U.S. patent application number 12/716198 was filed with the patent office on 2011-03-03 for acoustically stiffened gas turbine combustor supply.
This patent application is currently assigned to General Electric Company. Invention is credited to John Lipinski, Ilya Slobodyanskiy, Shiva Srinivasan, Dmitry Tretyakov.
Application Number | 20110048021 12/716198 |
Document ID | / |
Family ID | 43525383 |
Filed Date | 2011-03-03 |
United States Patent
Application |
20110048021 |
Kind Code |
A1 |
Slobodyanskiy; Ilya ; et
al. |
March 3, 2011 |
ACOUSTICALLY STIFFENED GAS TURBINE COMBUSTOR SUPPLY
Abstract
In one embodiment, a system includes a variable geometry
resonator configured to couple to a fluid path upstream from a
combustor of a turbine engine. The variable geometry resonator is
configured to dampen pressure oscillations in the fluid path and
the combustor.
Inventors: |
Slobodyanskiy; Ilya; (Kazan,
RU) ; Lipinski; John; (Simpsonville, SC) ;
Srinivasan; Shiva; (Greer, SC) ; Tretyakov;
Dmitry; (Moscow, RU) |
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
43525383 |
Appl. No.: |
12/716198 |
Filed: |
March 2, 2010 |
Current U.S.
Class: |
60/725 |
Current CPC
Class: |
F02C 7/24 20130101; Y02T
50/60 20130101; F05D 2260/96 20130101; Y02T 50/675 20130101; F01D
9/023 20130101 |
Class at
Publication: |
60/725 |
International
Class: |
F02C 7/24 20060101
F02C007/24 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2009 |
RU |
2009132684 |
Claims
1. A system, comprising: a turbine engine, comprising: a
compressor; a turbine; a combustor disposed downstream from the
compressor and upstream from the turbine; a fluid injection system
configured to inject one or more fluids into the combustor; a
variable geometry resonator coupled to the fluid injection system;
and a controller configured to tune the variable geometry resonator
in response to feedback.
2. The system of claim 1, wherein the variable geometry resonator
comprises a Helmholtz resonator.
3. The system of claim 1, wherein the variable geometry resonator
comprises a quarter wave resonator.
4. The system of claim 1, wherein the feedback comprises pressure
oscillations within the combustor.
5. The system of claim 1, wherein the variable geometry resonator
comprises a plurality of variable geometry resonators tuned to
different frequencies.
6. The system of claim 1, wherein the variable geometry resonator
is coupled to a fuel path of the fluid injection system.
7. The system of claim 1, wherein the variable geometry resonator
is coupled to a diluent path of the fluid injection system.
8. The system of claim 1, wherein the variable geometry resonator
is coupled to an air path of the fluid injection system.
9. The system of claim 1, wherein the variable geometry resonator
is configured to dampen pressure oscillations in the fluid
injection system and the combustor.
10. A system, comprising: a variable geometry resonator configured
to couple to a fluid path upstream from a combustor of a turbine
engine, wherein the variable geometry resonator is configured to
dampen pressure oscillations in the fluid path and the
combustor.
11. The system of claim 10, wherein the variable geometry resonator
comprises a Helmholtz resonator, a quarter wave resonator, or
both.
12. The system of claim 10, wherein the variable geometry resonator
comprises a plurality of variable geometry resonators tuned to
different frequencies.
13. The system of claim 10, comprising a fluid injection system
having the variable geometry resonator.
14. The system of claim 10, comprising the combustor having the
variable geometry resonator coupled to the fluid path upstream from
the combustor.
15. The system of claim 10, comprising a controller coupled to the
variable geometry resonator, wherein the controller is configured
to tune the variable geometry resonator in response to pressure
feedback associated with the combustor.
16. The system of claim 15, wherein the controller adjusts the
geometric configuration of the variable geometry resonator to tune
the variable geometry resonator.
17. A method, comprising: receiving pressure feedback associated
with a combustor of a turbine engine; and tuning a resonator
coupled to a fluid path upstream from the combustor based on the
feedback.
18. The method of claim 17, wherein tuning the resonator comprises
varying a geometry of the resonator to dampen pressure oscillations
in the fluid path and the combustor.
19. The method of claim 17, comprising injecting fluid from the
fluid path into the combustor downstream from the resonator,
wherein the fluid comprises a gas fuel, a liquid fuel, a diluent,
air, or a combination thereof.
20. The method of claim 17, comprising tuning a plurality of
resonators coupled to a fluid path upstream from the combustor
based on the feedback.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of
Russian Patent Application No. 2009132684, entitled "ACOUSTICALLY
STIFFENED GAS TURBINE COMBUSTOR SUPPLY", filed Aug. 31, 2009, which
is herein incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] The subject matter disclosed herein relates to a gas turbine
engine and, more specifically, to an acoustically stiffened gas
turbine combustor supply.
