U.S. patent application number 12/791056 was filed with the patent office on 2011-12-01 for seal and airfoil tip clearance control.
Invention is credited to Joel H. Wagner.
Application Number | 20110293407 12/791056 |
Document ID | / |
Family ID | 44118077 |
Filed Date | 2011-12-01 |
United States Patent
Application |
20110293407 |
Kind Code |
A1 |
Wagner; Joel H. |
December 1, 2011 |
SEAL AND AIRFOIL TIP CLEARANCE CONTROL
Abstract
A turbine section includes a housing and a blade outer air seal
to be mounted on the housing. A flex beam mounts the blade outer
air seal onto the housing, with the flex beam being supported on
the housing, but free to move relative to the housing. A pressure
air chamber is formed on an opposed side of the flex beam from the
blade outer air seal. A source of pressurized air is delivered into
the chamber to cause the flex beam to move the blade outer air seal
toward and away from a central axis of the housing.
Inventors: |
Wagner; Joel H.;
(Wethersfield, CT) |
Family ID: |
44118077 |
Appl. No.: |
12/791056 |
Filed: |
June 1, 2010 |
Current U.S.
Class: |
415/170.1 |
Current CPC
Class: |
F01D 11/22 20130101;
F05D 2260/406 20130101 |
Class at
Publication: |
415/170.1 |
International
Class: |
F04D 29/08 20060101
F04D029/08 |
Claims
1. A housing section for a gas turbine engine comprising: a
housing; a flex beam mounting a blade outer air seal onto said
housing, with said flex beam being supported on said housing, and
free to move relative to said housing; and a pressure chamber
formed on an opposed side of said flex beam from said blade outer
air seal, and a source of pressurized air to be delivered into said
pressure chamber to cause said flex beam to move said blade outer
air seal toward and away from a central axis of said housing.
2. The housing as set forth in claim 1, wherein said source of
pressurized air includes a valve controlled by a controller to
control the pressure of air delivered into said pressure
chamber.
3. The housing as set forth in claim 1, wherein said flex beam is
supported within said housing at axially upstream and downstream
ends, but free to move in an axial direction.
4. The housing as set forth in claim 3, wherein a seal is
positioned between said flex beam and said housing.
5. The housing as set forth in claim 4, wherein said seal on said
flex beam extends along at least one axial side of said flex beam,
and at least a portion of two circumferential edges.
6. The housing as set forth in claim 1, wherein said flex beam
removably mounts said blade outer air seal.
7. The housing as set forth in claim 1, wherein said flex beam
includes a two-bar connection which guides said flex beam during
flexing movement relative to said housing.
8. The housing as set forth in claim 1, wherein there are a
plurality of adjacent flex beam portions extending over a portion
of a circumferential extent of the housing.
9. The housing as set forth in claim 8, wherein each of said flex
beam portions have opposed circumferential edges that interfit with
an adjacent one of said flex beams, and a seal positioned between
said circumferential edges.
10. The housing as set forth in claim 1, wherein said housing is
utilized as part of a turbine section in a gas turbine engine.
11. The housing as set forth in claim 1, wherein a space is defined
radially between a side of said flex beam which faces said blade
outer air seal, and a radially outer portion of said blade outer
air seal to facilitate radially inward flexing of the flex
beam.
12. The housing as set forth in claim 11, wherein said flex beam is
relatively thin at least in an area aligned with said space, and
between 0.030-0.050 inches.
13. A turbine section for a gas turbine engine comprising: a
turbine rotor carrying a plurality of blades, said blades having a
radial outer tip; a housing; a flex beam removably mounting a blade
outer air seal onto said housing, with said flex beam being
supported on said housing, but free to move relative to said
housing; a pressure chamber formed on an opposed side of said flex
beam from said blade outer air seal, and a source of pressurized
air to be delivered into said chamber to cause said flex beam to
move said blade outer air seal toward and away from a central axis
of said housing; and said source of pressurized air includes a
valve controlled by an controller to control the pressure of air
delivered into said pressure chamber.
14. The turbine section as set forth in claim 13, wherein said flex
beam is supported within said housing at axially upstream and
downstream ends, but free to move in an axial direction.
