U.S. patent application number 17/071557 was filed with the patent office on 2021-04-22 for gas turbine combuster.
The applicant listed for this patent is Mitsubishi Power, Ltd.. Invention is credited to Satoshi DODO, Akinori HAYASHI, Yoshitaka HIRATA, Hirokazu TAKAHASHI, Shohei YOSHIDA.
Application Number | 20210116127 17/071557 |
Document ID | / |
Family ID | 1000005177975 |
Filed Date | 2021-04-22 |
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United States Patent
Application |
20210116127 |
Kind Code |
A1 |
YOSHIDA; Shohei ; et
al. |
April 22, 2021 |
Gas Turbine Combuster
Abstract
A gas turbine combustor with a relatively simple structure is
configured to attenuate pressure fluctuation owing to combustion
oscillation while securing mechanical reliability. The gas turbine
combustor includes a combustion liner that forms a combustion
chamber for generating combustion gas, a combustion casing disposed
at an outer circumferential side of the combustion liner, and a
burner for supplying air flowing between the combustion liner and
the combustion casing, and fuel to be supplied from a fuel supply
system to the combustion chamber. The combustor further includes a
vane disposed at the outer circumferential side of the combustion
liner, a plurality of supports disposed at an inner side of the
combustion casing for fixing the vane, and a pressure dynamics
damping hole formed in the combustion liner at a position
corresponding to the vane for communication with the combustion
chamber.
Inventors: |
YOSHIDA; Shohei;
(Yokohama-shi, JP) ; HIRATA; Yoshitaka;
(Yokohama-shi, JP) ; HAYASHI; Akinori;
(Yokohama-shi, JP) ; DODO; Satoshi; (Yokohama-shi,
JP) ; TAKAHASHI; Hirokazu; (Yokohama-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Power, Ltd. |
Yokohama-shi |
|
JP |
|
|
Family ID: |
1000005177975 |
Appl. No.: |
17/071557 |
Filed: |
October 15, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23R 3/10 20130101; F23R
3/28 20130101; F23R 3/06 20130101; F23R 3/286 20130101; F23R
2900/00014 20130101 |
International
Class: |
F23R 3/06 20060101
F23R003/06; F23R 3/10 20060101 F23R003/10; F23R 3/28 20060101
F23R003/28; F02K 1/34 20060101 F02K001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 17, 2019 |
JP |
2019-190106 |
Claims
1. A gas turbine combustor including a combustion liner that forms
a combustion chamber for generating combustion gas, a combustion
casing disposed at an outer circumferential side of the combustion
liner, and a burner for supplying air flowing between the
combustion liner and the combustion casing, and fuel to be supplied
from a fuel supply system to the combustion chamber, the gas
turbine combustor comprising: a vane disposed at the outer
circumferential side of the combustion liner; a plurality of
supports disposed at an inner side of the combustion casing for
fixing the vane; and a pressure dynamics damping hole formed in the
combustion liner at a position corresponding to the vane for
communication with the combustion chamber.
2. The gas turbine combustor according to claim 1, wherein the
support has a streamlined cross section.
3. The gas turbine combustor according to claim 1, wherein gaps
formed between the outer circumferential surface of the combustion
liner and an inner circumferential surface of the vane are made
different from each other in a circumferential direction of the
combustion liner.
4. The gas turbine combustor according to claim 1, wherein a gap
formed between the outer circumferential surface of the combustion
liner and an inner circumferential surface of the vane at one side
of the support is different from a gap formed between the outer
circumferential surface of the combustion liner and the inner
circumferential surface of the vane at the other side of the
support.
5. The gas turbine combustor according to claim 4, wherein four
pieces of the supports are disposed at equal intervals at the inner
side of the combustion casing.
6. A gas turbine combustor including a combustion liner that forms
a combustion chamber for generating combustion gas, a combustion
casing disposed at an outer circumferential side of the combustion
liner, and a burner for supplying air flowing between the
combustion liner and the combustion casing, and fuel to be supplied
from a fuel supply system to the combustion chamber, the gas
turbine combustor comprising: a flow sleeve disposed at the outer
circumferential side of the combustion liner; and a pressure
dynamics damping hole formed in the combustion liner at a position
corresponding to the flow sleeve for communication with the
combustion chamber.
7. The gas turbine combustor according to claim 6, further
comprising a rib formed as an annular member at the outer
circumferential side of the combustion liner downstream from the
pressure dynamics damping hole.
Description
CLAIM OF PRIORITY
[0001] The present application claims priority from Japanese Patent
application serial no. 2019-190106, filed on Oct. 17, 2019, the
content of which is hereby incorporated by reference into this
application.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a gas turbine
combustor.
[0003] Gas turbine combustors of some type use liquefied natural
gas as fuel. In this case, from an aspect of global environment
conservation, a premixed combustion mode for combustion of air-fuel
premixture is employed to suppress emission of nitrogen oxides
(NOx) as a cause of air pollution.
