U.S. patent application number 13/477839 was filed with the patent office on 2013-11-28 for turbomachine having clearance control capability and system therefor.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is Joseph Anthony Cotroneo. Invention is credited to Joseph Anthony Cotroneo.
Application Number | 20130315716 13/477839 |
Document ID | / |
Family ID | 48446123 |
Filed Date | 2013-11-28 |
United States Patent
Application |
20130315716 |
Kind Code |
A1 |
Cotroneo; Joseph Anthony |
November 28, 2013 |
TURBOMACHINE HAVING CLEARANCE CONTROL CAPABILITY AND SYSTEM
THEREFOR
Abstract
A turbomachine having clearance control capability is provided
and includes a turbine stage including a blade configured to rotate
around a centerline, a movable portion of a casing
circumferentially surrounding the turbine stage and a rotatable cam
operably coupled to the movable portion and thereby configured to
control an axial position of the movable portion. A radially
outermost tip of the blade and an interior surface of the movable
portion are sloped with respect to the centerline such that the
controlled axial position of the movable portion is determinative
of a clearance between the blade and the movable portion.
Inventors: |
Cotroneo; Joseph Anthony;
(Clifton Park, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cotroneo; Joseph Anthony |
Clifton Park |
NY |
US |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
48446123 |
Appl. No.: |
13/477839 |
Filed: |
May 22, 2012 |
Current U.S.
Class: |
415/130 |
Current CPC
Class: |
F05D 2230/644 20130101;
F01D 11/22 20130101 |
Class at
Publication: |
415/130 |
International
Class: |
F01D 7/00 20060101
F01D007/00 |
Claims
1. A turbomachine having clearance control capability, comprising:
a turbine stage including a blade configured to rotate around a
centerline; a movable portion of a casing circumferentially
surrounding the turbine stage; and a rotatable cam operably coupled
to the movable portion and thereby configured to control an axial
position of the movable portion, a radially outermost tip of the
blade and an interior surface of the movable portion being sloped
with respect to the centerline such that the controlled axial
position of the movable portion is determinative of a clearance
between the blade and the movable portion.
2. The turbomachine according to claim 1, wherein the blade is
plural and the plurality of the blades are circumferentially
arrayed around the centerline.
3. The turbomachine according to claim 1, wherein the tip and the
interior surface are disposable substantially in parallel with one
another.
4. The turbomachine according to claim 1, wherein the rotatable cam
comprises: a drive shaft; and a head portion, which is coupled
off-center to the drive shaft.
5. The turbomachine according to claim 1, wherein the movable
portion comprises a radially exterior surface defining a cam seat,
which is receptive of the rotatable cam.
6. The turbomachine according to claim 5, wherein the cam seat is
configured to interfere with the rotatable cam such that, as the
rotatable cam rotates in first or second opposite directions, the
movable portion moves in first or second opposite axial directions,
respectively.
7. The turbomachine according to claim 5, wherein the cam seat
comprises a pair of substantially parallel circumferential wall
surfaces.
8. The turbomachine according to claim 1, wherein the movable
portion comprises: a central body; and flanges extending in forward
and aft directions from the central body, respectively, the flanges
being movable in forward and aft axial directions within first and
second recesses defined in forward and aft portions, respectively,
the forward and aft portions being disposed forward and aft of the
movable portion, respectively.
9. The turbomachine according to claim 1, further comprising an
anti-rotation feature disposed on the movable portion.
10. The turbomachine according to claim 1, wherein the turbine
stage comprises at least one or more turbine stages, each of which
is circumferentially surrounded by the movable portion.
11. A turbomachine having clearance control capability, comprising:
a turbine stage including a blade configured to rotate around a
centerline; a casing circumferentially surrounding the turbine
stage and including forward, aft and movable portions, the movable
portion being axially interposed and secured between the forward
and aft portions and defining a cam seat in a radially exterior
surface thereof; and a rotatable cam received within and operably
coupled to the cam seat of the movable portion, the rotatable cam
being thereby configured to control an axial position of the
movable portion in accordance with rotation thereof, a radially
outermost tip of the blade and an interior surface of the movable
portion being sloped with respect to the centerline such that the
controlled axial position of the movable portion is determinative
of a clearance between the blade and the movable portion.
