U.S. patent application number 15/363105 was filed with the patent office on 2017-03-16 for combustion device for gas turbine engine.
This patent application is currently assigned to KAWASAKI JUKOGYO KABUSHIKI KAISHA. The applicant listed for this patent is KAWASAKI JUKOGYO KABUSHIKI KAISHA. Invention is credited to Atsushi HORIKAWA, Masahide KAZARI, Junichi KITAJIMA, Kunio OKADA.
Application Number | 20170074521 15/363105 |
Document ID | / |
Family ID | 54699050 |
Filed Date | 2017-03-16 |
United States Patent
Application |
20170074521 |
Kind Code |
A1 |
HORIKAWA; Atsushi ; et
al. |
March 16, 2017 |
COMBUSTION DEVICE FOR GAS TURBINE ENGINE
Abstract
A combustor includes: a combustion liner having a combustion
chamber formed therein; a fuel injector mounted to a top portion of
the combustion liner, and including a fuel injection member having
a plurality of fuel injection annular portions and an air guide
member including a plurality of combustion air annular portions
that guide air for combustion; and a supplemental burner. The fuel
injection annular portions and the combustion air annular portions
are arranged concentrically and alternately. The fuel injector
injects fuel and air into the combustion chamber. Each of the fuel
injection annular portions includes a plurality of fuel injection
holes that are open in a radial direction thereof, and each of the
combustion air annular portions includes a plurality of air guide
groove that are open in an axial direction thereof, and guide the
air to the fuel jetted from the fuel injection holes.
Inventors: |
HORIKAWA; Atsushi;
(Akashi-shi, JP) ; KAZARI; Masahide; (Akashi-shi,
JP) ; OKADA; Kunio; (Akashi-shi, JP) ;
KITAJIMA; Junichi; (Akashi-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KAWASAKI JUKOGYO KABUSHIKI KAISHA |
Kobe-shi |
|
JP |
|
|
Assignee: |
KAWASAKI JUKOGYO KABUSHIKI
KAISHA
Kobe-shi
JP
|
Family ID: |
54699050 |
Appl. No.: |
15/363105 |
Filed: |
November 29, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2015/065477 |
May 28, 2015 |
|
|
|
15363105 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02T 50/60 20130101;
F02C 7/232 20130101; F23R 3/283 20130101; F23R 3/16 20130101; F23D
2209/20 20130101; F23R 3/32 20130101; Y02T 50/675 20130101; F23R
2900/03044 20130101; F23R 3/30 20130101; F23R 3/002 20130101; Y02T
50/678 20130101; F23R 3/28 20130101; F23R 3/34 20130101; F23R 3/286
20130101; F23C 2900/9901 20130101 |
International
Class: |
F23R 3/28 20060101
F23R003/28; F23R 3/00 20060101 F23R003/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 30, 2014 |
JP |
2014-113269 |
Claims
1. A combustor comprising: a combustion liner having a combustion
chamber formed therein; a fuel injector mounted to a top portion of
the combustion liner and configured to inject fuel and air into the
combustion chamber, the fuel injector including a fuel injection
member having a plurality of fuel injection annular portions, and
an air guide member having a plurality of combustion air annular
portions that guide an air for combustion, the fuel injection
annular portions and the combustion air annular portions being
arranged concentrically and alternately; and a supplemental burner
disposed on a peripheral wall of the combustion liner in a
downstream region in the combustion chamber, wherein each of the
fuel injection annular portions includes a plurality of fuel
injection holes that are open in a radial direction thereof, and
each of the combustion air annular portions includes a plurality of
air guide grooves that are open in an axial direction thereof, and
guides the air to the fuel jetted from the fuel injection
holes.
2. The combustor as claimed in claim 1, wherein the supplemental
burner includes a premixing chamber configured to stir and mix a
fuel and an air, so as to inject a premixed gas generated in the
premixing chamber into the combustion chamber.
3. The combustor as claimed in claim 1, further comprising an
air-flow rectifying mechanism provided upstream of the fuel
injector, and configured to rectify flow of the air supplied to the
air guide member.
4. The combustor as claimed in claim 1, further comprising a
rectifying protrusion member that is provided on an axis of the
combustor and penetrates through the fuel injector so as to
protrude toward the combustion chamber.
5. The combustor as claimed in claim 4, wherein the rectifying
protrusion member includes a support portion, and a protruding
portion protruding from the support portion into the combustion
chamber, and has a cooling air introduction hole that is formed in
the support portion to introduce the air into the rectifying
protrusion member, and a cooling air discharge hole that is formed
in the protruding portion to discharge the air introduced into the
rectifying protrusion member to the combustion chamber.
6. The combustor as claimed in claim 1, wherein each of the fuel
injection annular portions is formed as a hollow portion, and a
hollow space in the fuel injection annular portion forms an annular
fuel flow passage that allows the fuel to flow in a circumferential
direction thereof.
7. The combustor as claimed in claim 5, wherein the fuel injection
annular portion includes: a first fuel flow passage that is
positioned on a combustion chamber side and is communicated with
the fuel injection holes; a second fuel flow passage that is
positioned on a side opposite to the combustion chamber, and is
supplied with the fuel to be jetted from the fuel injection holes;
and an injection nozzle configured to jet the fuel in the second
fuel flow passage to a wall surface of the first fuel flow passage
on the combustion chamber side.
8. A combustor as claimed in claim 1, comprising: a fuel supply
main pipe having a multiple pipe structure, and configured to
supply the fuel to the fuel injection member, wherein the fuel
supply main pipe includes a first supply passage configured to
supply the fuel to a first annular portion group of the plurality
of fuel injection annular portions, and a second supply passage
configured to supply the fuel to a second annular portion group of
the plurality of fuel injection annular portions.
Description
CROSS REFERENCE TO THE RELATED APPLICATION
[0001] This application is a continuation application, under 35
U.S.C. .sctn.111(a), of international application No.
PCT/JP2015/065477, filed May 28, 2015, which claims priority to
Japanese patent application No. 2014-113269, filed May 30, 2014,
the disclosure of which are incorporated by reference in their
entirety into this application.
BACKGROUND OF THE INVENTION
[0002] Field of the Invention
[0003] The present invention relates to combustors used in gas
turbine engines.
[0004] Description of Related Art
[0005] For environment protection purposes, in gas turbine engines,
strict environmental standards are set for the composition of
emitted combustion exhaust gas. It is required to reduce harmful
substances such as nitrogen oxide (hereinafter referred to as
NO.sub.x) from the exhaust gas. Under such circumstances, in recent
years, a combustion system adopting a premix combustion system
which effectively reduces the amount of generated NO.sub.x, for
example, a combined combustion system obtained by combining a lean
premix combustion system and a diffusion combustion system, has
been proposed (Patent Document 1).
[0006] When the premix combustion system is adopted, air and fuel
are premixed and combusted as a lean air-fuel mixture whose fuel
concentration is uniformized. Therefore, a combustion region where
the flame temperature is locally high does not exist. In addition,
the flame temperature can be lowered across the whole region by
dilution of the fuel. On this account, the amount of generated
NO.sub.x can be effectively reduced.