[0003] In general, gas turbine engines combust a mixture of
compressed air and fuel to produce hot combustion gases. Combustion
may occur in multiple combustors positioned radially around the
longitudinal axis of the gas turbine engine. Air and fuel pressures
within each combustor may vary cyclically with time. These
fluctuations may drive combustor pressure oscillations at various
frequencies. If one of the frequency bands corresponds to a natural
frequency of a part or subsystem within the gas turbine engine,
damage to that part or the entire engine may result.
BRIEF DESCRIPTION OF THE INVENTION
[0004] Certain embodiments commensurate in scope with the
originally claimed invention are summarized below. These
embodiments are not intended to limit the scope of the claimed
invention, but rather these embodiments are intended only to
provide a brief summary of possible forms of the invention. Indeed,
the invention may encompass a variety of forms that may be similar
to or different from the embodiments set forth below.
[0005] In a first embodiment, a system includes a turbine engine
that includes a compressor, a turbine and a combustor disposed
downstream from the compressor and upstream from the turbine. The
turbine engine also includes a fluid injection system configured to
inject one or more fluids into the combustor and a variable
geometry resonator coupled to the fluid injection system.
Furthermore, the turbine engine includes a controller configured to
tune the variable geometry resonator in response to feedback.
[0006] In a second embodiment, a system includes a variable
geometry resonator configured to couple to a fluid path upstream
from a combustor of a turbine engine. The variable geometry
resonator is configured to dampen pressure oscillations in the
fluid path and the combustor.
[0007] In a third embodiment, a method includes receiving pressure
feedback associated with a combustor of a turbine engine. The
method also includes tuning a resonator coupled to a fluid path
upstream from the combustor based on the feedback.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] These and other features, aspects, and advantages of the
present invention will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0009] FIG. 1 is a block diagram of a turbine system having
resonators coupled to an air supply, a fuel supply and a diluent
supply to reduce combustor pressure oscillations in accordance with
certain embodiments of the present technique;
[0010] FIG. 2 is a cutaway side view of the turbine system, as
shown in FIG. 1, in accordance with certain embodiments of the
present technique;
[0011] FIG. 3 is a cutaway side view of the combustor, as shown in
FIG. 1, with resonators coupled to an air supply, a fuel supply and
a diluent supply to reduce combustor driven oscillations in
accordance with certain embodiments of the present technique;
[0012] FIG. 4 is a diagrammatical view of a Helmholtz resonator
coupled to the fuel supply, as shown in FIG. 1, in accordance with
certain embodiments of the present technique;
[0013] FIG. 5 is a diagrammatical view of a Helmholtz resonator
coupled to the air supply, as shown in FIG. 1, in accordance with
certain embodiments of the present technique;
[0014] FIG. 6 is a diagrammatical view of a Helmholtz resonator
coupled to the diluent supply, as shown in FIG. 1, in accordance
with certain embodiments of the present technique;
[0015] FIG. 7 is a diagrammatical view of multiple quarter wave
resonators coupled to the diluent supply, as shown in FIG. 1, in
accordance with certain embodiments of the present technique;
and
[0016] FIG. 8 is a diagrammatical view of an alternative quarter
wave resonator coupled to the diluent supply, as shown in FIG. 1,
in accordance with certain embodiments of the present
technique.
DETAILED DESCRIPTION OF THE INVENTION
[0017] One or more specific embodiments of the present invention
will be described below. In an effort to provide a concise
description of these embodiments, all features of an actual
implementation may not be described in the specification. It should
be appreciated that in the development of any such actual
implementation, as in any engineering or design project, numerous
implementation-specific decisions must be made to achieve the
developers' specific goals, such as compliance with system-related
and business-related constraints, which may vary from one
implementation to another. Moreover, it should be appreciated that
such a development effort might be complex and time consuming, but
would nevertheless be a routine undertaking of design, fabrication,
and manufacture for those of ordinary skill having the benefit of
this disclosure.
[0018] When introducing elements of various embodiments of the
present invention, the articles "a," "an," "the," and "said" are
intended to mean that there are one or more of the elements. The
terms "comprising," "including," and "having" are intended to be
inclusive and mean that there may be additional elements other than
the listed elements.