[0004] In the premixed combustion mode, the air-fuel premixture may
suppress generation of a locally high-temperature combustion region
in burning. It is therefore possible to suppress generation of
nitrogen oxides from the high-temperature combustion region.
[0005] Generally, the premixed combustion mode succeeds in
suppressing quantity of generated nitrogen oxides. However, in a
certain case, the mode fails to stabilize the combustion state,
leading to combustion oscillation that periodically fluctuates the
pressure in the combustion chamber. Therefore, the premixed
combustion mode is combined with the diffusion combustion mode
excellent in stabilizing the combustion state.
[0006] When using both the diffusion combustion mode and the
premixed combustion mode for suppressing quantity of generated
nitrogen oxides, there may be the case that the proportion of the
premixed combustion to the diffusion combustion is increased, or
the premixed combustion is fully performed. In the above-described
case, an acoustic liner for attenuating pressure fluctuation owing
to combustion oscillation is attached to an outer circumferential
surface of the combustion liner constituting the combustion chamber
for the purpose of attenuating the pressure fluctuation owing to
the combustion oscillation.
[0007] An example of a background of the above-described technology
includes WO2013/077394.
[0008] The disclosed gas turbine combustor includes a combustion
cylinder and an acoustic liner attached to an outer side of the
combustion cylinder for forming space from the outer
circumferential surface of the combustion cylinder. The combustion
cylinder includes a group of through holes. The through holes are
formed at intervals circumferentially in a plurality of rows, and
arranged in axial rows at intervals (see description in SUMMARY OF
THE INVENTION of WO2013/077394).
SUMMARY OF THE INVENTION
[0009] WO2013/077394 discloses the gas turbine combustor including
the acoustic liner. The disclosed acoustic liner is attached to the
combustion cylinder (combustion liner).
[0010] If the disclosed acoustic liner is attached to the
combustion liner as a high-temperature component, the cooling
process is required by supplying purge air into the space between
the acoustic liner and the combustion liner for securing mechanical
reliability.
[0011] It is an object of the present invention to provide a gas
turbine combustor with a relatively simple structure for
attenuating the pressure fluctuation owing to combustion
oscillation while securing the mechanical reliability.
[0012] The gas turbine combustor according to the present invention
includes a combustion liner that forms a combustion chamber for
generating combustion gas, a combustion casing disposed at an outer
circumferential side of the combustion liner, and a burner for
supplying air flowing between the combustion liner and the
combustion casing, and fuel to be supplied from a fuel supply
system to the combustion chamber. The gas turbine combustor further
includes a vane disposed at the outer circumferential side of the
combustion liner, a plurality of supports disposed at an inner side
of the combustion casing for fixing the vane, and a pressure
dynamics damping hole formed in the combustion liner at a position
corresponding to the vane for communication with the combustion
chamber.
[0013] The present invention provides a gas turbine combustor with
a relatively simple structure for attenuating the pressure
fluctuation owing to the combustion oscillation while securing the
mechanical reliability.
[0014] Problems, structures, and advantageous effects other than
those described above will be clarified by descriptions of the
following examples.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 conceptually illustrates a gas turbine power
generation facility provided with a gas turbine combustor 3 to be
described in a first example;
[0016] FIG. 2 is a schematic partially enlarged sectional view of a
main part of the gas turbine combustor 3 to be described in the
first example;
[0017] FIG. 3 is a schematic partially enlarged sectional view of a
main part of the gas turbine combustor 3 to be described in a
second example;
[0018] FIG. 4 is a schematic partially enlarged sectional view of a
main part of the gas turbine combustor 3 to be described in a third
example;
[0019] FIG. 5 is a schematic view of the gas turbine combustor 3 to
be described in the third example when it is seen from a combustion
chamber; and
[0020] FIG. 6 schematically represents a method of operating the
gas turbine combustor 3 to be described in the third example.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Hereinafter, an explanation will be made with respect to
examples according to the present invention with reference to the
drawings. Substantially the same or similar structures will be
designated with the same codes, and repetitive explanations
thereof, thus, will be omitted.
First Example
[0022] An explanation will be made conceptually with respect to the
gas turbine power generation facility provided with a gas turbine
combustor 3 (hereinafter referred to as a combustor) according to a
first example.
[0023] FIG. 1 conceptually illustrates the gas turbine power
generation facility provided with the combustor 3 according to the
first example.
[0024] The gas turbine power generation facility (gas turbine power
plant) provided with the combustor 3 according to the first example
includes a turbine 2, a compressor 1 connected to the turbine 2 for
generating compressed air 5 for combustion, a plurality of gas
turbine combustors 3, and a generator 4 connected to the turbine 2
for generating power in association with driving of the turbine 2.
FIG. 1 shows one unit of the combustor 3 for convenience of
explanation.