RELATED ART DOCUMENT
Patent Document
[0007] [Patent Document 1] Japanese Laid-open Patent Publication
No. 8-210641
SUMMARY OF THE INVENTION
[0008] On the other hand, in the premix combustion system, in order
to maintain the combustion by the lean fuel, flame stabilization is
performed by causing a strong swirl flow in a combustion chamber to
form a reverse flow region. Therefore, backfiring phenomenon in
which flame generated in the combustion chamber is propagated to a
premixing passage, is likely to occur. In recent years, a gas
turbine engine using hydrogen as a fuel has been proposed. However,
in a gas turbine engine using a highly reactive fuel including
hydrogen, the backfiring phenomenon is particularly likely to
occur.
[0009] Therefore, in order to solve the above-described problems,
an object of the present invention is to provide a combustor of a
gas turbine engine, which device is able to prevent local
high-temperature combustion to suppress generation of NO.sub.x, and
prevent backfiring phenomenon to stably maintain flame.
[0010] In order to achieve the above objects, a combustor according
to the present invention includes: a combustion liner having a
combustion chamber formed therein; a fuel injector mounted to a top
portion of the combustion liner and configured to inject fuel and
air into the combustion chamber, the fuel injector including a fuel
injection member having a plurality of fuel injection annular
portions, and an air guide member having a plurality of combustion
air annular portions that guide an air for combustion, the fuel
injection annular portions and the combustion air annular portions
being arranged concentrically and alternately; and a supplemental
burner disposed on a peripheral wall of the combustion liner in a
downstream region in the combustion chamber, in which each of the
fuel injection annular portions includes a plurality of fuel
injection holes that are open in a radial direction thereof, and
each of the combustion air annular portions includes a plurality of
air guide grooves that are open in an axial direction thereof, and
guides the air to the fuel jetted from the fuel injection
holes.
[0011] According to the above configuration, the fuel is jetted
from the plurality of fuel injection holes formed in the fuel
injection member, and thereby minute flame is maintained at
multiple points. In addition, since the fuel radially jetted from
the fuel injection holes is deflected at 90.degree. by the axially
flowing air, mixing outside the fuel injector is promoted. Thereby,
local high-temperature combustion is prevented, and low NO
combustion is realized. Further, the structure in which the air is
supplied from upstream of the fuel jetted from the fuel injection
holes, prevents the flame from entering the fuel injector, whereby
backfiring phenomenon is suppressed.
[0012] In addition, by providing the supplemental burner in a
region, in which combustion reaction is progressed, in a downstream
area in the combustion chamber, a response to load change can be
achieved.
[0013] Therefore, even when a highly-reactive fuel containing
hydrogen is used as the fuel for the gas turbine, extremely stable
combustion is maintained while suppressing generation of
NO.sub.x.
[0014] In one embodiment of the present invention, the supplemental
burner may include a premixing chamber configured to stir and mix a
fuel and an air, so as to inject a premixed gas generated in the
premixing chamber into the combustion chamber. According to this
configuration, by providing the supplemental burner in a region, in
which combustion reaction is progressed, in a downstream area in
the combustion chamber, generation of NO can be further suppressed
while suppressing occurrence of backfiring phenomenon.
[0015] In one embodiment of the present invention, the combustor
may further include an air-flow rectifying mechanism provided
upstream of the fuel injector, and configured to rectify flow of
the air supplied to the air guide member. According to this
configuration, since uniform air flow is supplied to the fuel
injector, combustion is further uniformized, whereby generation of
NO is suppressed, and backfiring phenomenon can be prevented more
reliably.
[0016] In one embodiment of the present invention, the combustor
may further include a rectifying protrusion member which is
provided on an axis of the combustor, and penetrates through the
fuel injector and protrudes toward the combustion chamber.
According to this configuration, since flame which is formed by the
fuel and air jetted from the radially inner portion of the fuel
injector is stabilized, combustion is stably maintained.
[0017] In one embodiment of the present invention, the rectifying
protrusion member may include a support portion, and a protruding
portion protruding from the support portion into the combustion
chamber, and has a cooling air introduction hole that is formed in
the support portion and introduces the air into the rectifying
protrusion member, and a cooling air discharge hole that is formed
in the protruding portion and discharges the air introduced into
the rectifying protrusion member, to the combustion chamber.
According to the above configuration, the protruding portion can be
cooled with a part of the air for combustion, from the inner side,
by convection cooling.
[0018] In one embodiment of the present invention, each of the fuel
injection annular portions may be formed as a hollow portion, and a
hollow space in the fuel injection annular portion forms an annular
fuel flow passage that allows the fuel to flow in a circumferential
direction thereof. A portion, of the fuel injection annular
portion, opposing the combustion chamber is exposed to high
temperature caused by the flame in the combustion chamber. However,
according to the above configuration, since the annular fuel flow
passage that allows the fuel to flow is formed in the fuel
injection annular portion, the portion exposed to the high
temperature is efficiently cooled by the fuel that flows through
the fuel flow passage.
[0019] In one embodiment of the present invention, the fuel
injection annular portion may include: a first fuel flow passage
that is positioned on a combustion chamber side and is communicated
with the fuel injection holes; a second fuel flow passage that is
positioned on a side opposite to the combustion chamber, and is
supplied with the fuel jetted from the fuel injection holes; and an
injection nozzle configured to jet the fuel in the second fuel flow
passage to a wall surface of the first fuel flow passage on the
combustion chamber side. According to the above configuration, the
wall, of the fuel injection annular portion, opposing the
combustion chamber can be cooled with the fuel, from the inner
side, by impingement cooling.
[0020] In one embodiment of the present invention, the combustor
may include a fuel supply main pipe having a multiple pipe
structure, and configured to supply the fuel to the fuel injection
member. The fuel supply main pipe may include a first supply
passage configured to supply the fuel to a first annular portion
group of the plurality of fuel injection annular portions, and a
second supply passage configured to supply the fuel to a second
annular portion group of the plurality of fuel injection annular
portions. According to this configuration, since the fuel injection
member can be divided into the fuel injection annular portions that
perform fuel supply and the fuel injection annular portions that do
not perform fuel supply. Therefore, an operation according to
output change from a rated load to a partial load (staging
combustion) is realized.
[0021] Any combination of at least two constructions, disclosed in
the appended claims and/or the specification and/or the
accompanying drawings should be construed as included within the
scope of the present invention. In particular, any combination of
two or more of the appended claims should be equally construed as
included within the scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In any event, the present invention will become more clearly
understood from the following description of preferred embodiments
thereof, when taken in conjunction with the accompanying drawings.
However, the embodiments and the drawings are given only for the
purpose of illustration and explanation, and are not to be taken as
limiting the scope of the present invention in any way whatsoever,
which scope is to be determined by the appended claims. In the
accompanying drawings, like reference numerals are used to denote
like parts throughout the several views, and:
[0023] FIG. 1 is a block diagram showing a schematic configuration
of a gas turbine engine in which a combustor according to one
embodiment of the present invention is applied;
[0024] FIG. 2 is a cross-sectional view of the combustor according
to the embodiment of the present invention;
[0025] FIG. 3 is a cross-sectional view of the combustor according
to the embodiment of the present invention;
[0026] FIG. 4 is a front view of a fuel injector used in the
combustor shown in FIG. 2;
[0027] FIG. 5A is a front view showing an enlarged portion of the
fuel injector used in the combustor shown in FIG. 2;
[0028] FIG. 5B is a front view showing one modified example of the
fuel injector shown in FIG. 5A;
[0029] FIG. 6A is a perspective view showing an example of an
air-flow rectifying plate used in the combustor shown in FIG.
