that a plurality of low-angle, round holes may be circumferentially spaced and arranged in a relatively single axial plane. Alternatively, multiple rows may be included to provide axially staggered escape orifices. As noted above, the escape orifices 72 may be aligned at various angles, with respect to a surface tangent of the combustor liner 28. For example, the escape orifice 72 may be aligned at an angle of about 15 degrees to about 90 degrees. In addition to the above-described single angle configuration, it is contemplated that a secondary, or compound, angle may be present to form a first angled portion and a second angled portion of the escape orifice 72. In such an embodiment, the secondary, or compound, angle may be aligned at about 0 degrees to about 50 degrees, with respect to the axial direction of the first angled portion.
Although the combustor section 10 is illustrated and described above as having a single aperture and a single escape orifice, it is to be understood that a plurality of either or both of the aperture 64 and/or the escape orifice 72 is typically included and the escape orifice 72 may be configured as a single, circumferential annular portion rather than one or more orifices. Specifically, for embodiments having a plurality of apertures and/or escape orifices, such features may be present at any location along the length L of the cooling annulus 52, however, as with the case of the embodiments described above, the apertures and/or escape orifices are typically disposed proximate the forward region 60 and the aft region 62, respectively. Such an embodiment includes circumferentially spaced apertures and/or escape orifices, with the spacing between such features ranging depending on the application of use.
Referring now to
Referring now to
As is the case with the escape orifice 72 described in conjunction with the previous embodiments, although the combustor liner cooling assembly 200 is illustrated and described above as having a single aperture and a single cooling flow path, it is to be appreciated that a plurality of either or both of the aperture 64 and/or the at least one cooling flow path 202 may be included. Such an embodiment includes circumferentially and/or axially spaced apertures and cooling flow paths, with the spacing between such features ranging depending on the application of use.
In operation, subsequent to cooling of the combustor liner 28 due to the presence of the cooling flow 42 within the cooling annulus 52, based on impingement and convective cross-flow, the cooling flow 42 is expelled from the cooling annulus 52 through the at least one cooling flow path 202. The cooling flow 42 is then routed along a portion of the combustor liner inner surface 204, thereby providing a film cooling barrier 206 between the hot gas path 38 and the combustor liner inner surface 204.
Referring to
It is to be appreciated that either or both of the above-described third and fourth embodiments of the combustor liner cooling assembly 200, 300, respectively, may include the escape orifice 72 described in conjunction with the first and second embodiments, as illustrated by way of example for the third embodiment in
Referring to
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.