U.S. patent application number 13/738619 was filed with the patent office on 2014-07-10 for combustors with hybrid walled liners.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. The applicant listed for this patent is HONEYWELL INTERNATIONAL INC.. Invention is credited to Ian Critchley, Eduardo Guerra, Stony Kujala.
Application Number | 20140190171 13/738619 |
Document ID | / |
Family ID | 49326562 |
Filed Date | 2014-07-10 |
United States Patent
Application |
20140190171 |
Kind Code |
A1 |
Critchley; Ian ; et
al. |
July 10, 2014 |
COMBUSTORS WITH HYBRID WALLED LINERS
Abstract
A combustor for a turbine engine includes a first liner and a
second liner forming a combustion chamber with the first liner. The
combustion chamber is configured to receive an air-fuel mixture for
combustion therein and has a longitudinal axis that defines axial,
radial and circumferential directions. The first liner is a first
dual walled liner having a first hot wall facing the combustion
chamber and a first cold wall that forms a first liner cavity with
the first hot wall. The combustor further includes a primary air
admission hole defined in the first hot wall and a first fixed
liner seal between the first hot wall and the first cold wall
proximate to the primary air admission hole.
Inventors: |
Critchley; Ian; (Phoenix,
AZ) ; Kujala; Stony; (Mesa, AZ) ; Guerra;
Eduardo; (Queen Creek, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HONEYWELL INTERNATIONAL INC. |
Morristown |
NJ |
US |
|
|
Assignee: |
HONEYWELL INTERNATIONAL
INC.
Morristown
NJ
|
Family ID: |
49326562 |
Appl. No.: |
13/738619 |
Filed: |
January 10, 2013 |
Current U.S.
Class: |
60/755 |
Current CPC
Class: |
F23R 3/06 20130101; F23R
2900/00012 20130101; F23R 2900/03042 20130101; F23R 2900/03044
20130101; F23R 3/005 20130101; F23R 3/045 20130101; Y02T 50/60
20130101; F23R 3/002 20130101; Y02T 50/675 20130101 |
Class at
Publication: |
60/755 |
International
Class: |
F23R 3/00 20060101
F23R003/00 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0001] This invention was made with Government support under
Contract No. W911W6-08-2-0001 awarded by United States Army. The
Government has certain rights in this invention.
Claims
1. A combustor for a turbine engine, comprising: a first liner; a
second liner forming a combustion chamber with the first liner, the
combustion chamber configured to receive an air-fuel mixture for
combustion therein and having a longitudinal axis that defines
axial, radial and circumferential directions, the first liner being
a first dual walled liner comprising a first hot wall facing the
combustion chamber and a first cold wall that forms a first liner
cavity with the first hot wall, the first liner cavity having first
and second ends; and a primary air admission hole defined in the
first hot wall; and a first fixed liner seal between the first hot
wall and the first cold wall proximate to the primary air admission
hole.
2. The combustor of claim 1, wherein the first fixed liner seal has
a first portion proximate to and upstream of the primary air
admission hole.
3. The combustor of claim 2, wherein the first fixed liner seal has
a second portion proximate to and downstream of the primary air
admission hole.
4. The combustor of claim 1, wherein the first fixed liner seal
extends in the circumferential direction about the longitudinal
axis.
5. The combustor of claim 1, wherein the first fixed liner seal
circumscribes the primary air admission hole.
6. The combustor of claim 1, wherein the first fixed liner seal at
least partially forms the primary air admission hole.
7. The combustor of claim 6, wherein the primary air admission hole
is a first primary air admission hole and wherein the combustor
further comprises a second primary air admission hole defined in
the first cold wall, the first fixed liner seal circumscribing the
second primary air admission hole.
8. The combustor of claim 7, wherein the first fixed liner seal at
least partially forms the first primary air admission hole and the
second primary air admission hole.
9. The combustor of claim 1, wherein the first liner seal is formed
by brazing the first hot wall to the first cold wall.
10. The combustor of claim 1, further comprising a first sliding
liner seal configured to seal the first end of the first liner
cavity to accommodate relative movement of the first hot wall and
the first cold wall.
11. The combustor of claim 10, wherein the first sliding liner seal
is configured to accommodate relative movement of the first hot
wall and the first cold wall in the axial and radial direction.
12. The combustor of claim 10, further comprising a second sliding
liner seal configured to seal the second end of the first liner
cavity to accommodate relative to movement of the first hot wall
and the first cold wall.
13. The combustor of claim 10, wherein the first hot wall includes
radially extending first and second hot wall flanges that define a
first hot wall groove, and wherein the first sliding liner seal
includes a radially extending liner seal flange positioned within
the first hot wall groove, wherein the liner seal flange is movable
within the first hot wall groove relative to the first and second
hot wall flanges generally in the radial direction and is generally
retained by the first and second hot wall flanges in the axial
direction, wherein the first liner seal and the first hot wall
define a first axial cavity, and wherein one end of the first cold
wall is positioned within the first axial cavity, wherein the cold
wall is movable within the first axial cavity relative to the hot
wall and first liner seal generally in the axial direction and is
generally retained by the hot wall and first liner seal in the
radial direction.