2;
[0030] FIG. 6B is a perspective view showing another example of an
air-flow rectifying plate used in the combustor shown in FIG.
2;
[0031] FIG. 6C is a perspective view showing another example of an
air-flow rectifying plate used in the combustor shown in FIG.
2;
[0032] FIG. 6D is a perspective view showing another example of an
air-flow rectifying plate used in the combustor shown in FIG.
2;
[0033] FIG. 7A is a perspective view showing a modification of an
air-flow rectifying mechanism of the combustor shown in FIG. 2;
[0034] FIG. 7B is a perspective view showing another modification
of an air-flow rectifying mechanism of the combustor shown in FIG.
2;
[0035] FIG. 8 is a vertical cross-sectional view showing the fuel
injector used in the combustor shown in FIG. 2;
[0036] FIG. 9 is a vertical cross-sectional view showing a
modification of a fuel injector used in the combustor shown in FIG.
2;
[0037] FIG. 10 is a vertical cross-sectional view showing an
internal structure of a rectifying protrusion member used in the
combustor shown in FIG. 2;
[0038] FIG. 11 is a cross-sectional view showing a combustor
according to one embodiment in which the present invention is
applied to an annular combustor;
[0039] FIG. 12 is a partially cutaway perspective view of the
combustor shown in FIG. 11; and
[0040] FIG. 13 is a cross-sectional view showing a combustor
according to another embodiment in which the present invention is
applied to an annular combustor.
DESCRIPTION OF EMBODIMENTS
[0041] Hereinafter, embodiments of the present invention will be
described with reference to the drawings, but the present invention
is not limited to the embodiments.
[0042] FIG. 1 shows a schematic configuration of a gas turbine
engine (hereinafter referred to simply as a gas turbine) GT in
which a combustor according to an embodiment of the present
invention is applied. In the gas turbine GT, introduced air is
compressed by a compressor 1 and guided to a combustor 3, and fuel
is injected into the combustor 3. The fuel is combusted with the
air, and the resulting high-temperature and high-pressure
combustion gas drives a turbine 5. The turbine 5 is connected to
the compressor 1 via a rotary shaft 7, and the compressor 1 is
driven by the turbine 5. A load L such as a rotor of an aircraft or
a generator is driven by an output of the gas turbine GT. In the
present embodiment, hydrogen gas is used as the fuel injected into
the combustor 3. In the following description, a side, in an axial
direction of the gas turbine GT, on which the compressor 1 is
disposed is referred to as a "front side", and a side, in the axial
direction, on which the turbine 5 is disposed is referred to as a
"rear side".
[0043] FIG. 2 is a partially cutaway perspective view of the
combustor 3. The combustor 3 is a can type combustor, in which a
plurality of combustors 3 are annularly arranged about the axis of
the gas turbine GT. The combustor 3 includes a combustion liner 13
having a combustion chamber 11 formed therein, and a fuel injector
15 mounted to a top portion 13a of the combustion liner 13, and
injecting fuel and air into the combustion chamber 11. When the
fuel and the air jetted from the fuel injector 15 are ignited by an
ignition plug P provided in the combustion liner 13, flame is
formed in the combustion chamber 11. The combustion liner 13 and
the fuel injector 15 are concentrically housed in a substantially
cylindrical housing H which is an outer liner of the combustor 3.
An end cover 17 is fixed to a front end of the housing H by means
of bolts 19. As shown in FIG. 3, a support tube 21 cylindrically
extending from the combustion liner 13 is connected and fixed to
the end cover 17 by means of bolts or the like, whereby the top
portion 13a of the combustion liner 13 is mounted to the housing
H.
[0044] In the present embodiment, the combustor 3 is configured as
a reverse-flow type combustor, in which the flow directions of air
A and combustion gas G are opposite to each other. Specifically,
the combustor 3 includes an air introduction passage 25 formed
between the housing H, and the combustion liner 13 and the support
tube 21. The air introduction passage 25 guides the air A
compressed by the compressor 1 (FIG. 1) in a direction opposite to
the flow direction of the combustion gas G in the combustion
chamber 11. The combustor 3 may be of an axial-flow type in which
the flow direction of the air A is same as that of the combustion
gas. At a front end portion of a circumferential wall of the
support tube 21, a plurality of air introduction holes 27 are
arranged in a circumferential direction. The air A sent through the
air introduction passage 25 passes through the air introduction
holes 27, and is introduced to an air supply passage 29 formed
inside the support tube 21. The air introduced to the air supply
passage 29 is sent rearward, that is, toward the fuel injector 15.
In addition, a fuel supply main pipe 31 extending along an axis C
of the combustor 3 is provided in the center of the air supply
passage 29. A fuel F is supplied from the fuel supply main pipe 31
to fuel injection annular portions 33 of a fuel injection member 34
which will be described later. The structures of the air supply
passage 29 and the fuel supply main pipe 31 will be described later
in detail.
[0045] The combustor 3 includes supplemental burner 10 of a
premixing type disposed on a peripheral wall of the combustion
liner 13 in a downstream region. The combustor 3 may be provided
with a plurality of (for example, four) supplemental burners 10.
The air A supplied from the compressor 1 (FIG. 1) through the air
introduction passage 25 and the fuel F supplied through a fuel
supply system (a supplemental fuel supply passage 32) are
introduced into the supplemental burner 10. In the present
embodiment, the supplemental burner 10 of a premixing type includes
a premixing chamber 10a in which the air A and the fuel F are
stirred and mixed. As shown in FIG. 3, the air A is introduced into
the premixing chamber 10a from a side peripheral surface of the
supplemental burner 10, while the fuel F is firstly introduced into
fuel chamber 10b formed in the supplemental burner 10 from the fuel
supply system via supplemental adjustment valve 72, and
subsequently introduced into the premixing chamber 10a through a
fuel injection hole 10c. The fuel injection hole 10c may be
provided in the form of fuel injection nozzle having a tip portion
protruding into the premixing chamber 10a. According to the
configuration described above, a premixed gas M of the air A and
the fuel F is generated in the premixing chamber 10a, which is
subsequently injected into a downstream region in the combustion
chamber 11.
[0046] The supplemental burner 10 is operated in a condition in
which combustion by the fuel injector 15 that is a main burner is
substantially completed and a combustion gas G of high temperature
is generated. Therefore, the premixed gas M, which is injected into
the downstream region in the combustion chamber 11, can be stably
burned with the combustion gas G of high temperature while
suppressing generation of NOx. In addition, the supplemental burner
10 according to the present embodiment is highly durable against
backfiring, since any swirling flow generating mechanism or the
like for forming a reverse flow region for flame stabilization (a
flame stabilization mechanism) is necessary. For this reason,
hydrogen, which is normally difficult to be utilized as a fuel for
premixing combustion, may be used as a fuel for the supplemental
burner 10 without causing backfiring. The supplemental burner 10 is
not limited to the premixing type, and may be of a diffusive
combustion type.
