U.S. patent application number 14/132007 was filed with the patent office on 2015-06-18 for axial stage injection dual frequency resonator for a combustor of a gas turbine engine.
The applicant listed for this patent is Esam Abu-Irshaid, Perry L. Johnson, Walter R. Laster, Scott M. Martin, Jared M. Pent, Juan Enrique Portillo Bilbao, Rafik N. Rofail. Invention is credited to Esam Abu-Irshaid, Perry L. Johnson, Walter R. Laster, Scott M. Martin, Jared M. Pent, Juan Enrique Portillo Bilbao, Rafik N. Rofail.
Application Number | 20150167980 14/132007 |
Document ID | / |
Family ID | 52278792 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150167980 |
Kind Code |
A1 |
Pent; Jared M. ; et
al. |
June 18, 2015 |
AXIAL STAGE INJECTION DUAL FREQUENCY RESONATOR FOR A COMBUSTOR OF A
GAS TURBINE ENGINE
Abstract
A gas turbine engine (202) including a secondary fuel stage
(218) which also functions as a dual frequency resonator. The
engine includes a combustor (210) and a casing (205) enclosing the
combustor to define a volume (214). The secondary fuel stage
includes a nozzle (217) sized to be effective as a transverse
resonator at a high frequency. The nozzle and the volume (214) of
the casing are sized to be effective as a longitudinal resonator at
an intermediate frequency.
Inventors: |
Pent; Jared M.; (Gotha,
FL) ; Portillo Bilbao; Juan Enrique; (Oviedo, FL)
; Johnson; Perry L.; (Orlando, FL) ; Abu-Irshaid;
Esam; (Orlando, FL) ; Laster; Walter R.;
(Oviedo, FL) ; Martin; Scott M.; (Titusville,
FL) ; Rofail; Rafik N.; (Oviedo, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pent; Jared M.
Portillo Bilbao; Juan Enrique
Johnson; Perry L.
Abu-Irshaid; Esam
Laster; Walter R.
Martin; Scott M.
Rofail; Rafik N. |
Gotha
Oviedo
Orlando
Orlando
Oviedo
Titusville
Oviedo |
FL
FL
FL
FL
FL
FL
FL |
US
US
US
US
US
US
US |
|
|
Family ID: |
52278792 |
Appl. No.: |
14/132007 |
Filed: |
December 18, 2013 |
Current U.S.
Class: |
60/746 ;
60/740 |
Current CPC
Class: |
F23R 3/16 20130101; F23R
3/045 20130101; F23R 2900/00014 20130101; F23R 3/34 20130101; F23R
3/46 20130101 |
International
Class: |
F23R 3/16 20060101
F23R003/16 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED DEVELOPMENT
[0001] Development for this invention was supported in part by
Contract No. DE-FC26-05NT42644, awarded by the United States
Department of Energy. Accordingly, the United States Government may
have certain rights in this invention.
Claims
1. A gas turbine engine comprising: a combustor; a casing enclosing
the combustor and defining a volume; and a secondary fuel stage for
delivering fuel to the combustor; wherein the secondary fuel stage
comprises a nozzle sized to be effective as a transverse resonator;
and wherein the nozzle and the volume of the casing are configured
to be effective as a longitudinal resonator.
2. The gas turbine engine of claim 1, wherein a length of the
nozzle is selected to damp vibrations of a selected frequency.
3. The gas turbine engine of claim 1, wherein the nozzle defines an
opening, and wherein a cross-sectional width of the opening of the
nozzle is selected to damp vibrations of a selected frequency.
4. The gas turbine engine of claim 3, wherein the nozzle is conical
with a reduced cross-sectional width toward an outlet of the
nozzle.
5. The gas turbine engine of claim 1, wherein a plurality of
nozzles are arranged at the secondary fuel stage and wherein an
angle between adjacent nozzles in a plane transverse to a
longitudinal axis of the combustor is selected so that the
secondary fuel stage is effective to damp a selected transverse
vibration mode.
6. The gas turbine engine of claim 1, wherein the secondary fuel
stage comprises a first nozzle sized to be effective as a
transverse resonator at a first frequency and a second nozzle sized
to be effective as a transverse resonator at a second frequency
different than the first frequency.
