U.S. patent application number 15/743117 was filed with the patent office on 2018-08-09 for gas turbine seal arrangement.
The applicant listed for this patent is Siemens Energy, Inc.. Invention is credited to Christian Xavier Campbell, Abdullatif M. Chehab, Vincent Paul Laurello, Patrick M. Pilapil, Kok-Mun Tham, Yan Yin.
Application Number | 20180223683 15/743117 |
Document ID | / |
Family ID | 53761589 |
Filed Date | 2018-08-09 |
United States Patent
Application |
20180223683 |
Kind Code |
A1 |
Tham; Kok-Mun ; et
al. |
August 9, 2018 |
GAS TURBINE SEAL ARRANGEMENT
Abstract
A turbine arrangement including a rotor and a stator surrounding
the rotor and comprising guide vane segments, each guide vane
segment comprising an airfoil and a radially inner vane platform. A
seal arrangement includes a static seal inward from the inner vane
platforms and having a radially extending face plate, first and
second cylindrical seal walls extending from outer and inner ends
of the annular face plate, an annular seal plate extending radially
from the second cylindrical seal wall, and an angel wing extending
between the first cylindrical seal wall and the annular seal plate
to define a first annular cavity and a second annular cavity.
Circumferentially spaced cut-outs define passages through the
annular seal plate between the first and second annular cavities
and are aligned with fasteners that attach the annular face plate
to a support ring for supporting the inner vane platform.
Inventors: |
Tham; Kok-Mun; (Oviedo,
FL) ; Chehab; Abdullatif M.; (Chuluota, FL) ;
Pilapil; Patrick M.; (Kissimmee, FL) ; Yin; Yan;
(Oviedo, FL) ; Campbell; Christian Xavier;
(Charlotte, NC) ; Laurello; Vincent Paul; (Hobe
Sound, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Siemens Energy, Inc. |
Orlando |
FL |
US |
|
|
Family ID: |
53761589 |
Appl. No.: |
15/743117 |
Filed: |
July 20, 2015 |
PCT Filed: |
July 20, 2015 |
PCT NO: |
PCT/US2015/041056 |
371 Date: |
January 9, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01D 25/12 20130101;
F01D 5/081 20130101; F01D 11/02 20130101; F01D 11/001 20130101 |
International
Class: |
F01D 11/00 20060101
F01D011/00; F01D 11/02 20060101 F01D011/02 |
Claims
1. A turbine arrangement comprising: a rotor that rotates about a
rotor axis and comprises a plurality of rotor blade segments
extending radially outward, each rotor blade segment comprises an
airfoil and a radially inner blade platform; a stator surrounding
the rotor so as to form an annular flow path for a hot working gas,
the stator comprises a plurality of guide vane segments disposed
adjacent the plurality of rotor blade segments, the plurality of
guide vane segments extending radially inward, each guide vane
segment comprising an airfoil and a radially inner vane platform; a
seal arrangement comprising an annular face plate extending
radially inward from the vane platform, a first cylindrical seal
wall extending axially from an outer end of the face plate, a
second cylindrical seal wall extending axially from an inner end of
the face plate, an annular seal plate extending radially from an
end of the second cylindrical seal wall, and an angel wing
extending from the rotor and having a distal end between the first
cylindrical seal wall and the seal plate to define a first annular
cavity and a second annular cavity, wherein: the first annular
cavity is defined at least by the first and second cylindrical seal
walls and the annular seal plate; the second annular cavity is
defined at least by the angel wing and the annular seal plate; the
first annular cavity is in fluid communication with the annular
flow path via a first annular seal passage between the first
cylindrical seal wall and the angel wing; the first annular cavity
is in fluid communication with the second annular cavity via a
second annular seal passage between the angel wing and an outer end
of the annular seal plate; the annular face plate is attached to a
support ring that supports the inner vane platform, including a
plurality of circumferentially spaced fasteners passing through
apertures in the annular face plate into the support ring; and a
plurality of circumferentially spaced cut-outs in the annular seal
plate defining passages between the first and second annular
cavities.
2. The turbine arrangement according to claim 1, characterized in
that the fasteners include fastener heads that are located in the
first annular cavity.
3. The turbine arrangement according to claim 2, characterized in
that the cut-outs in the annular seal plate are each
circumferentially aligned with a fastener head.
4. The turbine arrangement according to claim 3, characterized in
that the cut-outs are each defined by a sidewall that is angled
circumferentially in a direction of rotor rotation extending from
the second annular cavity toward the first annular cavity.
5. The turbine arrangement according to claim 1, characterized in
that a cylindrical flange extends parallel to the first and second
cylindrical seal walls into the first annular cavity from the outer
end of the annular seal plate.
6. The turbine arrangement according to claim 1, characterized in
that a surface at the outer end of the annular seal plate is angled
radially inward from the first cavity toward the second cavity.