[0047] As shown in FIG. 4, the fuel injector 15 includes the fuel
injection member 34 having a plurality of fuel injection annular
portions 33, and an air guide member 36 having a plurality of
combustion air annular portions 35. In the present embodiment, four
fuel injection annular portions 33 having different diameters are
disposed concentrically with each other, and concentrically with
the combustor 3 (FIG. 2). In addition, five combustion air annular
portions 35 having different diameters are disposed concentrically
with each other, and concentrically with the combustor 3 (FIG. 2).
Further, the fuel injection annular portions 33 and the combustion
air annular portions 35 are alternately disposed so as to have the
same center axis. That is, the fuel injection annular portions 33
and the combustion air annular portions 35 are alternately and
concentrically disposed. Further, while in the present embodiment
the fuel injector 15 includes the four fuel injection annular
portions 33 and the five combustion air annular portions 35, the
numbers of these portions may be changed according to need. For
example, the fuel injector 15 may include three fuel injection
annular portions 33 and four combustion air annular portions
35.
[0048] In the present embodiment, the four fuel injection annular
portions 33 and the five combustion air annular portions 35 are
disposed in the same axial position (FIG. 3). However, the axial
positions of the four fuel injection annular portions 33 and the
five combustion air annular portions 35 may be displaced from each
other. For example, the four fuel injection annular portions 33 may
be disposed so that the axial positions thereof are displaced
alternately forward and rearward, and the five combustion air
annular portions 35 may be disposed so that the axial positions
thereof are displaced alternately forward and rearward in
accordance with the axial positions of the corresponding fuel
injection annular portions 33.
[0049] As shown in FIG. 5, in each fuel injection annular portion
33 of the fuel injection member 34, a plurality of fuel injection
holes 39 that are open in a radial direction R are provided in a
circumferential direction Q. The fuel F is jetted from each fuel
injection hole 39. As shown in FIG. 8, the fuel injection annular
portion 33 of the fuel injection member 34 is formed to have a
substantially rectangular cross-sectional outline, and is disposed
so that a rear wall 33a thereof opposing the combustion chamber 11
is perpendicular to the axis C direction. In the illustrated
example, the fuel injection holes 39 are provided on both the outer
diameter side and the inner diameter side of the fuel injection
annular portion 33 of the fuel injection member 34. In other words,
the fuel injection holes 39 are provided in each of an outer
circumferential wall and an inner circumferential wall of the fuel
injection annular portion 33, as through-holes penetrating through
the outer circumferential wall and the inner circumferential wall
in the radial direction R. However, the fuel injection holes 39 may
be provided on only one of the outer diameter side and the inner
diameter side of the fuel injection member 34. The fuel injection
holes 39 may be angled within a range of -10.degree. to +80.degree.
in the axis C direction with respect to the radial direction R. It
is to be noted that when the injection hole 39 is inclined towards
an upstream side of the axis C direction with respect to the radial
direction R, the inclination angle is defined as a negative angle,
while when the injection hole 39 is inclined towards a downstream
side of the axis C direction with respect to the radial direction
R, the inclination angle is defined as a positive angle.
[0050] The air guide member 36 guides the air A to the fuel F
jetted from the fuel injection holes 39 of the fuel injection
member 34. More specifically, the air guide member 36 guides the
air A to the fuel F from upstream side of the air supply passage 29
in the direction along the axis C. The air guide member 36 includes
the plurality of annular-plate shaped combustion air annular
portions 35. The fuel injection annular portions 33 of the fuel
injection member 34 and the combustion air annular portions 35 of
the air guide member 36 are alternately disposed so as to have the
same center axis. As shown in FIG. 5, in each combustion air
annular portion 35 of the air guide member 36, air guide grooves 41
recessed in the radial direction are formed at circumferential
positions corresponding to the respective fuel injection holes 39
of the fuel injection member 34. That is, in the illustrated
example, each air guide groove 41 recessed radially outward is
formed on the inner diameter side of the combustion air annular
portion 35 of the air guide member 36 positioned on the radially
outer side of the fuel injection annular portion 33 of the fuel
injection member 34, and each air guide groove 41 recessed radially
inward is formed on the outer diameter side of the combustion air
annular portion 35 positioned on the radially inner side of the
fuel injection annular portion 33.
[0051] As shown in FIG. 4, in the present embodiment, one
combustion air annular portion 35 is disposed between two fuel
injection annular portions 33, and the air guide grooves 41 are
provided on both the outer diameter side and the inner diameter
side of the combustion air annular portion 35. Therefore, the fuel
injector 15 includes the fuel injection member 34 having four fuel
injection annular portions 33, and the air guide member 36 having
five combustion air annular portions 35. Specifically, there are
provided the combustion air annular portion 35 disposed on the
outer circumferential side of the outermost-circumferential-side
fuel injection annular portion 33, the three combustion air annular
portions 35 disposed between the four fuel injection annular
portions 33, and the combustion air annular portion 35 disposed on
the inner circumferential side of the innermost-diameter-side fuel
injection annular portion 33. The outer circumference of the
combustion air annular portion 35 disposed at the outermost
circumference of the air guide member 36 is covered with an annular
supporting ring member 43. As shown in FIG. 2, by connecting the
supporting ring member 43 to the combustion liner 13, the fuel
injector 15 is supported by the combustion liner 13.
[0052] As shown in FIGS. 8 and 9, the air guide member 36 is
disposed on the front side relative to the fuel injection holes 39
of the fuel injection member 34, that is, disposed on the upstream
side in the flow direction of the air A. Thus, since the air guide
member 36 is provided so as to guide the air A in the axis C
direction from upstream to the fuel F jetted from each fuel
injection hole 39, the fuel F and the air A intersect each other
substantially perpendicularly, whereby the fuel F and the air A can
be uniformly mixed outside the fuel injector 15.
[0053] As shown in FIG. 5B, in one modified example of the present
embodiment, each combustion air annular portion 35 of the air guide
member 36 may be formed with a plurality of cooling holes 45. The
plurality of cooling holes 45 are arranged equally spaced from each
other in a circumferential direction of the combustion air annular
portion 35. Each of the cooling hole 45 is formed as a through-hole
having a substantially round sectional shape which extends
completely through the combustion air annular portion 35 from its
front side to rear side. In the illustrated example, each cooling
hole 45 is so formed as to extend obliquely in the circumferential
direction in the combustion air annular portion 35. Accordingly, at
respective surfaces of the combustion air annular portion 35, the
cooling hole has openings each having oval shape elongated in the
circumferential direction. When the cooling holes 45 are formed in
the combustion air annular portion 35, the air A having flowed in
the air supply passage 29 flows through the cooling hole 45 and is
subsequently injected onto the surface on the combustion chamber
side of the combustion air annular portion 35 to form an air film
layer along the circumferential direction to perform effusion
cooling on the surface. Even though the cooling hole 45 may be
inclined in the circumferential direction, the inclination
direction is not limited thereto. Alternatively, the cooling hole
45 may be formed as a through-hole extending parallel to the axial
direction without being inclined.