14. The combustor of claim 10, wherein the first hot wall includes
radially extending first hot wall flange, and wherein the first
liner seal comprises first and second portions, the first portion
having a first inner flange and a second inner flange that define
an inner groove, the first hot wall flange being positioned within
the inner groove, wherein the first hot wall flange is movable
within the inner groove relative to the first and second outer
flanges generally in the radial direction and is generally retained
by the first and second outer flanges in the axial direction,
wherein the first portion of the first liner seal further includes
a first outer flange and a second outer flange that define an outer
groove, wherein the first liner seal further includes a second
portion with a first leg and a second leg extending perpendicularly
to the first leg, and wherein the first leg of the second portion
is positioned within the outer groove such that the second portion
is movable within the outer groove generally in the radial
direction and is generally retained by the first and second outer
flanges in the axial direction, wherein first portion further
includes an axial flange extending from the first outer flange, the
second leg of the second portion and the axial flange of the first
portion defining an axial cavity for receiving one end of the cold
wall, and wherein the cold wall is movable within the axial cavity
relative to the axial flange of the first portion and the second
leg of the second portion generally in the axial direction and is
generally retained by the axial flange of the first portion and the
second leg of the second portion in the radial direction.
15. A combustor for a turbine engine, comprising: a first liner; a
second liner forming a combustion chamber with the first liner, the
combustion chamber configured to receive an air-fuel mixture for
combustion therein and having a longitudinal axis that defines
axial, radial and circumferential directions, the first liner being
a first dual walled liner comprising a first hot wall facing the
combustion chamber and a first cold wall that forms a first liner
cavity with the first hot wall, the first liner cavity having first
and second ends; and a first primary air admission hole defined in
the first hot wall; and a first fixed liner seal between the first
hot wall and the first cold wall proximate to the primary air
admission hole; and a first sliding liner seal between the first
hot wall and the first cold wall on the first end of the first
liner cavity.
16. The combustor of claim 15, further comprising a second primary
air admission hole downstream of the first primary air admission
hole, the first fixed liner seal extending from upstream of the
first primary air admission hole to downstream of the second
primary air admission hole.
17. The combustor of claim 15, wherein the first fixed liner seal
circumscribes the primary air admission hole.
18. The combustor of claim 15, wherein the first fixed liner seal
at least partially forms the primary air admission hole, and
wherein the combustor further comprises a second primary air
admission hole defined in the first cold wall, the first fixed
liner seal circumscribing the second primary air admission
hole.
19. The combustor of claim 15, wherein the first sliding liner seal
is configured to accommodate movement in the axial and radial
directions.
20. The combustor of claim 15, further comprising a dome assembly
and a retention ring at a forward end of the combustion chamber,
and wherein the first sliding seal is formed between the dome
assembly and the retention ring.
Description
TECHNICAL FIELD
[0002] The following description generally relates to combustors
for gas turbine engines, and more particularly relates to
combustors with hybrid walled liners.
BACKGROUND
[0003] A gas turbine engine may be used to power various types of
vehicles and systems. For example, one type of gas turbine engine
that may be used to power aircraft is a turbofan gas turbine
engine. A turbofan gas turbine engine conventionally includes, for
example, five major sections: a fan section, a compressor section,
a combustor section, a turbine section, and an exhaust section. The
fan section is typically positioned at the inlet section of the
engine and includes a fan that induces air from the surrounding
environment into the engine and accelerates a fraction of this air
toward the compressor section. The remaining fraction of air
induced into the fan section is accelerated into and through a
bypass plenum and out the exhaust section.
[0004] The compressor section raises the pressure of the air it
receives from the fan section, and the resulting compressed air
then enters the combustor section, where a ring of fuel nozzles
injects a steady stream of fuel into a combustion chamber formed
between inner and outer liners. The fuel and air mixture is ignited
to form combustion gases, which drive rotors in the turbine section
for power extraction. The gases then exit the engine at the exhaust
section.
[0005] Known combustors include inner and outer liners that define
an annular combustion chamber in which the fuel and air mixture is
combusted. During operation, a portion of the airflow entering the
combustor is channeled through the combustor outer passageway to
cool the liners and dilute the hot combustion gases within the
combustion chamber. Some combustors are dual walled combustors in
which the inner and outer liners each have so-called "hot" and
"cold" walls. These arrangements may enable impingement effusion
cooling in which cooling air flows through cavities formed between
the hot and cold walls. In order to maximize cooling, seals may be
provided between the respective hot and cold walls at the forward
and aft edges to seal the cavities.
[0006] A consequence of the dual walled combustor design is the
inherent difference in operating temperature between the walls of
the liners. For example, the hot walls are subjected to high
temperature combustion gases and thermal radiation, resulting in
thermal stresses and strains, while the cold walls are shielded
from the combustion gases and run much cooler. Differential
operating temperatures result in differential thermal expansion and
contraction of the combustor components. Such differential thermal
movement occurs both axially and radially, as well as during steady
state operation and during transient operation of the engine as
power is increased and decreased. This movement may particularly
cause undesirable leakage or stress issues with the seals of the
respective liner walls.
[0007] Accordingly, it is desirable to provide combustors with the
cooling advantages of dual walled liners, while also minimizing
undesirable leakage of cooling air. Furthermore, other desirable
features and characteristics of the present invention will become
apparent from the subsequent detailed description of the invention
and the appended claims, taken in conjunction with the accompanying
drawings and this background of the invention.