[0019] Embodiments of the present disclosure may reduce combustor
driven oscillations by dampening pressure fluctuations within fluid
supplies (e.g., liquid and/or gas lines). A geometrically
adjustable resonator may be coupled to each fluid supply (e.g.,
air, fuel or diluent) and tuned to a frequency of pressure
oscillation within the combustor. By coupling resonators to fluid
supplies instead of a combustion zone of the combustor, resonators
may be constructed of less temperature resistant materials because
they are not directly exposed to hot combustion gases. Certain
embodiments may include a controller configured to tune the
resonators to a frequency that dampens oscillations within the
fluid supplies and combustor. The controller may be communicatively
coupled to a pressure sensor in fluid communication with the
combustor to measure the frequencies of pressure oscillations. The
controller may also be communicatively coupled to the resonators,
and configured to tune the resonators to frequencies detected by
the pressure sensor. Resonators may include Helmholtz resonators
and/or quarter wave resonators, among others. In certain
embodiments, multiple resonators, tuned to different frequencies,
may be coupled to each fluid supply to dampen multiple frequencies
of pressure oscillations within the combustor.
[0020] Turning now to the drawings and referring first to FIG. 1, a
block diagram of an embodiment of a gas turbine system 10 is
illustrated. The diagram includes fuel nozzle 12, fuel supply 14,
and combustor 16. As depicted, fuel supply 14 routes a liquid
and/or gas fuel 18, such as natural gas, to the turbine system 10
through fuel supply 14 and fuel nozzle 12 into combustor 16. As
discussed below, fuel nozzle 12 is configured to inject fuel 18
into combustor 16. Air is injected directly into combustor 16 which
ignites and combusts a fuel-air mixture, and then passes hot
pressurized exhaust gas into a turbine 20. The exhaust gas passes
through turbine blades in turbine 20, thereby driving turbine 20 to
rotate. In turn, the coupling between blades in turbine 20 and
shaft 22 will cause the rotation of shaft 22, which is also coupled
to several components throughout turbine system 10, as illustrated.
Eventually, the exhaust of the combustion process may exit turbine
system 10 via exhaust outlet 24.
[0021] In an embodiment of turbine system 10, compressor vanes or
blades are included as components of compressor 26. Blades within
compressor 26 may be coupled to shaft 22, and will rotate as shaft
22 is driven to rotate by turbine 20. Compressor 26 may intake air
to turbine system 10 via air intake 28. Further, shaft 22 may be
coupled to load 30, which may be powered via rotation of shaft 22.
As appreciated, load 30 may be any suitable device that may
generate power via the rotational output of turbine system 10, such
as a power generation plant or an external mechanical load. For
example, load 30 may include an electrical generator, a propeller
of an airplane, and so forth. Air intake 28 draws air 32 into
turbine system 10 via a suitable mechanism, such as a cold air
intake, for subsequent mixture of air 32 with fuel 18 via combustor
16. As will be discussed in detail below, air 32 taken in by
turbine system 10 may be fed and compressed into pressurized air by
rotating blades within compressor 26. The pressurized air may then
be fed into combustor 16, as shown by arrow 34. Fuel may also be
fed into combustor 16 from fuel nozzle 12, as shown by arrow 36.
Combustor 16 may then mix the pressurized air and fuel to produce
an optimal mixture ratio for combustion, e.g., a combustion that
causes the fuel to more completely burn, so as not to waste fuel or
cause excess emissions.
[0022] Furthermore, a diluent 38 may be injected into fuel nozzle
12 or directly into combustor 16, as illustrated, via diluent
supply 40. Diluents may include steam, water, nitrogen and carbon
dioxide, among others. Diluent injection may reduce the emission of
oxides of nitrogen (NOx), particulates, oxides of sulfur (SOx)
and/or oxides of carbon (COx) when turbine system 10 operates at
reduced power. Diluents may also provide increased turbine
performance under certain operating conditions.
[0023] Turbine system 10 also includes resonators coupled to fluid
supplies which may reduce pressure oscillations within the fluid
supplies and combustor 16. Specifically, pressurized air 34 from
compressor 26 flows through an air supply 42 before entering
combustor 16. A resonator 44 is coupled to air supply 42 to dampen
air pressure oscillations. Similarly, a resonator 46 is coupled to
fuel supply 14 to dampen fuel pressure oscillations. In addition, a
resonator 48 is coupled to diluent supply 40 to dampen diluent
oscillations. By dampening oscillations within fluid supplies,
these resonators may reduce pressure oscillations within combustor
16, thereby protecting turbine system 10 against the possibility of
fatigue and premature wear to various components within combustor
16, and upstream and downstream of combustor 16.