12. The turbomachine according to claim 11, wherein the blade is
plural and the plurality of the blades are circumferentially
arrayed around the centerline.
13. The turbomachine according to claim 11, wherein the tip and the
interior surface are disposable substantially in parallel with one
another.
14. The turbomachine according to claim 11, wherein the rotatable
cam comprises: a drive shaft; and a head portion, which is coupled
off-center to the drive shaft.
15. The turbomachine according to claim 14, wherein the cam seat is
configured to interfere with the head portion of the rotatable cam
such that, as the rotatable cam rotates in first or second opposite
directions about the drive shaft, the movable portion moves in
first or second opposite axial directions, respectively.
16. The turbomachine according to claim 14, wherein the cam seat
comprises a pair of substantially parallel circumferential wall
surfaces.
17. The turbomachine according to claim 11, wherein the movable
portion comprises: a central body; and flanges extending in forward
and aft directions from the central body, respectively, the flanges
being movable in forward and aft axial directions within first and
second recesses defined in the forward and aft portions,
respectively.
18. The turbomachine according to claim 11, further comprising
anti-rotation features disposed on the movable portion.
19. The turbomachine according to claim 11, wherein the turbine
stage comprises at least one or more turbine stages, each of which
is circumferentially surrounded by the movable portion.
20. A system providing a turbomachine with clearance control
capability, comprising: at least one or more turbine stages, each
of the at least one or more turbine stages including a blade
configured to rotate around a centerline; a movable portion of a
casing circumferentially surrounding the at least one or more
turbine stages; a rotatable cam operably coupled to the movable
portion and thereby configured to control an axial position of the
movable portion; and a controller, a radially outermost tip of the
blade of each of the at least one or more turbine stages and an
interior surface of the movable portion being sloped with respect
to the centerline such that the controlled axial position of the
movable portion is determinative of a clearance between the blade
of each of the at least one or more turbine stages and the movable
portion, and the controller being operably coupled to the rotatable
cam and thereby configured to control operations of the rotatable
cam.
Description
BACKGROUND OF THE INVENTION
[0001] The subject matter disclosed herein relates to turbomachines
and, more particularly, to turbomachines having clearance control
capability.
[0002] A typical turbomachine, such as a gas turbine engine, a
steam turbine engine and a compressor, includes a compressor
section, a combustor section and a turbine section. The compressor
section compresses inlet air and transmits the compressed inlet air
to the combustor section. The combustor section combusts the
compressed inlet air along with fuel to produce high energy fluids,
which are transferred to the turbine section where they are
expanded in power generation operations. During these power
generation operations, the high energy fluids aerodynamically
interact with successive stages of turbine blades, which are
encompassed within a turbine casing with clearances provided
between the casing and the tips of the blades.
[0003] At each stage, the high energy fluids impinge upon the
turbine blades and induce rotation of the turbine blades about a
rotor. Since the high energy fluids have high temperatures and
pressures, the turbine blades and the casing often undergo thermal
deformation (i.e., expansion or contraction) based on a type of
turbine operation being conducted. Such deformation can be
accounted for by setting the clearances in accordance with worst
case scenarios. Under normal operating conditions, however,
clearances set in accordance with worst case scenarios may be
excessive and could lead to degraded performance due to leakages
between the casing and the tips of the blades.
BRIEF DESCRIPTION OF THE INVENTION
[0004] According to one aspect of the invention, a turbomachine
having clearance control capability is provided and includes a
turbine stage including a blade configured to rotate around a
centerline, a movable portion of a casing circumferentially
surrounding the turbine stage and a rotatable cam operably coupled
to the movable portion and thereby configured to control an axial
position of the movable portion. A radially outermost tip of the
blade and an interior surface of the movable portion are sloped
with respect to the centerline such that the controlled axial
position of the movable portion is determinative of a clearance
between the blade and the movable portion.