BRIEF SUMMARY
[0008] In accordance with an exemplary embodiment, a combustor for
a turbine engine includes a first liner and a second liner forming
a combustion chamber with the first liner. The combustion chamber
is configured to receive an air-fuel mixture for combustion therein
and has a longitudinal axis that defines axial, radial and
circumferential directions. The first liner is a first dual walled
liner having a first hot wall facing the combustion chamber and a
first cold wall that forms a first liner cavity with the first hot
wall. The combustor further includes a primary air admission hole
defined in the first hot wall and a first fixed liner seal between
the first hot wall and the first cold wall proximate to the primary
air admission hole.
[0009] In accordance with an exemplary embodiment, a combustor for
a turbine engine includes a first liner and a second liner forming
a combustion chamber with the first liner. The combustion chamber
is configured to receive an air-fuel mixture for combustion therein
and has a longitudinal axis that defines axial, radial and
circumferential directions. The first liner is a first dual walled
liner having a first hot wall facing the combustion chamber and a
first cold wall that forms a first liner cavity with the first hot
wall. The combustor further includes a first primary air admission
hole defined in the first hot wall. A first fixed liner seal is
formed between the first hot wall and the first cold wall proximate
to the primary air admission hole. A first sliding liner seal is
formed between the first hot wall and the first cold wall on the
first end of the first liner cavity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will hereinafter be described in
conjunction with the following drawing figures, wherein like
numerals denote like elements, and wherein:
[0011] FIG. 1 is a cross-sectional view of a gas turbine engine in
accordance with an exemplary embodiment;
[0012] FIG. 2 is a cross-sectional view of a combustor for the gas
turbine engine of FIG. 1 in accordance with an exemplary
embodiment;
[0013] FIG. 3 is an enlarged cross-sectional view of a portion of
the combustor of FIG. 2 in accordance with an exemplary
embodiment;
[0014] FIG. 4 is an enlarged cross-sectional view of another
portion of the combustor of FIG. 2 in accordance with an exemplary
embodiment;
[0015] FIG. 5 is a plan view of another portion of the combustor of
FIG. 2 in accordance with an exemplary embodiment;
[0016] FIG. 6 is an enlarged cross-sectional view of an aft inner
sliding liner seal of the combustor of FIG. 2 in accordance with an
exemplary embodiment;
[0017] FIG. 7 is an enlarged cross-sectional view of an aft outer
sliding liner seal of the combustor of FIG. 2 in accordance with an
exemplary embodiment; and
[0018] FIG. 8 is an enlarged cross-sectional view of a forward
inner sliding liner seal of the combustor of FIG. 2 in accordance
with an exemplary embodiment;
[0019] FIG. 9 is an enlarged cross-sectional view of a portion of a
combustor in accordance with a further exemplary embodiment;
[0020] FIG. 10 is an enlarged cross-sectional view of another
portion of the combustor of FIG. 9 in accordance with the further
exemplary embodiment; and
[0021] FIG. 11 is a plan view of another portion of the combustor
of FIG. 9 in accordance with the further exemplary embodiment.
DETAILED DESCRIPTION
[0022] The following detailed description is merely exemplary in
nature and is not intended to limit the invention or the
application and uses of the invention. Furthermore, there is no
intention to be bound by any theory presented in the preceding
background or the following
DETAILED DESCRIPTION
[0023] Broadly, exemplary embodiments discussed herein relate to
hybrid walled combustors. More particularly, inner and outer liners
of a generally dual walled combustor each include hot and cold
walls. The liners have a fixed seal between the hot and cold walls
proximate to the primary air admission holes to prevent leakage
from the liner cavities. The fixed seals may be formed by brazing
together the hot and cold walls. The forward and aft ends of the
liners may have sliding seals to accommodate relative axial and
radial movements.
[0024] FIG. 1 is a cross-sectional view of a gas turbine engine
100, according to an exemplary embodiment. The gas turbine engine
100 can form part of, for example, an auxiliary power unit for an
aircraft or a propulsion system for an aircraft. The gas turbine
engine 100 may be disposed in an engine case 110 and may include a
fan section 120, a compressor section 130, a combustion section
140, a turbine section 150, and an exhaust section 160. The fan
section 120 may include a fan 122, which draws in and accelerates
air. A fraction of the accelerated air exhausted from the fan 122
is directed through a bypass section 170 to provide a forward
thrust. The remaining fraction of air exhausted from the fan 122 is
directed into the compressor section 130.
[0025] The compressor section 130 may include a series of
compressors 132, which raise the pressure of the air directed into
it from the fan 122. The compressors 132 may direct the compressed
air into the combustion section 140. In the combustion section 140,
which includes an annular combustor, the high pressure air is mixed
with fuel and combusted. The combusted air is then directed into
the turbine section 150.
[0026] The turbine section 150 may include a series of turbines
152, which may be disposed in axial flow series. The combusted air
from the combustion section 140 expands through the turbines 152
and causes them to rotate. The air is then exhausted through a
propulsion nozzle 162 disposed in the exhaust section 160,
providing additional forward thrust. In an embodiment, the turbines
152 rotate to thereby drive equipment in the gas turbine engine 100
via concentrically disposed shafts or spools. Specifically, the
turbines 152 may drive the compressor 132 via one or more rotors
154.
[0027] FIG. 2 is a more detailed cross-sectional view of the
combustion section 140 of FIG. 1. In FIG. 2, only half the
cross-sectional view is shown, the other half being substantially
rotationally symmetric about a centerline and axis of rotation 200.
