U.S. patent application number 12/162307 was filed with the patent office on 2009-12-10 for guide blade segment of a gas turbine and method for its production.
This patent application is currently assigned to MTU Aero Engines GmbH. Invention is credited to Karl-Heinz Dusel, Roland Huttner, Reinhold Meier, Claus Mueller.
Application Number | 20090304497 12/162307 |
Document ID | / |
Family ID | 37872200 |
Filed Date | 2009-12-10 |
United States Patent
Application |
20090304497 |
Kind Code |
A1 |
Meier; Reinhold ; et
al. |
December 10, 2009 |
GUIDE BLADE SEGMENT OF A GAS TURBINE AND METHOD FOR ITS
PRODUCTION
Abstract
A guide blade segment of a gas turbine, having at least one
guide blade and having an inner cover band assigned to the radially
inner end of the or each guide blade, is disclosed. An integral
constituent part of the inner cover band of the guide blade segment
is a sealing element, which serves to seal a radially inner gap
between the guide blade segment and a gas turbine rotor.
Inventors: |
Meier; Reinhold; (Dorfen,
DE) ; Mueller; Claus; (Unterhaching, DE) ;
Dusel; Karl-Heinz; (Unterschleissheim, DE) ; Huttner;
Roland; (Jesenwang, DE) |
Correspondence
Address: |
CROWELL & MORING LLP;INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Assignee: |
MTU Aero Engines GmbH
Munich
DE
|
Family ID: |
37872200 |
Appl. No.: |
12/162307 |
Filed: |
January 19, 2007 |
PCT Filed: |
January 19, 2007 |
PCT NO: |
PCT/DE2007/000097 |
371 Date: |
June 30, 2009 |
Current U.S.
Class: |
415/170.1 ;
29/889.7 |
Current CPC
Class: |
F16J 15/444 20130101;
F01D 11/001 20130101; Y10T 29/49336 20150115 |
Class at
Publication: |
415/170.1 ;
29/889.7 |
International
Class: |
F01D 11/00 20060101
F01D011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 28, 2006 |
DE |
10 2006 004 090.2 |
Claims
1-13. (canceled)
14. A guide blade segment of a gas turbine, comprising a guide
blade and having an inner cover band assigned to a radially inner
end of the guide blade, wherein an integral constituent part of the
inner cover band of the guide blade segment is a sealing element,
which seals a radially inner gap between the guide blade segment
and a gas turbine rotor.
15. The guide blade segment according to claim 14, wherein the
sealing element is integrally cast on the inner cover band.
16. The guide blade segment according to claim 14, wherein the
sealing element is integrally formed on the inner cover band using
injection molding.
17. The guide blade segment according to claim 14, wherein the
sealing element is a honeycomb seal.
18. A method for producing a guide blade segment of a gas turbine,
wherein the guide blade segment has a guide blade and an inner
cover band assigned to a radially inner end of the guide blade,
wherein a sealing element, which seals a radially inner gap between
the guide blade segment and a gas turbine rotor, is formed on the
inner cover band of the guide blade segment as an integral
constituent part of the inner cover band.
19. The method according to claim 18, wherein the sealing element
is integrally cast on the inner cover band.
20. The method according to claim 18, wherein the sealing element
is integrally formed on the inner cover band using injection
molding.
21. The method according to claim 20, wherein a common molded
article or a green compact is produced during the injection molding
for the sealing element and the inner cover band.
22. The method according to claim 20, wherein separate molded
articles or green compacts are produced during the injection
molding for the sealing element and the inner cover band, which as
brown compacts are formed on one another and jointly sintered.
23. The method according to claim 20, wherein the injection molding
is carried out as two-component injection molding.
24. The method according to claim 20, wherein a homogeneous mass
made of a powder, a binding agent, and a plasticizing agent is used
during the injection molding and wherein a hard metal powder and/or
a powder of an intermetallic phase and/or a powder of metal alloys
and/or a ceramic powder is used as the powder.
25. The method according to claim 18, wherein the sealing element
and the inner cover band are integrally formed by a generative
manufacturing method.
26. The method according to claim 25, wherein the generative
manufacturing method is a rapid prototyping method.
27. The method according to claim 25, wherein the generative
manufacturing method is laser engineered net shaping, electron-beam
melting, laser sintering, laser melting, laser shaping, or laser
powder application welding.
28. A method for producing a guide blade segment of a gas turbine,
wherein the guide blade segment has a guide blade and an inner
cover band on a radially inner end of the guide blade, comprising
the step of: integrally forming a sealing element on the inner
cover band of the guide blade segment.
