U.S. patent application number 13/493435 was filed with the patent office on 2013-12-12 for method and apparatus for mitigating out of roundness effects at a turbine.
This patent application is currently assigned to General Electric Company. The applicant listed for this patent is Kenneth Damon Black, Steven Christopher Pisarski. Invention is credited to Kenneth Damon Black, Steven Christopher Pisarski.
Application Number | 20130330187 13/493435 |
Document ID | / |
Family ID | 48578858 |
Filed Date | 2013-12-12 |
United States Patent
Application |
20130330187 |
Kind Code |
A1 |
Pisarski; Steven Christopher ;
et al. |
December 12, 2013 |
METHOD AND APPARATUS FOR MITIGATING OUT OF ROUNDNESS EFFECTS AT A
TURBINE
Abstract
A turbine and a method of mitigating out-of-roundness effects at
a turbine is disclosed. An inner turbine shell and an outer turbine
shell of the turbine is provided. The inner turbine shell is
coupled to the outer turbine shell using a ring insert. The ring
insert is segmented into a plurality of ring insert segments that
reduce a transfer of load from the outer turbine shell to the inner
turbine shell to mitigate out-of-roundness of the inner turbine
shell.
Inventors: |
Pisarski; Steven Christopher;
(Simpsonville, SC) ; Black; Kenneth Damon;
(Travelers Rest, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pisarski; Steven Christopher
Black; Kenneth Damon |
Simpsonville
Travelers Rest |
SC
SC |
US
US |
|
|
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
48578858 |
Appl. No.: |
13/493435 |
Filed: |
June 11, 2012 |
Current U.S.
Class: |
415/213.1 ;
29/888.012 |
Current CPC
Class: |
F01D 25/26 20130101;
Y10T 29/49234 20150115; F05D 2230/642 20130101 |
Class at
Publication: |
415/213.1 ;
29/888.012 |
International
Class: |
F01D 25/26 20060101
F01D025/26; B21D 53/00 20060101 B21D053/00 |
Claims
1. A method of mitigating out-of-roundness effects at a turbine,
comprising: disposing an inner turbine shell of the turbine within
an outer turbine shell of the turbine; and coupling the inner
turbine shell to the outer turbine shell using a ring insert that
is segmented into a plurality of ring insert segments that reduce a
transfer of load from the outer turbine shell to the inner turbine
shell to mitigate out-of-roundness of the inner turbine shell.
2. The method of claim 1, wherein the plurality of ring insert
segments further comprises four ring insert segments.
3. The method of claim 2, wherein at least one of the ring insert
segments subtends an angle measured from a longitudinal axis of the
inner turbine shell selected from the group consisting of: (i) less
than 90 degrees; (ii) between about 15 degrees and about 85
degrees; and (iii) between about 30 degrees and about 70
degrees.
4. The method of claim 1, further comprising using a processor to
determine a length of the ring insert segments at which an
out-of-roundness of the inner turbine shell meets a selected
criterion.
5. The method of claim 1, wherein a length of a ring insert segment
is selected to reduce a load path between the outer turbine shell
and the inner turbine shell.
6. The method of claim 1, wherein the load is a result of a thermal
stress at the outer turbine shell.
7. The method of claim 1, wherein the ring insert segments are
disposed at a thrust collar of the inner turbine shell at
equidistant locations around a circumference of the inner turbine
shell.
8. The method of claim 1, wherein the inner turbine shell is formed
of at least two azimuthal shell sectors.
9. A turbine, comprising: an outer turbine shell; an inner turbine
shell; and a ring insert configured to couple the inner turbine
shell to the outer turbine shell and segmented into a plurality of
ring insert segments to reduce a load transfer from the outer
turbine shell to the inner turbine shell.
10. The turbine of claim 9, wherein the ring insert is segmented
into four ring insert segments.
11. The turbine claim 10, wherein an angle subtended by at least
one of the ring insert segments is selected from the group
consisting of: (i) less than 90 degrees; (ii) between about 15
degrees and 85 degrees; and (iii) between about 30 degrees and
about 70 degrees.
