[0001] The subject matter disclosed herein relates generally to turbomachines and, more
particularly, to turbomachines with trapped vortex features.
[0002] A typical turbomachine includes a compressor to compress inlet air, a combustor in
which the compressed inlet air is combusted along with fuel, a turbine in which products
of the combustion are receivable for power generation purposes and a transition piece.
The transition piece is fluidly interposed between the combustor and the turbine.
[0003] In some cases, the typical turbomachine is configured to support axially staged or
late lean injection. In these cases, fuel and air are injected into downstream sections
of the combustor or the transition piece in order to cause secondary combustion within
the downstream sections of the combustor or the transition piece. This secondary combustion
tends to reduce emissions of pollutants, such as oxides of nitrogen.
[0004] According to one aspect of the invention, a unibody liner formed to define a flow
path for combustion products, the unibody liner including first and second portions
defining first radial planes, a third portion defining a second radial plane and fourth
and fifth portions extending substantially radially between proximal ends of the first
and third portions and proximal ends of the second and third portions, respectively,
and an injector configured to deliver a fuel or a fuel/air mixture to a space partially
bound by the third, fourth and fifth portions.
[0005] According to another aspect of the invention, a turbomachine is provided and includes
a unibody liner formed to define a flow path for combustion products, the unibody
liner being formed to define a trapped vortex feature into which a portion of combustion
products flow, and an injector configured to deliver a fuel or a fuel/air mixture
to the trapped vortex feature.
[0006] According to yet another aspect of the invention, a turbomachine is provided and
includes a combustor liner defining a first interior in which combustion occurs and
a second interior through which products of combustion flow, a transition piece disposed
downstream from the combustor liner, the transition piece defining a third interior,
which is receptive of the products of combustion and through which the products of
combustion continue to flow, at least one of the combustor liner and the transition
piece being formed to define a recess into which a portion of the products of combustion
flow and an injector configured to deliver combustible materials to the recess whereby
the combustible materials and the portion of the products of combustion form respectively
trapped vortices.
[0007] Various advantages and features will become more apparent from the following description
taken in conjunction with the drawings.
[0008] 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:
FIG. 1 is a schematic illustration of a turbomachine; and
FIG. 2 is an enlarged view of a portion of the turbomachine of FIG. 1.
[0009] The detailed description explains embodiments of the invention, together with advantages
and features, by way of example with reference to the drawings.
[0010] With reference to FIGS. 1 and 2, a turbomachine 10 includes a compressor 11 to compress
inlet air, a combustor 12 in which the compressed inlet air is combusted along with
fuel, a turbine 13 in which products of combustion are receivable for power generation
purposes and a transition piece 14. The transition piece 14 is fluidly interposed
between the combustor 12 and the turbine 13. The turbomachine 10 is configured to
support axially staged injection or late lean injection (LLI) whereby fuel and air
are injected into downstream sections of the combustor 12 or the transition piece
14 in order to cause secondary combustion processes. This secondary combustion tends
to reduce emissions of pollutants, such as oxides of nitrogen, from the turbomachine
10.
[0011] In some axially staged injection or LLI configurations, it has been found that almost
all of the air available for turbomachine operations is utilized for combustion in
one form or another and that little to no air is bypassed in the form of combustor
dilution air. This means that air used for axially staged injection or LLI robs the
head end of the combustor 12 of some portion of air that could have otherwise been
used to improve head end performance for a given amount of fuel. Accordingly, the
turbomachine 10 is provided with a trapped vortex feature (which is described below)
that allows most of the air available for combustion to be provided through the pre-mixers
at the head end of the combustor 12 and then be re-utilized later for axially staged
injection or LLI.
[0012] With reference to FIG. 2, the combustor 12 includes a combustor liner 20 and a flow
sleeve 21. The combustor liner 20 is formed to define a first interior 201, in which
a first stage of the combustion occurs, and a second interior 202. The products of
combustion flow through the second interior 202 toward the turbine 13. The first interior
201 is generally defined proximate to a head end of the combustor 12 at an axially
upstream location and the second interior 202 is defined fluidly and axially downstream
from the first interior 201. The flow sleeve 21 is disposed about the combustor liner
20 to define a first annulus 22.
[0013] The transition piece 14 is disposed fluidly and axially downstream from the combustor
12 and includes a transition piece liner 30 and an impingement sleeve 31. The transition
piece liner 30 is formed to define a third interior 301, which is fluidly interposed
between the second interior 202 and an interior of the turbine 13. Thus, the third
interior 301 is receptive of the products of combustion from the second interior 202
of the combustor 12 and provides for a flow path along or through which the products
of combustion can continue to flow toward the turbine 13. The impingement sleeve 31
is disposed about the transition piece liner 30 to define a second annulus 32. The
second annulus 32 is fluidly coupled with the first annulus 22. The impingement sleeve
31 is formed to define impingement holes 310.
