U.S. patent application number 12/543066 was filed with the patent office on 2011-02-24 for integral liner and venturi for eliminating air leakage.
Invention is credited to William Kirk Hessler, Jeffrey Lebegue, Todd Daniel Paquin, Predrag Popovic.
Application Number | 20110041507 12/543066 |
Document ID | / |
Family ID | 43604185 |
Filed Date | 2011-02-24 |
United States Patent
Application |
20110041507 |
Kind Code |
A1 |
Hessler; William Kirk ; et
al. |
February 24, 2011 |
Integral Liner and Venturi for Eliminating Air Leakage
Abstract
A combustion liner assembly for a gas turbine combustor includes
a plurality of fuel nozzles disposed circumferentially about a
central axis of the combustor, and a venturi section disposed
downstream of the fuel nozzles and connected to a head end of the
liner assembly. The venturi section defines an annular throat area
downstream of the fuel nozzles. A liner sleeve is connected to and
commences at a downstream end of the venturi section. At least a
portion of the venturi section serves as a liner upstream of the
liner sleeve.
Inventors: |
Hessler; William Kirk;
(Newark, DE) ; Lebegue; Jeffrey; (Simpsonville,
SC) ; Popovic; Predrag; (Simpsonville, SC) ;
Paquin; Todd Daniel; (Easley, SC) |
Correspondence
Address: |
NIXON & VANDERHYE P.C.
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Family ID: |
43604185 |
Appl. No.: |
12/543066 |
Filed: |
August 18, 2009 |
Current U.S.
Class: |
60/772 ;
60/752 |
Current CPC
Class: |
F23R 2900/00016
20130101; F23R 3/002 20130101 |
Class at
Publication: |
60/772 ;
60/752 |
International
Class: |
F23R 3/42 20060101
F23R003/42 |
Claims
1. A combustion liner assembly for a gas turbine combustor, the
combustion liner assembly comprising: a plurality of fuel nozzles
disposed circumferentially about a central axis of the combustor; a
venturi section disposed downstream of the fuel nozzles and
connected to a head end of the liner assembly, the venturi section
defining an annular throat area downstream of the fuel nozzles; and
a liner sleeve connected to and commencing at a downstream end of
the venturi section, wherein at least a portion of the venturi
section serves as a liner upstream of the liner sleeve.
2. A combustion liner assembly according to claim 1, wherein the
liner sleeve is connected to the downstream end of the venturi
section via an annular weld.
3. A combustion liner assembly according to claim 1, wherein the
venturi section is connected to the head end via an annular
weld.
4. A combustion liner assembly according to claim 1, further
comprising a connector part that connects the venturi section to
the head end.
5. A combustion liner assembly according to claim 4, wherein the
venturi section comprises a double wall structure including an
inner wall and an outer wall, and wherein the connector part is
Y-shaped including an end post and a split end, the split end being
welded to the inner wall and the outer wall of the venturi section,
and the end post being welded to the head end.
6. A combustion liner assembly according to claim 5, wherein the
end post of the connector part is thicker than the split end.
7. A combustion liner assembly according to claim 1, wherein an
upstream end of the venturi section terminates in a flange that is
bent to extend axially in a downstream direction, wherein the
flange is secured to the head end via a plurality of rivets, and
wherein the flange is sealed via an annular weld.
8. A combustion liner assembly according to claim 1, wherein all
gaps and leak paths between the venturi section and the head end
and between the venturi section and the liner sleeve are sealed via
an annular seal.
9. A combustion liner assembly according to claim 8, wherein the
annular seal is brazed.
10. In a gas turbine, a method of reducing air flow losses between
a venturi section and a liner sleeve of a combustion liner
assembly, the method comprising: utilizing at least a portion of
the venturi section as a liner upstream of the liner sleeve; and
providing an annular weld at a joint between the venturi section
and the liner sleeve and at a joint between the venturi section and
a head end of the combustion liner assembly.
11. A method according to claim 10, further comprising utilizing
additional air flow by virtue of the reduced air flow losses to
allow more consistent air flow in a fuel-air mixture in the head
end.
12. A method according to claim 11, wherein the additional air flow
is utilized to tune turbine emissions.
13. A combustion liner assembly for a gas turbine combustor, the
combustion liner assembly comprising: a venturi section connected
to a head end of the liner assembly via an annular weld, the
venturi section defining an annular throat area within the liner
assembly; and a liner sleeve connected to and commencing at a
downstream end of the venturi section, wherein the liner sleeve is
connected to the downstream end of the venturi section via an
annular weld, wherein at least a portion of the venturi section
serves as a liner upstream of the liner sleeve.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to apparatus and methods for
minimizing or eliminating dilution air leakage paths in a gas
turbine combustor and, more particularly, the invention relates to
apparatus and methods for managing dilution air leakage to achieve
lower emission levels.