Although the depicted combustion section 140 is an annular-type
combustion section, any other type of combustor, such as a can
combustor, can be provided. The depicted combustion section 140 may
be, for example, a rich burn, quick quench, lean burn (RQL)
combustor section.
[0028] The combustion section 140 comprises a radially inner case
202 and a radially outer case 204 concentrically arranged with
respect to the inner case 202. The inner and outer cases 202, 204
circumscribe the axially extending engine centerline 200 to define
an annular pressure vessel 206. The combustion section 140 also
includes a combustor 208 residing within the annular pressure
vessel 206.
[0029] The combustor 208 is defined by an inner liner 210 and an
outer liner 230 that circumscribes the inner liner 210 to define an
annular combustion chamber 250. The combustion chamber 250 may be
considered to have a longitudinal axis 201 that generally defines
radial, axial, and circumferential directions. The liners 210, 230
cooperate with cases 202, 204 to define respective inner and outer
air plenums 260, 262.
[0030] The inner liner 210 is a dual walled liner with a "hot" wall
212 on the side of the combustion chamber 250 and a "cold" wall 214
on the side of the plenum 260. The hot and cold walls 212, 214
define a liner cavity 216 therebetween. Similar to the inner liner
210, the outer liner 230 shown is a dual walled liner with a "hot"
wall 232 on the side of the combustion chamber 250 and a "cold"
wall 234 on the side of the plenum 262. The hot and cold walls 232,
234 define a liner cavity 236 therebetween.
[0031] The combustor 208 additionally includes a front end assembly
270 with a shroud assembly 272, fuel injectors 274, a dome assembly
276, and retention ring 278. One fuel injector 274 is shown in the
partial cross-sectional view of FIG. 2. In one embodiment, the
combustor 208 includes a total of sixteen circumferentially
distributed fuel injectors 274, but it will be appreciated that the
combustor 208 could be implemented with more or less than this
number of injectors 274. Each fuel injector 274 is secured to the
outer case 204 and projects through a shroud port. Each fuel
injector 274 introduces a swirling, intimately blended fuel and air
mixture that supports combustion in the combustion chamber 250. As
described in greater detail below, retention ring 278 is provided
to couple together the inner liner 210, shroud assembly 272, and
dome assembly 276, while retention ring 280 is provided to couple
together the outer liner 212, shroud assembly 272, and dome
assembly 276. An igniter 282 extends through the outer case 204 and
the outer air plenum 262, and is coupled to the outer liner 230. It
will be appreciated that more than one igniter 282 can be provided
in the combustor 208, although only one is illustrated in FIG. 2.
The igniter 282 is arranged downstream from the fuel injector 274
and is positioned to ignite the fuel and air mixture within the
combustion chamber 250.
[0032] During engine operation, airflow exits a high pressure
diffuser and deswirler at a relatively high velocity and is
directed into the annular pressure vessel 206 of the combustor 208.
The airflow enters the combustion chamber 250 through openings in
the liners 210, 230, where it is mixed with fuel from the fuel
injector 274, and the airflow is combusted after being ignited by
the igniter 282. The combusted air exits the combustion chamber 250
and is delivered to the turbine section 150 (FIG. 1) for energy
extraction.
[0033] The hot and cold walls 212, 214, 232, 234 are sealed
relative to one another with a number of fixed liner seals 220, 240
and a number of sliding liner seals 226, 228, 246, 248.
Additionally details about the hot and cold walls 212, 214, 232,
234 will now be provided.
[0034] The hot wall 212 of the inner liner 210 extends, at a
forward end, from the dome assembly 276 and/or shroud assembly 272
at the sliding liner seal 226 to, at the aft end, the case 202. In
some exemplary embodiments, the hot wall 212 may be fixed to the
dome assembly 276. The cold wall 214 of the inner liner 210
extends, at a forward end, from the hot wall 212 at sliding liner
seal 226 to, at the aft end, the hot wall 212 at the sliding liner
seal 228. As described in greater detail below, the retention ring
278 and dome assembly 276 form the sliding liner seal 226 to enable
relative movement for the hot wall 212 and cold wall 214 at the
forward end. The hot wall 232 of the outer liner 230 extends, at
the forward end, between the dome assembly 276 and/or shroud
assembly 272 at the sliding liner seal 246 to, at the aft end, the
case 204. In some exemplary embodiments, the hot wall 232 may be
fixed to the dome assembly 276. The cold wall 234 of the outer
liner 230 extends, at the forward end, from the hot wall 232 to, at
the aft end, the hot wall 232 at the sliding liner seal 248. As
described in greater detail below, the retention ring 280 and the
dome assembly 276 form the sliding liner seal 246 to enable
relative movement for the hot wall 232 and cold wall 234. Both the
hot and cold walls 212, 214, 232, 234 are fully annular in shape.
As described below, the hot and cold walls 212, 214, 232, 234 are
permanently joined by welding or brazing in the particular regions
to locally form a single wall, while in other regions, the cold
walls 214, 234 are separated from the hot walls 212, 232 to form an
impingement cavity with sliding seals to accommodate relative
thermal movement at the forward and aft ends.