[0014] For purposes of clarity and brevity, in the following description and claims, the
combustor liner 20 and the transition piece liner 30 may be referred to separately
or as a unibody liner. Thus, it will be understood that a unibody liner includes at
least portions of both the combustor liner 20 and the transition piece liner 30.
[0015] Compressed air is exhausted from the compressor 11 and enters a compressor discharge
casing (CDC). From an interior of the CDC, the compressed air enters the second annulus
32 via the impingement holes 310. The compressed air then flows from the second annulus
32 through the first annulus 22 toward the head end of the combustor 12 where the
compressed air is mixed with fuel and combusted.
[0016] In some cases, a portion of the compressed air entering the second annulus 32 may
be used as a coolant for the transition piece liner 30 within the third interior 301.
In such cases, the transition piece liner 30 may include a flange 33 that is sealed
to the transition piece liner 30 by hula seal 34. The flange 33 is formed to define
a cooling path 35 by which the portion of the compressed air can be delivered to the
third interior 301 along an interior surface of the transition piece liner 30.
[0017] At least one or both of the combustor liner 20 and the transition piece liner 30
is formed to define a substantially annular recess 40 proximate to a connection of
the combustor liner 20 and the transition piece liner 30. The recess 40 acts as a
trapped vortex feature 41 that extends radially outwardly from the second interior
202 and/or the third interior 301. Thus, as the products of combustion travel downstream
through the second interior 202 and then through the third interior 301 as a main
flow, a portion of the products of combustion flow into the recess 40 with a flow
pattern (i.e., a second trapped vortex 70) to be described below. In accordance with
embodiments, the portion of the products of combustion include air provided through
the pre-mixers at the head end of the combustor 12 and which is to be re-utilized
in the recess 40/trapped vortex feature 41.
[0018] In being formed to define the recess 40, the at least one of the combustor liner
20 and the transition piece liner 30 includes a first axial portion 401, a second
axial portion 402, a third axial portion 403, a fourth radial portion 404 and a fifth
radial portion 405 with the recess at least partially bounded by the third axial portion
403, the fourth radial portion 404 and the fifth radial portion 405. The first axial
portion 401 may be disposed upstream from the second axial portion 402. The first
and second axial portions 401 and 402 may have annular shapes while respectively defining
first radial planes, RP1, which may be but need not be substantially similar to one
another. The third axial portion 403 may have an annular shape and defines a second
radial plane, RP2, which is displaced radially outwardly from the first radial planes,
RP1, by a predefined amount. The fourth radial portion 404 and the fifth radial portion
405 each extend substantially radially to connect the first and second axial portions
401 and 402 to the third axial portion 403. That is, the fourth radial portion 404
extends substantially radially between proximal ends of the first axial portion 401
and the third axial portion 403 while the fifth radial portion 405 extends substantially
radially between proximal ends of the second axial portion 402 and the third axial
portion 403.
[0019] In accordance with embodiments, the recess 40 may have a substantially rectangular
cross-sectional shape. In accordance with further embodiments, the corners of the
recess 40 (i.e., the connections between the first axial portion 401 and the fourth
radial portion 404, the fourth radial portion 404 and the third axial portion 403,
the third axial portion 403 and the fifth radial portion 405 and the fifth radial
portion 405 and the second axial portion 402) may be rounded to facilitate smooth
fluid flow into and out of the recess 40.
[0020] The turbomachine 10 further includes an injector 50. The injector 50 is configured
to deliver combustible materials, such as a fuel or a fuel and air mixture, to the
recess 40. In so doing, the combustible materials form a first trapped vortex 60 while
the portion of the products of combustion that have flown into the recess 40 form
the second trapped vortex 70. The combustible materials may include, for example,
fuel and a quantity of air derived from the CDC. As such, the combustible materials
have a pressure, P
CD, which is substantially similar to the pressure in the CDC interior.
[0021] As shown, the combustible materials forming the first trapped vortex 60 tend flow
in a first vortical pattern and the portion of the products of combustion forming
the second trapped vortex 70 tends to flow in a second vortical pattern. The first
and second vortical patterns may be substantially oppositely oriented. Thus, as the
first and second vortices 60 and 70 are adjacent to one another, the respective fluids
in each one mix along the shear line 80 such that the combustible materials injected
into the recess 40 by the injector 50 auto-ignite due to the temperatures and pressures
of the portion of the products of combustion. The respective fluids, including the
auto-ignited combustible materials, are then returned to the main flow and proceed
to flow toward the turbine 13.
