U.S. patent application number 14/240549 was filed with the patent office on 2014-11-27 for combustion chamber for a gas turbine plant.
This patent application is currently assigned to SIEMENS AKTIENGESELLSCHAFT. The applicant listed for this patent is Sebastian Pfadler. Invention is credited to Sebastian Pfadler.
Application Number | 20140345282 14/240549 |
Document ID | / |
Family ID | 46690502 |
Filed Date | 2014-11-27 |
United States Patent
Application |
20140345282 |
Kind Code |
A1 |
Pfadler; Sebastian |
November 27, 2014 |
COMBUSTION CHAMBER FOR A GAS TURBINE PLANT
Abstract
A combustion chamber (1) for a gas turbine plant having a
combustion chamber wall (10), through which combustion gases (G)
flow in the direction of a downstream gas turbine, wherein the
combustion chamber wall (10) has a dampening device (20) for
dampening thermoacoustic vibrations caused by the combustion gases
(G) and wherein the dampening device (20) comprises at least one
Helmholtz resonator. The resonator volume (21) opens into the
combustion chamber (1) with the resonator tube opening (M) in the
combustion chamber. At least one supply opening (23) with which
sealing air (S) for sealing the resonator tube opening (M) is
introduced into the combustion chamber (1) via the resonator volume
(21) and an at least one resonator tube (22, 22', 22'') from a
compressor plenum (2). The at least one resonator tube (22, 22',
22'') from a compressor plenum (2). The at least one resonator tube
(22', 22'') has a tube axis (A) in the combustion chamber wall and
the axis (A) lies outside of a surface normal (N) of the combustion
chamber wall (10) at the site of the resonator tube opening
(M).
Inventors: |
Pfadler; Sebastian; (Mulheim
an der Ruhr, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pfadler; Sebastian |
Mulheim an der Ruhr |
|
DE |
|
|
Assignee: |
SIEMENS AKTIENGESELLSCHAFT
Munchen
DE
|
Family ID: |
46690502 |
Appl. No.: |
14/240549 |
Filed: |
August 14, 2012 |
PCT Filed: |
August 14, 2012 |
PCT NO: |
PCT/EP2012/065856 |
371 Date: |
May 23, 2014 |
Current U.S.
Class: |
60/725 |
Current CPC
Class: |
F23R 3/16 20130101; F23R
3/002 20130101; F23R 2900/00014 20130101; F23M 20/005 20150115 |
Class at
Publication: |
60/725 |
International
Class: |
F23R 3/16 20060101
F23R003/16 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 1, 2011 |
DE |
10 2011 081 963.0 |
Claims
1. A burner with a combustion chamber for a gas turbine plant, the
combustion chamber includes: a combustion chamber wall , through
which combustion gases flow in a direction of a following gas
turbine; the combustion chamber wall having a damping device for
the damping of thermoacoustic vibrations caused by combustion
gases, the damping device comprising at least one Helmholtz
resonator which is configured such that a resonator volume thereof
lies on a side of the combustion chamber wall that faces away from
an inner side of the combustion chamber wall; the resonator has at
least one resonator tube in the combustion chamber wall, the tube
co-operates with internal volume of the resonator, and the
resonator tube has a mouth lying opposite the resonator volume on
the inner side of the combustion chamber wall and exits into the
combustion chamber; at least one delivery port into the resonator
configured for entry of barrier air in such manner as for barring
the resonator tube mouth from a compressor plenum that surrounds
the combustion chamber, wherein the barrier air is introduced into
the combustion chamber via the resonator volume and then by the at
least one resonator tube; and the at least one resonator tube has a
resonator tube axis in the combustion chamber wall such that, at
the location of a resonator tube mouth, which is into the
combustion chamber, the resonator tube axis lies outside a normal
to the surface of and oblique to the combustion chamber inner
wall.
2. The burner with a combustion chamber as claimed in claim 1,
wherein the resonator tube axis of the resonator tube is inclined
away from a surface of the inner wall normal, in an upstream
direction or a downstream direction of the combustion gases flowing
through the combustion chamber.
3. The burner with a combustion chamber as claimed in claim 2,
wherein there is flow in the combustion chamber past the inner wall
thereof from the upstream to the downstream directions; the
resonator tube axes of upstream inclined direction resonator tubes
of the Helmholtz resonator are inclined in the upstream direction,
and the resonator tube axes of downstream inclined direction
resonator tubes of the Helmholtz resonator are inclined in the
downstream direction.
4. The burner with a combustion chamber as claimed in claim 1,
wherein the damping device comprises a multiplicity of Helmholtz
resonators which are arranged over a circumference of the
combustion chamber wall, that the resonators are distributed on at
least one ring transversely to the combustion gases flowing
through.
5. The burner with a combustion chamber as claimed in claim 4,
wherein the upstream inclined resonator tubes are assigned to the
Helmholtz resonators of a first ring thereof and the downstream
inclined resonator tubes inclined downstream are assigned to the
Helmholtz resonators of a second ring lying downstream.
6. A gas turbine plant comprising: the burner of claim 1 for
admixing of fuel and for combustion of the fuel/air mixture; a
compressor for the compression of sucked-in air, a combustion
chamber following the compressor and receiving the air after
compression of the air; and an expansion turbine which follows the
burner and which converts the combustion exhaust gases of the burnt
fuel/air mixture into mechanical energy.
Description
[0001] The invention relates to a combustion chamber for a gas
turbine plant according to the preamble of claim 1 and to a
correspondingly designed gas turbine plant according to claim
6.
[0002] Gas turbine plants are composed essentially of a compressor,
of a combustion chamber with a burner and of an expansion turbine.
In the compressor, sucked-in air is compressed before it is mixed
with fuel in the combustion chamber in the following burner
arranged in the compressor plenum, and this mixture is burnt. The
expansion turbine following the combustion chamber then extracts
thermal energy from the combustion exhaust gases which have
occurred in the burner and converts this into mechanical energy. A
generator capable of being coupled to the expansion turbine can
convert this mechanical energy into electrical energy for current
generation.
[0003] Nowadays, gas turbine plants, like other current-generating
plants, too, must have, when working at maximum efficiency,
pollutant emissions which are as low as possible in all load
ranges. Major influencing variables are in this case the mass flow
rates, set in the combustion chamber of the burner, of the fuel, of
the compressed air and of the cooling air delivered for cooling the
burner components. However, the limitation of pollutant emissions,
in particular of NOx and unburnt fuel mostly in the form of CO, may
in this case lead to a minimization of the quantity of cooling air
or of leakage air in the combustion chamber and consequently to
parasitic flows which have an acoustically damping effect.
Furthermore, under the boundary condition of limiting the
emissions, an increase in efficiency also usually entails an
increase in the volumetric heat release density in the combustion
chamber. The two together, that is to say a reduction in acoustic
damping and an increase in the heat release density in the
combustion chamber, lead to a higher risk that thermoacoustically
induced vibrations commence.
[0004] However, thermoacoustic vibrations of this kind in the
combustion chamber present a problem in the design and, in
particular, in the operation of gas turbine plants.
[0005] To reduce such thermoacoustic vibrations, Helmholtz
resonators, which are composed of at least one resonator tube and
of a resonator volume, are employed nowadays for damping. Helmholtz
resonators of this kind damp the amplitude of vibrations at the
Helmholtz frequency in specific frequency ranges as a function of
the cross-sectional area and the length of the resonator tube and
of the resonator volume. Helmholtz resonators as damping devices
for limiting thermoacoustic vibrations in combustion chambers are
known, for example, from EP 1 605 209 A1 or US 2007/0125089 A1.
[0006] FIG. 1 shows, for example, the arrangement, known from US
2007/0125089 A1, of Helmholtz resonators 20 on a ring of the
combustion chamber wall 10 transverse to the flow direction. The
combustion chamber wall 10 is in this case of tubular form and
separates the combustion chamber 1 from the surrounding compressor
plenum 2. The perforations 22 in the combustion chamber wall 10
between the resonator volume 21 and combustion chamber 1 form the
resonator tubes of the Helmholtz resonators.
[0007] In this case, as illustrated in FIG. 1, each Helmholtz
resonator may have a plurality of resonator tubes or else only a
single resonator tube. So that none of the hot combustion gases
from the combustion chamber 1 are introduced into the Helmholtz
resonators 20, additional ports for the delivery of barrier air are
provided. In the exemplary embodiment shown in FIG. 1, these
delivery ports 23 are arranged on that wall of the resonator volume
21 which lies opposite the resonator tubes 22. These ports 23 make
it possible that compressed air S can flow out of the compressor
plenum 2 surrounding the combustion chamber into the resonator
volume 21 and from there, via the resonator tubes 22, into the
combustion chamber 1, thus barring the infiltration of hot
combustion gases into the resonator tubes 22.
[0008] However, Helmholtz resonators with deliveries of barrier air
via the volume body have the disadvantage that the barrier air
flows via the resonator tubes into the combustion chamber and
consequently influences the air/fuel mixture prevailing there.
Precisely where known designs are concerned, in which the resonator
tubes are arranged in the combustion chamber wall such that, on the
location where the resonator tubes issue into the combustion
chamber, the resonator tube axis comes to lie in the normal to the
surface of the combustion chamber inner wall, barrier air is
introduced with a maximum depth of penetration into the combustion
space of the combustion chamber. However, this maximum cross
current in relation to the internal flow of the combustion chamber
may lead, precisely in the low load range of the gas turbine plant,
to partial quenching of combustion and consequently to an increase
in CO pollutant emission.
[0009] The object of the invention is to provide a combustion
chamber which overcomes the disadvantages described above.
[0010] This object is achieved by means of the combustion chamber
having the features of claim 1.
[0011] Since a combustion chamber, designed according to the
preamble of claim 1, with at least one Helmholtz resonator has at
least one resonator tube which is arranged such that, at the
location of issue of the resonator tube into the combustion
chamber, it lies with its resonator tube axis outside a normal to
the surface of the combustion chamber inner wall, the maximum depth
of penetration of the barrier air into the combustion space of the
combustion chamber is reduced, the more so, the further the
resonator tube axis is inclined in relation to the surface normal.
Combustion in the combustion chamber is thereby influenced to a
lesser extent, so that an increase in pollutant emission, in
particular increased CO emission when the gas turbine plant is
under part load, can be largely avoided.
[0012] At the same time, with an increasing inclination angle, a
region with film cooling is formed increasingly on the combustion
chamber inner wall by the injected barrier air. Since the air
flowing in from the compressor plenum via the Helmholtz resonator
is colder than the combustion gases in the combustion chamber, an
improved capacity for cooling the combustion chamber wall can thus
be achieved. At larger inclination angles, in particular at
inclination angles of approximately 45 degrees or more, between the
normal to the surface of the inside of the combustion chamber wall
and the resonator tube axis in the downstream direction, a
significant part of the barrier air flowing in via the resonator
tube is entrained by the flow inside the combustion chamber and
flows downstream along the combustion chamber inner wall, near the
wall, so as to have a cooling effect over a larger region, before
the barrier air is mixed more and more with the combustion gases
and therefore assumes the same temperature as the combustion gases.
Moreover, with an increasing inclination angle, the resonator tubes
become increasingly longer, with the result that ever better
convection cooling of the combustion chamber wall is achieved.
[0013] Further preferred exemplary embodiments may be gathered from
the subclaims. What is essential in all the combustion chamber
versions is that a zone for mixing the cooler barrier air with the
hot mass flows is configured in the combustion chamber such that,
particularly in the low load range, partial quenching of combustion
by the cooler barrier air is suppressed, but without the damping
properties of the Helmholtz resonators being influenced. Gas
turbine plants equipped with such combustion chambers can thus have
as low pollutant emissions as possible in all load ranges, while
working at maximum efficiency.
[0014] The invention is in this case not restricted to the
inclination of the resonator tubes being solely in the flow
direction of the combustion exhaust gases. On the contrary, without
any further restriction of the present invention, versions may also
be envisaged in which the resonator tubes have in relation to the
normal to the surface of the combustion chamber inner wall an
inclination which is composed both of an inclination fraction in
the flow direction and of an inclination fraction transversely
thereto.
[0015] The resonator tubes can thus be adapted optimally to the
local conditions of the internal flow of the combustion
chamber.
[0016] The invention, then, may be explained by way of example by
means of the following figures in which:
[0017] FIG. 1 shows diagrammatically a damping device known from
the prior art,
[0018] FIG. 2 shows diagrammatically a first version according to
the invention of a damping device,
[0019] FIG. 3 shows diagrammatically a second version according to
the invention of a damping device.
[0020] The concept according to the invention for injecting barrier
air S into the combustion space of the combustion chamber 1 of a
gas turbine plant is described below, by way of example, by means
of a burner which is based on a tubular combustion chamber and in
which the damping device 20 is adapted essentially to the outside
of the combustion chamber wall 10. However, the invention is also
just as suitable for use in burners in which the damping device 20
is integrated completely in the combustion chamber wall 10, or else
in any other version in which barrier air S is delivered via the
damping device 20.
[0021] FIG. 2 illustrates a detail of a combustion chamber 1 along
the flow direction of the combustion gases G, with a routing of
barrier air in which, in contrast to the prior art, the barrier air
S is routed into the combustion space 1 at an angle .alpha. larger
than zero degrees (here approximately 45 degrees) in relation to
the normal N to the surface of the combustion chamber inner wall of
the combustion chamber 10. As a result, the depth of penetration of
the barrier air S into the combustion chamber 1 can be reduced
significantly, and moreover the zone of the mixing of the barrier
air S with the combustion gases G is relieved axially.
Consequently, that region of the combustion chamber internal flow
which is intermixed with cooler barrier air is made smaller, thus
leading, overall, to a marked reduction in pollutant emission. At
the same time, by the flow being routed near the surface on the
combustion chamber inner wall, a region B is formed, in which
significant mixing between cooler barrier air S and the combustion
gases G has not yet taken place, so that, in addition, the film
cooling properties of the injected barrier air S can be improved,
with the result that the thermal load upon the combustion chamber
walls can be reduced.
[0022] Since, due to the oblique arrangement of the resonator
tubes, the damping properties of the Helmholtz resonators may, with
the resonator volume otherwise being the same and with the number
of resonator tubes kept constant, deviate from those of the
Helmholtz resonators known from the prior art and having
perpendicular injection, it is usually necessary for the damping
properties of the resonator parameters to be adapted. This may take
place, for example, by a variation in the number of resonator tubes
22' and/or the delivery ports 23 and/or their diameters or by a
change in the resonator volume 21.
[0023] In the event that a combination with a plurality of
Helmholtz resonators composed of resonators having different
Helmholtz frequencies and therefore different damping properties is
employed, it is recommended that subsets with Helmholtz resonators
of a different type be formed. FIG. 3 illustrates the case where
Helmholtz resonators of a different type are arranged in different
axial positions of the combustion chamber. The variant illustrated
here is aimed at injecting part of the barrier air S as far
upstream as possible, that is to say in the direction of the heat
release zone (resonator type 1), and at injecting part of the
barrier air S as far downstream as possible (resonator type 2). For
this purpose, the Helmholtz resonators of type 1 arranged on a
first ring around the tubular combustion chamber have resonator
tubes 22'', the axes A of which are inclined at an angle .alpha. in
the upstream direction to the normal N to the surface of the
combustion chamber inner wall, and the Helmholtz resonators of type
2 arranged in a second ring have resonator tubes 22', the axes A of
which are inclined at an angle .alpha. in the downstream direction
to the surface normal N.
[0024] As a result, on the one hand, as near-wall a flow as
possible for intensified film cooling B can be achieved by the ring
having type 2 resonators and at the same time further superposed
film cooling B' can be achieved with the ring having type 1
resonators, and this can lead, overall, to a reduction in barrier
air. However, the invention is in this case not restricted only to
the embodiment illustrated in FIG. 2. On the contrary, it is also
intended to embrace versions which are composed, for example, only
of type 1 or type 2 resonators or else of resonator types with
different inclination angles .alpha.. It may just as well be
envisaged that a ring already has various resonator types over the
circumference of the combustion chamber wall, in order thereby to
achieve optimal adaptation to the local conditions of the internal
flow of the combustion chamber.
* * * * *