[0035] The inner and outer liners 210, 230 define a number of air
admission holes 218, 238. In the exemplary embodiment, the hot and
cold walls 212, 214 of the inner liner 210 define air admission
holes 218, and the hot and cold walls 232, 234 of the outer liner
230 define air admission holes 238. The air admission holes 218,
238 function to admit air into the combustion chamber 250 to
support the combustion process, e.g., as primary air admission
holes, dilution holes, and/or quench jet holes. The air admission
holes 218, 238 may be arranged in axial and circumferential rows
around the inner and outer liners 210, 230 in any suitable pattern.
Although FIG. 3 depicts an embodiment with two rows of air
admission holes 218, 238, each of the inner and outer liners 210,
230 may include one row of air admission holes or additional rows
of air admission holes. In general, air admission holes 218, 238
will be sufficiently large to provide air jets which penetrate into
the combusting gas flow to enhance mixing. As examples, typical
diameter sizes for small engines will be in the range of 0.1-0.5
inches or may be up to 1 inches for larger engines.
[0036] In general, the hot and cold walls 212, 214 are fixed and
sealed relative to one another in the areas proximate to the air
admission holes 218 with the inner fixed liner seal 220 and are
engaged with the sliding liner seals 226, 228 at the forward ends
and the aft ends, respectively. As is discussed in greater detail
below in reference to FIG. 3, the sliding liner seals 226, 228 seal
the liner cavity 216 while accommodating relative movement between
the hot and cold walls 212, 214 in one or more of the radial and
axial directions resulting, for example, from thermal expansions
and contractions. In one exemplary embodiment, the sliding liner
seals 226, 228 only seal the hot and cold walls 212, 214 of the
inner liner 210 and are separate from the seals that couple the
combustion section 140 to the turbine section 150 (FIG. 1).
[0037] In general, the hot and cold walls 232, 234 are fixed and
sealed relative to one another in the areas proximate to the air
admission holes 238 with fixed inner liner seal 240 and are engaged
with inner sliding liner seals 246, 248 at the forward ends and aft
ends, respectively. As is discussed in greater detail below in
reference to FIG. 4, the sliding liner seals 246, 248 seal the
liner cavity 236 while accommodating relative movement between the
hot and cold walls 232, 234 in one or more of the radial and axial
directions resulting, for example, from thermal expansions and
contractions. In one exemplary embodiment, the sliding liner seals
246, 248 only seal the hot and cold walls 232, 234 of the outer
liner 230 and are separate from the seals that couple the
combustion section 140 to the turbine section 150 (FIG. 1).
[0038] FIG. 3 is an enlarged cross-sectional view of a portion of
the combustor 208 of FIG. 2 in accordance with an exemplary
embodiment. FIG. 3 particularly shows the air admission holes 238
in the outer liner 230. In this exemplary embodiment, the air
admission holes 238 are defined by both of the hot wall 232 and the
cold wall 234.
[0039] FIG. 3 additionally depicts the outer fixed liner seal 240
between the hot wall 232 and the cold wall 234. The outer fixed
liner seal 240 functions to seal the outer liner cavity 236 in the
regions proximate to the air admission holes 238.
[0040] The outer fixed liner seal 240 is formed by brazing,
welding, or otherwise fixing the hot wall 232 to the cold wall 234
in a brazed (or fixed) region 352. In one exemplary embodiment,
brazing may include any metal joining process whereby a filler
metal is heated above melting point and distributed between two or
more close-fitting parts by capillary action. Suitable filler
material may include, for example, aluminum-silicon, copper,
Copper-silver, copper-zinc, nickel alloy, amorphous brazing foil
using nickel, iron, copper, silicon, boron, phosphorus, etc.,
and/or any other suitable metal. As such, in the brazed region 352,
the hot and cold walls 232, 234 are permanently fixed or sealed
together throughout. The outer fixed liner seal 240 is additionally
shown in FIGS. 4 and 5. FIG. 4 is an enlarged cross-sectional view
of another portion of the combustor 208 of FIG. 2 in accordance
with an exemplary embodiment, and FIG. 5 is a plan view of another
portion of the combustor 208 of FIG. 2 in accordance with an
exemplary embodiment. FIG. 4 is a cross-sectional view similar to
that of FIG. 3, e.g., in a similar radial and axial position, but
in a different circumferential position that does not include air
admission holes.
[0041] As shown, the outer fixed liner seal 240 is defined by the
brazed region 352 that extends from an area just upstream of the
air admission holes 238 to an area just downstream of the air
admission holes 238. As such, the brazed region 352 encompasses the
axial extent of the air admission holes 238. The brazed region 352
is arranged such that the outer fixed liner seal 240 completely
surrounds and circumscribes that air admission holes 238. For
example, in the view depicted by FIG. 4, the brazed region 352 at
least partially forms the air admission holes 238. As a result of
the brazed region 352 at the air admission holes 238, the liner
cavity is eliminated in this area and an insert is not
necessary.
[0042] The brazed region 352 is generally continuous, except for
the areas defining the air admission holes 238. As such, the brazed
region 352 extends between air admission holes 238 in both axial
and circumferential directions. For example, the brazed region 352
shown in FIG. 4 corresponds to the circumferential areas between
air admission holes 238. As another example, FIG. 5 schematically
depicts the circumferential and axial extent of the brazed region
352.