[0025] The compressed air 5 discharged from the compressor 1 is
supplied to the combustor 3 via a compressed air passage 6. In a
combustion chamber 8 formed inside a combustion liner 7 for
combustor (hereinafter referred to as a combustion liner),
combustion gas 9 is generated by burning the compressed air 5 and
the fuel. The combustion gas 9 is supplied to the turbine 2 for
driving via a transition piece 10.
[0026] The combustor 3 includes a diffusion burner 20, a premix
burner 30, the combustion liner 7, the transition piece 10, a
casing 11 for combustor (hereinafter referred to as a combustion
casing), and an end cover 12. The diffusion burner 20 receives fuel
supplied from a diffusion fuel supply system 21, and the premix
burner 30 receives fuel supplied from a premix fuel supply system
31.
[0027] The diffusion burner 20 has a fuel jet hole 25 through which
the diffusion fuel spouts via a fuel passage (fuel nozzle) 22. The
diffusion burner 20 is provided with a swirler 23 for imparting a
swirling component to air for combustion (compressed air 5). The
diffusion burner 20 mixes the diffusion fuel with air for
combustion, to which the swirling component is imparted by the
swirler 23 to generate a diffusion flame downstream from the
diffusion burner 20.
[0028] The premix burner 30 allows a premixer 34 to preliminarily
mix premix fuel spouting through a fuel passage (fuel nozzle) 32
with the air for combustion (compressed air 5). A premix flame is
generated by a mixture of the premix fuel and the compressed air 5
downstream from a flame stabilizer 35.
[0029] The combustor 3 includes a vane 40 and a plurality of
supports 41 in an annular passage 13 formed between the combustion
liner 7 that constitutes the combustion chamber 8 for generating
the combustion gas 9 and the combustion casing 11 that encases the
combustion liner 7 (disposed at the outer circumferential side of
the combustion liner 7). The vane 40 is disposed at the outer
circumferential side of the combustion liner 7 in the annular
passage 13. The support 41 is attached to an inner side of the
combustion casing 11 in the annular passage 13 for fixing the vane
40.
[0030] The combustor 3 has a pressure dynamics damping hole 42 in
the combustion liner 7 at a position corresponding to the vane 40
for communication with the combustion chamber 8.
[0031] A main part of the combustor 3 according to the first
example will be briefly described.
[0032] FIG. 2 is a schematic partially enlarged sectional view of
the main part of the combustor 3 according to the first
example.
[0033] In the diffusion burner 20, diffusion fuel 24 flowing
through the fuel passage (fuel nozzle) 22 spouts through the fuel
jet hole 25. The diffusion fuel 24 is mixed with air 5a for
combustion (compressed air 5) to which the swirling component is
imparted by the swirler 23 so that a diffusion flame is generated
downstream from the diffusion burner 20. In other words, the
diffusion burner 20 supplies the air 5a for combustion and the
diffusion fuel 24 to the combustion chamber 8.
[0034] The premix burner 30 allows the premixer 34 to mix premix
fuel 33 spouting through the fuel passage 32 with air 5b for
combustion (compressed air 5). The sufficiently mixed mixture of
the premix fuel 33 and the compressed air 5b generates the premix
flame downstream from the flame stabilizer 35. In other words, the
premix burner 30 is disposed at an outer circumferential side of
the diffusion burner 20 for supplying the air 5b for combustion and
the premix fuel 33 to the combustion chamber 8.
[0035] Upon reception of thermal energy from the diffusion flame,
the premix flame stably burns in the combustion chamber 8
(suppressing generation of the locally high-temperature combustion
region in burning). This makes it possible to suppress quantity of
generated nitrogen oxides.
[0036] The combustor 3 includes the vane 40 and the supports 41 in
the annular passage 13 formed between the combustion liner 7 that
constitutes the combustion chamber 8, and the combustion casing 11
that encases the combustion liner 7. The vane 40 is disposed in the
annular passage 13 at the outer circumferential side of the
combustion liner 7. The support 41 is attached to the inner side of
the combustion casing 11 in the annular passage 13 for fixing the
vane 40. The combustor 3 further has the pressure dynamics damping
hole 42 in the combustion liner 7 at the position corresponding to
the vane 40 (combustion liner 7 at the position corresponding to
the part where the vane 40 is formed) for communication with the
combustion chamber 8.
[0037] The vane 40 and the supports 41 are disposed in the annular
passage 13 formed at an outer circumferential side of the
combustion chamber 8. Especially, it is preferable to dispose the
vane and the supports downstream (around an outer circumferential
side of the flame stabilizer 35) in the flow direction of the
compressed air 5 flowing through the annular passage 13.
[0038] The supports 41 are attached to the inner side of the
combustion casing 11 in the circumferential direction while
extending to the center for fixing the vane 40 to the combustion
casing 11. For example, four supports 41 may be attached in the
circumferential direction. Preferably, the support 41 has a
streamlined cross section so that turbulence of the compressed air
5 is suppressed.
