U.S. patent application number 13/017147 was filed with the patent office on 2012-08-02 for turbomachine supports having thermal control system.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Kumar Navjot, Daniel Ross Predmore, Asmabanu Abdulkadar Shaikh.
Application Number | 20120195750 13/017147 |
Document ID | / |
Family ID | 46511584 |
Filed Date | 2012-08-02 |
United States Patent
Application |
20120195750 |
Kind Code |
A1 |
Navjot; Kumar ; et
al. |
August 2, 2012 |
TURBOMACHINE SUPPORTS HAVING THERMAL CONTROL SYSTEM
Abstract
Supports for a first casing of a turbomachine are disclosed that
each include a thermal control system to control thermal expansion
thereof. The thermal control system may include: a sealed duct
surrounding a support column of the turbomachine, the duct being
coupled to a source of a cooling fluid flow, and/or a hollow leg
supporting the inner casing on the support column with a conduit
supplying operative fluid, e.g., steam, from a stage of
turbomachine to the hollow leg.
Inventors: |
Navjot; Kumar; (Jamshedpur,
IN) ; Predmore; Daniel Ross; (Ballston Lake, NY)
; Shaikh; Asmabanu Abdulkadar; (Vadodara, IN) |
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
46511584 |
Appl. No.: |
13/017147 |
Filed: |
January 31, 2011 |
Current U.S.
Class: |
415/213.1 |
Current CPC
Class: |
F05D 2230/642 20130101;
F05D 2220/31 20130101; F05D 2260/602 20130101; F05D 2260/20
20130101; F01D 25/28 20130101 |
Class at
Publication: |
415/213.1 |
International
Class: |
F01D 25/28 20060101
F01D025/28 |
Claims
1. A turbomachine comprising: a plurality of supports for a first
casing of the turbomachine, each support including a thermal
control system to control thermal expansion thereof.
2. The turbomachine of claim 1, wherein each support includes a
support column fixedly attached to a foundation, and each thermal
control system includes: a duct surrounding the support column, the
duct coupled to a source of a cooling fluid flow; and a seal
between the support column and the duct sealing a space between the
duct and the support column.
3. The turbomachine of claim 2, wherein each support column extends
through a second casing that surrounds the first casing.
4. The turbomachine of claim 2, wherein the source of cooling fluid
flow includes atmospheric air.
5. The turbomachine of claim 2, further comprising a pump for
propelling the cooling fluid flow along the support column within
the duct.
6. The turbomachine of claim 2, wherein each support further
includes a hollow leg extending from the first casing and
configured to slidingly couple to the support column, and each
thermal control system includes a conduit configured to supply
operative fluid from a stage of the turbomachine to the hollow
leg.
7. The turbomachine of claim 6, wherein the hollow leg includes a
drain opening.
8. The turbomachine of claim 6, further comprising an insulation
layer about the hollow leg.
9. The turbomachine of claim 1, wherein each support includes a
hollow leg extending from the first casing, and each thermal
control system includes a conduit configured to supply operative
fluid from a stage of the turbomachine to the hollow leg.
10. The turbomachine of claim 9, wherein the hollow leg includes a
drain opening.
11. The turbomachine of claim 9, further comprising an insulation
layer about the hollow leg.
12. The turbomachine of claim 9, wherein each support further
includes a support column fixedly attached to a foundation, and
each thermal control system further includes: a duct surrounding
the support column, the duct coupled to a source of a cooling fluid
flow; and a seal between the support column and the duct sealing a
space between the duct and the support column, wherein each hollow
leg is configured to be slidingly coupled to one of the support
columns.
13. The turbomachine of claim 12, wherein each support column
extends through a second casing that surrounds the first casing,
the source of cooling fluid flow including atmospheric air from
outside of the second casing.
14. A support for a turbomachine, the support comprising: a support
column fixedly attached to a foundation; and a thermal control
system to control thermal expansion of the support.
15. The support of claim 14, wherein each thermal control system
includes: a duct surrounding the support column, the duct coupled
to a source of a cooling fluid flow; and a seal between the support
column and the duct sealing a space between the duct and the
support column.
16. The support of claim 14, wherein each support includes a hollow
leg extending from a first casing of the turbomachine and slidingly
coupled to a respective support column, and each thermal control
system includes a conduit configured to supply operative fluid from
a stage of the turbomachine to the hollow leg.
17. The support of claim 14, wherein the support further includes a
hollow leg coupled to a first casing of the turbomachine and
configured to be slidingly coupled to the support column, and the
thermal control system includes: a duct surrounding the support
column, the duct coupled to a source of a cooling fluid flow; a
seal between the support column and the duct sealing a space
between the duct and the support column; and a conduit supplying
operative fluid from a stage of the turbomachine to the hollow
leg.