[0005] According to another aspect of the invention, a turbomachine
having clearance control capability is provided and includes a
turbine stage including a blade configured to rotate around a
centerline, a casing circumferentially surrounding the turbine
stage and including forward, aft and movable portions, the movable
portion being axially interposed and secured between the forward
and aft portions and defining a cam seat in a radially exterior
surface thereof and a rotatable cam received within and operably
coupled to the cam seat of the movable portion, the rotatable cam
being thereby configured to control an axial position of the
movable portion in accordance with rotation thereof. A radially
outermost tip of the blade and an interior surface of the movable
portion are sloped with respect to the centerline such that the
controlled axial position of the movable portion is determinative
of a clearance between the blade and the movable portion.
[0006] According to yet another aspect of the invention, a system
providing a turbomachine with clearance control capability is
provided and includes at least one or more turbine stages, each of
the at least one or more turbine stages including a blade
configured to rotate around a centerline, a movable portion of a
casing circumferentially surrounding the at least one or more
turbine stages, a rotatable cam operably coupled to the movable
portion and thereby configured to control an axial position of the
movable portion and a controller. A radially outermost tip of the
blade of each of the at least one or more turbine stages and an
interior surface of the movable portion are sloped with respect to
the centerline such that the controlled axial position of the
movable portion is determinative of a clearance between the blade
of each of the at least one or more turbine stages and the movable
portion. The controller is operably coupled to the rotatable cam
and thereby configured to control operations of the rotatable
cam.
[0007] These and other advantages and features will become more
apparent from the following description taken in conjunction with
the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The subject matter, which is regarded as the invention, is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
features, and advantages of the invention are apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0009] FIG. 1 is a side view of a portion of a turbomachine in
accordance with embodiments;
[0010] FIG. 2 is a radial view of a rotatable cam and cam seat of
the turbomachine portion of FIG. 1 along the line A-A;
[0011] FIG. 3 is a side view of a portion of a turbomachine in
accordance with alternative embodiments;
[0012] FIG. 4 is a radial view of the turbomachine portion of FIG.
3 along the line B-B; and
[0013] FIG. 5 is a side view of a portion of a turbomachine in
accordance with further embodiments.
[0014] The detailed description explains embodiments of the
invention, together with advantages and features, by way of example
with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0015] With reference to FIGS. 1 and 2, a portion of a turbomachine
10 having clearance control capability is illustrated. As shown in
FIG. 1, the portion of the turbomachine 10 includes a turbine stage
20 that is normally defined with a stationary blade row (i.e.,
nozzles) and a rotating blade row (i.e., buckets), a casing 40, a
rotatable cam 60 and a controller 80. The turbine stage 20 may be
any one of at least one or more of several turbine stages disposed
at various axial locations along the turbomachine 10, including,
but not limited to, the last turbine stage. In any case, the
turbine stage 20 includes a blade 21 that is configured to rotate
along with a blade row around a centerline 22. That is, the blade
21 may be provided as a plurality of blades that is arranged in a
circumferential array 210 around the centerline 22. Each blade 21
has an airfoil shape such that aerodynamic interactions between the
blade 21 and a working fluid flowing through the turbine stage 20
induces rotation of the blade 21 around the centerline 22. Each
blade 21 also includes a sloped tip 23 at a radially outermost edge
thereof.
[0016] As the turbine stage 20 may be unshrouded, the casing 40 is
provided to circumferentially surround the turbine stage 20 and, in
some cases, additional stages as shown in FIG. 5, which is
described below. The casing 40 includes an annular forward portion
41, an annular aft portion 42 and an annular movable portion 43.