7. The gas turbine engine of claim 1, wherein the secondary fuel
stage comprises a first nozzle sized to be effective as a
transverse resonator at a first frequency and wherein a third fuel
stage downstream of the secondary fuel stage comprises a second
nozzle sized to be effective as a transverse resonator at a second
frequency different than the first frequency.
8. The gas turbine engine of claim 1, wherein the nozzle extends
beyond an inner diameter of a combustion liner wall of the
combustor.
9. The gas turbine engine of claim 1, wherein the nozzle does not
extend beyond an inner diameter of a combustion liner wall of the
combustor.
10. The gas turbine engine of claim 1, wherein a ratio of a length
to a diameter of the nozzle is in a range of 0.5-5.0.
11. The gas turbine engine of claim 1, wherein a ratio of a
diameter of the nozzle to a diameter of the combustor is in a range
of 0.01-0.1.
12. In a gas turbine engine comprising a casing defining a volume
enclosing a combustor, a resonator located at a downstream
secondary fuel injection location of the combustor, said resonator
comprising: a fuel line outlet positioned to inject fuel into an
inlet of a nozzle effective to deliver fuel to the combustor
through the nozzle; wherein the nozzle is configured to be
effective as a transverse resonator for transverse vibrations in a
range of 1200-4500 Hz; and wherein the nozzle and the volume of the
casing enclosing the combustor are configured to be effective as a
longitudinal resonator for longitudinal vibrations in a range of
50-150 Hz.
13. The resonator of claim 12, wherein a ratio of a length to a
diameter of the nozzle is in a range of 0.5-5.0.
14. The resonator of claim 12, wherein a ratio of a diameter of the
nozzle to a diameter of the combustor is in a range of
0.01-0.1.
15. The resonator of claim 12, wherein a plurality of nozzles are
arranged at the downstream secondary fuel injection location and
wherein an angle between adjacent nozzles in a plane transverse to
a longitudinal axis of the combustor is selected so to damp a
selected transverse vibration mode.
16. The resonator of claim 12, wherein the nozzle extends beyond an
inner diameter of a combustion liner wall of the combustor.
17. The resonator of claim 12, wherein the nozzle does not extend
beyond an inner diameter of a combustion liner wall of the
combustor.
18. In a gas turbine engine comprising a casing defining a volume
and a can-annular combustor disposed within the casing volume, the
improvement comprising: a plurality of nozzles formed in a wall of
the combustor to define a secondary fuel injection location; a fuel
outlet disposed proximate an inlet of each nozzle for delivering a
secondary fuel into the combustor through the nozzles; wherein the
nozzles are configured to be effective as a resonator to dampen a
transverse frequency mode of pressure oscillations developed within
the combustor during operation of the engine; and wherein the
nozzle and the casing volume are jointly configured to be effective
as a resonator to dampen a longitudinal frequency mode of the
pressure oscillations.
19. The gas turbine engine of claim 18, further comprising a first
of the nozzles configured differently than a second of the nozzles
to be effective at different respective frequencies.
20. The gas turbine engine of claim 18, further comprising: wherein
the nozzles are configured to be effective to damp transverse
vibrations in a range of 1200-4500 Hz; and the nozzles and the
casing volume are configured to be effective to damp longitudinal
vibrations in a range of 50-150 Hz.
Description
FIELD OF THE INVENTION
[0002] The invention relates to gas turbine engines, and more
particularly to a resonator used to dampen resonance frequencies in
a combustor of a gas turbine engine.
BACKGROUND OF THE INVENTION
[0003] A conventional combustible gas turbine engine includes a
compressor section, a combustion section including a plurality of
can-annular combustor apparatuses, and a turbine section. Ambient
air is compressed in the compressor section and directed to the
combustor apparatuses in the combustion section. FIG. 1 illustrates
a conventional combustor 10. As illustrated in FIG. 1, it is known
that injecting fuel at two axially spaced apart fuel injection
locations, i.e., via an upstream fuel stage 16 associated with a
main combustion zone and a secondary fuel stage 18 downstream from
the main combustion zone, reduces the production of NO.sub.x by the
combustor 10. For example, if a significant portion of fuel is
injected at the secondary fuel stage 18, the amount of time that
secondary combustion products are at a high temperature is reduced
as compared to first combustion products, created by the fuel
injected by the upstream fuel stage 16.