[0002] As is well known, significant products of combustion in gas
turbine emissions are oxides of nitrogen, i.e., NO and NO.sub.2
collectively called NOx, carbon monoxide CO, and unburned
hydrocarbons as well as other particulates. Various systems have
been proposed and utilized for reducing emissions. For example,
water or steam injection into the burning zone of the gas turbine
combustor, catalytic clean-up of NOx and CO from the gas turbine
exhaust and dry low NOx combustors have been used in the past.
Compressor discharge dilution air introduced into the liner sleeve
of the combustor and transition piece has also been utilized to
reduce emissions.
[0003] It would be desirable to substantially reduce or eliminate
leaks so that air flow in more non-critical areas is conserved and
made more consistent from can to can. Additionally, it would be
desirable to substantially reduce or eliminate leaks so that air
flow can be increased in usable areas in a more dispersed and even
mixing through the mixing holes.
BRIEF DESCRIPTION OF THE INVENTION
[0004] In an exemplary embodiment, a combustion liner assembly for
a gas turbine combustor includes a plurality of fuel nozzles
disposed circumferentially about a central axis of the combustor,
and a venturi section disposed downstream of the fuel nozzles and
connected to a head end of the liner assembly. The venturi section
defines an annular throat area downstream of the fuel nozzles. A
liner sleeve is connected to and commences at a downstream end of
the venturi section. At least a portion of the venturi section
serves as a liner upstream of the liner sleeve.
[0005] In another exemplary embodiment, a method of reducing air
flow losses between a venturi section and a liner sleeve of a
combustion liner assembly in a gas turbine includes the steps of
utilizing at least a portion of the venturi section as a liner
upstream of the liner sleeve; and providing an annular weld at a
joint between the venturi section and the liner sleeve and at a
joint between the venturi section and a head end of the combustion
liner assembly.
[0006] In still another exemplary embodiment, a combustion liner
assembly for a gas turbine combustor includes a venturi section
connected to a head end of the liner assembly via an annular weld,
where the venturi section defines an annular throat area within the
liner assembly; and a liner sleeve connected to and commencing at a
downstream end of the venturi section, where the liner sleeve is
connected to the downstream end of the venturi section via an
annular weld. At least a portion of the venturi section serves as a
liner upstream of the liner sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a fragmentary cross-sectional view of one-half of
a combustion liner assembly about a combustor center line;
[0008] FIG. 2 shows an embodiment with the venturi section serving
as part of the liner;
[0009] FIG. 3 is an alternative design;
[0010] FIG. 4 shows another embodiment utilizing a connector;
[0011] FIG. 5 is a cross-sectional view of still another
alternative embodiment; and
[0012] FIG. 6 is a cross-sectional view of yet another
embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Referring now to the drawings, particularly to FIG. 1, there
is illustrated a combustion liner assembly, generally designated
10, including a cap centerbody 12, a liner sleeve 14, a primary
fuel nozzle cup assembly 16 and a venturi section 18. It will be
appreciated that the combustion liner assembly 10 is cylindrical or
annular in configuration about a centerline axis 20 and that a
plurality of primary fuel nozzles 16 are spaced circumferentially
one from the other about axis 20. A swirler 22 is shown as part of
the cap centerbody 12. The liner sleeve 14 has an inlet including a
plurality of circumferentially spaced apertures 24 which receive
compressor discharge air from a plenum (not shown) between the
combustion liner assembly and the combustion flowsleeve/casing. The
venturi 18 comprises a prefabricated double walled annular
structure disposed within the liner sleeve 14 and includes an inner
liner/wall 26 and an outer liner/wall 28. The venturi 18 has a
radial inward apex 30 which defines a throat area 32 with the
center cap body 12. The inner and outer liners 26 and 28 of venturi
18 include inner and outer wall portions 34 and 36, respectively,
which extend axially upstream and radially outwardly toward cup
assembly 16. The wall portions 34 and 36 terminate in a pair of
flanges 38 and 40, respectively, which are turned to extend in a
generally axially downstream direction. The flanges may be secured
to the liner sleeve 14 by rivets 42. In the prior art design, the
outer liner 28 of the venturi section 18 is also secured to the
liner sleeve 14 downstream of the venturi by a plurality of
circumferentially spaced rivets 44. As best illustrated in FIG. 1,
the liner sleeve 14 is recessed radially inwardly to overlay the
outer liner 28 of venturi 18 forming essentially an indented band
for securing the liner sleeve 14 and outer venturi sleeve 28 to one
another.