7. The turbine arrangement according to claim 6, characterized in
that the surface at the outer end of the annular seal plate is
defined by an inner seal member affixed to the cylindrical flange
and cooperates with the angel wing to define the second annular
seal passage.
8. The turbine arrangement according to claim 6, characterized in
that the surface at the outer end of the annular seal plate is
stepped radially inward from the first cavity toward the second
cavity.
9. The turbine arrangement according to claim 6, characterized in
that an outer seal member is affixed to an inner side of the first
cylindrical seal wall and cooperates with the angel wing to define
the first annular seal passage.
10. The turbine arrangement according to claim 1, characterized in
that the distal end of the angel wing is formed with a hammerhead
configuration cooperating with surfaces at the first cylindrical
seal wall and the outer end of the annular seal plate to define the
first and second annular seal passages, respectively.
11. The turbine arrangement according to claim 1, characterized in
that the outer end of the annular seal plate is formed with a
knife-edge and cooperates with the angel wing to define the second
annular seal passage.
12. The turbine arrangement according to claim 11, characterized in
that a knife-edge extends radially inward from the first
cylindrical seal wall and cooperates with the angel wing to define
the first annular seal passage.
13. A turbine arrangement comprising: a rotor that rotates about a
rotor axis and comprises a plurality of rotor blade segments
extending radially outward, each rotor blade segment comprises an
airfoil and a radially inner blade platform; a stator surrounding
the rotor so as to form an annular flow path for a hot working gas,
the stator comprises a plurality of guide vane segments disposed
adjacent the plurality of rotor blade segments, the plurality of
guide vane segments extending radially inward, each guide vane
segment comprising an airfoil and a radially inner vane platform; a
seal arrangement comprising an annular face plate extending
radially inward from the vane platform, a first cylindrical seal
wall extending axially from an outer end of the face plate, a
second cylindrical seal wall extending axially from an inner end of
the face plate, an annular seal plate extending radially from an
end of the second cylindrical seal wall, and an angel wing
extending from the rotor and having a distal end between the first
cylindrical seal wall and the seal plate to define a first annular
cavity and a second annular cavity, wherein: the first annular
cavity is defined at least by the first and second cylindrical seal
walls and the annular seal plate; the second annular cavity is
defined at least by the angel wing and the annular seal plate; the
first annular cavity is in fluid communication with the annular
flow path via a first annular seal passage between the first
cylindrical seal wall and the angel wing; the first annular cavity
is in fluid communication with the second annular cavity via a
second annular seal passage between the angel wing and an outer end
of the annular seal plate; the annular face plate is attached to a
support ring that supports the inner vane platform, including a
plurality of circumferentially spaced fasteners passing through
apertures in the annular face plate into the support ring; and a
plurality of circumferentially spaced cut-outs in the annular seal
plate defining passages between the first and second annular
cavities, wherein the cut-outs are each circumferentially aligned
with a fastener and are defined by a sidewall that is angled
circumferentially in a direction of rotor rotation extending from
the second annular cavity toward the first annular cavity.
14. The turbine arrangement according to claim 13, characterized in
that a cylindrical flange extends parallel to the first and second
cylindrical seal walls into the first annular cavity from the outer
end of the annular seal plate.
15. The turbine arrangement according to claim 14, characterized in
that an inner seal member is affixed to the cylindrical flange and
cooperates with the angel wing to define the second annular seal
passage.
16. The turbine arrangement according to claim 15, characterized in
that the inner seal member has an outer sealing surface that has a
reduced downstream radial dimension adjacent to the second annular
cavity in comparison to the upstream radial dimension of the
honeycomb seal adjacent to the first annular cavity.
17. A turbine arrangement comprising: a rotor that rotates about a
rotor axis and comprises a plurality of rotor blade segments
extending radially outward, each rotor blade segment comprises an
airfoil and a radially inner blade platform; a stator surrounding
the rotor so as to form an annular flow path for a hot working gas,
the stator comprises a plurality of guide vane segments disposed
adjacent the plurality of rotor blade segments, the plurality of
guide vane segments extending radially inward, each guide vane
segment comprising an airfoil and a radially inner vane platform; a
seal arrangement comprising an annular face plate extending
radially inward from the vane platform, a first cylindrical seal
wall extending axially from an outer end of the face plate, a
second cylindrical seal wall extending axially from an inner end of
the face plate, an annular seal plate extending radially from an
end of the second cylindrical seal wall, and an angel wing
extending from the rotor and having a distal end between the first
cylindrical seal wall and the seal plate to define a first annular
cavity and a second annular cavity, wherein: the first annular
cavity is defined at least by the first and second cylindrical seal
walls and the annular seal plate; the second annular cavity is
defined at least by the angel wing and the annular seal plate; the
first annular cavity is in fluid communication with the annular
flow path via a first annular seal passage between the first
cylindrical seal wall and the angel wing; the first annular cavity
is in fluid communication with the second annular cavity via a
second annular seal passage between the angel wing and an outer end
of the annular seal plate; and a cylindrical flange extends
parallel to the first and second cylindrical seal walls into the
first annular cavity from the outer end of the annular seal
plate.