18. The support of claim 17, wherein each support column extends
through a second casing that surrounds the first casing of the
turbomachine.
19. The support of claim 17, wherein the hollow leg includes a
drain opening and an insulation layer about the hollow leg.
20. A steam turbomachine comprising: a plurality of stages; a first
casing enclosing the plurality of stages, the first casing
including a plurality of supports therefor, each support including
a support column fixedly attached to a foundation and a hollow leg
coupled to the first casing and configured to be slidingly coupled
to the support column; a thermal control system for each support,
each thermal control system including: a duct surrounding the
support column, the duct coupled to a source of a cooling fluid
flow, a seal between the support column and the duct sealing a
space between the duct and the support column, and a conduit
configured to supply steam from a stage of the plurality of stages
to the hollow leg.
Description
BACKGROUND OF THE INVENTION
[0001] The disclosure relates generally to turbo-machinery, and
more particularly, to turbomachine supports having a thermal
control system.
[0002] In a steam turbine, after the steam has been used, it is
exhausted from the turbine through an outer casing or exhaust hood.
For example, a low pressure (LP) exhaust hood for a side exhaust
unit houses the inner casing of the turbine. The inner casing is
typically supported by various combinations of transverse and
vertical plates which form a complex support structure for the
inner casing's vertical support. Since the weight of the inner
casing and related diaphragms is very large, this supporting
structure needs to be very stiff. Consequently, the hood is very
heavy and causes airflow blockages, reducing the effective area for
diffusion.
[0003] Another way of supporting an inner casing in a side exhaust
design is to bring a pedestal from the bottom of the hood so that
the hood is supported from the bottom and the base of the hood is
the foundation or plant floor. In this complex internal structure,
the load of the inner casing is directly transmitted to the
foundation. However, in this case, the thermal expansion of the
pedestal is very large. Further, with the change in back pressure
and the resulting change in exhaust temperature, the thermal
expansion of the pedestal varies over time. This varying thermal
expansion of the pedestal causes clearance problems as the movement
of rotor does not vary since the bearings are supported on
standards mounted on the foundation.
BRIEF DESCRIPTION OF THE INVENTION
[0004] A first aspect of the disclosure provides a turbomachine
comprising: a plurality of supports for a first casing of the
turbomachine, each support including a thermal control system to
control thermal expansion thereof
[0005] A second aspect of the disclosure provides a support for a
turbomachine, the support comprising: a support column fixedly
attached to a foundation; and a thermal control system to control
thermal expansion of the support.
[0006] A third aspect of the disclosure provides a steam
turbomachine comprising: a plurality of stages; a first casing
enclosing the plurality of stages, the first casing including a
plurality of supports therefor, each support including a support
column fixedly attached to a foundation and a hollow leg coupled to
the first casing and configured to be slidingly coupled to the
support column; a thermal control system for each support, each
thermal control system including: a duct surrounding the support
column, the duct coupled to a source of a cooling fluid flow, a
seal between the support column and the duct sealing a space
between the duct and the support column, and a conduit configured
to supply steam from a stage of the plurality of stages to the
hollow leg.
[0007] The illustrative aspects of the present disclosure are
designed to solve the problems herein described and/or other
problems not discussed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] These and other features of this disclosure will be more
readily understood from the following detailed description of the
various aspects of the disclosure taken in conjunction with the
accompanying drawings that depict various embodiments of the
disclosure, in which:
[0009] FIG. 1 shows a perspective partial cut-away illustration of
a steam turbine.
[0010] FIG. 2 shows a side, partial cross-sectional view of a
turbomachine having supports according to embodiments of the
invention.
[0011] FIG. 3 shows a partial end, cross-sectional view of the
turbomachine of FIG. 2 through line A-A.
[0012] FIG. 4 shows an enlarged perspective view of a portion of a
support according to embodiments of the invention.
[0013] FIG. 5 shows an end, cross-sectional view of a portion of a
support according to embodiments of the invention.
[0014] It is noted that the drawings of the disclosure are not to
scale. The drawings are intended to depict only typical aspects of
the disclosure, and therefore should not be considered as limiting
the scope of the disclosure. In the drawings, like numbering
represents like elements between the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Referring to the drawings, FIG. 1 shows a perspective