[0004] FIG. 2 illustrates another conventional combustor 110.
During engine operation, acoustic pressure oscillations at
undesirable frequencies can develop in the combustor 110 due to,
for example, burning rate fluctuations inside the combustor 110.
Such pressure oscillations can damage components in the combustor
110. To avoid such damage, one or more damping devices, such as a
resonator 124, can be formed by attaching a resonator box 126 to an
outer peripheral surface 128 of the combustor liner 122. As
illustrated in FIG. 2, a plurality of resonators 124 can be aligned
circumferentially about the liner 122. The resonators 124 can be
tuned to provide damping at a single transverse frequency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The invention is explained in the following description in
view of the drawings that show:
[0006] FIG. 1 is a cross-sectional side view of a conventional
combustor used in a gas turbine engine;
[0007] FIG. 2 is a side view of a conventional combustor used in a
gas turbine engine;
[0008] FIG. 3 is a cross-sectional side view of a gas turbine
engine;
[0009] FIG. 4 is a cross-sectional side view of a resonator located
at a downstream secondary fuel injection location of a
combustor;
[0010] FIG. 5 is a cross-sectional side view of a resonator located
at a downstream secondary fuel injection location of a
combustor;
[0011] FIG. 6 is a cross-sectional side view of a resonator located
at a downstream secondary fuel injection location and a downstream
third fuel injection location of a combustor;
[0012] FIG. 7 is a cross-sectional end view of the resonator of
FIG. 4; and
[0013] FIG. 8 is a plot of a frequency response function versus
frequency for the resonator of FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The present inventors have recognized several limitations of
the conventional resonator that is used to dampen pressure
oscillations within a combustor of a gas turbine engine. For
example, the inventors recognized that conventional resonators in a
combustor take the form of additional components beyond those that
are needed to direct and combust fluid in the combustion chamber.
Based on this recognition, the present inventors developed a
resonator using the existing components that direct and combust
fluid in the combustion chamber, and thus eliminated the need for
additional components.
[0015] The present inventors also recognized that conventional
resonators in a combustor are limited to dampening one resonant
frequency mode, per resonator design. Based on this recognition,
the present inventors developed a resonator for a combustor, which
simultaneously dampens a high frequency transverse mode and an
intermediate frequency longitudinal mode, thereby reducing the
number of required resonator designs to dampen multiple resonant
frequency modes.
[0016] FIG. 3 illustrates a gas turbine engine 202 including a
compressor 204 that generates compressed air which is passed
through a diffuser 207 and into a casing 205 with a volume 214. The
compressed air then enters a can-annular combustor 210, where the
compressed air is mixed with a fuel from a primary fuel stage and
is ignited. As illustrated in FIG. 3, the casing volume 214
encloses the combustor 210. A secondary fuel line 234 is directed
to a secondary fuel stage 218 of the combustor 210, to inject fuel
into the air/fuel mixture within the combustor 210 at the secondary
fuel stage 218. Additionally, compressed air is injected into the
combustor 210 at the secondary fuel stage 218. The ignited air/fuel
mixture is subsequently passed to a turbine 206, to perform work,
such as rotating a shaft 208 connecting the compressor 204 and the
turbine 206, for example. As illustrated in FIG. 3, the combustor
210 includes a resonator 200 at the secondary fuel stage 218, to
dampen multiple frequencies corresponding to resonant frequency
modes of the combustor 210, as described below.
[0017] FIG. 4 illustrates the resonator 200, which includes the
combustor 210 and a flow sleeve 212 that encloses the combustor
210. As further illustrated in FIG. 4, the combustor 210 includes
the secondary fuel stage 218 located at a downstream secondary fuel
injection location 246. The secondary fuel line 234 is located at
the secondary fuel stage 218 and includes an outlet 236 positioned
to inject fuel into an inlet 238 of a nozzle 217 to deliver fuel to
a combustion chamber 240 of the combustor 210 through the nozzle
217.