18. The turbine arrangement according to claim 17, characterized in
that a plurality of circumferentially spaced cut-outs in the
annular seal plate define passages between the first and second
annular cavities.
19. The turbine arrangement according to claim 18, characterized in
that the annular face plate is attached to a support ring that
supports the inner vane platform, and a plurality of
circumferentially spaced fasteners pass through apertures in the
annular face plate into the support ring and are located in
circumferential alignment with the cut-outs.
20. The turbine arrangement according to claim 17, characterized in
that an inner seal member is affixed to the cylindrical flange and
cooperates with the angel wing to define the second annular seal
passage.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to gas turbine engines and, in
particular, to seal arrangements providing a seal between a hot gas
flow path and a disk cavity supplied with secondary air.
BACKGROUND OF THE INVENTION
[0002] In a gas turbine engine, hot combustion gases are routed
from a combustor to a turbine section, in which stator vanes are
designed to direct the hot gases onto rotor blades resulting in
rotational movement of a rotor to which the rotor blades are
connected. Radially inwards and outwards of airfoils of these
stator vanes and rotor blades, platforms, casing structure, or
other components may be present such as to form an annular fluid
passage into which the airfoils of the stator vanes and the rotor
blades extend and through which the hot combustion gases pass.
[0003] As the rotating rows of rotor blades and non-rotating rows
of stator vanes are arranged alternately, gaps may be present
between the rows of rotor blades and the rows of stator vanes. Seal
structure is typically provided to reduce the size of the gaps
and/or to seal these gaps so as to minimize or limit the amount of
hot combustion gas that is lost via these gaps and to minimize the
amount of secondary air that can pass into the hot gas flow. The
structure to seal these gaps between rotor blades and stator vanes
is commonly referred to as a turbine rim seal.
[0004] In the turbine front stages, effective operation of the rim
seal is particularly important to ensure mechanical integrity of
the steel turbine disks, as even a small amount of ingestion of gas
from the gas path can potentially raise turbine disk cavity
temperatures significantly. In turbine engines where the first row
turbine blade platforms are cooled by air supplied from the first
disk cavity, an effective rim seal ensures effectual blade platform
cooling, and has a reduced requirement for cavity purge flow.
Hence, an improvement in rim sealing can result in a reduction in
overall cooling and sealing air consumption, and an improved
turbine aerodynamic performance, since mixing loss from purge flow
induction can be reduced. The turbine rim seal on the upstream side
of the first row of turbine blades can comprise a stationary static
seal housing a honeycomb for mating with a rotor angel wing. The
static seal may be held in position by bolts having heads that
extend into the disk cavity and which can increase drag in the disk
cavity, leading to increased cavity temperatures due to
windage.
SUMMARY OF THE INVENTION
[0005] In accordance with an aspect of the invention, a turbine
arrangement is provided comprising a rotor that rotates about a
rotor axis and comprises a plurality of rotor blade segments
extending radially outward, each rotor blade segment comprises an
airfoil and a radially inner blade platform. A stator surrounds the
rotor so as to form an annular flow path for a hot working gas, and
the stator comprises a plurality of guide vane segments disposed
adjacent the plurality of rotor blade segments. The plurality of
guide vane segments extend radially inward, each guide vane segment
comprising an airfoil and a radially inner vane platform. A seal
arrangement comprises an annular face plate extending radially
inward from the vane platform, a first cylindrical seal wall
extending axially from an outer end of the face plate, a second
cylindrical seal wall extending axially from an inner end of the
face plate, an annular seal plate extending radially from an end of
the second cylindrical seal wall, and an angel wing extending from
the rotor and having a distal end between the first cylindrical
seal wall and the seal plate to define a first annular cavity and a
second annular cavity. The first annular cavity is defined at least
by the first and second cylindrical seal walls and the annular seal
plate. The second annular cavity is defined at least by the angel
wing and the annular seal plate. The first annular cavity is in
fluid communication with the annular flow path via a first annular
seal passage between the first cylindrical seal wall and the angel
wing. The first annular cavity is in fluid communication with the
second annular cavity via a second annular seal passage between the
angel wing and an outer end of the annular seal plate. The annular
face plate is attached to a support ring that supports the inner
vane platform, including a plurality of circumferentially spaced
fasteners passing through apertures in the annular face plate into
the support ring. A plurality of circumferentially spaced cut-outs
are formed in the annular seal plate defining passages between the
first and second annular cavities.
[0006] The fasteners may include fastener heads that are located in
the first annular cavity. The cut-outs in the annular seal plate
may each be circumferentially aligned with a fastener head. The
cut-outs can each be defined by a sidewall that is angled
circumferentially in a direction of rotor rotation extending from
the second annular cavity toward the first annular cavity.