[0024] However, due to varying combustor temperature and turbine
load conditions, the frequency of combustor driven oscillations may
vary with time. To compensate, the resonators may be geometrically
configurable such that they may be continuously tuned to dampen
combustor oscillations of varying frequency. In the present
embodiment, a controller 50 is communicatively coupled to each of
the resonators 44, 46 and 48, and to a pressure sensor 55 in fluid
communication with combustor 16. Controller 50 may be configured to
detect the frequency of pressure oscillations within combustor 16,
fuel supply 14, diluent supply 40 and/or air supply 42. In
alternative embodiments, controller 50 may also be configured to
detect the frequency of pressure oscillations downstream of
combustor 16, vibrations within turbine system 10, flame
temperature within combustor 16 and/or other parameters indicative
of pressure oscillations. Controller 50 may then tune the
resonators 44, 46 and 48 to match the detected frequency. In this
manner, fluid supply oscillations may be dampened, reducing the
magnitude of pressure oscillations within combustor 16.
[0025] FIG. 2 shows a cutaway side view of an embodiment of turbine
system 10. As depicted, the embodiment includes compressor 26,
which is coupled to an annular array of combustors 16. For example,
six combustors 16 are located in the illustrated turbine system 10.
Each combustor 16 includes one or more fuel nozzles 12, which feed
fuel to a combustion zone located within each combustor 16. For
example, each combustor 16 may include 1, 2, 3, 4, 5, 6, 7, 8, 9,
10, or more fuel nozzles 12 in an annular or other suitable
arrangement. Combustion of the air-fuel mixture within combustors
16 will cause vanes or blades within turbine 20 to rotate as
exhaust gas passes toward exhaust outlet 24. As will be discussed
in detail below, resonator 44 coupled to air supply 42, resonator
46 coupled to fuel supply 14 and resonator 48 coupled to diluent
supply 40 may reduce pressure oscillations within the respective
supplies and combustor 16.
[0026] FIG. 3 is a detailed cutaway side view illustration of an
embodiment of combustor 16. As depicted, combustor 16 includes fuel
nozzles 12 that are attached to end cover 52 at a base of combustor
16. An embodiment of combustor 16 may include five or six fuel
nozzles 12. Other embodiments of combustor 16 may use a single
large fuel nozzle 12. The surfaces and geometry of fuel nozzles 12
are designed to provide an optimal flow path for fuel as it flows
downstream into combustor 16, thereby enabling increased combustion
in the chamber, thus producing more power in the turbine engine.
The fuel is expelled from fuel nozzles 12 downstream in direction
54 and mixes with air before entering a combustion zone 56 inside
combustor casing 58. Combustion zone 56 is the location where
ignition of the air fuel mixture is most appropriate within
combustor 16. In addition, it is generally desirable to combust the
air-fuel mixture downstream of the base to reduce the heat transfer
from the combustion zone 56 to the fuel nozzles 12. In the
illustrated embodiment, combustion zone 56 is located inside
combustor casing 58, downstream from fuel nozzles 12 and upstream
from a transition piece 60, which directs the pressurized exhaust
gas toward turbine 20. Transition piece 60 includes a converging
section that enables a velocity increase as the combusted exhaust
flows out of combustor 16, producing a greater force to turn
turbine 20. In turn, the exhaust gas causes rotation of shaft 22 to
drive load 30. In an embodiment, combustor 16 also includes liner
62 located inside casing 58 to provide a hollow annular path for a
cooling air flow, which cools the casing 58 and liner 62 around
combustion zone 56. Liner 62 also may provide a suitable contour to
improve flow from fuel nozzles 12 to turbine 20.
[0027] FIG. 3 also presents the fluid supplies and associated
resonators 44, 46 and 48 disposed upstream from combustor 16.
Pressurized air from compressor 26 flows through air supply 42
before entering combustor 16. Resonator 44 is coupled to air supply
42 to dampen oscillations within air supply 42 and combustor 16.
Fuel enters combustor 16 through fuel supply 14. As seen in this
figure, resonator 46 is in fluid communication with fuel supply 14
and may serve to dampen oscillations within fuel supply 14, thereby
reducing combustor driven oscillations. Similarly, diluent enters
combustor 16 through diluent supply 40. Resonator 48 is coupled to
diluent supply 40 to dampen oscillations within diluent supply 40
and combustor 16. Resonators 44, 46 and 48 may be mounted at
various distances upstream from combustion zone 56. The resonators
depicted in FIG. 3 are geometrically variable Helmholtz resonators.
However, other embodiments may employ quarter wave and/or
concentric hole-cavity resonators, among others. Furthermore, each
fluid supply may include multiple resonators tuned to different
frequencies.