29. The method according to claim 28, wherein the step of
integrally forming the sealing element on the inner cover band of
the guide blade segment includes integrally casting the sealing
element on the inner cover band.
30. The method according to claim 28, wherein the step of
integrally forming the sealing element on the inner cover band of
the guide blade segment includes injection molding.
31. The method according to claim 28, wherein the step of
integrally forming the sealing element on the inner cover band of
the guide blade segment includes a generative manufacturing
method.
32. The method according to claim 31, wherein the generative
manufacturing method is a rapid prototyping method.
33. The method according to claim 31, wherein the generative
manufacturing method is laser engineered net shaping, electron-beam
melting, laser sintering, laser melting, laser shaping, or laser
powder application welding.
Description
[0001] This application claims the priority of International
Application No. PCT/DE2007/000097, filed Jan. 19, 2007, and German
Patent Document No. 10 2006 004 090.2, filed Jan. 28, 2006, the
disclosures of which are expressly incorporated by reference
herein.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The invention relates to a guide blade segment of a gas
turbine. In addition, the invention relates to a method for
producing a guide blade segment of a gas turbine.
[0003] Gas turbines, particularly gas turbine aircraft engines,
have stationary guide blade rings and rotating rotor blade rings in
the region of their compressors and turbines, wherein the
stationary guide blade rings are assigned to a stationary housing
and the rotating rotor blade rings to a rotating rotor of the gas
turbine. The stationary guide blade rings are formed by several
guide blade segments, wherein each guide blade segment includes at
least one guide blade. Assigned to the radially inner end of the or
each guide blade of a guide blade segment is an inner cover band,
wherein, in order to guarantee an optimal degree of efficiency of a
gas turbine, a radially inner gap between the inner cover band of
the guide blades and the rotor of the gas turbine needs to be
sealed. Sealing the radial inner gap between the inner cover band
and the rotor of the gas turbine is accomplished using what is
commonly called an inner air seal, wherein, for this purpose,
sealing elements are assigned to the inner band of the guide blade
segments. These sealing elements can be designed as honeycomb
seals.
[0004] In the case of guide blade segments known from practice, the
sealing elements are designed as separate components and are
permanently connected to the inner cover band of the guide blade
segments by soldering for example. The result of this is a high
manufacturing effort, since, on the one hand, the sealing elements
must be manufactured as a separate component using separate
manufacturing methods, and since, on the other hand, the sealing
elements have to be connected to the inner cover band using a
joining method. Furthermore, soldered connections for the most part
represent thermo-mechanical weak points.
[0005] Starting herefrom, the present invention is based on the
objective of creating a novel guide blade segment of a gas turbine
and a method for producing same. According to the invention, an
integral constituent part of the inner cover band of the guide
blade segment is a sealing element, which serves to seal a radially
inner gap between the guide blade segment and a gas turbine
rotor.
[0006] In terms of the present invention, it is provided in the
case of a guide blade segment of a gas turbine, that the sealing
element be designed as an integral constituent part of the inner
cover band of the guide blade segment. This is preferably
accomplished in that the sealing element and the inner cover band
of the guide blade segment are manufactured integrally in a forming
process. Manufacturing costs can be reduced due to the integral
design of the sealing element with the inner cover band of the
guide blade segment, because, on the one hand, a separate
manufacturing process for the sealing element and, on the other
hand, a joining of the sealing element to the inner cover band of
the guide blade segment are eliminated. By eliminating joined
connections between the sealing element and the inner cover band of
the guide blade segment, the service life of the guide blade
segments can also be increased, because the joined connections or
joined points that are required by the prior art between the
sealing element and the inner cover band of the guide blade segment
represent weak points. In particular, eliminating the soldering
heat treatment that is customary in the case of compressor guide
blade segments does not reduce the fatigue strength of the guide
blade segments.
[0007] Preferred developments of the invention are disclosed in the
subsequent description. Without being limited hereto, exemplary
embodiments of the invention are explained in greater detail on the
basis of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic section of an inventive guide blade
segment of a gas turbine in the region of an inner cover band of
the guide blade segment; and
[0009] FIG. 2 is a detail of the inner cover band from FIG. 1 in
the region of a sealing element embodied as an integral constituent
part of the inner cover band.