[0039] The vane 40 is an annular member (formed by continuously
surrounding the outer circumferential side of the combustion liner
7) attached to the support 41 in the annular passage 13, having a
predetermined width in the axial direction of the combustion liner
7. In other words, the vane 40 is disposed between the inner
circumferential side of the combustion casing 11 and the outer
circumferential side of the combustion liner 7 (annular passage
13), and fixed to the combustion casing 11 via the support 41. The
vane 40 is disposed substantially parallel to the combustion liner
7 in the radial direction of the annular passage 13. In other
words, the vane 40 is disposed in the annular passage 13 formed
between the combustion liner 7 and the combustion casing 11 at a
position around the outer circumferential side of the flame
stabilizer 35 (downstream in the flow direction of the compressed
air 5 flowing through the annular passage 13).
[0040] The pressure dynamics damping hole 42 is formed in the
combustion liner 7 at a position corresponding to a part where the
vane 40 is disposed (combustion liner 7 facing the vane 40 in the
radial direction, in other words, at the position corresponding to
the vane 40) for communication between the combustion chamber 8 and
the annular passage 13.
[0041] A plurality of pressure dynamics damping holes 42 are formed
in the row in a circumferential direction of the combustion liner
7. The circumferential rows are arranged in an axial direction.
Each interval among the pressure dynamics damping holes 42 in the
circumferential direction may be set to a fixed value or an
irregular value. Preferably, the pressure dynamics damping holes 42
in one of the rows at predetermined intervals, and those in the
next row are formed in a zigzag arrangement.
[0042] Namely, the combustor 3 according to the first example
includes the combustion liner 7 that constitutes the combustion
chamber 8 for generating the combustion gas 9, the combustion
casing 11 that encases the combustion liner 7 at its outer
circumferential side, burners (diffusion burner 20 for supplying
the air 5a for combustion and the diffusion fuel 24 to the
combustion chamber 8, and a premix burner 30 disposed at an outer
circumferential side of the diffusion burner 20 for supplying the
air 5b for combustion and the premix fuel 33 to the combustion
chamber 8) for supplying air for combustion, flowing through the
annular passage 13 formed between the combustion liner 7 and the
combustion casing 11, and the fuel (the diffusion fuel 24, and the
premix fuel 33) supplied from the fuel supply system (the diffusion
fuel supply system 21, and the premix fuel supply system 31).
[0043] The combustor 3 includes the vane 40, the supports 41, and
the pressure dynamics damping hole 42. The vane 40 is disposed in
the annular passage 13 formed between the combustion liner 7 and
the combustion casing 11 (outer circumferential side of the
combustion liner 7 and inner circumferential side of the combustion
casing 11) downstream in the flow direction of the compressed air 5
flowing through the annular passage 13. The supports 41 are
disposed at the inner side of the combustion casing 11 for fixing
the vanes 40. The pressure dynamics damping hole 42 is formed in
the combustion liner 7 at the position corresponding to the part
where the vane 40 is formed for communication with the combustion
chamber 8.
[0044] The combustor 3 with a relatively simple structure
attenuates the pressure fluctuation owing to the combustion
oscillation while securing the mechanical reliability. The vanes 40
and the supports 41 allow the compressed air 5 flowing through the
annular passage 13 to smoothly flow while suppressing pressure
loss.
[0045] Preferably, the position where the pressure dynamics damping
hole 42 is formed (position at which the vane 40 is disposed)
corresponds to the position as a base point where the flame
stabilizer 35 starts generating the premix flame. This makes it
possible to introduce the compressed air 5 into the base point of
the premix flame through the pressure dynamics damping hole 42.
[0046] Especially when the pressure dynamics damping holes 42 are
irregularly formed in the circumferential direction, properties of
the premix flame (flame shape and flame temperature) may be made
non-uniform in the circumferential direction of the ring-shaped
premix flame. This makes it possible to suppress increase in an
amplitude value of the combustion oscillation.
[0047] The pressure wave generated by the combustion oscillation in
the combustion chamber 8 is propagated to the annular passage 13
via the pressure dynamics damping hole 42 formed in the combustion
liner 7, and reflected by the vane 40. In other words, the pressure
wave propagated to the annular passage 13 is reflected by the vane
40, and then attenuated to suppress increase in the amplitude value
of the combustion oscillation. The pressure wave is attenuated as a
result of attenuating energy of the combustion oscillation.
[0048] It is preferable to design a gap g1 between the outer
circumference (outer circumferential surface) of the combustion
liner 7 and the inner circumference (inner circumferential surface)
of the vane 40 based on the frequency of the pressure wave
generated by the combustion oscillation. It is preferable to design
the gap g1 in consideration of the phase of the pressure wave
propagated to the annular passage 13, and the phase of the
reflection wave reflected by the vane 40. This makes it possible to
attenuate the pressure wave propagated to the annular passage 13,
and suppress increase in the amplitude value of the combustion
oscillation.