The annular movable portion 43 is axially interposed and secured
between the annular forward portion 41 and the annular aft portion
42 and includes an annular central body 44, a first annular flange
45, a second annular flange 46, a sloped interior facing surface 47
and a radially exterior surface 48. The annular forward portion 41
is formed to define an aft facing recess 410 and the annular aft
portion 42 is similarly formed to define a forward facing recess
420.
[0017] The first annular flange 45 extends in a forward axial
direction from the annular central body 44 and is movably
receivable within the aft facing recess 410. The second annular
flange 46 extends in an aft axial direction from the annular
central body 44 and is movably receivable in the forward facing
recess 420. As the annular movable portion 43 moves axially
forwardly, the first annular flange 45 penetrates relatively deeply
into the aft facing recess 410 while the second annular flange 46
recedes from but does not exit the forward facing recess 420. By
contrast, as the annular movable portion 43 moves axially aft, the
first annular flange 45 recedes from but does not exit the aft
facing recess 410 while the second annular flange 46 penetrates
relatively deeply into the forward facing recess 420.
[0018] Anti-rotation features, such as annularly discrete tabs 49
may be disposed on the movable portion 43 at, for example, either
or both of the first annular flange 45 and the second annular
flange 46. Such annularly discrete tabs 49 are receivable in
secondary recesses 430 defined in the annular forward portion 41
and the annular aft portion 42. As described above, as the annular
movable portion 43 moves axially forward or aft, the annularly
discrete tabs 49 penetrate relatively deeply into and recede from
the secondary recesses 430. While receding, the annularly discrete
tabs 49 do not exit the secondary recesses 430.
[0019] The sloped interior facing surface 47 of the annular movable
portion 43 is disposable radially outwardly from the sloped tip 23
of the blade 21 at a distance that is defined by the controlled
clearance between the blade 21 and the annular movable portion 43.
The sloped tip 23 and the sloped interior facing surface 47 may be
provided substantially in parallel with one another and slope away
from the centerline 22 with increasing distance in the aft axial
direction, D. The sloped tip 23 provides for improved boundary
layer conditions downstream from the turbine stage 20 and thereby
allows for relatively aggressive exhaust diffuser performance.
[0020] The rotatable cam 60 is operably coupled to the annular
movable portion 43 and is thereby configured to control an axial
position of the annular movable portion 43. With the sloped tip 23
and the sloped interior facing surface 47 being mutually sloped
with respect to the centerline 22, the controlled axial position of
the annular movable portion 43 is determinative of a controlled
amount of clearance between the blade 21 and the annular movable
portion 43 or, more specifically, between the sloped tip 23 and the
sloped interior facing surface 47. This control allows for improved
efficiency and output for the turbine stage 20 in the unshrouded
condition and could be similarly applicable and useful for shrouded
turbine stages as well.
[0021] The rotatable cam 60 includes a drive shaft 61, which may be
operably coupled to the controller 80 to be described in greater
detail below, and a head portion 62. The head portion 62 may be
generally circular, for example, and may be coupled in an
off-center condition to the drive shaft 61. As the drive shaft 61
rotates about longitudinal axis 610, the head portion 62 bobs back
and forth on either side of the drive shaft 61.
[0022] The radially exterior surface 48 of the annular movable
portion 43 is formed to define a cam seat 90. The cam seat 90 is
receptive of the head portion 62 of the rotatable cam 60 such that
the drive shaft 61 appears to extend, for example, radially
outwardly from the annular movable portion 43. The cam seat 90 is
configured to mechanically interfere with the head portion 62 such
that, as the rotatable cam 60 rotates in first or second opposite
directions about the longitudinal axis 610, the annular movable
portion 43 correspondingly moves in first or second opposite axial
directions, respectively. To this end, in accordance with
embodiments, the cam seat 90 may include a recess 91 formed in the
radially exterior surface 48, which is bounded on forward and aft
sides by a pair of substantially parallel circumferential wall
surfaces 92.