[0028] FIG. 4 shows a diagrammatical view of resonator 46 coupled
to fuel supply 14. As previously discussed, fuel supply 14 is
positioned upstream from combustor 16. In this configuration, fuel
flows in a downstream direction 51 through fuel supply 14 to
combustor 16. Pressure within fuel supply 14 may vary with time,
inducing oscillations within combustor 16. These oscillations may
be measured by a waveguide 53 and a pressure sensor 55 coupled to
combustor 16. A waveguide is a duct configured to propagate and
guide acoustical energy. Pressure fluctuations within combustor 16
induce corresponding oscillations of equal frequency within
waveguide 53. Sensor 55, coupled to waveguide 53, is configured to
measure these oscillations by detecting pressure variations within
waveguide 53. This arrangement may facilitate accurate pressure
measurement without directly exposing pressure sensor 55 to hot
combustion gases. Pressure sensor 55 may include a fiber optic
sensor, a mechanical deflection sensor, a piezoelectric sensor, or
a microelectromechanical systems (MEMS) sensor, among others.
[0029] Pressure sensor 55 transmits pressure measurements to
controller 50 by an electrical connection or wireless transmission,
for example. Controller 50, in turn, analyzes the pressure
measurements and determines the dominant frequencies of pressure
oscillation within combustor 16. For example, controller 50 may
perform a fast Fourier transformation (FFT) on the pressure signal
from pressure sensor 55. This transformation converts a time domain
pressure signal into the frequency domain. In other words,
controller 50 establishes a relationship between acoustical energy
and frequency within combustor 16. Controller 50 may then determine
the dominant frequency or frequencies of pressure oscillation. For
example, controller 50 may identify a single frequency that emits
the greatest acoustical energy. Controller 50 may then tune
resonator 46 to this frequency to dampen oscillations within
combustor 16. Alternatively, controller 50 may be configured with
an established threshold acoustical energy. Any frequency emitting
acoustical energy above this threshold may be considered a dominant
frequency. In configurations employing multiple resonators,
controller 50 may tune each resonator to a respective dominant
frequency. In this manner, multiple dominant frequencies within
combustor 16 may be dampened.
[0030] Controller 50 is also communicatively coupled to resonator
46 by an electrical connection or wireless transmission, for
example. As previously discussed, resonator 46 may be geometrically
configurable such that it may be tuned to a desired frequency. As
such, controller 50 may send a signal to resonator 46 indicating
the desired frequency to dampen oscillations within combustor 16.
Resonator 46 may, in turn, alter its geometric configuration to
correspond to the desired frequency. In one embodiment, controller
50 tunes resonator 46 to a dominant frequency within combustor 16.
However, as appreciated, controller 50 may tune resonator 46 to any
desired frequency which reduces combustor oscillations.
[0031] A resonator is an acoustical chamber that induces a
pressurized fluid to oscillate at a particular frequency. The
geometric configuration of the resonator directly determines the
frequency of oscillation. If the fluid pressure is fluctuating due
to the influence of an external force, a resonator, tuned to the
frequency of these fluctuations, may dampen the magnitude of the
fluctuations. One type of resonator is a Helmholtz resonator. A
Helmholtz resonator includes a body and a throat having a smaller
diameter than the body. Pressurized fluid entering the throat is
collected in the body until the pressure within the body becomes
greater than the external fluid pressure. At that point, the fluid
within the body exits the throat, thereby reducing the pressure
within the body. The lower body pressure induces the fluid to enter
the body, where the process repeats. The cyclic movement of air
establishes a resonant frequency of the Helmholtz resonator.
[0032] In the embodiment depicted in FIG. 4, resonator 46 is a
cylindrical Helmholtz resonator, including a body 57 and a throat
59. A volume 61 is defined by resonator body 57, a base member 63
and a piston 64 inserted into an open end of resonator body 57. As
appreciated, resonant frequency of a Helmholtz resonator is
determined by the geometric configuration of the resonator.
Specifically, a cylindrical Helmholtz resonator produces a resonant
frequency based on the following equation:
f = c 2 .pi. d 2 LHD 2 ##EQU00001##
where c is the speed of sound through the fluid (e.g., air, fuel,
or diluent), d is the diameter of throat 59, L is the length of
throat 59, H is the distance between piston 64 and base member 63
of resonator body 57, and D is the diameter of resonator body 57.
In the present embodiment, throat diameter d, throat length L and
resonator body diameter D are fixed. Therefore, resonant frequency
f of resonator 46 may be adjusted by altering height H. Height H
may be decreased by translating piston 64 along an axis 66 in a
direction 68 toward base member 63. Alternatively, height H may be
increased by translating piston 64 in a direction 70 along axis 66
away from base member 63. In this manner, resonant frequency f may
be adjusted to any frequency within the geometric constraints of
resonator 46.
[0033] Piston 64 is coupled to shaft 72 which passes through piston
driver 74. Piston driver 74 may be any form of linear actuator
capable of translating piston 64 via shaft 72. For example, shaft
72 may include a rack with teeth configured to interlock with
respective teeth of a pinion within driver 74. The pinion may be
coupled to an electric motor, for example, configured to rotate the
pinion based on controller input. As the pinion rotates, piston 64
may be linearly driven by the rack of shaft 72. Other linear
actuators (e.g., screw drive, pneumatic, hydraulic,
electromechanical, etc.) may be employed in alternative
embodiments.