[0049] Since the frequency of the attenuating pressure wave varies
under the combustion conditions (load of the turbine 2, that is,
fuel flow rate, flow rate of the compressed air 5), it is
preferable to use the frequency of the pressure wave generated
under the combustion condition at the rated load of the turbine 2
on the assumption of a long operation period.
[0050] The combustor according to the first example keeps quantity
of generated nitrogen oxides low for maintaining the stable
combustion state (stable flame burning), and suppresses the
combustion oscillation that periodically fluctuates the pressure in
the combustion chamber 8 (holding the amplitude value of the
combustion oscillation at a predetermined level or lower).
[0051] The combustor according to the first example has a
relatively simple structure, and is capable of suppressing increase
in the amplitude value of the combustion oscillation generated in
burning. The combustor secures the mechanical reliability of the
member (vane 40) that attenuates the pressure fluctuation owing to
the combustion oscillation.
Second Example
[0052] A main part of the combustor 3 according to a second example
will be briefly described.
[0053] FIG. 3 is a schematic partially enlarged sectional view of
the main part of the combustor 3 according to the second
example.
[0054] The combustor 3 according to the second example is different
from the combustor 3 according to the first example in the use of a
flow sleeve 50 instead of the supports 41 and the vane 40.
[0055] The flow sleeve 50 is an annular member disposed in the
annular passage 13 in substantially parallel to the combustion
liner 7 in the radial direction of the annular passage 13 for
narrowing its cross section area through which the compressed air 5
flows.
[0056] The flow sleeve 50 is disposed to expand toward the outer
circumferential side downstream in the flow direction of the
compressed air 5 flowing through the annular passage 13 (around the
outer circumferential side of the flame stabilizer 35). The flow
sleeve 50 is fixed to the inner circumferential side of the
combustion casing 11.
[0057] The flow sleeve 50 has a part extending substantially
parallel to the combustion liner 7, and the other part expanding
toward the outer circumference.
[0058] The flow sleeve 50 reflects the pressure wave propagated to
an annular passage 130 (narrowed annular passage 13) via the
pressure dynamics damping hole 42 formed in the combustion liner 7.
The pressure dynamics damping hole 42 is formed in the combustion
liner 7 in substantially parallel thereto at the position
corresponding to the flow sleeve 50.
[0059] Specifically, the combustor 3 according to the second
example includes the combustion liner 7 that constitutes the
combustion chamber 8 for generating the combustion gas 9, the
combustion casing 11 disposed at the outer circumferential side of
the combustion liner 7, and the burners (the diffusion burner 20
and the premix burner 30) for supplying the compressed air 5
flowing between the combustion liner 7 and the combustion casing
11, and the fuel (the diffusion fuel 24 and the premix fuel 33)
supplied from the fuel supply system (the diffusion fuel supply
system 21 and the premix fuel supply system 31).
[0060] The combustor 3 includes the flow sleeve 50 disposed at the
outer circumferential side of the combustion liner 7, and the
pressure dynamics damping hole 42 formed in the combustion liner 7
at the position corresponding to the flow sleeve 50 for
communication with the combustion chamber 8.
[0061] The pressure wave generated by the combustion oscillation in
the combustion chamber 8 is propagated to the annular passage 130
via the pressure dynamics damping hole 42 formed in the combustion
liner 7, and reflected by the flow sleeve 50. The pressure wave
propagated to the annular passage 130 is reflected by the flow
sleeve 50, and then attenuated so that increase in the amplitude
value of the combustion oscillation is suppressed. The flow sleeve
50 attenuates the pressure fluctuation owing to the combustion
oscillation, and improves effect for cooling the combustion liner
7, a flow velocity of the compressed air 5, and an effect for
rectifying the compressed air 5.
[0062] When providing the flow sleeve 50 in the combustor 3, the
gap g1 between the outer circumference (outer circumferential
surface) of the combustion liner 7 and the inner circumference
(inner circumferential surface) of the flow sleeve 50 is designed
based on the frequency of the pressure wave generated by the
combustion oscillation. In other words, the gap g1 is designed in
accordance with the combustor 3 for adjusting the cross section
area of the annular passage 13. The flow sleeve 50 is designed in
consideration of the predetermined performance of the combustor 3
(cooling of the combustion liner 7, flow velocity and rectification
of the compressed air 5).
[0063] As described above, the gap g1 is designed based on the
frequency of the pressure wave generated by the combustion
oscillation, and the predetermined performance of the combustor
3.
[0064] Preferably, the position at which the pressure dynamics
damping hole 42 is formed corresponds to the position as the base
point where the flame stabilizer 35 starts generating the premix
flame. This makes it possible to introduce the compressed air 5
into the position as the base point of the premix flame through the
pressure dynamics damping hole 42.
[0065] Especially when forming the pressure dynamics damping holes
42 irregularly in the circumferential direction, properties of the
premix flame may be made non-uniform in the circumferential
direction of the ring-like shaped premix flame. As the premix flame
properties are made non-uniform in the circumferential direction,
increase in the amplitude value of the combustion oscillation may
be suppressed.