12. The turbine claim 9, wherein a length of the ring insert
segments is determined using a processor running a program of a
model of the turbine.
13. The turbine claim 9, wherein a length of the ring insert
segments is selected to reduce a load path between the outer
turbine shell and the inner turbine shell.
14. The turbine of claim 9, wherein the load is related to thermal
stress at the outer turbine shell.
15. The turbine of claim 9, wherein the ring insert segments are
evenly spaced around a circumference of the inner turbine
shell.
16. The turbine of claim 9, wherein the inner turbine shell is
formed of at least two shell sectors extending over a selected
azimuthal angle.
Description
BACKGROUND OF THE INVENTION
[0001] The subject matter disclosed herein relates to an apparatus
and method for mitigating out-of-roundness effects at an inner
turbine shell of a gas turbine. Several turbine section designs
include an inner turbine shell that provides a flow path for a
working gas through the turbine and an outer turbine shell that
surrounds the inner turbine shell. Generally, a rotor having a
plurality of blades is disposed within the inner turbine shell and
rotates as a result of the working gas passing through the turbine.
The clearance between the inner turbine shell and the plurality of
turbine blades determines turbine efficiency and power production
and can be affected by a deviation of the inner turbine shell from
a circular cross-section, also known as out-of-roundness. Due to
connections between inner turbine shell and outer turbine shell,
loads due to various operational stresses are often transferred
from the outer turbine shell to the inner turbine shell and cause
the inner turbine shell to distort, a condition known as
out-of-roundness. There is therefore a desire to design turbine
shells that mitigate out-of-roundness effects. The present
disclosure provides a method and apparatus that reduces load
transfer between outer turbine shell and inner turbine shell to
reduce out-of-roundness effects.
BRIEF DESCRIPTION OF THE INVENTION
[0002] According to one aspect, the present disclosure provides a
method of mitigating out-of-roundness effects at a turbine, the
method including: providing an inner turbine shell of the turbine
within an outer turbine shell of the turbine; and coupling the
inner turbine shell to the outer turbine shell using a ring insert
that is segmented into a plurality of ring insert segments that
reduce a transfer of load from the outer turbine shell to the inner
turbine shell to mitigate out-of-roundness of the inner turbine
shell.
[0003] According to another aspect, the present disclosure provides
a turbine including an outer turbine shell; an inner turbine shell;
and a ring insert configured to couple the inner turbine shell to
the outer turbine shell and segmented into a plurality of ring
insert segments to reduce a load transfer from the outer turbine
shell to the inner turbine shell.
[0004] These and other advantages and features will become more
apparent from the following description taken in conjunction with
the drawings.
BRIEF DESCRIPTION OF THE DRAWING
[0005] 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:
[0006] FIG. 1 shows a side view cross-section of an exemplary inner
turbine shell of a turbine generator in one embodiment of the
present disclosure;
[0007] FIG. 2 shows a section of the inner turbine shell of FIG. 1
that includes a thrust collar;
[0008] FIG. 3 shows a profile view of an exemplary shell sector in
an exemplary embodiment; and
[0009] FIGS. 4 and 5 show plots of circumference of an exemplary
inner turbine shell of the present disclosure at various times
during an operation cycle of an exemplary turbine.