[0054] As shown in FIG. 2, in the air supply passage 29, an
air-flow rectifying plate 47 is provided as an air-flow rectifying
mechanism that rectifies flow of the air A introduced from the air
introduction holes 27 to the air supply passage 29 into a uniform
air flow toward the air guide member 36. The air-flow rectifying
plate 47 is a disk-like member, and has a plurality of
through-holes 49 penetrating the air-flow rectifying plate 47 in
the axial direction. The air-flow rectifying plate 47 has an outer
diameter corresponding to the inner diameter of the support tube 21
shown in FIG. 3, and includes, in a center portion thereof, a
fitting hole 51 having an inner diameter corresponding to the outer
diameter of the fuel supply main pipe 31. In the present
embodiment, a cylindrical fitting part 53 that fits an outer
circumferential surface of the fuel supply main pipe 31 is provided
so as to protrude forward in the axis C direction from the fitting
hole 51 of the air-flow rectifying plate 47. The air-flow
rectifying plate 47 is connected and fixed to the end cover 17 via
a flange 55 provided at a front end of the fitting part 53, by
means of rectifying plate bolts 57.
[0055] In the illustrated example, the air-flow rectifying plate 47
includes a plurality of circular through-holes 49 having the same
diameters. More specifically, the through-holes 49 are arranged in
such a manner that a plurality of annular arrays, each array having
the through-holes 49 disposed at equal intervals in the same radial
position on the air-flow rectifying plate 47 along the
circumferential direction thereof, are arranged at equal intervals
in the radial direction. That is, the air-flow rectifying plate 47
includes a plurality of annular arrays of through-holes 49, each in
which the through-holes 49 are disposed at equal intervals on the
same circumference, and the annular arrays are concentrically
arranged on the air-flow rectifying plate 47. FIG. 6A shows the
air-flow rectifying mechanism including the air-flow rectifying
plate 47, the fitting part 53, and the flange 55.
[0056] However, the shape, number, and positions of the plurality
of through-holes 49 in the air-flow rectifying plate 47 are not
limited to those shown in FIG. 6A, and may be appropriately
designed. For example, as shown in FIG. 6B, an array of a plurality
of circular through-holes 49 having the same diameter may be
provided in each of an inner circumferential edge portion and an
outer circumferential edge portion of the air-flow rectifying plate
47, and an array of circular through-holes 49 having a larger
diameter may be provided in an intermediate portion between the
inner circumferential edge portion and the outer circumferential
edge portion. Alternatively, as shown in FIG. 6C, an array of a
plurality of circular through-holes 49 having the same diameter may
be provided in the inner circumferential edge portion of the
air-flow rectifying plate 47, and an array of ellipsoidal
through-holes 49 whose major axis direction corresponds to the
radial direction of the air-flow rectifying plate 47 may be
provided on the outer circumferential side of the air-flow
rectifying plate 47. Alternatively, as shown in FIG. 6D, only an
array of ellipsoidal through-holes 49 whose major axis direction
corresponds to the radial direction of the air-flow rectifying
plate 47 may be provided.
[0057] Regardless of any shape, number, and positions designed for
the through-holes of the air-flow rectifying plate 47, the ratio
(hole area ratio) of the total area of all the through-holes 49 to
the entire area of the air-flow rectifying plate 47 is preferably
in a range of 20 to 50%, and more preferably, in a range of 30 to
40%, taking the balance between the rectification effect and the
pressure loss into account.
[0058] As the air-flow rectifying mechanism that rectifies flow of
the air A introduced from the air introduction hole 27 to the air
supply passage 29 into a uniform air flow toward the fuel injector
15, in place of the air-flow rectifying plate 47, a rectifying duct
unit 61 may be provided as shown in FIGS. 7A and 7B. FIG. 7A shows
a rectifying duct unit 61 including: a rectifying duct 61a
extending from the upstream side of the air introduction hole 27 to
the fuel injector 15 so as to have a diameter decreasing toward the
downstream side; and a rectifying duct 61b extending from the
downstream side of the air introduction hole 27 to the fuel
injector 15 so as to have a diameter increasing toward the
downstream side. FIG. 7B shows a rectifying duct 61 unit including:
a rectifying duct 61a extending from the upstream side of the air
introduction hole 27 to the fuel injector 15 so as to have a
diameter decreasing toward the downstream side; a rectifying duct
61c extending from the center position of the air introduction hole
27 to the fuel injector 15 so as to have a diameter decreasing
toward the downstream side; and a rectifying duct 61d extending
from the downstream side of the air introduction hole 27 to the
fuel injector 15 so as to have a diameter decreasing toward the
downstream side. By providing the air-flow rectifying plate 47 or
the rectifying duct 61 as the air-flow rectifying mechanism,
uniform air flow is supplied to the fuel injector 15. Therefore,
generation of NO.sub.x is suppressed by uniform combustion, and
backfiring phenomenon can be reliably prevented.
[0059] Further, as shown in FIG. 3, the combustor 3 is provided
with a rectifying protrusion member 63 that is positioned on the
axis C, and protrudes through the fuel injector 15 toward the
combustion chamber 11. The rectifying protrusion member 63 is
positioned in the air supply passage 29, and includes a cylindrical
support portion 63a, and a protruding portion 63b positioned in the
combustion chamber 11. While the rectifying protrusion member 63 is
mounted to the fuel injector 15 in the illustrated example, the
rectifying protrusion member 63 may be mounted to the fuel supply
main pipe 31. In either case, a front end (an end portion on the
fuel supply main pipe 31 side) of the support portion 63a of the
rectifying protrusion member 63 is positioned upstream of the fuel
injector 15. An end portion of the protruding portion 63b is formed
in a substantially hemispherical shape. The rectifying protrusion
member 63 may be dispensed with. However, when the rectifying
protrusion member 63 is provided, flame can be stably maintained in
the vicinity of the axis C position in the combustion chamber 11,
which flame is formed by the fuel jetted from the fuel injection
annular portions 33 positioned on the radially inner side of the
fuel injector 15, and the air supplied from the combustion air
annular portions 35.
[0060] The fuel injection member 34, the air guide member 36, the
supporting ring member 43, and the rectifying protrusion member 63,
which are components of the fuel injector 15, may be integrally
formed, or may be separately formed and then connected to each
other by, for example, inserting pins in the radial direction.
[0061] Next, a mechanism for supplying a fuel to the fuel injection
member 34 in the combustor 3 will be described. The combustor 3 of
the present embodiment includes a plurality of fuel supply passages
capable of independently supplying the fuel F to the respective
fuel injection annular portions 33 of the fuel injection member 34.
Specifically, the fuel supply main pipe 31 is connected to the
respective fuel injection annular portions 33 through a plurality
of branch fuel supply pipes 66 that independently branch from the
main pipe 31. The fuel supply main pipe 31 has a multiple pipe
structure (double pipe structure) in which a plurality of (two in
the illustrated example) cylindrical pipes, i.e., an inner first
fuel supply pipe 64 and a second fuel supply pipe 65 disposed
outside the first fuel supply pipe 64 are concentrically
superposed. An inner space of the first fuel supply pipe 64 forms a
first fuel supply passage 67, and a space between the first fuel
supply pipe 64 and the second fuel supply pipe 65 forms a second
fuel supply passage 69. The fuel F supplied from the outside to the
fuel supply passages 67 and 69 in the fuel supply main pipe 31 is
supplied to the respective fuel injection annular portions 33
through the fuel supply passages formed in the respective branch
fuel supply pipes 66. In the present embodiment, the fuel F which
flowed through the first fuel supply passage 67 is supplied to two
fuel injection annular portions 33 (hereinafter referred to as
"first annular portion group") disposed on the inner diameter side
among the plurality of fuel injection annular portions 33, via two
branch fuel supply pipes 66 connected to the first fuel supply pipe
64. The fuel F which flowed through the second fuel supply passage
69 is supplied to two fuel injection annular portions 33
(hereinafter referred to as "second annular portion group")
disposed on the outer diameter side among the plurality of fuel
injection annular portions 33, via two branch fuel supply pipes 66
connected to the second fuel supply pipe 65. A control valve 71
capable of adjusting the fuel flow rate is provided in each of an
upstream portion 67a, of the first fuel supply passage 67, extended
to the outside of the housing H, and an upstream portion 69a, of
the second fuel supply passage 69, extended to the outside of the
housing H. By adjusting an opening degree of the control valve 71
of each fuel supply passage 67, 69, the flow rate of the fuel F
supplied to each annular portion group of the fuel injection
annular portions 33 can be independently controlled.