[0022] With the auto-ignited combustible materials returned to the main flow, axially staged
injection or LLI processes may be engaged. This allows for secondary combustion to
occur with the associated advantages in terms of reduced pollutant emissions, for
example, but without the need to deprive the head end of the combustor 12 of any of
the air necessary for a given amount of fuel.
[0023] The injector 50 may include a vane 51 and a fuel source 52. The vane 51 is formed
to define a flowpath 510 by which the compressed air is transmittable from the CDC
to the recess 40. The fuel source 52 may include a flexible hose 520 and is configured
to provide a supply of fuel to the flowpath 510. The vane 51 is substantially radially
oriented and traverses the first annulus 22 and/or the second annulus 32. The vane
51 may be cylindrical or otherwise aerodynamically formed to generate as little a
disturbance as possible in compressed air moving through the first annulus 22 or the
second annulus 32. The vane 51 may include a micromixer 511 that is formed to mix
the combustible materials to be injected into the recess 40 and to prevent or substantially
reduce the possibility of flameholding in the recess 40 or the vane 51.
[0024] For most of the radial length of the vane 51, the flowpath 510 is oriented substantially
radially. At a radially inward location, however, the vane 51 may be configured such
that the flowpath 510 runs along the axial dimension of the turbomachine 10. In this
way, the injector 50 is configured to inject the combustible materials into the recess
40 in a substantially axial direction thus facilitating the formation of the first
trapped vortex 60.
[0025] In accordance with further embodiments, the fifth radial portion 405 may be formed
to define through-hole 53 by which compressed air may flow from the second annulus
32 into the recess 40. In this way, additional air may be provided to enhance the
combustion of the fuel injected by the injector 50. Moreover, since the through-hole
53 is defined through the fifth radial portion 405, the through-hole has a substantially
axial orientation whereby the compressed air flowing through the through-hole 53 flows
in the axial direction and thereby facilitates the formation of the first trapped
vortex 60. It will be understood that a similar effect can be achieved with the through-hole
53 defined through a downstream section of the third axial portion 403. In this case,
the compressed air flowing into the recess flows in the radial direction and again
facilitates the formation of the first trapped vortex 60.
[0026] 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.
[0027] Various aspects and embodiments of the present invention are defined by the following
numbered clauses:
- 1. A turbomachine with a trapped vortex feature, comprising:
a unibody liner formed to define a flow path for combustion products, the unibody
liner comprising:
first and second portions defining first radial planes, a third portion defining a
second radial plane and fourth and fifth portions extending substantially radially
between proximal ends of the first and third portions and proximal ends of the second
and third portions, respectively; and
an injector configured to deliver a fuel or a fuel/air mixture to a space partially
bound by the third, fourth and fifth portions.
- 2. The turbomachine according to clause 1, wherein the injector is configured to deliver
the fuel or the fuel/air mixture to the space in a substantially axial direction.
- 3. The turbomachine according to any preceding clause, wherein the unibody liner comprises
a combustor liner and a transition piece liner and the space is defined proximate
to a connection of the combustor liner and the transition piece.
- 4. The turbomachine according to any preceding clause, wherein the space has an annular
shape.
- 5. The turbomachine according to any preceding clause, wherein the space has a substantially
rectangular cross-sectional shape.
- 6. A turbomachine, comprising:
a unibody liner formed to define a flow path for combustion products;
the unibody liner being formed to define a trapped vortex feature into which a portion
of combustion products flow; and
an injector configured to deliver a fuel or a fuel/air mixture to the trapped vortex
feature.
- 7. The turbomachine according to any preceding clause, wherein the injector is configured
to deliver the fuel or the fuel/air mixture to the trapped vortex feature in a substantially
axial direction.
- 8. The turbomachine according to any preceding clause, wherein the unibody liner comprises
a combustor liner and a transition piece liner and the trapped vortex feature is defined
proximate to a connection of the combustor liner and the transition piece.
- 9. The turbomachine according to any preceding clause, wherein the trapped vortex
feature has an annular shape.
- 10. The turbomachine according to any preceding clause, wherein the trapped vortex
feature has a substantially rectangular cross-sectional shape.
- 11. A turbomachine, comprising:
a combustor liner defining a first interior in which combustion occurs and a second
interior through which products of combustion flow;
a transition piece liner disposed downstream from the combustor liner, the transition
piece liner defining a third interior, which is receptive of the products of combustion
and through which the products of combustion continue to flow,
at least one of the combustor liner and the transition piece liner being formed to
define a recess into which a portion of the products of combustion flow; and
an injector configured to deliver combustible materials to the recess whereby the
combustible materials and the portion of the products of combustion form respectively
trapped vortices.
- 12. The turbomachine according to any preceding clause, wherein the combustible materials
comprise fuel or a fuel mixed with compressor discharge casing air.