[0007] A cylindrical flange may extend parallel to the first and
second cylindrical seal walls into the first annular cavity from
the outer end of the annular seal plate.
[0008] A surface at the outer end of the annular seal plate can be
angled radially inward from the first cavity toward the second
cavity.
[0009] The surface at the outer end of the annular seal plate can
be defined by an inner seal member affixed to the cylindrical
flange and cooperate with the angel wing to define the second
annular seal passage.
[0010] The surface at the outer end of the annular seal plate can
be stepped radially inward from the first cavity toward the second
cavity.
[0011] An outer inner seal member can be affixed to an inner side
of the first cylindrical seal wall and cooperate with the angel
wing to define the first annular seal passage.
[0012] The distal end of the angel wing can be formed with a
hammerhead configuration cooperating with surfaces at the first
cylindrical seal wall and the outer end of the annular seal plate
to define the first and second annular seal passages,
respectively.
[0013] The outer end of the annular seal plate can be formed with a
knife-edge and can cooperate with the angel wing to define the
second annular seal passage.
[0014] A knife-edge can extend radially inward from the first
cylindrical seal wall and can cooperate with the angel wing to
define the first annular seal passage.
[0015] In accordance with another aspect of the invention, a
turbine arrangement is provided comprising a rotor that rotates
about a rotor axis and comprises a plurality of rotor blade
segments extending radially outward, each rotor blade segment
comprises an airfoil and a radially inner blade platform. A stator
surrounds the rotor so as to form an annular flow path for a hot
working gas, and the stator comprises a plurality of guide vane
segments disposed adjacent the plurality of rotor blade segments.
The plurality of guide vane segments extend radially inward, each
guide vane segment comprising an airfoil and a radially inner vane
platform. A seal arrangement comprises an annular face plate
extending radially inward from the vane platform, a first
cylindrical seal wall extending axially from an outer end of the
face plate, a second cylindrical seal wall extending axially from
an inner end of the face plate, an annular seal plate extending
radially from an end of the second cylindrical seal wall, and an
angel wing extending from the rotor and having a distal end between
the first cylindrical seal wall and the seal plate to define a
first annular cavity and a second annular cavity. The first annular
cavity is defined at least by the first and second cylindrical seal
walls and the annular seal plate. The second annular cavity is
defined at least by the angel wing and the annular seal plate. The
first annular cavity is in fluid communication with the annular
flow path via a first annular seal passage between the first
cylindrical seal wall and the angel wing. The first annular cavity
is in fluid communication with the second annular cavity via a
second annular seal passage between the angel wing and an outer end
of the annular seal plate. The annular face plate is attached to a
support ring that supports the inner vane platform, including a
plurality of circumferentially spaced fasteners passing through
apertures in the annular face plate into the support ring. A
plurality of circumferentially spaced cut-outs in the annular seal
plate define passages between the first and second annular
cavities. The cut-outs are each circumferentially aligned with a
fastener and are defined by a sidewall that is angled
circumferentially in a direction of rotor rotation extending from
the second annular cavity toward the first annular cavity.
[0016] A cylindrical flange may extend parallel to the first and
second cylindrical seal walls into the first annular cavity from
the outer end of the annular seal plate. An inner seal member can
be affixed to the cylindrical flange and cooperate with the angel
wing to define the second annular seal passage. The inner seal
member can have an outer sealing surface that has a reduced
downstream radial dimension adjacent to the second annular cavity
in comparison to the upstream radial dimension of the inner seal
member adjacent to the first annular cavity.
[0017] In accordance with a further aspect of the invention, a
turbine arrangement is provided comprising a rotor that rotates
about a rotor axis and comprises a plurality of rotor blade
segments extending radially outward, each rotor blade segment
comprises an airfoil and a radially inner blade platform. A stator
surrounds the rotor so as to form an annular flow path for a hot
working gas, and the stator comprises a plurality of guide vane
segments disposed adjacent the plurality of rotor blade segments.
The plurality of guide vane segments extend radially inward, each
guide vane segment comprising an airfoil and a radially inner vane
platform. A seal arrangement comprises an annular face plate
extending radially inward from the vane platform, a first
cylindrical seal wall extending axially from an outer end of the
face plate, a second cylindrical seal wall extending axially from
an inner end of the face plate, an annular seal plate extending
radially from an end of the second cylindrical seal wall, and an
angel wing extending from the rotor and having a distal end between
the first cylindrical seal wall and the seal plate to define a
first annular cavity and a second annular cavity. The first annular
cavity is defined at least by the first and second cylindrical seal
walls and the annular seal plate. The second annular cavity is
defined at least by the angel wing and the annular seal plate. The
first annular cavity is in fluid communication with the annular
flow path via a first annular seal passage between the first
cylindrical seal wall and the angel wing. The first annular cavity
is in fluid communication with the second annular cavity via a
second annular seal passage between the angel wing and an outer end
of the annular seal plate. A cylindrical flange extends parallel to
the first and second cylindrical seal walls into the first annular
cavity from the outer end of the annular seal plate.