[0023] The head portion 62 sits tightly within the recess 91 such
that its sidewalls abut each of the wall surfaces 92 in opposite
directions. As the rotatable cam 60 rotates about the longitudinal
axis 610, the forward and aft sides of the head portion 62 impinge
upon the wall surfaces 92 and, therefore, force the annular movable
portion 43 to movably reciprocate in forward and aft
directions.
[0024] Although the head portion 62 and the cam seat 90 are
described above as being a generally circular element and as a
recess 91 that is bounded by wall surfaces 92, it is to be
understood that this is merely exemplary and that other embodiments
exist. For example, where the head portion 62 is generally
circular, the cam seat 90 may also be provided as a circular or
polygonal recess defined within the radially exterior surface
48.
[0025] The controller 80 is provided as a component of a system for
providing the turbomachine 10 with clearance control capability.
The controller 80 is operably coupled to the rotatable cam 60 and
is configured to control operations of the rotatable cam 60. That
is, the controller 80 could cause the rotatable cam 60 to rotate
about the longitudinal axis 610 such that, at various operational
conditions such as start-up conditions, turn-down conditions,
transient conditions and base-load condition, the controlled amount
of clearance between the blade 21 and the annular movable portion
43 has various predefined and/or appropriate values. In addition,
the controller 80 may be further configured to sense or otherwise
measure current clearance amounts and, if such current clearance
amounts are excessive or decreased given current operational
conditions, to correct the current clearance amounts by selectively
operating the rotatable cam 60 accordingly.
[0026] In accordance with embodiments, the features described above
could be provided as single components or as multiple components.
In the latter case, multiple rotatable cams 60 may each be operably
coupled to the controller 80 and disposed circumferentially about
the centerline 22. With such a configuration, each rotatable cam 60
may be jointly or separately operable based on current
conditions.
[0027] With reference to FIGS. 3 and 4 and, in accordance with
alternative embodiments, a turbomachine 100 is provided with
clearance control capability. The turbomachine 100 includes several
of the features mentioned above, which need not be described in
detail again, such as the turbine stage 20, the blade 21 and the
movable portion 43. In this case, a rotatable cam 101 is operably
disposed at a location that is axially adjacent to the movable
portion 43 and is configured to urge the movable portion 43 against
a bias of elastic element 102 by rotating about drive shaft 103.
The elastic element 102 may be a compression spring where the
elastic element 102 is disposed on an opposite side of the movable
portion 43 from the rotatable cam 101 or a tension spring in an
opposite configuration. As shown in FIG. 3, an anti-rotation
feature 104 may be disposed on a radially exterior surface of the
movable portion 43 and a torsional spring 105 may be provided on
the rotatable cam 101 to bias the movable portion 43 toward
increased clearance to avoid rubbing in case of failure of control
algorithms and systems.
[0028] With reference to FIG. 5 and, in accordance with further
embodiments, the casing 40 and particularly the movable portion 43
may be configured to circumferentially surround at least one or
more turbine stages. For example, the movable portion 43 may
circumferentially surround first turbine stage 200 and second
turbine stage 210. As shown in FIG. 5, the first and second turbine
stages 200 and 210 may be disposed sequentially with respect to one
another with the second turbine stage 210 downstream from the first
turbine stage 200. The first turbine stage 200 includes a
stationary blade row (i.e., nozzles) 201 and a rotating blade row
(i.e., buckets) 202 and the second turbine stage 210 includes a
stationary blade row (i.e., nozzles) 211 and a rotating blade row
(i.e., buckets) 212.
[0029] While the invention has been described in detail in
connection with only a limited number of embodiments, it should be
readily understood that the invention is not limited to such
disclosed embodiments. Rather, the invention can be modified to
incorporate any number of variations, alterations, substitutions or
equivalent arrangements not heretofore described, but which are
commensurate with the spirit and scope of the invention.
Additionally, while various embodiments of the invention have been
described, it is to be understood that aspects of the invention may
include only some of the described embodiments. Accordingly, the
invention is not to be seen as limited by the foregoing
description, but is only limited by the scope of the appended
claims.
* * * * *