[0062] The number of the fuel injection annular portions 33
constituting the annular portion group as a unit to which the fuel
F is independently supplied is not limited to the above example.
For example, one fuel injection annular portion 33 may constitute
one annular portion group (four annular portion groups are
constituted in total). Alternatively, two fuel injection annular
portions 33 on the inner diameter side may constitute one annular
portion group, and each of two fuel injection annular portions 33
on the outer diameter side may constitute one annular portion group
(three annular portion groups are constituted in total). In
accordance with the number of the annular portion groups thus
constituted, the number of the fuel supply passages and the number
of the control valves are determined.
[0063] The above fuel supply mechanism allows the fuel supply
amount to each fuel injection annular portion 33 of the fuel
injection member 34 to be independently controlled in accordance
with the load on the gas turbine GT. That is, the fuel injection
member 34 can be divided into the fuel injection annular portions
33 that perform fuel supply and the fuel injection annular portions
33 that do not perform fuel supply. Therefore, an operation
according to output change from a rated load to a partial load
(staging combustion) is realized. In the case where the fuel F is
dispersively jetted from the plurality of fuel injection holes 39
of the fuel injection member 34 as shown in the present embodiment,
it is more effective for stable and low-NO.sub.x combustion to cope
with the load change by selecting the fuel injection annular
portions 33 to be operated and the fuel injection annular portions
33 not to be operated than by averagely changing the fuel supply
amount from all the fuel injection annular portions 33. In the
present embodiment, the plurality of fuel supply passages 67 and 69
are branched from a single fuel supply source (not shown), and the
fuel supply amount is independently controlled by means of the
control valves 71 provided in the fuel supply passages 67 and 69.
However, the fuel F may be independently supplied from a plurality
of fuel supply sources to the respective fuel supply passages 67
and 69.
[0064] The number of the branch fuel supply pipes 66 connected to
each fuel injection annular portion 33 of the fuel injection member
34 may be appropriately set in accordance with the fuel injection
amount from the fuel injection annular portion 33. For example,
preferably, the number of the branch fuel supply pipes 66 connected
to the fuel injection annular portion 33 disposed on the inner
diameter side is decreased while the number of the branch fuel
supply pipes 66 connected to the fuel injection annular portion 33
disposed on the outer diameter side is increased. When a plurality
of branch fuel supply pipes 66 are connected to one fuel injection
annular portion 33, the connection positions in the fuel injection
annular portion 33 are preferably at equal intervals in the
circumferential direction.
[0065] Further, the multiple pipe structure of the fuel supply main
pipe 31 is not limited to the example shown in FIG. 3, and any
structure may be adopted as long as a plurality of fuel supply
passages independent from each other can be formed by using a
plurality of pipes. For example, a multiple pipe structure may be
employed in which, in one main pipe having a large diameter, a
plurality of fuel supply pipes having same diameters smaller than
the diameter of the main pipe are extended in parallel. However, in
the case where, as illustrated referring to the present embodiment,
the fuel supply main pipe 31 has the multiple pipe structure in
which a plurality of fuel supply pipes having different diameters
are concentrically superposed, and the inner space of the
innermost-diameter-side fuel supply pipe and the space between the
respective pipes are used as fuel supply passages, it is easy to
set the areas of the passages such that the area of the
outer-diameter-side fuel supply passage (the second fuel supply
passage 69 in the example shown in FIG. 3) that supplies the fuel
to the outer-diameter-side fuel injection annular portion 33 that
requires more amount of fuel is set to be large while the area of
the inner-diameter-side fuel supply passage (the first fuel supply
passage 67 in the example of FIG. 3) that supplies the fuel to the
inner-diameter-side fuel injection annular portion 33 that requires
less amount of fuel is set to be small.
[0066] Next, a description will be given of an internal cooling
mechanism or a heat shielding mechanism for the fuel injection
member 34 and the rectifying protrusion member 63 which face the
combustion chamber 11 and are exposed to high temperature of the
combustion chamber 11.
[0067] Regarding the fuel injection member 34, as described above,
the rear wall 33a, of the fuel injection member 34, opposing the
combustion chamber 11 is disposed perpendicularly to the axis C
direction. As shown in FIG. 8, the air guide member 36 guides, in
the axis C direction, the air A supplied from upstream to the fuel
F jetted from the fuel injection holes 39 of the fuel injection
member 34. The fuel injection annular portion 33 is formed as a
hollow portion, and the follow space forms an annular fuel flow
passage 73 that allows the fuel F to flow in the circumferential
direction in the fuel injection annular portion 33. That is, the
rear wall 33a of the fuel injection member 34 and a portion of an
inner wall of the annular fuel flow passage 73 are the same wall,
and a wall surface thereof on the combustion chamber side is a rear
wall surface 33ab while a wall surface thereof on the fuel flow
passage side is an inner wall surface 33aa.
[0068] The branch fuel supply pipe 66 is connected from a front
wall (a wall on the air supply passage 29 side) 33b side of the
fuel injection member 34 to an annular fuel flow passage 73a so as
to supply the fuel F. In the fuel injection annular portion 33 of
the fuel injection member 34, two annular fuel flow passages 73a
and 73b partitioned in the axis C direction of the combustor 3 are
formed. In other words, in the fuel injection annular portion 33,
the downstream side fuel flow passage 73b (first fuel flow passage)
that is positioned on the rear side (on the combustion chamber 11
side) and supplies the fuel F to the fuel injection holes 39, and
an upstream side fuel flow passage 73a (second fuel flow passage)
that is positioned on the front side (the air supply passage 29
side) and is directly supplied with the fuel F, are formed.
[0069] On an annular first partition wall 77 partitioning the
upstream side fuel flow passage 73a and the downstream side fuel
flow passage 73b, a plurality of through-holes that introduce the
fuel from the upstream side fuel flow passage 73a to the downstream
side fuel flow passage 73b are arranged in the circumferential
direction. These through-holes serve as supply holes 79 that
connect the two fuel flow passages 73a and 73b, and supply the fuel
F from the upstream side fuel flow passage 73a to the downstream
side fuel flow passage 73b. The fuel F introduced from the branch
fuel supply pipe 66 to the upstream side fuel flow passage 73a
flows in the upstream side fuel flow passage 73a in the
circumferential direction, and successively flows into the
downstream side fuel flow passage 73b through the supply holes 79.