[0018] A plurality of circumferentially spaced cut-outs in the
annular seal plate may define passages between the first and second
annular cavities. The annular face plate may be attached to a
support ring that supports the inner vane platform, and a plurality
of circumferentially spaced fasteners can pass through apertures in
the annular face plate into the support ring and may be located in
circumferential alignment with the cut-outs.
[0019] An inner seal member can be affixed to the cylindrical
flange and can cooperate with the angel wing to define the second
annular seal passage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] While the specification concludes with claims particularly
pointing out and distinctly claiming the present invention, it is
believed that the present invention will be better understood from
the following description in conjunction with the accompanying
Drawing Figures, in which like reference numerals identify like
elements, and wherein:
[0021] FIG. 1 is a schematic section through a turbine section of a
gas turbine engine illustrating a seal arrangement in accordance
with an aspect of the present invention;
[0022] FIG. 2 is an axial view of a portion of an annular seal
plate in a seal arrangement illustrating an aspect of the present
invention;
[0023] FIG. 2A is a cross-sectional view taken along line 2A-2A in
FIG. 2;
[0024] FIG. 3A is a schematic section similar to FIG. 1
illustrating a variation of the seal arrangement;
[0025] FIG. 3B is a schematic section similar to FIG. 1
illustrating a variation of the seal arrangement;
[0026] FIG. 4 is a schematic section similar to FIG. 1 illustrating
a variation of the seal arrangement;
[0027] FIG. 5 is a schematic section similar to FIG. 1 illustrating
a variation of the seal arrangement;
[0028] FIG. 6 is a schematic section similar to FIG. 1 illustrating
a variation of the seal arrangement; and
[0029] FIG. 7 is a schematic section through a turbine section of a
prior art gas turbine engine.
DETAILED DESCRIPTION OF THE INVENTION
[0030] In the following detailed description of the preferred
embodiment, reference is made to the accompanying drawings that
form a part hereof, and in which is shown by way of illustration,
and not by way of limitation, a specific preferred embodiment in
which the invention may be practiced. It is to be understood that
other embodiments may be utilized and that changes may be made
without departing from the spirit and scope of the present
invention.
[0031] The present invention is directed to a turbine arrangement
such as may comprise a gas turbine engine comprising a compressor
section, a combustor section and a turbine section which are
arranged adjacent to each other. In operation of the gas turbine
engine, ambient air may be compressed by the compressor section,
mainly provided as an input to the combustor section with one or
more combustors. In the combustor section the compressed air can be
mixed with liquid and/or gaseous fuel and this mixed fluid is
burnt, resulting in a hot working gas. The hot working gas is then
guided from the combustor to the turbine section, in which the hot
working gas will drive one or more rows of rotor blades resulting
in a rotational movement of a shaft.
[0032] The direction of the fluid flow will be called "downstream"
from the inlet via the compressor section, via the combustor
section to the turbine section and finally to an exhaust. The
opposite direction will be called "upstream". The term "leading"
corresponds to an upstream location, "trailing" corresponds to a
downstream location. The turbine section may be substantially
rotational symmetric about an axis of rotation. A positive axial
direction may be defined as the downstream direction. In the
figures provided herein, the hot working gas will be guided
substantially from left to right in parallel to the positive axial
direction.
[0033] Referring now to FIG. 1, a set of guide vanes 10 and rotor
blades 12 are shown, it being understood that the guide vanes 10
and rotor blades 12 are located in respective circumferentially
extending rows about a rotational center axis A.sub.c. The first
set of guide vanes 10 is located immediately downstream of the
combustor section (not shown). Each guide vane 10 in the set of
guide vanes 10 includes an airfoil 14 extending in an approximately
radial direction, indicated by arrow r, with respect to the center
axis A.sub.c of the turbine section and an outer platform (not
shown) for the mounting of the guide vane 10 in a housing or a
casing, the housing and the outer platform being a part of a
stator, i.e. being non-rotational. Each airfoil 14 extends radially
inward from the outer platform to an inner vane platform 16 of the
guide vane 10 for forming a stationary, annular supporting
structure at a radially inner position of the airfoils 14 of the
guide vane 10.
[0034] The outer platform, inner vane platform 16 and the airfoil
14 typically are built as a one-piece guide vane segment and a
plurality of guide vane segments are arranged circumferentially
around the center axis A.sub.c to build one guide vane stage, and
is generally referred to as the stator 17. The outer platform and
inner platform 16 are arranged to form an annular flow path or flow
passage 18 for hot working gases to flow in the flow direction,
indicated by an arrow with reference sign 20. Consequently, the
outer platforms and inner platforms 16 may need to be cooled, such
as by cooling air provided directly from the compressor section of
the gas turbine engine without passing through combustors in the
combustion section.