- 13. The turbomachine according to any preceding clause, further comprising:
a flow sleeve disposed about the combustor liner to define a first annulus; and
an impingement sleeve disposed about the transition piece liner to define a second
annulus,
the second annulus being fluidly coupled to the first annulus.
- 14. The turbomachine according to any preceding clause, wherein the injector comprises:
a vane formed to define a flowpath by which air is transmitted from a compressor discharge
casing to the recess; and
a fuel source configured to provide a supply of fuel to the flowpath.
- 15. The turbomachine according to any preceding clause, wherein the vane comprises
a micromixer.
- 16. The turbomachine according to any preceding clause, wherein the fuel source comprises
a flexible hose.
- 17. The turbomachine according to any preceding clause, wherein the injector is configured
to deliver the combustible materials to the recess in a substantially axial direction.
- 18. The turbomachine according to any preceding clause, wherein the recess is defined
proximate to a connection of the combustor liner and the transition piece liner.
- 19. The turbomachine according to any preceding clause, wherein the recess has an
annular shape.
- 20. The turbomachine according to any preceding clause, wherein the recess has a substantially
rectangular cross-sectional shape.
1. A turbomachine (10) with a trapped vortex feature (41), comprising:
a unibody liner (30) formed to define a flow path (510) for combustion products, the
unibody liner (30) comprising:
first and second portions (401, 402) defining first radial planes, a third portion
(403) defining a second radial plane and fourth and fifth portions (404, 405) extending
substantially radially between proximal ends of the first and third portions (401,
403) and proximal ends of the second and third portions (402, 403), respectively;
and
an injector (50) configured to deliver a fuel or a fuel/air mixture to a space partially
bound by the third, fourth and fifth portions (403, 404, 405).
2. The turbomachine (10) according to claim 1, wherein the injector (50) is configured
to deliver the fuel or the fuel/air mixture to the space in a substantially axial
direction.
3. The turbomachine (10) according to any preceding claim, wherein the unibody liner
(30) comprises a combustor liner (20) and a transition piece liner (30) and the space
is defined proximate to a connection of the combustor liner (20) and the transition
piece (14).
4. The turbomachine (10) according to any preceding claim, wherein the space has an annular
shape.
5. The turbomachine (10) according to any preceding claim, wherein the space has a substantially
rectangular cross-sectional shape.
6. A turbomachine (10), comprising:
a unibody liner (30) formed to define a flow path for combustion products;
the unibody liner (30) being formed to define a trapped vortex feature (41) into which
a portion of combustion products flow; and
an injector (50) configured to deliver a fuel or a fuel/air mixture to the trapped
vortex feature.
7. The turbomachine (10) according to claim 6, wherein the injector (50) is configured
to deliver the fuel or the fuel/air mixture to the trapped vortex feature in a substantially
axial direction.
8. The turbomachine (10) according to claim 6 or claim 7, wherein the unibody liner (30)
comprises a combustor liner and a transition piece liner and the trapped vortex feature
is defined proximate to a connection of the combustor liner and the transition piece.
9. The turbomachine (10) according to any of claims 6 to 8, wherein the trapped vortex
feature (41) has an annular shape.
10. The turbomachine (10) according to any of claims 6 to 9, wherein the trapped vortex
feature (41) has a substantially rectangular cross-sectional shape.
11. A turbomachine (10), comprising:
a combustor liner (30) defining a first interior in which combustion occurs and a
second interior through which products of combustion flow;
a transition piece liner (30) disposed downstream from the combustor liner, the transition
piece liner defining a third interior, which is receptive of the products of combustion
and through which the products of combustion continue to flow,
at least one of the combustor liner (20) and the transition piece liner (30) being
formed to define a recess into which a portion of the products of combustion flow;
and
an injector (50) configured to deliver combustible materials to the recess whereby
the combustible materials and the portion of the products of combustion form respectively
trapped vortices.
12. The turbomachine (10) according to claim 11, wherein the combustible materials comprise
fuel or a fuel mixed with compressor discharge casing air.
13. The turbomachine (10) according to claim 11 or claim 12, further comprising:
a flow sleeve (21) disposed about the combustor liner (20) to define a first annulus;
and
an impingement sleeve (31) disposed about the transition piece liner to define a second
annulus,
the second annulus being fluidly coupled to the first annulus.
14. The turbomachine (10) according to any of claims 11 to 13, wherein the injector (50)
comprises:
a vane (51) formed to define a flowpath (510) by which air is transmitted from a compressor
discharge casing to the recess; and
a fuel source configured to provide a supply of fuel to the flowpath (510).
15. The turbomachine (10) according to claim 14, wherein the vane (51) comprises a micromixer
(511).