The fuel F having flowed in the downstream side fuel flow passage
73b through the supply holes 79 collides against the inner wall
surface 33aa of the rear wall 33a and flows in the downstream side
fuel flow passage 73b in the circumferential direction, and is
guided to the fuel injection holes 39. Thus, by partitioning the
inside of the fuel injection annular portion 33 of the fuel
injection member 34 into the upstream side fuel flow passage 73a
and the downstream side fuel flow passage 73b in the axis C
direction of the combustor 3, the fuel F is supplied to the fuel
injection holes 39 while being uniformly distributed in the
circumferential direction. Further, when the fuel F having flowed
in the downstream side fuel flow passage 73b collides against the
inner wall surface 33aa of the rear wall 33a, the fuel F cools the
rear wall 33a by impingement cooling. In the illustrated example,
the first partition wall 77 is provided with a nozzle wall 81
protruding rearward and extending in the circumferential direction,
and a plurality of supply holes 79 are provided in the
circumferential direction in the nozzle wall 81. The nozzle wall 81
forms an injection nozzle that jets the fuel F in the upstream side
fuel flow passage 73a toward the rear surface 33aa that is the wall
surface of the downstream side fuel flow passage 73b on the
combustion chamber 11 side. Specifically, the fuel injection
annular portion 33 includes: the downstream side fuel flow passage
73b that is positioned on the combustion chamber 11 side and is
connected to the fuel injection holes 39; the upstream side fuel
flow passage 73a that is positioned on the opposite side from the
combustion chamber 11 and is supplied with the fuel F jetted from
the fuel injection holes 39; and the injection nozzle that jets the
fuel F in the upstream side fuel flow passage 73a toward the inner
wall surface 33aa of the downstream side fuel flow passage 73b on
the combustion chamber 11 side. Thereby, the fuel F is jetted to
the inner wall surface 33aa of the downstream side fuel flow
passage 73b on the combustion chamber 11 side, whereby the inner
wall surface 33aa is cooled by impingement cooling. That is, the
rear wall 33a is extremely effectively cooled by the fuel F. The
injection nozzle may not necessarily have the nozzle wall 81, and
may be a throttle nozzle formed in the first partition wall 77.
Further, in the middle of the passage from the inner wall surface
33aa of the rear wall 33a to which the fuel F is jetted from the
supply holes 79 to the fuel injection holes 39, a protruding wall
83 extending in the circumferential direction is provided so as to
protrude from the inner wall surface 33aa of the rear wall 33a,
whereby the effect of convection cooling caused by the fuel F
flowing in the downstream-side fuel flow passage 73b is further
enhanced.
[0070] Further, regarding the shape of the fuel flow passage 73
provided in the fuel injection annular portion 33 of the fuel
injection member 34, only one fuel flow passage 73 may be provided
as shown in a modification of FIG. 9. In this case, the rear wall
33a, of the fuel injection annular portion 33, opposing the
combustion chamber 11 can be cooled from the inner side (the inner
wall surface 33aa side) by convection cooling with the fuel F.
[0071] Further, a second partitioning wall 87 may be provided in
the middle of the passage along which the fuel F is guided from the
fuel flow passage 73 to the fuel injection holes 39, so that the
fuel F supplied from each branch fuel supply pipe 66 flows
substantially uniformly in the fuel flow passage 73, and thereby
the effect of convection cooling is sufficiently achieved. In other
words, the annular fuel flow passage 73 may be divided into three
annular spaces by an outer-circumferential-side partitioning wall
87a and an inner-circumferential-side partitioning wall 87b.
[0072] Further, a heat shielding plate 85 may be provided on the
rear wall surface 33ab of the rear wall 33a. As a material of the
heat shielding plate 85, for example, Hastelloy-X (Haynes
International. Inc.: registered trademark) or HA188 (Haynes
International. Inc.: registered trademark) which are alloys having
corrosion resistance and thermal resistance, or a combination of
the alloy and ceramic coating, may be used. Also in the example
shown in FIG. 8, the heat shielding plate 85 can be selectively
combined.
[0073] As shown in FIG. 10, the rectifying protrusion member 63 is
formed as a hollow member as a whole. The support portion 63a of
the rectifying protrusion member 63 is formed of a cylindrical
member having a bottom, and cooling air introduction holes 91 in
the form of radial through-holes are formed in a front-end
(upstream-end) circumferential wall thereof. A plurality of cooling
air introduction holes 91 are formed at equal intervals in the
circumferential direction of the front-end circumferential wall of
the support portion 63a. The protruding portion 63b of the
rectifying protrusion member 63 has a double-wall structure
including a dome-shaped inner wall 93 and a dome-shaped outer wall
95 each having a diameter decreasing toward the combustion chamber
side (right side in FIG. 10). The protruding portion 63b does not
necessarily have the dome shape, and may have a cylindrical shape.
Further, the protruding portion 63b does not necessarily have the
double-wall structure, and may have a single-wall structure
including only the outer wall. In a circumferential wall of the
inner wall 93 of the protruding portion 63b, first cooling air
injection holes 97 as radial through-holes are provided. A
plurality of first cooling air injection holes 97 are formed at
equal intervals in the circumferential direction and the axial
direction of the circumferential wall of the inner wall 93. In
addition, the outer wall 95 of the protruding portion 63b has a
circumferential wall provided with a plurality of second cooling
air injection holes 98 each formed as a through-hole extending
obliquely rearward with respect to radial direction. The plurality
of second cooling air injection holes 98 are arranged equally
spaced from each other in the circumferential direction and the
axial direction of the circumferential wall of the outer wall
95.
[0074] In the center of an end portion of the outer wall 95 of the
protruding portion 63b, a cooling air discharge hole 99 as an axial
through-hole is provided. In other words, the rectifying protrusion
member 63 includes the cooling air introduction hole 91 that is
formed at the front end of the support portion 63a and introduces
the air A from upstream of the fuel injector 15 into the rectifying
protrusion member 63, and the cooling air discharge hole 99 that is
formed in the protruding portion 63b and discharges the air A
introduced into the rectifying protrusion member 63, to the
combustion chamber 11.
[0075] An inner space S defined by the support portion 63a and the
inner wall 93 of the protruding portion 63b and a gap G defined by
the inner wall 93 and the outer wall 95 of the protruding portion
63b communicate with each other via only the first cooling air
injection holes 97 of the inner wall 93. In the illustrated
example, a fitting protruding wall 63aa is provided at an opening
edge portion of the support portion 63a, and an opening edge
portion 93a of the inner wall 93 fits the inner circumferential
side of the fitting protruding wall 63aa, and an opening edge
portion 95a of the outer wall 95 fits the outer circumferential
side of the fitting protruding wall 63aa. Thereby, the support
portion 63a and the protruding portion 63b are connected to each
other.