[0066] The pressure dynamics damping holes 42 are formed downstream
(around the outer circumference of the flame stabilizer 35) in the
flow direction of the compressed air 5 flowing through the annular
passage 13 for communication between the combustion chamber 8 and
the annular passage 13. The pressure dynamics damping holes 42 are
arranged in the row in the circumferential direction of the
combustion liner 7. A plurality of rows (two rows in the second
example) in the circumferential direction are arranged in the axial
direction. The pressure dynamics damping holes 42 either in the
single row or three or more rows may suppress increase in the
amplitude value of the combustion oscillation.
[0067] If the pressure dynamics damping holes 42 are formed in many
rows in the axial direction, the flow rate of the compressed air 5
to be introduced into the combustion chamber 8 through the pressure
dynamics damping holes 42 will be increased. As a result, the
effect for suppressing increase in the amplitude value of the
combustion oscillation is enhanced. However, the flow rate of the
air for combustion is reduced to increase quantity of generated
nitrogen oxides. The pressure dynamics damping holes 42 are
designed in consideration of the balance between the flow rate of
the compressed air 5 introduced into the combustion chamber 8
through the pressure dynamics damping holes 42 and the flow rate of
the air for combustion.
[0068] Preferably, the combustor 3 includes a rib 51 has an annular
member disposed at the outer circumferential side of the combustion
liner 7 downstream from the pressure dynamics damping holes 42
(downstream in the flow direction of the compressed air 5 flowing
through the annular passage 13). The rib 51 is capable of adjusting
the flow velocity of the compressed air 5 flowing through an
annular passage 130 formed between the outer circumference of the
combustion liner 7 and the inner circumference of the flow sleeve
50 in accordance with the specification (size, configuration) and
the attachment position.
[0069] The pressure wave generated by the combustion oscillation in
the combustion chamber 8 is propagated to the annular passage 130
via the pressure dynamics damping holes 42, and reflected by the
flow sleeve 50. The flow velocity of the compressed air 5 flowing
through the annular passage 130 may affect the pressure wave
attenuating performance. The rib 51 serves to adjust the flow
velocity of the compressed air 5 flowing through the annular
passage 130 to maintain the pressure wave attenuating
performance.
[0070] In the second example, the rib 51 is attached to the outer
circumference of the combustion liner 7 downstream from the
pressure dynamics damping holes 42. The rib 51 may also be attached
to the outer circumference of the combustion liner 7 upstream from
the pressure dynamics damping holes 42. Alternatively, each of the
ribs 51 may be attached to the outer circumference of the
combustion liner 7 upstream and downstream from the pressure
dynamics damping holes 42, respectively. The rib in any of the
above-described cases is capable of adjusting the flow velocity of
the compressed air 5 flowing through the annular passage 130.
[0071] The rib 51 may be formed in the combustor 3 according to the
first example. The rib 51 does not have to be necessarily formed in
the combustor 3 according to the second example.
[0072] The combustor according to the second example suppresses
quantity of generated nitrogen oxides to maintain the stable
combustion state (stable flame burning), and ensures to suppress
the combustion oscillation that periodically fluctuates the
pressure in the combustion chamber 8 (holding the amplitude value
of the combustion oscillation at a uniform level or lower).
[0073] The combustor according to the second example has a
relatively simple structure, and is capable of suppressing increase
in the amplitude value of the combustion oscillation in burning.
The combustor secures mechanical reliability of the member (flow
sleeve 50) for attenuating the pressure fluctuation owing to the
combustion oscillation.
Third Example
[0074] A main part of the combustor 3 according to a third example
will be briefly described.
[0075] FIG. 4 is a schematic partially enlarged sectional view of
the main part of the combustor 3 according to the third
example.
[0076] The combustor 3 according to the third examples is different
from the combustor 3 according to the first example in the state
where the supports 41 and the vane 40 are disposed in the
circumferential direction.
[0077] The combustor 3 according to the first example is configured
to set the uniform gap g1 between the outer circumference (outer
circumferential surface) of the combustion liner 7 and the inner
circumference (inner circumferential surface) of the vane 40 in the
circumferential direction. Meanwhile, the combustor 3 according to
the third example is configured to set the non-uniform gap between
the outer circumference (outer circumferential surface) of the
combustion liner 7 and the inner circumference (circumferential
surface) of the vane 40 in the circumferential direction.
[0078] Specifically, in the third example, the gap between the
outer circumference of the combustion liner 7 and the inner
circumference of the vane 40 is made variable in the
circumferential direction of the combustion liner 7. At a position
A of the combustion liner 7 in the circumferential direction, the
distance between the outer circumferential surface of the
combustion liner 7 and the inner circumferential surface of a vane
40a is set to the gap g1. At a position B of the combustion liner 7
in the circumferential direction, the distance between the outer
circumferential surface of the combustion liner 7 and the inner
circumferential surface of a vane 40d is set to a gap g2.