[0035] Immediately downstream of the illustrated guide vane stage,
there is the first rotor stage including a number of rotor blades
12. The rotor blades 12 comprise an inner platform 22 and an outer
shroud (not shown) forming a continuation of the annular flow path
18 so that the hot working gas will be guided downstream as
indicated by arrow a (or arrow with reference symbol 20). A
plurality of rotor blades 12 extend outward between the inner
platform 22 and the outer shroud. A single inner platform section
22 and a single rotor blade airfoil 24 may form one rotor blade
segment. A plurality of rotor blade segments are connected to a
rotor disc 26 supported for rotational movement and defining a
portion of a rotor shaft, the assembled structure being generally
referred to as a rotor 28.
[0036] In accordance with an aspect of the invention, a seal
arrangement 30 is provided between the rotating parts, i.e., the
rotor 28, and the stationary parts, i.e., the stator 17, so that
the hot working gas will stay in the annular flow path 18 and will
not mix directly with a secondary fluid, e.g., air provided for
cooling. The seal arrangement 30 will be described herein with
reference to a location between the row 1 vanes and the row 1
blades forming a first turbine stage, however, it may be understood
that the concept described herein may be incorporation at other
locations including between adjacent vanes and blades of other
stages in the turbine section.
[0037] Referring now to FIG. 7, a prior art turbine arrangement is
shown comprising a stator 117 for which a guide vane 110 is shown.
The guide vane 110 comprises an outer platform 115, an inner
platform 116, and an airfoil 114. Furthermore the turbine
arrangement also comprises a rotor 128 for which a rotor blade 112
is shown. The rotor blade 112 comprises an inner blade platform 122
and an airfoil 124. Further, a shroud 113 may be provided at a
radial distant end of the rotor blade 112, the distant end being at
an opposite end compared to the inner blade platform 122. Between
the mentioned outer and inner platforms an annular flow path 118 is
formed through which a hot working gas, indicated by an arrow 120,
is guided to drive the plurality of rotor blades 112.
[0038] A seal arrangement 130 formed according to the prior art is
shown between the guide vane 110 and the rotor blade 112. The seal
arrangement 130 provides a sealing mechanism between the guide vane
110 and rotor blade 112. Hot gases from the main annular flow path
118 may enter the seal arrangement 130 during operation. In other
modes of operation, secondary air 132B may enter the main annular
flow path 118. This may be caused by a pressure difference between
a provided secondary air 132A and the pressurized hot working gas
120 in the main annular flow path 118. The pressure difference may
be caused by local pressure gradients surrounding the blades and
vanes at the seal arrangement 130 during operation of the gas
turbine engine.
[0039] Referring again to FIG. 1, details of the seal arrangement
30 according to an aspect of the invention will be described. The
seal arrangement 30 is depicted located radially inward from a
downstream portion of the inner vane platform 16 and upstream from
the inner blade platform 22. The seal arrangement 30 comprises a
static seal member 31 including an annular face plate 34 extending
in a radial plane radially inward from the inner vane platform 16.
A first cylindrical seal wall 36 extends axially from an outer end
38 of the face plate 34, and a second cylindrical seal wall 40
extends axially from an inner end 42 of the face plate 34. An
annular seal plate 44 extends radially from an axial downstream end
46 of the second cylindrical seal wall 40. The seal arrangement
additionally includes an angel wing 48 extending from the rotor 28,
i.e., from an axial forward side of the rotor disk 26, and having a
distal end 50 between the first cylindrical seal wall 36 and an
outer end 52 of the seal plate 44 to define a first annular cavity
C.sub.1 and a second annular cavity C.sub.2.
[0040] The first annular cavity C.sub.1 is defined at least by the
first and second cylindrical seal walls 36, 40 and the annular seal
plate 44, and is further defined by the annular face plate 34. The
second annular cavity C.sub.2 is defined at least by the angel wing
48 and the annular seal plate 44, and can be further defined by the
rotor disk 26, wherein it may be understood that at least a portion
of the second annular cavity C.sub.2 is radially aligned with the
first annular cavity C.sub.1, and is located on an axially opposite
side of the annular seal plate 44 from the first annular cavity
C.sub.1. Additionally, it may be noted that the second annular
cavity C.sub.2 corresponds to a disk cavity that receives a supply
of secondary air, i.e., cooling and purge air, from the compressor
for supplying platform coolant to the platform 22 for the rotor
blade 12.
[0041] The first annular cavity C.sub.1 is in limited fluid
communication with the annular flow path 18 via a first annular
seal passage P.sub.1 between the first cylindrical seal wall 36 and
the angel wing 48. In particular, the first annular seal passage
P.sub.1 can be formed between a radially extending rim portion 50a
defined on the distal end 50 of the angel wing 48 and an outer
circumferential seal member 54, such as a honeycomb seal, located
on a radial inner side of the inner vane platform 16.