[0043] Although not described in detail or depicted in an enlarged
view, the inner fixed liner seal 220 has a similar arrangement to
that of the outer fixed liner seal 240. As such, the inner fixed
liner seal 220 is formed by a brazed region between the hot wall
212 and cold wall 214 in areas proximate to the air admission holes
218. In one exemplary embodiment, the inner fixed liner seal 220
extends from a position just upstream of the air admission holes
218 to an area just downstream of the air admission holes 218, and
the inner fixed liner seal 220 includes brazed portions axially and
circumferentially between the air admission holes 218.
[0044] As noted above, due to the arrangement of the inner and
outer fixed liner seals 220, 240, the air admission holes 218, 238
may be formed without inserts or guide tubes extending between the
hot walls 212, 232 and cold walls 214, 234. Considering the fixed
liner seals 220, 240 function to seal the hot and cold walls 212,
214, 232, 234 without leakage, the liners 210, 230 function in
these areas as single walled liners, while the separation between
the hot and cold walls 212, 214, 232, 234 outside of the fixed
liner seals 220, 240 enable the advantageous impingement effusion
cooling arrangement of a dual walled liner. As such, the liners
210, 230 may be considered hybrid walled liners.
[0045] Referring briefly again to FIG. 3, the cross-sectional view
of FIG. 3 additionally depicts a schematic representation of the
impingement effusion cooling arrangement of the outer liner 230.
Although not specifically shown, a similar impingement effusion
cooling arrangement may be provided in any suitable area of the
inner liner 210 and/or outer liner 230. As shown, the impingement
cooling air may flow from the inner air plenum 260 through
impingement cooling holes 360 in the cold wall 234 at an angle of
approximately 90.degree. relative to the cold wall 234, and then
pass through effusion cooling holes 362 in the hot wall 232 as
effusion cooling air at an angle of approximately 15.degree.
-45.degree. to the surface of the hot wall 232 such that a film of
cooling air forms on the hot wall 232. In an exemplary embodiment,
this impingement effusion cooling arrangement enables improved
cooling of the outer liner 230 with a consequent improvement in the
durability of the combustor and/or lead to additional air available
for the combustion process and a corresponding decrease in unwanted
emissions.
[0046] The sliding liner seals 226, 228, 246, 248, will now be
discussed in greater detail. FIG. 6 is an enlarged cross-sectional
view of an aft inner sliding liner seal 228 suitable for use in the
combustor 208 of FIG. 2 in accordance with an exemplary embodiment.
In particular, FIG. 6 shows an aft portion of the hot wall 212 and
the cold wall 214 of the inner liner 210, and the aft inner sliding
liner seal 228 functions to seal the aft end of the inner liner
cavity 216 formed between the hot wall 212 and the cold wall 214.
In general, the hot wall 212 of the inner liner 210 may include
first and second radial flanges 610, 612. The first and second
radial flanges 610, 612 cooperate to form a hot wall groove
614.
[0047] The aft inner sliding liner seal 228 is generally an
annular, single-piece seal and includes an axial main body 652 and
a radial flange 654. The axial main body 652 defines a groove 656.
In general, the radial flange 654 is positioned within the hot wall
groove 614 to retain the aft inner sliding liner seal 228 in an
axial direction relative to the hot wall 212. The first radial
flange 610 of the hot wall 212 is also positioned within the inner
liner seal groove 656 to additionally retain the aft inner sliding
liner seal 228 in an axial direction relative to the hot wall 212.
The aft inner sliding liner seal 228 and hot wall 212 further
define a seal cavity 658 extending generally in an axial direction.
The aft end of the cold wall 214 is positioned within the seal
cavity 658 to retain the cold wall 214 in a radial direction
relative to the aft inner sliding liner seal 228.
[0048] In one exemplary embodiment, the aft inner sliding liner
seal 228 is a split ring seal with ends that may be separated for
installation over the hot and cold walls 212, 214 of the inner
liner 210. The two ends may then be welded or otherwise attached
together to complete the installation. Other installation
mechanisms may also be provided. For example, the annular aft inner
sliding liner seal 228 may actually have two or more pieces that
are arranged around the hot and cold walls 212, 214 of the inner
liner 210. In this alternate embodiment, the ends of the
multi-piece aft inner sliding liner seal 228 may then be welded or
otherwise attached to complete the installation.
[0049] As noted above, the hot and cold wall 212, 214 may have
relative movement to one another in both the radial and axial
directions as a result of, for example, temperature differentials.
The aft inner sliding liner seal 228 is configured to accommodate
this relative movement, as will now be described.
[0050] In particular, the cold wall 214 is not fixed in an axial
direction relative to the hot wall 212 at the aft inner sliding
liner seal 228. As such, the cold wall 214 may slide in an axial
direction within the seal cavity 658, as indicated by arrows 670.
This accommodates relative axial movement of the hot wall 212 and
the cold wall 214. The cold wall 214 may have a relative movement
of a first distance 662 and still be retained in a radial
direction. In one exemplary embodiment, the first distance 662 may
be the distance from the first radial flange 610 to a forward edge
664 of the aft inner sliding liner seal 228.