15. The turbine section as set forth in claim 13, wherein a seal is
positioned between said flex beam and said housing.
16. The turbine section as set forth in claim 15, wherein said seal
on said flex beam extends along at least one axial side of said
flex beam, and at least a portion of two circumferential edges.
17. The turbine section as set forth in claim 13, wherein said flex
beam includes a two-bar connection which guides said flex beam
during flexing movement relative to said housing.
18. The turbine section as set forth in claim 13, wherein there are
a plurality of adjacent flex beam portions extending over a portion
of a circumferential extent of the housing.
19. The turbine section as set forth in claim 13, wherein a space
is defined radially between the face of said flex beam which faces
said blade outer air seal, and a radially outer portion of said
blade outer air seal to facilitate radially inward flexing of the
flex beam, said flex beam is relatively thin at least in an area
aligned with said space, and between 0.030-0.050 inches.
20. A turbine section for a gas turbine engine comprising: a
turbine rotor carrying a plurality of blades, said blades having a
radial outer tip; a housing; a plurality of adjacent flex beam
portions extending over a portion of a circumferential extent of
the housing, each of said flex beam portions removably mounting a
blade outer air seal portion onto said housing, with said flex beam
portions being supported on said housing, but free to move relative
to said housing; a pressure chamber formed on an opposed side of
each said flex beam portion from said blade outer air seal
portions, and a source of pressurized air to be delivered into said
pressure chamber to cause said flex beam portion to move said blade
outer air seal toward and away from a central axis of said housing;
said source of pressurized air includes a valve controlled by a
controller to control the pressure of air delivered into said
pressure chamber; a space defined radially between a side face of
said flex beam which faces said blade outer air seal portion, and a
radially outer portion of said blade outer air seal portion to
facilitate radially inward flexing of the flex beam; and said flex
beam portion is relatively thin at least in an area aligned with
said space, and between 0.030-0.050 inches.
Description
BACKGROUND
[0001] Gas turbine engines are known and typically include a
compressor delivering compressed gas into a combustion chamber. The
compressed air is mixed with fuel and combusted in the combustion
chamber. The hot products of combustion pass downstream over
turbine rotors, driving the rotors to create power.
[0002] In the design of gas turbine rotors, it is desired to ensure
that the bulk of the products of combustion pass across the turbine
rotors. Thus, blade outer air seals are typically placed radially
outwardly of the radially outermost tip of the airfoil on turbine
blades associated with the rotors.
[0003] The clearance between the blade outer air seal and the tip
of the airfoil is desirably tightly controlled. However, various
factors raise challenges with maintaining this clearance. In the
past, various ways for adjusting this clearance such as the use of
thermal control methods have been proposed.
SUMMARY
[0004] A turbine section includes a housing and a blade outer air
seal to be mounted on the housing. A flexible beam member enables
mounting of the blade outer air seal onto the housing, with the
flex beam being supported on the housing, but free to move relative
to the housing. A pressure air chamber is formed on an opposed side
of the flex beam from the blade outer air seal. A source of
pressurized air is delivered into the chamber to cause the flex
beam to move the blade outer air seal toward and away from a
central axis of the housing.
[0005] These and other features of the present invention can be
best understood from the following specification and drawings, the
following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a cross-sectional view through a first
embodiment.
[0007] FIG. 2 is a view along line 2-2 as shown in FIG. 1.
[0008] FIG. 3 shows a perspective view of a component.
[0009] FIG. 4 shows a second embodiment.
DETAILED DESCRIPTION
[0010] A portion of a turbine section 20 of a gas turbine engine is
illustrated in FIG. 1. An air inlet 22 communicates with a valve
24. The valve 24 is controlled by a control 26. The control 26
controls the valve 24 to supply high pressure air such as from a
compressor 28 which is part of the gas turbine engine through the
valve 24, the air inlet 22, and into a pressure chamber 30. The
pressure chamber 30 is defined by a housing 31 having static mounts
32 holding a flex beam 34. The flex beam 34 is formed of an
appropriate material and is formed to be thin enough such that it
can flex radially inwardly and outwardly. Of course, the housing 31
can be formed by plural housing portions.