[0079] In the third example, the gap formed between the outer
circumferential surface of the combustion liner 7 and the inner
circumferential surface of the vane 40 becomes different in the
circumferential direction of the combustion liner 7.
[0080] An explanation will be made with respect to the combustor 3
according to the third examples when it is seen from the combustion
chamber.
[0081] FIG. 5 is a schematic view of the gas turbine combustor 3
according to the third example when it is seen from the combustion
chamber.
[0082] The combustor 3 according to the third example has the
premix burner 30 divided by four premix burner partitions 36a, 36b,
36c, and 36d. The premixer 34 is divided into four premixers 34a,
34b, 34c, and 34d. The premix fuel supply system 31 for supplying
the premix fuel to the premix burner 30 is divided into four premix
fuel supply systems 31a, 31b, 31c, and 31d correspondingly. Each of
the premix fuel supply systems supplies the premix fuel to the
premixers 34a, 34b, 34c, and 34d, individually.
[0083] Four supports 41a, 41b, 41c, and 41d are disposed at
positions corresponding to the four premixers 34a, 34b, 34c, and
34d, correspondingly at each center of the premixers at the outer
circumferential side. The four supports 41a, 41b, 41c, and 41d
extend from the inner side of the combustion casing 11 toward the
center, and arranged at equal intervals along the circumference of
the combustion casing 11.
[0084] The vanes 40a, 40b, 40c, and 40d are fixed to the four
supports 41a, 41b, 41c, and 41d, respectively. Specifically, the
vane 40b extends between the supports 41a and 41b, the vane 40c
extends between the supports 41b and 41c, the vane 40d extends
between the supports 41c and 41d, and the vane 40a extends between
the supports 41d and 41a.
[0085] Each of the gap between the outer circumference of the
combustion liner 7 and the inner circumference of the vane 40a, and
the gap between the outer circumference of the combustion liner 7
and the inner circumference of the vane 40c is set to the gap g1.
Each of the gap between the outer circumference of the combustion
liner 7 and the inner circumference of the vane 40b, and the gap
between the outer circumference of the combustion liner 7 and the
inner circumference of the vane 40d is set to the gap g2.
[0086] The position A of the combustion liner 7 in the
circumferential direction as shown in FIG. 4 corresponds to the
position A as shown in FIG. 5. The position B of the combustion
liner 7 in the circumferential direction as shown in FIG. 4
corresponds to the position B as shown in FIG. 5.
[0087] A cone 26 supports the diffusion burner 20, and has air
holes 27 formed therein.
[0088] Two kinds of gaps (g1 and g2) may be formed in the combustor
3 according to the third example. This makes it possible to
suppress increase in the amplitude value of the combustion
oscillation to each frequency of two kinds of pressure waves
generated by the combustion oscillation. In other words, two kinds
of phases (phase of the wave reflected by the vane 40) may be
considered for cancelling phases of the two kinds of pressure
waves.
[0089] An explanation will be made with respect to a method of
operating the gas turbine combustor 3 according to the third
example.
[0090] FIG. 6 schematically illustrates the method of operating the
gas turbine combustor 3 according to the third example, having an
x-axis representing the load of the turbine 2, and a y-axis
representing the flow rate of the fuel supplied to each burner (the
diffusion burner 20 and the premix burner 30).
[0091] The flow rate of the fuel to the diffusion burner 20 is
designated as fuel F-21. The premix fuel supplied to the premixer
34a is designated as fuel F-34a. The premix fuel supplied to the
premixer 34b is designated as fuel F-34b. The premix fuel supplied
to the premixer 34c is designated as fuel F-34c. The premix fuel
supplied to the premixer 34d is designated as fuel F-34d. A point a
denotes a no-load state at a rated speed, and a point f denotes a
rated load.
[0092] In a load range from the point a to the point b, the fuel
F-21 is supplied to the diffusion burner 20.
[0093] When the load reaches the point b, supply of the fuel F-21
is reduced, and the fuel F-34a is supplied to the premixer 34a for
starting premixed combustion.
[0094] As the load is increased, each supply of the fuel F-21 and
F-34a is increased in the load range from the point b to the point
c.
[0095] When the load reaches the point c, each supply of the fuel
F-21 and F-34a is reduced, and the fuel F-34b is supplied to the
premixer 34b.
[0096] As the load is increased, each supply of the fuel F-21,
F-34a, and F-34b is increased in the load range from the point c to
the point d.
[0097] When the load reaches the point d, each supply of the fuel
F-21, F-34a, and F-34b is reduced, and the fuel F-34d is supplied
to the premixer 34d.
[0098] As the load is increased, each supply of the fuel F-21,
F-34a, F-34b, and F-34d is increased in the load range from the
point d to the point e.
[0099] When the load reaches the point e, each supply of the fuel
F-21, F-34a, F-34b, and F-34d is reduced, and the fuel F-34c is
supplied to the premixer 34c.