[0018] Each nozzle 217, by itself, is sized to be effective as a
transverse resonator, to dampen a transverse frequency
corresponding to a resonant transverse mode combustion-induced
vibrations of the combustor 210. In an exemplary embodiment, as
illustrated in FIG. 4, a length 220 of the nozzle 217 is sized such
that the nozzle is effective as the transverse resonator. In an
exemplary embodiment, a ratio of the nozzle length to nozzle
diameter may be in a range of 0.5-5.0, for example. However, the
ratio of nozzle length to nozzle diameter is not limited to any
specific range. In an exemplary embodiment, the nozzle 217 acts as
a half-wave resonator in a transverse dimension, such that the
length 220 is sized in order for an integral number of
half-wavelengths of a transverse frequency to fit along the length
220, where the transverse frequency corresponds to a resonant
transverse mode of the combustor 210. In another exemplary
embodiment, as illustrated in FIG. 4, the nozzle 217 defines an
opening 222, and a cross-sectional width 221 of the opening 222 is
sized such that the nozzle is effective as the transverse
resonator. In an exemplary embodiment, a ratio of the nozzle
diameter to combustor diameter may be in a range of 0.01-0.1, for
example. However, the ratio of the nozzle diameter to combustor
diameter is not limited to any specific range. In another exemplary
embodiment, the cross-sectional width 221, in addition to the
nozzle length 220 and a volume within the nozzle 217 are sized such
that the nozzle is effective as the transverse resonator. FIG. 5
illustrates an alternate resonator 200' with a nozzle 217' that is
located at the downstream secondary fuel injection location 246 of
the combustor 210. As illustrated in FIG. 5, the nozzle 217'
defines a conical opening 222' with a reduced cross-sectional width
221' toward an outlet 226' of the nozzle 217'. In an exemplary
embodiment, the conical opening may be angled within a range of
75-90 degrees, for example. However, the angle of the conical
opening is not limited to any specific range. Although FIGS. 4-5
illustrate nozzles with cylindrical (FIG. 4) and conical (FIG. 5)
shaped cross-sectional areas, the embodiments of the present
invention is not limited to these arrangements and the nozzles may
have any cross-sectional area arrangement, provided that the
cross-sectional area is such that the nozzle is effective as the
transverse resonator. In an exemplary embodiment, the nozzle 217 is
sized to dampen a transverse frequency in a range of 2900-2950 Hz,
for example, which corresponds to a resonant transverse mode of the
combustor 210. However, this transverse frequency range is merely
exemplary and the resonator of the present invention is not limited
to dampening any specific transverse frequency range, since the
design parameters (i.e. length, cross-sectional area, shape,
volume, number of nozzles, etc) of the resonator nozzle can be
adjusted such that the resonator dampens any desired transverse
frequency range. In an exemplary embodiment, the number of nozzles
217 at the secondary fuel stage 218 may be within a range of 8-12
nozzles, for example. However, this range is merely exemplary and
any number of nozzles may be used at the secondary fuel stage 218,
provided that the resonator is effective as a transverse
resonator.
[0019] The combination of the nozzle 217 and the casing volume 214
(FIG. 3) are effective as a longitudinal resonator, and the nozzle
217 and the volume 214 are sized in order for the longitudinal
resonator to dampen a longitudinal frequency corresponding to a
resonant longitudinal mode of the combustor 210. In an exemplary
embodiment, the longitudinal frequency dampened by the longitudinal
resonator may depend on the casing volume and/or on a longitudinal
dimension within the casing volume, depending on the geometry of
the casing and the target resonant longitudinal mode to be
dampened. In an exemplary embodiment, the longitudinal frequency
dampened by the longitudinal resonator may depend on a combination
of the casing volume and the sum of all of nozzles within each
combustor. In an exemplary embodiment, the casing volume 214 acts
as a cavity and the nozzles 217 act as a neck of a Helmholtz
resonator, for example. In order to be effective as the
longitudinal resonator, the quantity of the nozzles 217 may be
adjusted. In an exemplary embodiment, the number of nozzles 217 at
the secondary fuel stage 218 may be within a range of 8-12 nozzles,
for example. However, this range is merely exemplary and any number
of nozzles may be used at the secondary fuel stage 218, provided
that the resonator is effective as a longitudinal resonator. In an
exemplary embodiment, the nozzle 217 and the casing volume 214 are
sized to dampen a longitudinal frequency in a range of 50-150 Hz,
for example, which corresponds to a resonant longitudinal mode of
the combustor 210. However, this longitudinal frequency range is
merely exemplary and the resonator of the present invention is not
limited to dampening any specific longitudinal frequency range,
since the parameter (i.e. number of nozzles) of the resonator
nozzle and the volume of the casing can be adjusted during a design
phase such that the resonator dampens any desired longitudinal
frequency range.