[0010] 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
[0011] FIG. 1 shows a side view cross-section of an exemplary inner
turbine shell 100 of a gas turbine in one embodiment of the present
disclosure. The exemplary inner turbine shell 100 provides a hollow
casing extending along a longitudinal axis 102 and having an inlet
104 at a first end of the longitudinal axis and an outlet 106 at a
second end of the longitudinal axis. The turbine shell is
substantially rotationally symmetric about its longitudinal axis
102. A rotor having a plurality of turbine blades (not shown) is
disposed substantially along the longitudinal axis 102 within the
inner turbine shell 100. A working gas injected into the inner
turbine shell 100 at the inlet 104 displaces the turbine blades to
cause the turbine blades to rotate, thereby causing the rotor to
rotate to generate power. In various embodiments, the inner turbine
shell 100 is composed of two or more sections, also referred to
herein as shell sectors, that are mated together to form the inner
turbine shell 100. An exemplary shell sector generally spans a
selected azimuthal angle around the longitudinal axis 102. The two
or more shell sectors are mated together at interfaces 110 via
bolts 112. The mated shell sectors provide a cooling hole or air
passage 114 passing through the inner turbine shell 100 that
provides air to nozzles (not shown) that are assembled at the inner
turbine shell. The inner turbine shell is coupled to the outer
turbine shell at a thrust collar 116 of the inner turbine shell
100. The inner turbine shell includes a thrust collar 116.
[0012] FIG. 2 shows a section of the inner turbine shell of FIG. 1
that includes a thrust collar 116. In various embodiments, the
thrust collar 116 is segmented. The segmented thrust collar 116 of
the inner turbine shell includes a slot 118 into which a ring
insert can be inserted. The ring insert couples the inner turbine
shell to the outer turbine shell to provide support for the inner
turbine shell. The ring insert provides an area of contact between
the outer turbine shell and the inner turbine shell. In an
exemplary embodiment, the ring insert is segmented into a plurality
of ring insert segments that are separated from each other to
provide gaps between them along the circumference. Thus, the total
angle subtended by the plurality of ring insert segments is less
than 360 degrees.
[0013] FIG. 3 shows a profile view of a shell sector in an
exemplary embodiment of the present disclosure. The exemplary inner
turbine shell is composed of four shell sectors, each of which
forms a quadrant of the inner turbine shell 300. Exemplary shell
sector 315 is shown. A ring insert segment 302 is shown on the
exemplary shell sector 315. The ring insert segment 302 extends
from a first azimuthal location 304 to a second azimuthal location
306 along a circumference of sector 315 to subtend angle 320. In
one embodiment, angle 320 is less than 90 degrees. In another
embodiment, angle 320 is between about 15 degrees and 85 degrees.
In yet another embodiment, angle 320 is between about 30 degrees
and about 70 degrees. In an exemplary embodiment, the ring insert
segment 302 is disposed evenly between the first mating interface
310 and second mating interface 312 of shell sector 315 such that a
distance between the first azimuthal location 304 and the first
mating interface 310 is substantially the same as a distance
between the second azimuthal location 306 and the second mating
interface 312. Thus, the area of contact between the outer turbine
shell and the inner turbine shell is less than 360 degrees. This
reduced contact area reduces a load transfer area between the outer
turbine shell and the inner turbine shell. In alternate
embodiments, the exemplary shell sector 315 can include two or more
ring segments separated from each other.
[0014] In one aspect, the length of the ring insert segment can be
determined using a processor. The exemplary processor can run a
simulation to determine the length of the ring insert segment at
which an out-of-roundness of the inner turbine shell meets a
selected criterion. The processor can simulate various operating
cycles of the turbine and determine out-of-roundness of the inner
turbine shell at various times during the cycle.
[0015] Alternately, a turbine having the exemplary ring insert
segments can be constructed and operated. Sensors can be disposed
at various locations of the inner turbine shell and the
out-of-roundness of the inner turbine shell can be observed as the
turbine is run through various operational cycles. A ring insert
segment length and spacing can thereby be determined by observing
an effectiveness of the various ring insert segment lengths with
respect to mitigating out-of-roundness effects.
[0016] In one aspect, the length of the ring segment is selected at
which the out-of roundness meets a selected criterion. In various
embodiments, the right segment is selected when a length of the
ring segment keeps the out-of-roundness of the inner turbine shell
within an acceptable tolerance level. In another embodiment, the
selected criterion can be an out-of-roundness tolerance over a
selected time frame.