partial cut-away view of an illustrative turbomachine 100 in the
form of a steam turbine. Although the embodiments of the invention
will be described relative to a steam turbine, it will be
understood that the teachings are also applicable to any form of
turbomachine, e.g., a gas turbine, compressor, etc. Further, the
embodiments of the invention may be applied to any kind of system
where an inner casing is inside an outer casing or hood, e.g., for
side exhaust, down exhaust or axial exhaust. The illustrative
turbomachine 100 includes a rotor 102 that includes a rotating
shaft 114 and a plurality of axially spaced rotor wheels 118. A
plurality of rotating blades 120 are mechanically coupled to each
rotor wheel 118. More specifically, blades 120 are arranged in rows
that extend circumferentially around each rotor wheel 118. A
plurality of stationary vanes 122 extends circumferentially around
shaft 114, and the vanes are axially positioned between adjacent
rows of blades 120. Stationary vanes 122 cooperate with blades 120
to form a stage and to define a portion of a steam flow path
through turbomachine 100. A casing 130 surrounds the rotor wheels
118. Casing 130 is supported by a plurality of supports 132 (FIG.
2), each support including a thermal control system 150 (FIG. 2) to
control thermal expansion thereof
[0016] In operation, steam 124 enters an inlet 126 of the steam
turbine and is channeled through stationary vanes 122. Vanes 122
direct steam 124 downstream against blades 120. Steam 124 passes
through the remaining stages imparting a force on blades 120
causing shaft 114 to rotate. At least one end of turbine 100 may
extend axially away from rotor 112 and may be attached to a load or
machinery (not shown) such as, but not limited to, a generator,
and/or another turbine.
[0017] Referring to FIGS. 2 and 3, FIG. 2 shows a side, partial
cross-sectional view of turbomachine 100 having a plurality of
supports 132 for a first (inner) casing 130 of turbomachine 100.
FIG. 3 shows a partial, end, cross-sectional view of the
turbomachine of FIG. 2 through line A-A, with the right side set of
supports 132 removed for clarity. As noted above and as will be
described in greater detail herein, each support 132 includes a
thermal control system 150 to control thermal expansion
thereof.
[0018] As shown in FIGS. 2 and 3, each support 132 may include a
support column 134 fixedly attached to a foundation 136, e.g., of a
plant, for supporting first, inner casing 130. As illustrated, four
columns 134 are used to support inner casing 130; however, other
than four columns may be employed. Columns 134 are designed to
support the entire load of inner casing 130, any diaphragm (not
shown) within inner casing 130 and any dynamic loading during
operation. They may be made of, for example, steel, concrete, or a
combination thereof. Foundation 136 may also include vertical
columns 138 that support, for example, bearings 140 for shaft 114
(FIG. 1) and/or a second, outer casing 142 (also referred to as a
hood). Each support column 134 may extend through second, outer
casing 142 that surrounds first, inner casing 130.
[0019] A thermal control system 150 according to embodiments of the
invention may take a number of forms, which may be used alone or in
combination.
[0020] In one embodiment, as shown in FIGS. 2 and 3, thermal
control system 150 may include a duct 152 surrounding support
column 134. Duct 152 may be made, for example, of the same material
as second, outer casing 142 (e.g., steel). A seal 154 may be
provided between support column 134 and duct 152 for sealing a
space 155 (FIGS. 3 and 4 only, FIG. 4 without the seal) between
duct 152 and support column 134. Seal 154 may take any variety of
forms for coupling a duct to a surface, e.g., a polymer sheet or
diaphragm sealed to duct 152 and column 134. As illustrated in FIG.
3, in one embodiment, seal 154 is provided on an upper end of duct
152 just below where support column 134 is coupled to support
first, inner casing 130, e.g., by a standard mount 156. Seal 154
seals the upper end of duct 152 and isolates any exchange of force
between second, outer casing 142 and hollow legs 170, described
below. Consequently, supports 132 isolate columns 134 from being
exposed to exhaust steam within second, outer casing 142.
[0021] Under steady state operation, space 155 may eventually
attain the same temperature as within second, outer casing 142.
Duct 152, however, may be coupled to a source of a cooling fluid
flow to cool support column 134. In one embodiment, the source of
cooling fluid flow includes atmospheric air. For example, source of
cooling fluid flow may include exposure to atmospheric air from
outside of second, outer casing 142 through duct 152, the latter of
which is open at a lower end through second, outer casing 142. That
is, each support column 134 extends through second, outer casing
142 that surrounds first, inner casing 130 and the source of
cooling fluid flow includes atmospheric air from outside of the
second casing. Alternatively, a pump 156 such as a fan arrangement
may be provided for propelling the cooling fluid flow along support
column 134 within duct 152. In this case, the cooling fluid flow
may be forced to move along the dashed line 158 in FIG. 3. A pump
156 may be desired to ensure continuous air circulation in space
155. Constant air circulation may be required to maintain the air
temperature in space 155 close to atmospheric temperature so as to
prevent an increased temperature for column 134 and thermal
expansion thereof even though the back pressure may change. In one
embodiment, the volume of cooling fluid flow can be controlled by
pump 155 based on feedback from any variety of sensors (not shown),
e.g., temperature sensors within duct 152, on support column 134,
within second, outer casing 142, etc. Consequently, the movement of
supports 132 will be completely isolated from the back pressure
changes. As a result, this arrangement can be used for variable
back pressure operation, especially under high back pressure where
exhaust temperature is significantly high such as in power plants
where air-cooled condensers are used.