DETAILED DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 shows a section of an inventive guide blade segment
of a gas turbine in the region of an inner cover band 10 arranged
on radially inner ends of guide blades of the guide blade segment,
wherein a sealing element 11 is assigned to the inner cover band 10
in the exemplary embodiment in FIG. 1. The sealing element 11
serves to seal a radially inner gap between the guide blade segment
and a gas turbine rotor.
[0011] In terms of the present invention, the sealing element 11 is
an integral constituent part of the inner cover band 10 of the
guide blade segment. The sealing element 11 in this case is either
integrally cast on the inner cover band 10 of the guide blade
segment or integrally formed on the inner cover band 10 using
powder metallurgical injection molding. The sealing element
according to FIG. 2 is preferably embodied as a honeycomb seal made
of several honeycombs 12, wherein the honeycombs 12 can have any
contour. Thus, FIG. 2 exemplarily shows honeycombs 12, which have a
round contour in cross section, as well as honeycombs 12, which
have a hexagonal or honeycombed contour in cross section.
[0012] As already stated above, the inventive guide blade segment
is preferably manufactured in that the sealing element is either
integrally cast on the inner cover band, integrally formed on the
inner cover band using powder metallurgical injection molding, or
the sealing element and the inner cover band are integrally
manufactured using generative manufacturing methods.
[0013] If the manufacturing variant of powder metallurgical
injection molding, which is also known as the metal injection
molding (MIM) method, is selected, the preferred procedure is that
a common molded article is manufactured by injection molding for
the inner cover band and thus the guide blade segment as well as
the sealing element, wherein the molded article is also designated
as a green compact. In this case, the sealing element is then
already an integral constituent part of the inner cover band in the
green compact, wherein subsequently, as is customary in powder
metallurgical injection molding, a binding agent and plasticizing
agent are expelled from the green compact to produce a brown
compact. The brown compact is then sintered in order to make the
guide blade segment available.
[0014] Alternatively, it is also possible to manufacture separate
green compacts for the inner cover band or the guide blade segment
and the sealing element, wherein brown compacts are manufactured
from these green compacts by expelling the binding agent and
plasticizing agent, and the brown compacts are then formed on one
another and jointly sintered.
[0015] A further alternative for powder metallurgical injection
molding can be seen in first manufacturing a green compact for the
inner cover band or guide blade segment and converting this green
compact into a brown compact by expelling the binding agent and
plasticizing agent, wherein the sealing element is then integrally
formed on this brown compact by injection molding.
[0016] In powder metallurgical injection molding, the composition
of a homogeneous mass made of metal powder, binding agent, and
plasticizing agent that is used for injection molding can be
adapted. Thus, when a common molded article or green compact is
manufactured by injection molding for the inner cover band and the
sealing element, during injection molding, the composition of the
homogenous mass used for injection molding can be modified in order
to thereby guarantee different properties in the region of the
sealing element than in the rest of the guide blade segment.
[0017] Instead of the one-component injection molding, a
two-component injection molding can also be carried out, wherein a
first homogenous mass is then used for the injection molding of the
guide blade segment, and a second homogeneous mass is used for the
injection molding of the sealing element, and these two homogenous
masses differ in terms of their compositions. The compositions are
adapted respectively to the required properties of the guide blade
segment and sealing element.
[0018] A hard metal powder and/or a powder of intermetallic phases,
such as, e.g., titanium aluminide, and/or a powder of metal alloys
can be used as the metal powder in the respective, homogeneous mass
required for injection molding. In addition or as an alternative to
the metal powder, a ceramic powder can also be used as the
homogeneous mass required for injection molding.
[0019] In the case of the alternative manufacturing route using
generative manufacturing methods, the sealing element and the inner
cover band are built up in layers integrally, i.e., made of one
piece, in particular using rapid prototyping methods. Used
preferably as the generative manufacturing method is laser
engineered net shaping, which uses electron-beam melting, laser
sintering, laser melting, laser shaping, or laser powder
application welding. Cobalt, nickel, iron, or even titanium-based
alloys can be used for this, in that as sinterable powders, these
materials are built up in layers by means of a source of radiation
in a natural or artificial environment directly from the
component's CAD data.
[0020] Due to this layered structure, solid and even hollow
structures can be manufactured in a manner that is satisfactory in
terms of load. The sealing element can consequently be structured
in a simple manner as a hollow space that is open on one side
(e.g., honeycombs), as a metallic grid structure, or a foam
structure.
[0021] Following the different manufacturing routes, finish
machining for the final contour can also still be performed by
removal methods such as milling, lathing, eroding, or
electrochemical processing.
* * * * *