[0051] Additionally, the hot wall 212 is not fixed in a radial
direction relative to the cold wall 214 at the aft inner sliding
liner seal 228. As such, the first and second radial flanges 610,
612 of the hot wall 212 may slide in a radial direction, as
indicated by arrows 672, relative to the radial flange 654 of the
aft inner sliding liner seal 228. This accommodates relative radial
movement of the hot wall 212 and the cold wall 214. The cold wall
214 may have a relative movement of a second distance 668 and still
be retained in a radial direction. In one exemplary embodiment, the
second distance 668 may be the depth of the hot wall groove 614 of
the hot wall 212. Accordingly, the aft inner sliding liner seal 228
accommodates the relative movement between the hot and cold walls
212, 214 while maintaining the seal at the aft end of the inner
liner cavity 216 to minimize leakage of cooling air and provide
improved cooling effectiveness. The freedom of axial and radial
movements may additionally relieve thermal stresses.
[0052] FIG. 7 is an enlarged cross-sectional view of an aft outer
sliding liner seal 248 suitable for use in the combustor 208 of
FIG. 2 in accordance with an exemplary embodiment. In particular,
FIG. 7 shows an aft portion of the hot wall 232 and the cold wall
234 of the outer liner 230, and the aft outer sliding liner seal
248 functions to seal the aft end of the outer liner cavity 236
formed between the hot wall 232 and the cold wall 234. In general,
the hot wall 232 of the outer liner 230 may include a radial flange
710.
[0053] The aft outer sliding liner seal 248 is generally an
annular, two-piece seal and includes a first outer liner seal
portion 752 and a second outer liner seal portion 772. The first
outer liner seal portion 752 generally has a cross-sectional
H-shape with a cross piece 754. The first outer liner seal portion
752 has a forward outer flange 756 and an aft outer flange 758
extending in a radial direction from the cross piece 754 and
defining an outer radial groove 760. The first outer liner seal
portion 752 further has a forward inner flange 762 and an aft inner
flange 764 extending in a radial direction from the cross piece 754
and defining an inner radial groove 766. The first outer liner seal
portion 752 additionally includes an axial flange 768 extending in
a forward axial direction from the forward outer flange 756. As
shown, the radial flange 710 of the hot wall 232 is positioned
within the inner radial groove 766 to retain the first outer liner
seal portion 752 and hot wall 232 relative to one another in an
axial direction.
[0054] The aft outer sliding liner seal 248 further includes the
second outer liner seal portion 772. The second outer liner seal
portion 772 generally has a cross-sectional L-shape. The second
outer liner seal portion 772 has a radial leg 774 and an axial leg
776. The axial leg 776 of the second outer liner seal portion 772
and the axial flange 768 of the first outer liner seal portion 752
define an axial cavity 778. The aft end of the cold wall 234 is
positioned within the axial cavity 778, and the radial leg 774 of
the second outer liner seal portion 772 is positioned within the
outer radial groove 760.
[0055] In one exemplary embodiment, the first and second outer
liner seal portions 752, 772 are a split ring seal portions that
may have ends that separate for appropriate installation over the
hot and cold walls 232, 234 of the outer liner 230. Particularly,
the first outer liner seal portion 752 is installed on the hot wall
232, and the two ends of the first outer liner seal portion 752 may
then be welded or otherwise attached together to complete the
installation of the first outer liner seal portion 752. The cold
wall 734 is then positioned over the hot wall 232 and first outer
liner seal portion 752. Finally, the second outer liner seal
portion 772 is installed over the cold wall 234 and the first outer
liner seal portion 752. The two ends of the second outer liner seal
portion 772 may then be welded or otherwise attached together to
complete installation of the outer liner seal portion 772 and the
aft outer sliding liner seal 248. Other installation arrangements
may also be provided. For example, the annular first and second
outer liner seal portions 752, 772 may actually have two or more
pieces that are arranged around the hot and cold walls 232, 234 of
the outer liner 230. In this alternate embodiment, the ends of the
multi-piece outer liner seal portions 752, 772 may then be welded
or otherwise attached to complete the installation.
[0056] As noted above, the hot and cold walls 232, 234 may have
relative movement to one another in both the radial and axial
directions as a result of, for example, temperature differentials.
The aft outer sliding liner seal 248 is configured to accommodate
this relative movement.
[0057] For example, the cold wall 234 is not fixed in an axial
direction relative to the first outer liner seal portion 752 and
the hot wall 232. In particular, the cold wall 234 slides within
the axial cavity 778 as indicated by arrows 780. This accommodates
relative axial movement of the hot wall 232 and the cold wall 234.
The cold wall 234 may have a relative movement of a first distance
782 and still be retained in a radial direction. In one exemplary
embodiment, the first distance 782 may be the depth of the axial
cavity 778.
[0058] Additionally, neither the hot wall 232 nor the cold wall 234
is fixed in a radial direction relative to the first outer liner
seal portion 752. In particular, the radial flange 710 of the hot
wall 232 slides within the inner radial groove 766 as indicated by
arrows 784. This accommodates relative radial movement between the
hot wall 232 and the cold wall 234. The cold wall 234 may have a
movement of a second distance 786 relative to the first outer liner
seal portion 752 and still be retained in an axial direction. In
one exemplary embodiment, the second distance 786 may be the depth
of the inner radial groove 766. The radial leg 774 of the second
outer liner seal portion 772 may also slide within the outer radial
groove 760 of the first outer liner seal portion 752, as indicated
by arrows 788. This also accommodates relative radial movement
between the hot wall 232 and cold wall 234, particularly radial
movement at a third distance 790 between the cold wall 234 and the
first outer liner seal portion 752. In one exemplary embodiment,
the third distance 790 may be the depth of the outer radial groove
760. Accordingly, the aft outer sliding liner seal 248 accommodates
the relative movement between the hot and cold walls 232, 234 while
maintaining the seal at the aft end of the outer liner cavity 236
to minimize leakage of cooling air and provide improved cooling
effectiveness. The freedom of axial and radial movements may
additionally relieve thermal stresses.