[0076] In the case where the protruding portion 63b has the
single-wall structure including only the outer wall, a part of the
air A in the air supply passage 29 flows from the cooling air
introduction hole 91 into the inner space S of the rectifying
protrusion member 63, and is discharged from the cooling air
discharge hole 99 to the combustion chamber 11 while cooling, as a
cooling medium, the protruding portion 63b facing the combustion
chamber 11, from the inner side by convection cooling. Further, in
the case where the protruding portion 63b has the double-wall
structure including the inner wall 93 and the outer wall 95, a part
of the air A that has flowed from the cooling air introduction hole
91 into the inner space S of the rectifying protrusion member 63 is
radially jetted as a cooling medium from the first cooling air
injection holes 97 of the inner wall 93. This air A collides
against the inner circumferential surface of the outer wall 95,
flows along this inner circumferential surface, passes through the
cooling passage which is the gap G between the inner wall 93 and
the outer wall 95, and is discharged from the cooling air discharge
hole 99 to the combustion chamber 11. Since the air A collides
against the inner circumferential surface of the outer wall 95 and
flows along the inner circumferential surface, the outer wall 95 is
cooled from the inner side, by impingement cooling. On the other
hand, a portion of the air A having flowed into the gap G between
the inner wall 93 and the outer wall 95 is discharged to the
combustion chamber 11 through the second cooling air injection
holes 98 of the outer wall 95. The air A injected from the second
cooling air injection holes 98 forms an air film layer on a surface
of the outer wall 95 to cool the outer wall 95 from the outside by
effusion cooling. In this way, burnout of the rectifying protrusion
member 63 can be prevented. The second cooling air injection holes
98 may be omitted.
[0077] Further, the outer circumferential surface of the outer wall
95 may be coated with a heat insulating material 100. As the heat
insulating material 100, ceramics, Hastelloy-X (Haynes
International. Inc.: registered trademark) or HA188 (Haynes
International. Inc.: registered trademark) which are alloys having
corrosion resistance and thermal resistance, and the like may be
used. The coating with the heat insulating material 100 more
reliably prevents burnout of the rectifying protrusion member
63.
[0078] As described above, in the combustor 3 of a gas turbine
shown in FIG. 2 according to the present embodiment, the fuel
injector 15 includes the fuel injection member 34 having the
plurality of fuel injection annular portions 33, and each fuel
injection annular portion 33 includes the plurality of fuel
injection holes 39 in the outer circumferential surface thereof.
Therefore, the fuel F is uniformly jetted from the entire surface
of the fuel injector 15. Thereby, minute flame is maintained at
multiple points on the entire surface of the fuel injector 15.
Thus, occurrence of local high-temperature combustion is prevented,
and low NO.sub.x combustion is realized. In addition, the structure
in which the air A is supplied from upstream of the fuel F jetted
from the fuel injection holes 39 prevents the flame from entering
the fuel injector 15, whereby backfiring phenomenon is
suppressed.
[0079] Further, the combustor 3 includes supplemental burner 10 of
a premixing type disposed on a peripheral wall of the combustion
liner 13 in a downstream region. The supplemental burner 10 is
operated in a condition in which combustion by the fuel injector 15
that is a main burner is substantially completed and a combustion
gas G of high temperature is generated. Therefore, the premixed gas
M, which is injected into the downstream region in the combustion
chamber 11, can be stably burned with the combustion gas G of high
temperature while suppressing generation of NOx. In addition, the
supplemental burner 10 according to the present embodiment is
highly durable against backfiring, since any swirling flow
generating mechanism or the like for forming a reverse flow region
for flame stabilization (a flame stabilization mechanism) is
necessary. Therefore, even when a highly-reactive fuel containing
hydrogen is used as the fuel for the gas turbine GT, extremely
stable combustion is maintained while suppressing generation of
NO.sub.x.
[0080] The fuel F used for the combustor 3 of the present
embodiment is not limited to hydrogen gas, and may be, for example,
liquid hydrogen, or a mixture fuel of hydrogen gas and other fuel
gas (natural gas, CO, etc.), or other fuel gas (natural gas, CO,
etc.) including no hydrogen. Further, while in the present
embodiment the can type combustor 3 is described as an example, the
above-described structure can also be applied to an annular
combustor.
[0081] An embodiment in which the present invention is applied to
an axial-flow type annular combustor is shown in FIGS. 11 and 12,
and an embodiment in which the present invention is applied to a
reverse-flow type annular combustor is shown in FIG. 13. The
combustors 3 according to these embodiments are identical to the
embodiment shown in FIG. 2 in that each combustor 3 includes a
combustion liner 13 having a combustion chamber 11 formed therein,
and a fuel injector 15 mounted to a top portion of the combustion
liner 13. The fuel injector 15 includes a fuel injection member 34
including a plurality of fuel injection annular portions 33 and an
air guide member 36 including a plurality of combustion air annular
portions 35 that guide the air for combustion. The fuel injection
annular portions 33 and the combustion air annular portions 35 are
arranged concentrically and alternately. The fuel injector 15
injects the fuel and the air into the combustion chamber 11. As
described for the above embodiments with reference to FIG. 5, each
fuel injection annular portion 33 has a plurality of fuel injection
holes 39 that are open in the radial direction R, and each
combustion air annular portion 35 has a plurality of air guide
grooves 41 that are open in the axial direction thereof and guide
the air A to the fuel F jetted from the fuel injection holes
39.
[0082] In the axial-flow type annular combustor 3 shown in FIG. 11,
the combustion liner 13 is composed of a cylindrical inner wall
101, and an outer wall 103 disposed outside and concentrically with
the inner wall 101. A space between the inner wall 101 and the
outer wall 103 forms an annular combustion chamber 11. The air A
compressed by the compressor 1 (FIG. 1) is introduced from the
front side through a diffuser 105 into an annular combustor housing
H, and is supplied to the fuel injector 15. A front end of the fuel
injector 15 is covered with an air-flow rectifying cowl 107 as an
air-flow rectifying mechanism. As shown in FIG. 12, the air-flow
rectifying cowl 107 is an annular member having a forwardly
swelling cross-sectional shape, and a plurality of holes allowing
the air A to pass therethrough are formed therein.
[0083] Also in the reverse-flow type annular combustor 3 shown in
FIG. 13, the combustion liner 13 is composed of a cylindrical inner
wall 101, and an outer wall 103 disposed outside and concentrically
with the inner wall 101, and a space between the inner wall 101 and
the outer wall 103 forms an annular combustion chamber 11. The air
A compressed by the compressor 1 (FIG. 1) passes, from the rear
side, through an air introduction passage 25 formed between an
housing H and the combustion liner 13, and thereafter, is supplied
to the fuel injector 15. A front end of the fuel injector 15 is
covered with an air-flow rectifying cowl 107 as an air-flow
rectifying mechanism. Like in the example shown in FIG. 12, the
air-flow rectifying cowl 107 is an annular member having a
forwardly swelling cross-sectional shape, and a plurality of holes
allowing the air to pass therethrough are formed therein.
[0084] Although the present invention has been described above in
connection with the preferred embodiments thereof with reference to
the accompanying drawings, numerous additions, changes, or
deletions can be made without departing from the gist of the
present invention. Accordingly, such additions, changes, or
deletions are to be construed as included in the scope of the
present invention.
REFERENCE NUMERALS
[0085] 3 Combustor [0086] 10 Supplemental burner [0087] 11
Combustion chamber [0088] 13 Combustion liner [0089] 15 Fuel
injector [0090] 33 Fuel injection annular portion [0091] 34 Fuel
injection member [0092] 35 Combustion air annular portion [0093] 36
Air guide member [0094] 39 Fuel injection hole [0095] 41 Air guide
groove [0096] A Air [0097] C Axis of combustor [0098] F Fuel
* * * * *