[0042] The first annular cavity C.sub.1 is in limited fluid
communication with the second annular cavity C.sub.2 via a second
annular seal passage P.sub.2 between the angel wing 48 and the
outer end 52 of the annular seal plate 44. In particular, the
second annular seal passage P.sub.2 can be formed between an inner
side of the distal end 50 of the angel wing 48 and an inner
circumferential seal member 56, such as a honeycomb seal, located
on the radial outer end 52 of the annular seal plate 44. In this
regard, a cylindrical flange 58 can be formed extending parallel to
the first and second cylindrical seal walls 36, 40 from the outer
end 52 of the annular seal plate 44 into the first cavity C.sub.1
and defines a support surface for the seal member 56.
[0043] An axial forward side 60 of the axial distal end 50a of the
angel wing 48 faces toward and cooperates with a surface on the
annular face plate 34, which may optionally be provided by a
honeycomb seal member 61. In particular, as the gas turbine engine
ramps up to a steady state temperature and operating speed, the
stator and rotor can shift or move axially and radially relative to
each other, such as by movement of the honeycomb seal member 61
toward the axial forward side 60 on the angel wing 48.
[0044] The annular face plate 34 is attached to a support ring 62
that supports the inner vane platform 16. The support ring 62 can
be conventional stationary vane support structure on the interior
of the turbine assembly and may be supported, for example, to a
compressor discharge casing (not shown). The annular face plate 34
may include a planar face surface 34a that is in facing engagement
with a planar facing surface 62a of the support ring 62. The
annular face plate 34 can be rigidly affixed to the support ring 62
by a plurality of circumferentially spaced fasteners 64, such as
bolts, passing through apertures 66 in the annular face plate 34
into the support ring 62. The fasteners 64 can typically include
fastener or bolt heads 64a that extend from the annular face plate
34 into the first annular cavity C.sub.1.
[0045] Referring to FIG. 2, the annular seal plate 44 can be
provided with a plurality of circumferentially spaced cut-outs 68
defining passages between the first and second annular cavities
C.sub.1, C.sub.2. In particular, the cut-outs 68 can extend
radially inward through the outer end 52 of the annular seal plate
44 and through a portion of the cylindrical flange 58. The cut-outs
68 are circumferentially aligned with the bolt heads 64a and
provide an access opening for a tool to pass axially through the
annular seal plate 44 into engagement with the bolt heads 64a for
mounting and removal of the static seal member 31 to and from the
support ring 62. Referring further to FIG. 2A, the cut-outs 68 can
be defined by opposing cut-out side walls 68a, 68b that are angled
circumferentially with respect to the axial direction, as depicted
by arrow a in FIG. 1, and as is discussed further below.
Additionally, slits 70 may be formed in the annular seal plate 44,
extending radially inward from the cut-outs 68 to a location
adjacent to the second cylindrical seal wall 40. The slits 70 can
optionally be included to provide stress relief to the annular seal
plate 44.
[0046] Operation of the seal assembly 30 will now be described with
respect to operation of the gas turbine engine. As described above,
the distal end of the angel wing 48 is positioned in the space
between the first cylindrical seal wall 36 and the annular seal
plate 44 and rotates relative to the static seal member 31 as the
rotor 28 rotates during operation of the engine. The first annular
cavity C.sub.1 serves as a buffer cavity separating the hot gas
flow 20 from the secondary air contained in the disk cavity defined
by the second annular cavity C.sub.2. In addition to trapping any
hot gas that passes through the first annular seal passage P.sub.1,
the first annular cavity C.sub.1 damps out any remaining pressure
asymmetry associated with pressure in the hot gas path 18 driving
ingestion of the hot gases toward the second annular cavity
C.sub.2. The cylindrical flange 58, in addition to providing a
support surface for the inner seal member 56, also operates to
orient flow away from the second annular seal passage P.sub.2, as
shown by arrow F.sub.1 (FIG. 1), to inhibit hot gas flow entering
the first annular cavity C.sub.1 from passing into the second
annular cavity C.sub.2. That is, the cylindrical flange 58 can
direct the isolated flow in the first annular cavity C.sub.1 in the
upstream direction away from the second annular cavity C.sub.2 to
limit passage of the hot gases to the second annular cavity
C.sub.2. In addition, the junction 59 between the annular seal
plate 44 and the cylindrical flange 58 may be rounded to make use
of disk pumping flow, i.e., highly-swirled flow from the second
annular cavity C.sub.2 induced by rotor 28 rotation flowing in
axially-upstream direction through P.sub.2 to annular cavity
C.sub.1, to counter any ingestion flow through the second annular
passage P.sub.2 from the first annular cavity C.sub.1 to the second
annular cavity C.sub.2.