[0020] FIG. 6 illustrates an alternate combustor 200'' including
the nozzle 217 positioned at the secondary fuel stage 218, as with
the combustor 200 of FIG. 4 discussed above. As with the combustor
200 of FIG. 4, the nozzle 217 of the combustor 200'' is sized to be
effective as a transverse resonator at a first frequency that
corresponds to a first resonant transverse mode of the combustor
210. However, the combustor 200'' further includes a third fuel
stage 254 at a downstream third fuel injection location 252 that is
downstream of the second fuel stage 218 at the downstream secondary
fuel injection location 246. The combustor 200'' includes a second
nozzle 219'' at the third fuel stage 254 that is sized to be
effective as a transverse resonator at a second frequency that
corresponds to a second resonant transverse mode of the combustor
210, where the second frequency is different than the first
frequency and the second resonant transverse mode is different than
the first resonant transverse mode. The second nozzle 219'' does
not extend beyond an inner diameter of the combustion liner wall
230 of the combustor 210. In contrast, the nozzle 217 extends
beyond the inner diameter of the combustion liner wall 230.
Although FIG. 6 depicts the first nozzle 217 positioned at the
secondary fuel stage 218 and extending beyond the inner diameter of
the combustion liner wall 230, and the second nozzle 219''
positioned at the third fuel stage 254 and not extending beyond the
inner diameter of the combustion liner wall 230, this arrangement
is merely exemplary, and the nozzles at each of the second and
third stages may all extend beyond the inner diameter of the
combustion liner wall or may all not extend beyond the inner
diameter of the combustion liner wall, or some combination thereof,
for example. Additionally, although FIG. 6 depicts that one nozzle
may be arranged at a secondary fuel stage and one nozzle may be
arranged at a third fuel stage downstream of the secondary fuel
stage, this is merely exemplary, as more than one nozzle may be
arranged at each of the secondary or third fuel stages, and one or
more nozzle(s) may be arranged at additional fuel stages downstream
of the third fuel stage, for example. In an exemplary embodiment,
the number of nozzles that are arranged at each of the second and
third fuel stages may be within the range of 8-12 nozzles, for
example. However, this range is merely exemplary and any number of
nozzles may be used at each of the second and third stages,
provided that the resonator is effective as a transverse
resonator.
[0021] FIG. 7 illustrates an end view of the resonator 200 of FIG.
4 at the downstream secondary fuel injection location 246 and a
plurality of nozzles 217, 219 arranged at the secondary fuel stage
218. The nozzles 217, 219 are arranged at the downstream second
fuel injection location 246 with an angle 228 between adjacent
nozzles 217, 219 in a plane transverse to the combustor
longitudinal axis. In an exemplary embodiment, the angle 228 is
selected such that the nozzles 217, 219 are effective as transverse
and longitudinal resonators. In an exemplary embodiment, the angle
may be within a range of 15-90 degrees, for example. However, the
angle is not limited to any specific range. In an exemplary
embodiment, the angle may be determined based on the specific
transverse mode that needs to be dampened, for example. Although
FIG. 7 illustrates two nozzles 217, 219 arranged at the secondary
fuel stage 218, the embodiment of the present invention is not
limited to this number of nozzles and any plurality of nozzles may
be arranged at the secondary fuel stage, provided that the angle
between adjacent nozzles is sized such that the nozzles are
effective transverse and longitudinal resonators.