[0022] Referring to FIGS. 2 and 4, in another embodiment, each
support 132 includes a hollow leg 170 extending from first, inner
casing 130 and configured to slidingly couple to support column
134. In this case, each thermal control system 150 includes a
conduit 172 supplying operative fluid, e.g., gas or steam, from a
stage of turbomachine 100 (FIG. 1) to hollow leg 170. The pressure
within hollow leg 170 is thus that of the selected stage(s) P(L-1)
and the pressure outside of hollow leg 170 is the exhaust pressure
P(exh). Numerous parameters relative to this embodiment can be
selected so as to assist in cooling support 132. For example, the
height of hollow leg 170 and operative fluid's temperature (out of
various stages) can be chosen such that net thermal growth of the
entire stationary structure matches rotor 102 growth. One advantage
of this concept is that the operative fluid temperature within
turbomachine 100 does not vary substantially with back pressure
change, which means that under all operating condition of
turbomachine 100, the stationary structure will move by
approximately the same amount. Conduit 172 may take operative fluid
from any stage(s) at which the conditions of the operative fluid
may be advantageous in cooling support 132. Although conduit 172 is
shown in an external position relative to first, inner casing 130,
it is understood that conduit 172 may be positioned internally of
casing 130 with appropriate openings being provided to hollow leg
170 for fluid communication of the operative fluid thereto.
[0023] Hollow leg 170 may be slidingly coupled to support column
134 in any now known or later developed fashion, e.g., a slide
bearing 180, to allow fairly free movement but prevent disconnect
due to thermal expansion and/or other operational conditions. As
shown in FIG. 5, intervening structure 182, e.g., of steel, may be
provided between hollow leg 170 and slide bearing 180 to provide
for proper alignment. In order to provide proper drainage of
condensed operative fluid, e.g., water, hollow leg 170 may include
a drain opening 184. Drain opening 184 also assists in maintaining
a high heat transfer co-efficient inside hollow leg 170, which
promotes legs' 170 response to the chosen operative fluid
temperature rather than to the exhaust temperature. Further, an
insulation layer 186 may be provided about hollow leg 170 to
prevent condensation on an exterior of hollow leg 170 and/or adjust
thermal conditions within hollow leg 170. Insulation layer 186 may
include, for example, a thin sheet metal or any other thermally
insulated blanket which will maintain a low heat transfer
co-efficient on an outer surface of hollow leg 170 so as to further
reduce the impact of the exhaust temperature (within second, outer
casing 142) on the hollow legs. If provided, drain opening 184 may
extend through insulation layer 186. Hollow leg 170 may be made of
any material capable of withstanding the environmental and
structural loads applied thereto, e.g., steel.
[0024] As is typical, a finite amount of clearance is given between
rotor 102 and stationary structure thereabout to avoid rubs. This
clearance is essential because the relative thermal growth and
deflection of rotor 102 and stationary structure is not zero.
Because any clearance essentially gives an extra path for steam to
escape without being used for power generation, the clearance used
is minimized as much as possible. Hollow legs 170, among other
things, reduce thermal expansion between rotor 102 (FIG. 1) and
stationary structure thereabout. In particular, using the described
arrangement, rotor 102 (FIG. 1) which is supported on foundation
136 by supports 132 will grow vertically from an aligned position,
which is usually the horizontal dividing plane for the entire steam
turbomachine. Here, rotor 102 thermal growth will be primarily due
to support 132 thermal growth, oil film rise and growth of rotor
102 due to steam temperature. Consequently, the clearance between
rotor 102 (FIG. 2) and the surrounding stationary structure can be
further minimized, resulting in improved turbomachine 100
performance.
[0025] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the disclosure. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0026] The corresponding structures, materials, acts, and
equivalents of all means or step plus function elements in the
claims below are intended to include any structure, material, or
act for performing the function in combination with other claimed
elements as specifically claimed. The description of the present
disclosure has been presented for purposes of illustration and
description, but is not intended to be exhaustive or limited to the
disclosure in the form disclosed. Many modifications and variations
will be apparent to those of ordinary skill in the art without
departing from the scope and spirit of the disclosure. The
embodiment was chosen and described in order to best explain the
principles of the disclosure and the practical application, and to
enable others of ordinary skill in the art to understand the
disclosure for various embodiments with various modifications as
are suited to the particular use contemplated.
* * * * *