[0034] Tuning resonator 46 to a dominant frequency of combustor 16
may reduce combustor driven oscillations by dampening pressure
oscillations within fuel supply 14. For example, pressure within
fuel supply 14 may oscillate based on variations in fuel pump
speed, turbulent flow and/or back pressure fluctuations, among
other causes. These fuel pressure oscillations may drive
corresponding oscillations within combustor 16 at a substantially
similar frequency. Therefore, tuning resonator 46 to a dominant
frequency of combustor 16 may dampen oscillations within fuel
supply 14 and combustor 16. Furthermore, if fuel supply 14 includes
multiple resonators, each resonator may be tuned to a dominant
frequency within combustor 16. For example, certain embodiments may
employ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more resonators, each
tuned to a different frequency. The resonators may be arranged in
parallel about a particular axial position of fuel supply 14, in
series along the length of fuel supply 14, or a combination
thereof. In this manner, multiple frequencies may be simultaneously
dampened.
[0035] FIG. 5 shows a diagrammatical view of air supply resonator
44. As previously discussed, air supply 42 is positioned upstream
from combustor 16. In this configuration, air enters combustor 16
in a direction 75 and then flows in a downstream direction 77
between combustor casing 58 and liner 62. The air then mixes with
fuel flowing in the downstream direction 51 from fuel supply 14.
FIG. 5 presents an alternative location of resonator 44, directly
mounted to combustor casing 58. Coupling resonator 44 to combustor
casing 58 may serve to dampen oscillations within combustor 16
because pressure oscillations within air supply 42 may propagate
downstream through combustor casing 58 before entering combustor
zone 56. Therefore, coupling resonator 44 to combustor casing 58
may dampen air pressure oscillations prior to inducing combustor
driven oscillations. Similar to resonator 46 depicted in FIG. 4,
Helmholtz resonator 44 includes a body 76, a throat 78, an interior
volume 80, a base 82 and a piston 84. Interior volume 80 may be
varied by translating piston 84 along an axis 86 in a direction 88
toward base 82, or a direction 90 along axis 86 away from base 82.
Piston 84 is translated via a shaft 92 and a piston driver 94. In
this manner, resonator 44 may be tuned to dampen oscillations
within air supply 42 and combustor 16.
[0036] As depicted in FIG. 5, combustor 16 includes a waveguide 53
and pressure sensor 55. Pressure sensor 55 is communicatively
coupled to controller 50. Controller 50, in turn, is
communicatively coupled to piston driver 94. In this configuration,
controller 50 may determine the dominant frequencies within
combustor 16 and instruct piston driver 94 to tune resonator 44 to
the appropriate frequency to dampen oscillations within combustor
16.
[0037] Mounting resonator 44 to combustor casing 58 may provide
enhanced dampening of oscillations within combustor 16 compared to
coupling resonator 44 to air supply 42. Furthermore, as shown in
FIG. 5, resonator 44 is mounted adjacent to a diluent inlet 96.
This configuration may further enhance dampening of combustor
pressure oscillations.
[0038] While only one resonator 44 is present in the embodiment
depicted in FIG. 5, other embodiments may employ several resonators
to dampen multiple frequencies within air supply 42 and combustor
16. For example, certain embodiments may employ 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, or more resonators, each tuned to a different
frequency. Furthermore, these resonators may be mounted to air
supply 42 and/or combustor casing 58. For example, the resonators
may be arranged about the circumference and/or along the
longitudinal axis of combustor casing 58 and/or air supply 42.
[0039] FIG. 6 shows a diagrammatical view of diluent resonator 48.
As previously discussed, diluent supply 40 is positioned upstream
from combustor 16. In this configuration, diluent flows in a
downstream direction 97 through diluent supply 40 to combustor 16.
As illustrated, diluent then mixes with air flowing in the
downstream direction 77 prior to entering combustion zone 56. In
alternative embodiments, diluent may flow in a downstream direction
directly into fuel nozzle 12. Similar to resonator 46 depicted in
FIG. 4, Helmholtz resonator 48 includes a body 98, a throat 100, an
interior volume 102, a base 104 and a piston 106. Interior volume
102 may be varied by translating piston 106 along an axis 108 in a
direction 110 toward base 104, or a direction 112 along axis 108
away from base 104. Piston 106 may be translated via a shaft 114
and a piston driver 116. In this manner, resonator 48 may be tuned
to dampen oscillations within diluent supply 40 and combustor
16.