[0017] FIG. 4 shows a plot of a circumference of an exemplary inner
turbine shell of the present disclosure at various times during
operation of an exemplary turbine. The plot of FIG. 4 is output
from an analytical model in measurements of radial displacement of
the circumference are obtained at approximately every 5 degrees
around the circumference. A plot may alternatively be obtained for
a test of a constructed shell, generally using about 10 sensors
placed around the circumference. Radial measurements are obtained
at various times, as indicated by reference numbers 401 (1654
seconds after start-up), 402 (2374 seconds), 403 (2874 seconds),
404 (4174 seconds), 405 (100000 seconds) and 406 (100967 seconds).
FIG. 5 shows a plot of the circumference of the exemplary inner
turbine shell of FIG. 4 at later times. Radial measurements are
obtained at various times indicated by 501 (105618 seconds), 502
(114400 seconds), 503 (116055 seconds), 504 (116271 seconds), 505
(116775 seconds) and 506 (214400 seconds). The exemplary inner
turbine shell is generally run through one or more cycles of
increasing and decreasing power output. The circumference of the
inner turbine shell generally increases with heating and decreases
with cooling. Early times (i.e., time 401) show an inner turbine
shell that has a substantially round cross-section. The turbine
operating at high output levels (i.e. times 404, 405 and 406) are
shown. Time 404 in particular shows an inner turbine shell with
large out-of roundness effects at high output levels. Times 503 and
504 shown the circumference as the operation cycle is lowered to a
lower output levels. Various degrees of out-of-roundness is shown.
Time 506 shows the circumference as the operation cycle is raised
again to high output levels. As seen in FIG. 5, the degree of
out-of-roundness of the shell at time 506 is relatively little.
When the out-of-roundness effects are within an acceptable
tolerance an operator can select the ring segment for use in a
turbine.
[0018] Therefore, in one aspect, the present disclosure provides a
method of mitigating out-of-roundness effects at a turbine, the
method including: providing an inner turbine shell of the turbine
within an outer turbine shell of the turbine; and coupling the
inner turbine shell to the outer turbine shell using a ring insert
that is segmented into a plurality of ring insert segments that
reduce a transfer of load from the outer turbine shell to the inner
turbine shell to mitigate out-of-roundness of the inner turbine
shell. In one embodiment, the plurality of ring insert segments
includes four ring insert segments. At least one of the ring insert
segments subtends an angle measured from a longitudinal axis of the
inner turbine shell selected from the group consisting of: (i) less
than 90 degrees; (ii) between about 15 degrees and about 85
degrees; and (iii) between about 30 degrees and about 70 degrees. A
processor can be used to determine a length and position of the
ring insert segments at which an out-of-roundness of the inner
turbine shell meets a selected criterion. The length of a ring
insert segment is selected to reduce a load path between the outer
turbine shell and the inner turbine shell. In various embodiments,
the load is a result of a thermal stress at the outer turbine
shell. The ring insert segments are disposed at a thrust collar of
the inner turbine shell at equidistant locations around a
circumference of the inner turbine shell. In various embodiments,
the inner turbine shell is formed of at least two azimuthal shell
sectors.
[0019] A turbine including an outer turbine shell; an inner turbine
shell; and a ring insert configured to couple the inner turbine
shell to the outer turbine shell and segmented into a plurality of
ring insert segments to reduce a load transfer from the outer
turbine shell to the inner turbine shell. In an exemplary
embodiment, the ring insert is segmented into four ring insert
segments. An angle subtended by at least one of the ring insert
segments is selected from the group consisting of: (i) less than 90
degrees; (ii) between about 15 degrees and 85 degrees; and (iii)
between about 30 degrees and about 70 degrees. A processor running
a program of a model of the turbine can be used to determine a
length of the ring insert. The length of the ring insert segments
is generally selected to reduce a load path between the outer
turbine shell and the inner turbine shell. The load is generally
related to thermal stress at the outer turbine shell. In an
exemplary embodiment, the ring insert segments are evenly spaced
around a circumference of the inner turbine shell. In various
embodiments, the inner turbine shell is formed of at least two
shell sectors extending over a selected azimuthal angle.
[0020] 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.
* * * * *