[0011] The flex beam should be designed for repeated flexure
operation and formed of an appropriate material that is able to
retain reliable spring deflection characteristics in a high
temperature environment, and have consistent spring deflection
characteristics over a wide temperature range.
[0012] The flex beam is relatively thin. As one example only, it
may be on the order of 0.030 in-0.050 in (0.762 mm-1.27 mm). The
thickness of the beam is shown exaggerated in the Figures, as the
beam would be so thin as to be hard to see if illustrated
proportionally. In addition, as is clear from the Figures, the beam
may have a relatively thinner portion aligned with the space 300,
which will be described below.
[0013] The flex beam 34 is not fixed within channels defined by the
static mounts 32, but rather supported there. Seals 36 are placed
in a slot 56 in the flex beam to provide a seal at the location.
Wire seals are shown although other seal configurations could be
used. Blade outer air seal mounts 44 and 48 on the flex beam secure
hooks 50 on a blade outer air seal 42. The blade outer air seal 42
is removable from the flex beam 34 for service and repair. The
blade outer air seal 42 is shown schematically. The blade outer air
seal has an inner peripheral surface closely spaced from an outer
tip of an airfoil of a rotor blade 40. A vane 38 is positioned
upstream of the blade 40.
[0014] During operation of the gas turbine engine, pressurized air
may be delivered into the pressure chamber 30. The opposed side of
the flex beam from the pressure chamber 30 is exposed to lower
pressure air. Thus, the delivery of the high pressure air into
pressure chamber 30 will flex the flex beam 34 downwardly, such
that the blade outer air seal 42 approaches the blade 40, and the
clearance is reduced. Additionally, applying a lower pressure air
to the opposed side will flex the beam upwardly, such that the
blade outer air seal 42 is moved away from the blade 40, and the
clearance is increased.
[0015] The control 26 can take in information about a variety of
engine characteristics, and determine the amount of pressure to be
delivered into the pressure chamber 30 to achieve a desired
clearance. These aspects of the invention are generally as known.
That is, the amount of clearance desirable would be as known, but
the way of achieving the desired clearance is inventive here. Known
electronic controls can be utilized. On the other hand, other type
controllers, such as, for example, a pneumatic controller, may be
utilized.
[0016] FIG. 2 shows that the flex beams 34 are positioned adjacent
to each other in a circumferential direction about a center axis X
(see FIG. 1) of rotation of the blade 40. Each flex beam 34 has one
circumferential edge 52 and an opposed circumferential edge 150.
The seal 54 is received in a slot 56 at the edge 150.
[0017] FIG. 3 shows the flex beam 34 having the slot 56 which
includes side slot portions 58 and 60. The seal 54 may be c-shaped
and positioned within the slot 56, 58, 60.
[0018] FIG. 4 shows another embodiment 100 having a blade 146, vane
148, and blade outer air seal 140. The blade outer air seal 140 has
hooks 142 and 144 associated with blade outer air seal mounts 136
and 138 defining channels in a flex beam 134. One edge 150 of the
flex beam is received on a static mount 152 of a housing 110. As
can be appreciated, there is clearance at this interface such that
the flex beam can move to the right or left in this Figure.
[0019] The opposed end 156 of the flex beam has a surface 161 in
contact with an inner surface of the housing 110. The opposed end
156 is fixed to move with a portion 158, which is in contact with a
seal 160 in a housing channel 162. This two-bar connection guides
the flex beam 134 for movement such that it maintains the blade
outer air seal 140 in a proper orientation relative to the blade
146 even when it flexes.
[0020] As can be appreciated from both FIGS. 1 and 4, there is a
space 300 formed between the flex beams 34 or 134 and their
associated blade outer air seals 42 or 140. The space 300
facilitates the radially inward flexing of the flex beam 34, 134,
which might otherwise be less pronounced if there was contact
between the blade outer air seal 42, 140 and the flex beam 34,134
at that location.
[0021] Although embodiments of this invention have been disclosed,
a worker of ordinary skill in this art would recognize that certain
modifications would come within the scope of this invention. For
that reason, the following claims should be studied to determine
the true scope and content of this invention.
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