[0022] In an exemplary embodiment, the nozzles 217, 219 at the
secondary fuel stage 218 may be individually sized (i.e. length,
cross-sectional area, etc.) such that a first nozzle 217 is
effective as a transverse resonator at a first frequency and a
second nozzle 219 is effective as a transverse resonator at a
second frequency that is different than the first frequency. For
example, the nozzles 217, 219 may have different lengths and/or
different cross-sectional areas, such that the nozzle 217 and the
nozzle 219 are sized to be effective as transverse resonators at a
respective first and second frequency. Although the above example
discusses that two nozzles at the secondary fuel stage may be sized
differently to be effective transverse resonators at two distinct
frequencies, the embodiment of the present invention is not limited
to this arrangement, and includes any plurality of nozzles at the
secondary fuel stage being sized differently, to be effective
transverse resonators at a plurality of distinct frequencies, for
example. Additionally, the length and cross-sectional areas of the
nozzles 217, 219 may be sized, in addition to the casing volume
214, to ensure that the desired longitudinal frequency is
dampened.
[0023] FIG. 8 depicts a plot of the frequency response function
(FRF) of the resonator 200 for a range of frequencies during
operation of the combustor 210. As illustrated in FIG. 8, the
resonator 200 is effective to simultaneously dampen a transverse
frequency 242 corresponding to a resonant transverse mode of the
combustor 210 and to dampen a longitudinal frequency 244
corresponding to a resonant longitudinal mode of the combustor 210.
The transverse frequency 242 dampened by the nozzle 217 corresponds
to a high frequency mode with a range of approximately 2900-2950
Hz, and is based on the sizing characteristics (i.e. length,
opening, cross-sectional area, etc) of the nozzle 217. The FRF 248
of the resonator 200 at the transverse frequency 242 is based on
the combination of the individual dampening effects of each nozzle
217 at the secondary fuel stage 218. Although the transverse
frequency 242 discussed above lies within a sample range of
2900-2950 Hz, this range is merely exemplary, may include a wider
range of 1200-4500 Hz and the embodiments of the present invention
is not limited to these ranges and may include any resonant
transverse mode of the combustor, provided that the nozzles can be
sized to dampen the transverse frequency corresponding to the
resonant transverse mode.
[0024] As further illustrated in FIG. 8, the longitudinal frequency
244 is an intermediate frequency mode with a range of approximately
50-150 Hz. The FRF 250 of the resonator 200 at the longitudinal
frequency 244, and the range of the longitudinal frequency mode
244, are based on the volume 214 of the casing 205 in combination
with the characteristics of the nozzles 217, 219 in each combustor
210 of the engine 202. The number of nozzles 217 at the secondary
fuel stage 218 may affect the longitudinal frequency 244, such as
the center frequency within the range of the longitudinal frequency
244, for example. Although the longitudinal frequency mode 244
discussed above lies within a sample range of 50-150 Hz, this range
is merely exemplary, may include a wider range of 50-400 Hz and the
embodiments of the present invention is not limited to these ranges
and may include any resonant longitudinal mode of the combustor,
provided that the casing volume and the nozzles are sized to dampen
the longitudinal frequency corresponding to the resonant
longitudinal mode.
[0025] In the above embodiment, the resonator 200 dampens a wider
range of the longitudinal frequency 244 (100 Hz) than the range of
the transverse frequency 242 (50 Hz). Since the range of the
dampened transverse frequency 242 for each nozzle design is
relatively narrow, more than one nozzle design may be employed in
the resonator, to increase the total range of dampened transverse
frequencies. As previously discussed, multiple nozzle designs may
be provided, where each nozzle design is configured to dampen a
respective transverse frequency range.
[0026] While various embodiments of the present invention have been
shown and described herein, it will be obvious that such
embodiments are provided by way of example only. Numerous
variations, changes and substitutions may be made without departing
from the invention herein. Accordingly, it is intended that the
invention be limited only by the spirit and scope of the appended
claims.
* * * * *