[0014] It has been discovered that variations in the leakage paths
of the dilution air supplied to the combustor have a significant
effect on emissions and that these variations are a result of parts
tolerances and assembly of the parts. For example, a primary
leakage path of concern is between the liner sleeve 14 and the
outer sleeve 28 of the venturi 18 in the area of the rivets 44. It
will be seen that the compressor discharge air supplied to the
annular plenum 46 from externally of the combustion liner via
apertures 24 may leak past the riveted connection. Variations in
leakage flow past the riveted joint, however, have been discovered
with respect to various identical combustors, and consequently,
emissions will vary. Those emissions resulting from leakage path
flows heretofore have not been identified or controlled.
[0015] There is an additional leakage path for the dilution air
flowing from plenum 46 into the space between the inner and outer
venturi sleeves 26 and 28, respectively, via apertures 50 in the
outer venturi sleeve 28. This additional leakage path passes
between the flanges 38 and 40 of the inner and outer liners 34 and
36 respectively of venturi 18. While these flanges 38 and 40 in the
past engaged each another and were riveted to the liner sleeve 14,
a variable gap between the flanges and from combustion liner to
identical combustion liner appeared, resulting in variable
emissions from ostensibly identical combustors.
[0016] A further leakage gap appears between the liner sleeve 14
and the overlapped flanges 38 and 40 of venturi 18. These gaps have
been demonstrated to vary between identically constructed
combustors and hence result in leakage flows causing variable
emissions. Also, it is important that the venturi throat area 32
must be maintained within pre-determined limits, notwithstanding
the removability of the venturi from the liner sleeve for
maintenance and service. It is also important that the throat area
be maintained upon original manufacture of the venturi and liner
sleeve and throughout the various service procedures performed on
the combustor during its life.
[0017] FIGS. 2 and 5 show an exemplary embodiment with an
integrated venturi section and liner that substantially reduces or
eliminates leakage areas and leakage losses. As shown, the venturi
section 18 is connected to a head end 62 of the liner assembly.
Like the current design, the flanges 38, 40 of the wall portions
34, 36 extend in a generally axially downstream direction. In the
embodiment shown in FIG. 2, however, in an area between the
position at which an upstream end of the venturi section 18 is
secured to the head end 62 and a downstream end of the venturi
section 18, the liner sleeve 14 is removed. An annular weld 64
seals the joint between the upstream end of the venturi section 18
and the head end 62. Additionally, the downstream end of the
venturi section 18 is connected to the liner sleeve 14 via an
annular weld 66. In this manner, a portion of the venturi section
18 serves as a liner upstream of the shortened liner sleeve 14.
This structure effectively integrates the venturi section 18 and
the liner sleeve 14.
[0018] FIG. 3 shows a more complex design utilizing an expansion
joint or slip joint 68 including a fork section 681 and a straight
section 682. In this embodiment, the fork section 681 is integral
with the head end 62 and venturi section 18. As a consequence, a
leak path at the venturi section connection to the head end is
eliminated. Cooling air is passed through apertures 69 in the
straight section 682. If air leaks around the slip joint 68, then
it has no affect on the performance of the combustor because air is
already being allowed into the hollow venturi cavity from the
apertures 69 in the outermost liner wall.
[0019] Yet another alternative embodiment is shown in FIG. 4. In
this embodiment, a connector part 70, which is preferably a
machined connector part, connects the venturi section 18 to the
head end 62. As shown, in a preferred construction, the connector
part 70 is Y-shaped including an end post 72 and a split end 74.
The split end 74 is welded to the inner and outer walls of the
venturi section 18, and the end post 72, which is thicker than the
split end 74, is welded to the head end 62. With the connector
part, a larger area of the combustion liner 14 is removed. Arrow A
in FIG. 4 illustrates the axial length over which the liner is
removed.
[0020] FIG. 6 illustrates yet another alternative embodiment. In
this embodiment, all gaps and leak paths between the venturi
section 18 and the head end 62 in between the venturi section 18
and the liner sleeve 14 are sealed via an annular seal, such as by
brazing or the like. During assembly, the liner can be tipped
upright to allow the braze material to wick into the gaps.
[0021] The described embodiments substantially reduce or eliminate
air flow losses between the venturi wall and the liner wall.
Elimination of air flow losses will allow more consistent air flow
to be utilized in the fuel air mixture in the head end combustion
zone rather than leaking air flow into direct stream. The simple
constructions as described use similar parts and technology as is
found in current designs. The embodiments are easy to manufacture
and will produce a more repeatable air flow from can to can and
will in turn help to create better fuel air mixture patterns than
the current design while also lowering combustion emissions. The
design substantially reduces or eliminates air flow leaks in areas
between the venturi and the liner wall so that the air flow can be
used in areas in a more dispersed and even mixing through the
mixing holes than with the current design. The components can be
used as control points to adjust air flow such that additional air
flow by virtue of the reduced air flow losses can be utilized to
lower emissions as well as lower variation from can to can.
[0022] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiments, it is to be understood that the invention is not to be
limited to the disclosed embodiments, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *