U.S. patent application number 10/311251 was filed with the patent office on 2003-09-11 for transition piece for non-annular gas turbine combustion chambers.
Invention is credited to Coppola, Alessandro.
Application Number | 20030167776 10/311251 |
Document ID | / |
Family ID | 11445283 |
Filed Date | 2003-09-11 |
United States Patent
Application |
20030167776 |
Kind Code |
A1 |
Coppola, Alessandro |
September 11, 2003 |
Transition piece for non-annular gas turbine combustion
chambers
Abstract
A transition piece (10) for non-annular gas turbine combustion
chambers has a projecting connection arm (22) for support on the
turbine stator, wherein the projecting connection arm (22) makes it
possible to obtain a lead-in axis with an angle of between
5.degree. and 7.degree. relative to an axis, which is parallel to
the axis of the machine, and is perpendicular to the plane on which
there lies the frame for interfacing of the transition piece (10)
with the ring of nozzles of the first stage of the gas turbine.
Inventors: |
Coppola, Alessandro; (Prato,
IT) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
1100 N GLEBE ROAD
8TH FLOOR
ARLINGTON
VA
22201-4714
US
|
Family ID: |
11445283 |
Appl. No.: |
10/311251 |
Filed: |
March 19, 2003 |
PCT Filed: |
June 8, 2001 |
PCT NO: |
PCT/EP01/06484 |
Current U.S.
Class: |
60/800 ;
60/752 |
Current CPC
Class: |
F01D 9/023 20130101 |
Class at
Publication: |
60/800 ;
60/752 |
International
Class: |
F23R 003/42 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 16, 2000 |
IT |
MI00A001362 |
Claims
1. A transition piece (10) for non-annular gas turbine combustion
chambers, suitable for connection between a non-annular gas turbine
combustor (25) and a first stage (17) of the gas turbine (18), said
transition piece (10) comprising a tubular body (11) with a
cylindrical section (13), having an upstream end (14) for
connection to the gas turbine combustor (25) and a downstream end
(16), surrounding a flow aperture (15), for connection to the
turbine (18) first stage (17), characterised in that a mount
connector device (22) is provided on the transition piece (10),
said mount connector device (22) comprising a tubular projection
protruding upwardly from the body (11) of the transition piece (10)
and then curving in a rearward direction for securing the
transition piece (10) to said first stage (17) of the gas turbine
(18), said transition piece (10) thus having a geometric profile so
that the direction of the gas flow flowing at said upstream end
(14) forms an angle of 5-7 degrees with an axis perpendicular to
the plane on which said flow aperture (15) lies.
2. A transition piece (10) according to claim 1, characterised in
that said cylindrical section (13) has an anti-wear deposit, made
of Stellite 6 or another similar material, at said upstream end
(14).
3. A transition piece (10) according to claim 1, characterised in
that a deposit of the TBC type is provided on the inner surface of
the transition piece (10).
4. A transition piece (10) according to claim 1, characterised in
that said tubular body (11) is made of Nimonic 263 or Hastelloy-X.
Description
[0001] The present invention relates to a transition piece for
non-annular gas turbine combustion chambers.
[0002] As is known, gas turbines comprise a compressor, to which
air from the external environment is supplied in order to
pressurise the compressor.
[0003] The compressed air passes into a series of combustion
chambers which end in a nozzle, into each of which an injector
supplies fuel, which is mixed with the air in order to form a
mixture of combustible air to be burnt.
[0004] Subsequently, the burnt gases are conveyed towards the
turbine, which transforms the enthalpy of the burnt gases in the
said combustion chamber into mechanical energy which is available
to a user.
[0005] It is also known that the transition pieces in a gas turbine
are substantially tubular elements, each of which is used to
connect a combustion chamber, which belongs to the combustion
system of the gas turbine, to the first stage of the said gas
turbine.
[0006] More particularly, the combustion chambers comprise a
plurality of elements with a generally cylindrical shape, which are
provided with nozzles disposed around an annular development.
[0007] Similarly, the transition pieces are disposed with an
annular development, in order to direct the flow of hot burnt gases
from the combustion chambers to the first stage of the gas
turbine.
[0008] The transition pieces have an upstream aperture for the flow
of gas, which is generally cylindrical, and is used to receive the
flow of gas directly from the corresponding combustion chamber, and
are configured in a longitudinal direction such that their
downstream ends comprise arcuate segments which open towards the
first stage of the gas turbine.
[0009] This means that the transition pieces can direct the flow of
gas with a high level of enthalpy obtained from spaced, generally
cylindrical flow configurations, towards arcuate segments which
form a ring-type configuration relative to the first stage of the
gas turbine.
[0010] In order to introduce the technical problems which are faced
and solved by means of the present invention, it should be noted
that the continual quest which is in progress at present, for
increases in the performance of gas turbines, and increases in the
intervals between the various stoppages for maintenance, as well as
the pressing need to reduce to a minimum the pollutant emissions
produced by the gas turbine, necessitates optimisation of all the
components inserted in the so-called hot gas path.
[0011] In particular, these components comprise the combustion
chamber, the nozzles and the transition pieces, and are the ones
which are subjected to the highest temperatures.
[0012] It should be emphasised at this point that, since the
combustion system has an energising function in relation to the
thermal carrier fluid, it is the true heart of the turbine engine,
and thus defines its level of emission, and, according to the
service life of its own components, also defines the intervals of
functioning between machine stoppages, which are necessary in order
to carry out inspections of the combustion chambers.
[0013] In addition, the requirement to develop the machines in
operation, with increases in the compression ratios and fire
temperatures, are a further reason for emphasising the criticality
of the hot components.
[0014] Reduction of the emissions, with an increase in the service
life of the components, and optionally also in the efficiency of
the system, also constitutes a general target which undoubtedly has
an impact on the clientele of heavy duty machines, and is a
stimulating technological challenge for the designers.
[0015] In particular, in the case of machines which have had a
certain length of service, it is possible to gather sufficient
statistical data to determine the parameters and details which are
critical in achieving overall improvements, such as to justify the
cost of the design and subsequent marketing, optionally in uprate
packages for the aftermarket.
[0016] A major technical problem therefore consists substantially
of determining solutions which permit achievement of maximum
satisfaction of the client for the three aforementioned aspects,
all by means of innovative creations which are economically
acceptable.
[0017] In order better to understand the technical problems which
are involved in the present invention, at this point reference is
made to the following state of the art.
[0018] The solutions which are currently used in order to achieve
the three above-described objectives (greater efficiency, longer
service life of the machine, and fewer pollutant emissions), are
not in general combined in a single product, but are on the other
hand implemented in ranges of alternative components.
[0019] In order to increase the service life, and thus the
intervals of inspection of the combustion chambers, use is
generally made of materials, such as stellite 6, deposited onto
elements which may become worn by relative vibratory motion, and of
super-alloys with a nickel/cobalt base, with high levels of
mechanical characteristics and of resistance to corrosion at high
temperatures.
[0020] Use is also made of additions of a ceramic type, to reduce
the temperatures of the metal (for the same cooling flows), and the
design of the components is being optimised, on the basis of
experience acquired.
[0021] In the case of known turbine engines, the original
combustion system has been completely redesigned, both in terms of
the overall arrangement and component elements.
[0022] The original system, having six combustion chambers,
arranged in two rows of three parallel chambers stacked on both
sides of the machine, in an arrangement at right-angles to the
machine axis, with interposition of 90.degree. connection elbows
between the liners and transition pieces, has thus been replaced by
an arrangement characterised by chambers inclined by only a few
degrees in relation to the machine axis, and insertion of the
liners directly in the transition piece, and therefore without the
need for further connection elements.
[0023] In this embodiment, there is thus implementation of all the
solutions known in the present state of the art, for the three
above-described objectives (efficiency, service life of the
machine, and fewer pollutant emissions), such as to obtain a unit
device which combines the advantages thus accumulated.
[0024] The object of the present invention is therefore to provide
a transition piece for non-annular gas turbine combustion chambers,
which permits optimisation of the performance in operation.
[0025] A further object of the invention is to provide a transition
piece for non-annular gas turbine combustion chambers, which
permits improved efficiency in operation.
[0026] Another object of the invention is to provide a transition
piece for non-annular gas turbine combustion chambers, which
permits a longer service life of the machine.
[0027] A further object of the invention is to provide a transition
piece for a non-annular gas turbine combustion chamber system,
which generates fewer pollutant emissions.
[0028] These objects and others are obtained by a transition piece
for non-annular gas turbine combustion chambers, comprising a body
which has a cylindrical section, relative to a first terminal end,
which ends with an aperture for connection to a combustion chamber,
and a second terminal end, which is connected to the first stage of
a gas turbine, characterised in that it has a projecting connection
arm, for support on the turbine stator, wherein the said projecting
connection arm makes it possible to obtain a lead-in axis with an
angle of between 5.degree. and 7.degree. relative to an axis, which
is parallel to the axis of the machine, and is perpendicular to the
plane on which there lies the frame for interfacing of the
transition piece with the ring of nozzles which belong to the first
stage of the said gas turbine.
[0029] According to a preferred embodiment of the present
invention, the transition piece has a support arm, with a circular
or elliptical base, which is present at the said second terminal
end, and surrounds the flow aperture of the said transition piece,
wherein the said support arm with a circular or elliptical base has
an upper side and a lower side, for its own connection to the first
stage of the said gas turbine.
[0030] According to a preferred embodiment of the present
invention, the cylindrical section, relative to the first terminal
end, has an anti-wear deposit made of Stellite 6 or another,
similar material.
[0031] In addition, a deposit of the TBC type is provided on the
entire inner surface of the said transition piece, in order to
reduce the temperature of the metal.
[0032] According to a further preferred embodiment of the present
invention, the distance between the centre of the lead-in of the
said transition piece and the support plane of the flange for
anchorage to the stator of the said gas turbine is between 350 mm
and 380 mm.
[0033] According to a further preferred embodiment of the present
invention, the body of the transition piece can be made of Nimonic
263 or of Hastelloy-X.
[0034] Further characteristics of the invention are defined in the
claims attached to the present patent application.
[0035] Further objects and advantages of the present invention, as
well as its structural and functional characteristics, will become
apparent from the following description and the attached drawings,
which are provided purely by way of explanatory, non-limiting
example, and in which:
[0036] FIG. 1 represents a view, partially in cross-section, of a
gas turbine to which there is fitted the transition piece according
to the present invention, for non-annular gas turbine combustion
chambers;
[0037] FIG. 2 represents a plan view of a transition piece
according to the present invention, for non-annular gas turbine
combustion chambers;
[0038] FIG. 3 represents a view in cross-section according to the
plane III-III, of the transition piece in FIG. 2;
[0039] FIG. 4 represents a front view of the transition piece in
FIGS. 2-3; and
[0040] FIG. 5 represents a view in cross-section of a detail
belonging to the transition piece in FIGS. 2-4.
[0041] With particular reference to the aforementioned figures, the
transition piece according to the present invention, for
non-annular gas turbine combustion chambers, is indicated globally
by the reference number 10.
[0042] The transition piece 10 consists of a body 11, which
receives upstream the flow of burnt gases, directly from the
corresponding combustion chamber 25, and is configured
longitudinally such as to have a downstream end which opens towards
the first stage 17 of the gas turbine 18.
[0043] More particularly, the body 11 of the transition piece 10
has a cylindrical section 13, relative to a first terminal end,
which ends with an aperture 14 for connection to a combustion
chamber 25.
[0044] The body 11 of the transition piece 10 also has a second
terminal end 16, which is connected to the first stage 17 of a gas
turbine 18, and thus has a flow aperture 15.
[0045] The transition piece 10 thus consists of a body 11, which is
provided with a support arm, with a circular or elliptical base,
which is present at the second terminal end 16, and surrounds the
flow aperture 15.
[0046] In particular, the support arm with a circular or elliptical
base has an upper side 20 and a lower side 21.
[0047] The body 11 is provided with characteristics of resilience,
such as to minimise the stresses associated with its anchorage onto
the stator of the said gas turbine 18.
[0048] In addition, the body 11 is preferably made of Nimonic 263,
or, alternatively, of Hastelloy-X, and is produced in a single
component part, indicated by the reference number 11, which reduces
the parts necessary and the assembly time, and thus permits
considerable savings.
[0049] The cylindrical section 13, relative to the first terminal
end, has an anti-wear deposit made of Stellite 6, or of another
material homologous with that used on the Hula Seals of the
liners.
[0050] In addition, a deposit of the TBC type is provided on the
entire inner surface of the body 11 of the transition piece 10, in
order to reduce the temperature of the metal.
[0051] The transition piece 11 also has a projecting connection
arm, indicated as a whole by the reference number 22, for support
on the turbine stator.
[0052] At its own terminal end, the projecting connection arm 22
also has a hole 30, for its own connection to the first stage of
the gas turbine 18, and a centring pin 31.
[0053] The geometry of the transition piece 11 is thus completely
re-shaped, compared with the known art.
[0054] In fact, it has a lead-in axis with an angle of between
5.degree. and 7.degree., relative to an axis which is parallel to
the axis of the machine, and is perpendicular to the plane on which
there lies the frame for interfacing of the transition piece 10
with the ring of nozzles which belong to the first stage 17 of the
gas turbine 18.
[0055] In addition, it can be noted that the distance between the
centre of the lead-in of the transition piece 10 and the support
plane of the flange for anchorage to the stator of the gas turbine,
is between 350 mm and 380 mm.
[0056] In particular, according to the invention described, the
most significant functioning parameters are: Tmax of the
gas<1300.degree. C., and Pmax of the gas<10 Ata.
[0057] The description provided makes apparent the characteristics
and advantages of the transition piece which is the subject of the
present invention, for nonannular gas turbine combustion
chambers.
[0058] The following concluding considerations and comments are now
provided, in order to define the said advantages more clearly and
accurately.
[0059] In particular, the elimination of the intermediate elbows,
with the arrangement of the combustion chambers in the gap between
the flanging on the stator of the turbine and the compressor
suction air feed pipe (which is further limited in the lower area
by the presence of the front support fork of the machine), in
association with the provision of new liners with low LHE emission,
with dilution air feed holes in the head, and calendered Hula seals
with anti-wear material deposited, have led to the re-design of the
transition piece, with materials used and a configuration which
reflect the best which can be obtained for industrial gas
turbines.
[0060] Since this application is designed for the aftermarket, and
thus has pre-defined constraints of geometries and functional
parameters, the design of the component elements, and their
integration in the system, has led to the development of details
which are innovative in terms of design and functionality.
[0061] In view of the operative conditions of the machine for which
this application is planned, there has been definition of the
specific geometry parameters necessary in order to obtain the
functional characteristics required for integration of the
combustion system as a whole.
[0062] The transition piece 11 thus formed has an optimal geometric
profile, which, inter alia, makes it possible to keep the thermal
stresses within acceptable limits.
[0063] The particular design of the transition piece 11 described
makes it possible to obtain increased structural stability, with
consequent reduction of the vibratory motion.
[0064] To summarise, a transition piece for non-annular gas turbine
combustion chambers has been produced, which makes it possible also
to obtain the significant advantages of ease of fitting and
removal, as well as of improved overall mechanical reliability and
efficiency of the machine to which it is fitted.
[0065] The theoretical and experimental results have been so
satisfactory, that they show that the system can be used on widely
distributed gas turbines.
[0066] It is apparent that many variations can be made to the
transition piece which is the subject of the present invention, for
non-annular gas turbine combustion chambers, without departing from
the principles of novelty which are inherent in the inventive
concept illustrated.
[0067] Finally, it is apparent that, in the practical embodiment of
the invention, any forms and dimensions can be used for the details
illustrated, according to requirements, and can be replaced by
others which are equivalent from a technical point of view.
[0068] The scope of the invention is defined by the attached
claims.
* * * * *