[0047] The presence of the bolt heads 64a extending into the first
annular cavity C.sub.1 further operates to decrease passage of the
hot gases into the second annular cavity C.sub.2 in that the bolt
heads 64a can increase energy loss of the ingested flow of hot
gases, which is highly swirled, reducing the flow energy of the
gases trapped in the first annular cavity C.sub.1. The annular seal
plate 44 serves as a windage cover to reduce windage in the second
annular cavity C.sub.2, such as might otherwise be caused by the
bolt heads 64a as an effect of stationary bolt drag to rotor
rotation. Windage can result in heating of the cooling air in the
second annular cavity C.sub.2 such that the windage cover provided
by the annular seal plate 44 can inhibit heating and improve
cooling efficiency.
[0048] An additional sealing aspect of the seal assembly 30 is
provided by the angled sidewalls 68a, 68b, as illustrated in FIG.
2A, in that the sidewalls 68a, 68b are angled in the downstream
circumferential direction of rotor rotation R.sub.1, extending from
the second annular cavity C.sub.2 toward the first annular cavity
C.sub.1. The angled orientation of the sidewalls 68a, 68b can
operate to use the disk pumping flow, i.e., the circumferential
flow in the R.sub.1 direction in the second annular cavity C.sub.2,
to induce a flow of a portion of secondary air from the second
annular cavity C.sub.2 toward the first annular cavity C.sub.1 to
provide some aerodynamic sealing, such as to inhibit flow of the
trapped gases from the first annular cavity C.sub.1 through the
cut-outs 68.
[0049] Referring to FIGS. 3A and 3B, a variation on the inner
circumferential seal member 56 of FIG. 1 is shown in which the
outer sealing surface has a reduced downstream radial dimension in
comparison to its upstream radial dimension. FIG. 3A illustrates an
inner circumferential seal member 56' in which its outer sealing
surface 56a' is ramped or angled radially inward in the downstream
direction from the first cavity C.sub.1 toward the second cavity
C.sub.2. FIG. 3B illustrates an inner circumferential seal member
56'' including an outer dimension that is stepped radially inward
from the first annular cavity C.sub.1 toward the second annular
cavity C.sub.2, and defined by a first outer surface 56a'' having a
greater circumference than a second outer surface 56b'' that is
located stepwise inward from the first outer surface 56a''. Each of
the seal members 56', 56'' may provide an angled contour that
accommodates axial and radial movement of the distal end 50 of the
angel wing 48 to maintain a smaller gap at the second annular
passage P.sub.2 as the gas turbine engine ramps up to steady state
temperature and speed. In particular, the configurations shown in
FIGS. 3A and 3B are believed to achieve tighter steady state, or
hot-running, clearances since it is contoured to align with
relative movements of static seal 31 and angel wing 48 expected
during transient conditions associated with engine startup.
[0050] Referring to FIG. 4, a variation on the outer end 52 of the
annular seal plate 44 illustrated in FIG. 1 is shown. FIG. 4
illustrates an outer end 52' of an annular seal plate 44' formed
with a knife-edge for cooperating with the distal end 50 of the
angel wing 48 to define the second annular passage P.sub.2. The
knife-edge outer end 52' is formed with an angled surface 52a',
angled in the upstream direction and radially outward, that can
facilitate disk pumping flow and deter ingestion flow from the
first annular cavity C.sub.1 to the second annular cavity C.sub.2.
Additionally, the knife-edge geometry can minimize damage in the
event of unintended contact with the angel wing 48.
[0051] FIG. 5 illustrates a further variation similar to FIG. 4 in
which the outer circumferential seal member 54 is replaced by an
outer annular seal knife-edge 55 extending radially inward from the
first cylindrical seal wall 36. The outer knife-edge 55 is formed
with an angled surface 55a, angled in the downstream direction and
radially inward to reduce ingestion flow into the first annular
cavity C.sub.1, and cooperates with a distal knife-edge end 50' of
the angel wing 48' to define the first annular passage P.sub.1.
[0052] Referring to FIG. 6, a variation on the distal end 50 of the
angel wing 48 of FIG. 1 is shown in which a distal end 50'' is
formed as a hammerhead having an outwardly extending rim portion
50a cooperating with the outer seal member 54 and an inwardly
extending rim portion 50b cooperating with the inner seal member
56. The hammerhead distal end 50'' is configured to accommodate the
transient clearance behavior resulting in variations in the gaps
defined at the first and second annular passages P.sub.1, P.sub.2
to provide effective sealing through the entire engine operating
cycle. Specifically, during startup, the first annular passage
P.sub.1 will be tight and rubbing at the seal member 54 may occur,
and during steady state operation, the second annular passage
P.sub.2 will be tight due to the stator 17 being hotter than the
rotor 28 and growing or expanding outwardly relative to the rotor
28.
[0053] It should be noted that, although the seal arrangement
described herein includes reference to honeycomb seals, i.e., seal
members 54, 56, 56', 56'' and 61, these seal members are optional,
and the seal arrangement can operate without these seal members or
can be provided with other seal elements than the described
honeycomb seals.
[0054] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
* * * * *