[0059] FIG. 8 is an enlarged cross-sectional view of the forward
inner sliding liner seal 226 of the combustor 208 of FIG. 2 in
accordance with an exemplary embodiment. The forward inner sliding
liner seal 226 is formed between a retention ring 278 and the dome
assembly 276 such that the hot wall 232 and the cold wall 234 are
engaged between the retention ring 278 and the dome assembly 276.
As a result of this arrangement, the hot wall 232 and the cold wall
234 may have a freedom of movement in the radial direction relative
to the retention ring 278, dome assembly 276, and one another. The
forward outer sliding liner seal 246 has a similar arrangement.
[0060] FIGS. 9-11 depict an alternate exemplary embodiment. FIG. 9
is an enlarged cross-sectional view of a portion of a combustor
908. Unless otherwise noted, the combustor 908 may be similar to
combustor 208 discussed above. As such, FIG. 9 generally
corresponds to the view depicted in FIG. 3. FIG. 10 is an enlarged
cross-sectional view of another portion of the combustor 908 of
FIG. 9. FIG. 10 generally corresponds to the view depicted in FIG.
4. FIG. 11 is a plan view of another portion of the combustor 908
of FIG. 9. FIG. 11 generally corresponds to the view depicted in
FIG. 5. Although FIGS. 3-5 depicted the outer liner 230, the
arrangement of FIGS. 9-11 may represent the inner or outer
liner.
[0061] Referring initially to FIG. 9, as above, the combustor 908
includes a liner 930 with a hot wall 932 and a cold wall 934 that
define a liner cavity 936. The liner 930 further includes air
admission holes 938. In this embodiment, the air admission holes
938 are formed only by the hot wall 932, thereby eliminating the
need for an insert or air guide tube. A fixed seal 940 functions to
seal the liner cavity 936 at the air admission holes 938. In this
exemplary embodiment, the fixed seal 940 is formed by a first
brazed region 952 and a second brazed region 954. The brazed
regions 952, 954 are discontinuous. As shown, the first brazed
region 952 is positioned upstream of the air admission holes 938
and the second brazed region 954 is positioned downstream of the
air admission holes 938. As additionally shown in FIGS. 10 and 11,
the brazed regions 952, 954 generally extend in a circumferential
direction about the liner 930, and are additionally discontinuous
relative to one another in the circumferential direction. In
effect, the brazed regions 952, 954 function to separate the cold
wall 934 into discontinuous upstream and downstream portions.
[0062] As a result of this arrangement, the hot wall 932 and cold
wall 934 function as a dual walled liner in areas other than the
air admission holes 938, while the hot wall 932 functions as a
single walled liner in areas proximate to the air admission holes
938. As such, the liner 930 may be considered a hybrid walled
liner.
[0063] Although not shown in detail, the alternate exemplary
embodiment described by FIGS. 9-11 may include sliding liner seals,
such as sliding liner seals 226, 228, 246, 248 discussed above to
enable relative axial and/or radial movement.
[0064] Accordingly, as a result of the sealing arrangements
provided by the inner and outer liner seals 220, 226, 228, 240,
246, 248, cooling characteristics of the liners 210, 230 may be
improved. Particularly, the liners 210, 230 may achieve a lower
temperature, which will enable improved durability of the
combustor. For example, the inner and outer liner seals 220, 226,
228, 240, 246, 248 enable effective impingement effusion cooling.
As a result, a reduced amount of air can be used to effectively
cool the liners 210, 230. Reduced temperatures may result in lower
thermal stresses and improved component life in a cost-effective
and reliable manner. In some embodiments, the inner and outer liner
seals 220, 226, 228, 240, 246, 248 may provide satisfactory cooling
with reduced weight, parts count and cost as compared with
conventional arrangements. In various embodiments, the inner and
outer liner seals 220, 226, 228, 240, 246, 248 may be used in
combination with one another or individually. Different
configurations and arrangements of the inner and outer sliding
liner seals 220, 226, 228, 240, 246, 248 can be provided as
necessary in dependence on the desired temperature of the
respective liner 210, 230 and the sensitivity of the combustor 208
to additional cooling air. Exemplary embodiments may find
beneficial uses in many industries, including aerospace and
particularly in high performance aircraft, as well as automotive
and electrical generation. Although a turbofan engine is referenced
above, the inner and outer liner seals 220, 226, 228, 240, 246, 248
may be used in any type of engine, including gas turbine engines,
turboshaft engines, turboprop engines, and static power generation
units.
[0065] While at least one exemplary embodiment has been presented
in the foregoing detailed description of the invention, it should
be appreciated that a vast number of variations exist. It should
also be appreciated that the exemplary embodiment or exemplary
embodiments are only examples, and are not intended to limit the
scope, applicability, or configuration of the invention in any way.
Rather, the foregoing detailed description will provide those
skilled in the art with a convenient road map for implementing an
exemplary embodiment of the invention. It being understood that
various changes may be made in the function and arrangement of
elements described in an exemplary embodiment without departing
from the scope of the invention as set forth in the appended
claims.
* * * * *