[0040] As depicted in FIG. 6, combustor 16 includes a waveguide 53
and pressure sensor 55. Pressure sensor 55 is communicatively
coupled to controller 50. Controller 50, in turn, is
communicatively coupled to piston driver 116. In this
configuration, controller 50 may determine the dominant frequencies
within combustor 16 and instruct piston driver 116 to tune
resonator 48 to the appropriate frequency to dampen oscillations
within combustor 16.
[0041] While only one resonator 48 is present in the embodiment
depicted in FIG. 6, other embodiments may employ multiple
resonators 48 to dampen multiple frequencies with diluent supply 40
and combustor 16. Furthermore, while cylindrical Helmholtz
resonators are depicted in the embodiments of FIGS. 4-6, other
cross sections (e.g., polygonal, elliptical, etc.) may be employed
in alternative embodiments. In addition, further embodiments may
employ a combination of resonators depicted in FIGS. 4-6. For
example, certain embodiments may include resonator 46 coupled to
fuel supply 14, resonator 44 coupled to combustor casing 58 and
resonator 48 coupled to diluent supply 40. Each of these resonators
may be communicatively coupled to controller 50. Furthermore,
controller 50 may tune each of the resonators to the same frequency
or different frequencies based on an analysis of combustor
oscillations. For example, controller 50 may determine that a first
combustor oscillation frequency is driven by diluent supply 40 and
a second combustor oscillation frequency is driven by air supply
42. Controller 50 may then tune diluent supply resonator 48 to the
first frequency and air supply resonator 44 to the second
frequency. In this manner, both combustor oscillation frequencies
may be dampened.
[0042] FIG. 7 presents an alternative embodiment of diluent
resonator 48. In this embodiment, resonator 48 includes multiple
quarter wave resonators, 118, 124 and 134. Quarter wave resonator
118 includes a tube of height A that terminates in an end cap 120.
Resonator 118 also includes an isolation valve 122 which may open
to couple resonator 118 to diluent supply 40. When isolation valve
122 is closed, resonator 118 is isolated from diluent supply 40,
effectively uncoupling resonator 118 from diluent supply 40.
[0043] As the name implies, a quarter wave resonator is tuned to a
quarter of the wavelength of an acoustical oscillation. Therefore,
the resonant frequency of quarter wave resonator 118 is as
follows:
f = c 4 A ##EQU00002##
where c is the speed of sound in the fluid (e.g., air, fuel or
diluent), and A is the height of resonator 118. Consequently,
resonator 118 may dampen a frequency corresponding to a wavelength
four times height A.
[0044] Similarly, resonator 124 terminating in end cap 126 may
dampen a frequency corresponding to a wavelength four times height
B. Resonator 124 includes an isolation valve 128 to facilitate
uncoupling of resonator 124 from diluent supply 40. Under certain
operating conditions combustor pressure oscillations may include
multiple dominant frequencies. For example, combustor 16 may
experience pressure oscillations at frequencies corresponding to
wavelengths four times greater than height A and four times greater
than height B. In such a situations, both isolation valves 122 and
128 may be opened such that resonators 118 and 124 may dampen the
oscillations at both frequencies. In other operating conditions,
combustor 16 may only experience oscillations corresponding to a
wavelength four times greater than height A. In such a situation,
isolation valve 128 may be closed to uncouple resonator 124 from
diluent supply 40. Leaving isolation valve 128 open when no
pressure oscillation corresponding to a wavelength four times
height B is present in combustor 16 may have a detrimental effect
on diluent flow.
[0045] As previously discussed, the resonant frequency of quarter
wave resonators is dependent on tube length. Therefore, a quarter
wave resonator may be tuned by increasing or decreasing its length.
One method of changing resonator length is through a series of
valves. For example, resonator 124 includes a lower valve 130 and
an upper valve 132. Valve 130 is located a height F above diluent
supply 40, while valve 132 is at height E. These valves may be
opened and closed to adjust the effective length of resonator 124.
If valve 130 is closed while valve 128 is open, resonator 124 may
dampen oscillations corresponding to a wavelength four times height
F. If valves 128 and 130 are open while valve 132 is closed,
resonator 124 may dampen oscillations corresponding to a wavelength
four times height E. If all three valves 128, 130 and 132 are
opened, resonator 124 may dampen oscillations corresponding to a
wavelength four times height B.