[0100] As the load is increased, full-burner combustion is started
in the load range from the point e to the point f.
[0101] Under the load at the point f (rated load), the supply of
the fuel F-21 to the diffusion burner 20 is reduced for suppressing
quantity of generated nitrogen oxides. Then each ratio of the
premix fuel (F-34a, F-34b, F-34c, and F-34d) supplied to the
premixers 34a, 34b, 34c, and 34d to the F-21 is increased.
[0102] Referring to FIG. 6, the combustor 3 reaches the rated load
under various combustion conditions. In the process for increasing
the load of the turbine 2, it is preferable to suppress increase in
the amplitude value of the combustion oscillation to frequencies of
the pressure waves generated by the combustion oscillation. In the
third example, the combustor is capable of suppressing increase in
the amplitude value of the combustion oscillation to each frequency
of two kinds of pressure waves generated by the combustion
oscillation. In other words, each combustion oscillation at two
different frequencies may be suppressed.
[0103] Preferably, the gap is formed corresponding to the frequency
(frequency of the combustion oscillation that occurs at the rated
load) of the pressure wave under the combustion condition at the
rated load of the turbine 2. Even at the rated load, the combustion
oscillation at a plurality of frequencies may occur in response to
change in fuel properties, fuel conditions, and fuel heat values.
Even in the case of the combustion oscillation generated at
different frequencies, the combustor according to the third example
ensures to suppress the combustion oscillation.
[0104] As FIG. 5 illustrates, in the third example, the support 41a
is disposed at the outer circumferential center of the premixer
34a. The vane 40a is attached to the support 41a at the side of the
premixer 34d, and the vane 40b is attached to the support 41a at
the side of the premixer 34b.
[0105] Specifically, in the circumferential direction of the
premixer 34a, the gap between the outer circumferential surface of
the combustion liner 7 and the inner circumferential surface of the
vane 40 at one side of the support 41a is different from the gap at
the other side of the support 41a. This structure will change the
flow phase of the air for combustion to be introduced into the
premixer 34a along its circumferential direction.
[0106] The premix flame properties may be made non-uniform in the
circumferential direction of the ring-like shaped premix flame. The
non-uniform premix flame properties may suppress increase in the
amplitude value of the combustion oscillation.
[0107] Preferably, the combustor 3 according to the third example
has the ribs 51 each disposed upstream and downstream from the
pressure dynamics damping holes 42. This makes it possible to
maintain the pressure wave attenuating performance.
[0108] The combustor according to the third example is capable of
suppressing quantity of generated nitrogen oxides, maintaining the
stable combustion state (stable flame burning), and suppressing the
combustion oscillation that periodically fluctuates the pressure in
the combustion chamber 8 (holding the amplitude value of the
combustion oscillation at a predetermined level or lower).
[0109] The combustor according to the third example has a
relatively simple structure, and is capable of suppressing increase
in the amplitude value of the combustion oscillation generated in
burning, securing the mechanical reliability of the member (vane
40) for attenuating the pressure fluctuation owing to the
combustion oscillation.
[0110] The operation method as represented by FIG. 6 may be applied
to the first and the second examples.
[0111] The present invention is not limited to the above-described
examples, but includes various modifications. Specifically, the
examples have been described in detail for readily understanding of
the present invention. The present invention is not necessarily
limited to the one provided with all structures as described above.
It is possible to partially replace a structure of one of the
examples with a structure of another example, or partially add the
structure of one of the examples to the structure of another
example. It is also possible to add, eliminate, and replace a part
of the structure of one of the examples to, from, and with a part
of the structure of another example.
REFERENCE SIGNS LIST
[0112] 1 . . . compressor, [0113] 2 . . . turbine, [0114] 3 . . .
combustor, [0115] 4 . . . generator, [0116] 5 . . . compressed air,
[0117] 6 . . . compressed air passage, [0118] 7 . . . combustion
liner, [0119] 8 . . . combustion chamber, [0120] 9 . . . combustion
gas, [0121] 10 . . . transition piece, [0122] 11 . . . combustion
casing, [0123] 12 . . . end cover, [0124] 13 . . . annular passage,
[0125] 20 . . . diffusion burner, [0126] 21 . . . diffusion fuel
supply system, [0127] 22 . . . fuel nozzle, [0128] 23 . . .
swirler, [0129] 24 . . . diffusion fuel [0130] 25 . . . fuel jet
hole, [0131] 26 . . . cone, [0132] 27 . . . air hole, [0133] 30 . .
. premix burner, [0134] 31 . . . premix fuel supply system, [0135]
32 . . . fuel nozzle, [0136] 33 . . . premix fuel, [0137] 34 . . .
premixer, [0138] 35 . . . flame stabilizer, [0139] 36 . . . premix
burner partition, [0140] 40 . . . vane, [0141] 41 . . . support,
[0142] 42 . . . pressure dynamics damping hole, [0143] 50 . . .
flow sleeve,
* * * * *