[0046] Diluent supply 40 also includes a third resonator 134 having
an end cap 136. Similar to resonator 124, resonator 134 includes an
isolation valve 138 and two length adjusting valves 140 and 142. As
previously discussed, if isolation valve 138 is closed, resonator
134 may be isolated from diluent supply 40, nullifying the effect
of resonator 134. However, if isolation valve 138 and length
adjusting valves 140 and 142 are open, resonator 134 may dampen
frequencies corresponding to a wavelength four times height C of
resonator 134. The effective height of resonator 134 depends on the
state of valves 140 and 142. Specifically, if valves 140 and 142
are open, resonator 134 may dampen oscillations corresponding to
four times height C, the distance between diluent supply 40 and end
cap 136. If valves 138 and 140 are open while valve 142 is closed,
the effective height of resonator 134 decreases to a height G. If
valve 140 is closed while valve 138 is open, the effective height
of resonator 134 further decreases to height I. In this manner,
resonator 134 may be tuned to a desired frequency based on dominant
frequencies detected within combustor 16.
[0047] While three quarter wave resonators are employed in the
embodiment depicted in FIG. 7, other embodiments may include more
or fewer resonators (e.g., 1, 2, 4, 5, 6, 7, 8, 9, 10, or more).
For example, certain turbine system configurations may produce four
dominant frequencies within combustor 16. In such a system, four
resonators may be coupled to diluent supply 40 to dampen
oscillations at each of these four frequencies. Other turbine
system configurations may employ two resonators to dampen two
dominant frequencies. Furthermore, because individual resonators
may be decoupled by closing isolation valves, a turbine system that
produces two dominant frequencies may include more than two
resonators coupled to diluent supply 40. In such a configuration,
additional frequencies may be dampened by opening the isolations
valves of the previously uncoupled resonators.
[0048] Other embodiments may include a different number of valves
within each resonator. For example, resonators may include 1, 2, 3,
4, 5, 6, 7, 8, 9, 10, or more valves, in certain embodiments.
Furthermore, the height and spacing between each valve may vary.
Specifically, tighter spacing between valves facilitates greater
control of the effective length of the resonators. In addition,
operation of the valves may be controlled by controller 50. For
example, controller 50 may determine the number of dominant
frequencies and open a corresponding number of isolation valves.
Similarly, controller 50 may adjust the resonant frequency of each
resonator to correspond to each dominant frequency detected within
combustor 16 by opening and closing length adjusting valves. While
the quarter wave resonators shown in FIG. 7 are disposed to diluent
supply 40, a similar configuration may be employed for air supply
resonator 44 and/or fuel supply resonator 46.
[0049] FIG. 8 illustrates an alternative configuration for varying
the height of quarter wave resonator 48. Instead of employing a
series of valves, resonator height may be continuously varied. In
this embodiment, resonator 48 includes a base member 144 coupled to
diluent supply 40, and an adjustable end cap 146 disposed about an
open end of base member 144. The cross section of base member 144
and end cap 146 may be circular or polygonal, among other
configurations. The outer diameter of base member 144 may be
substantially similar to the inner diameter of end cap 146 to
establish a seal. The seal may substantially block passage of fluid
between base member 144 and end cap 146, while enabling end cap 146
to translate with respect to base member 144.
[0050] A height J of resonator 48 may be adjusted by translating
end cap 146 along axis 148. Specifically, if end cap 146 is
translated in a direction 150 along axis 148, height J is reduced.
If end cap 146 is translated in a direction 152 along axis 148,
height J is increased. End cap 146 may be coupled to a linear
actuator 154 configured to translate end cap 146 in both directions
150 and 152 along axis 148. Linear actuator 154 may be any suitable
type such as pneumatic, hydraulic, or electromechanical, among
others. In this configuration, height J of resonator 48 may be
adjusted to dampen a diluent pressure oscillation frequency,
reducing combustor driven oscillations.
[0051] Linear actuator 154 may be communicatively coupled to the
controller 50 and continuously tuned to a frequency that dampens
combustor oscillations. In addition, several resonators of this
configuration may be coupled to diluent supply 40 to dampen
multiple frequencies. Furthermore, in certain embodiments,
continuously variable quarter wave resonators may be combined with
valve-adjustable quarter wave resonators and/or non-adjustable
quarter wave resonators to dampen oscillations of multiple
frequencies. Furthermore, continuously variable quarter wave
resonators may be employed to dampen oscillations within air supply
42 and/or fuel supply 14.
[0052] Other acoustical resonator configurations (e.g., concentric
hole-cavity resonators) may be employed in alternative embodiments.
Furthermore, combinations of different resonator types may be
employed throughout the turbine system and/or among the fluid
supplies. For example, in certain embodiments, air supply 42 may
employ a Helmholtz resonator while fuel supply 14 and diluent
supply 40 may employ quarter wave resonators. In other embodiments,
air supply 42 may employ a Helmholtz resonator and a quarter wave
resonator to dampen multiple frequencies. Furthermore, the number
of resonators may vary between fluid supplies. For example, air
supply 42 may include a single resonator, fuel supply 14 may
include three resonators and diluent supply 40 may not include any
resonators.
[0053] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *