U.S. patent application number 13/171521 was filed with the patent office on 2013-01-03 for turbo-machinery with flow deflector system.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Prabakaran Modachur Krishnan.
Application Number | 20130004290 13/171521 |
Document ID | / |
Family ID | 47355301 |
Filed Date | 2013-01-03 |
United States Patent
Application |
20130004290 |
Kind Code |
A1 |
Krishnan; Prabakaran
Modachur |
January 3, 2013 |
Turbo-Machinery With Flow Deflector System
Abstract
The present application provides a turbo-machine. The
turbo-machine may include a number of buckets, a number of nozzles,
and a flow deflector system. The flow deflector system may include
a bucket deflector and a nozzle deflector so as to limit leakage
flow losses therethrough.
Inventors: |
Krishnan; Prabakaran Modachur;
(Bangalore, IN) |
Assignee: |
GENERAL ELECTRIC COMPANY
Schnectady
NY
|
Family ID: |
47355301 |
Appl. No.: |
13/171521 |
Filed: |
June 29, 2011 |
Current U.S.
Class: |
415/1 ;
415/208.1 |
Current CPC
Class: |
F01D 11/127 20130101;
F02C 7/28 20130101; F04D 29/164 20130101; F01D 11/001 20130101 |
Class at
Publication: |
415/1 ;
415/208.1 |
International
Class: |
F01D 11/00 20060101
F01D011/00; F01D 1/02 20060101 F01D001/02 |
Claims
1. A turbo-machine, comprising: a plurality of buckets; a plurality
of nozzles; and a flow deflector system; the flow deflector system
comprising a bucket deflector and a nozzle deflector so as to limit
leakage flow losses therethrough.
2. The turbo-machine of claim 1, wherein the bucket deflector
comprises one or more bucket extensions.
3. The turbo-machine of claim 2, wherein the one or more bucket
extensions comprise an upstream extension.
4. The turbo-machine of claim 2, wherein the one or more bucket
extensions comprise a downstream extension.
5. The turbo-machine of claim 2, wherein the one or more bucket
extensions comprise a blunt shape or a tip.
6. The turbo-machine of claim 2, wherein the one or more bucket
extensions comprise a bucket abradable.
7. The turbo-machine of claim 1, wherein the nozzle deflector
comprises one or more nozzle extensions.
8. The turbo-machine of claim 7, wherein the one or more nozzle
extensions comprise an upstream extension.
9. The turbo-machine of claim 7, wherein the one or more nozzle
extensions comprise a downstream extension.
10. The turbo-machine of claim 7, wherein the one or more nozzle
extensions comprise a nozzle abradable.
11. The turbo-machine of claim 7, wherein the one or more nozzle
extensions comprise a nozzle cavity.
12. The turbo-machine of claim 7, wherein the one or more nozzle
extensions comprise a flange, blunt shape, or tip.
13. The turbo-machine of claim 1, further comprising a turbine.
14. The turbo-machine of claim 1, further comprising a
compressor.
15. A method of limiting leakage flow losses in a turbine,
comprising: flowing a leakage flow through a nozzle clearance;
placing a bucket extension into an axial gap between a bucket and a
nozzle adjacent to the nozzle clearance; overlapping the bucket
extension in the axial gap with a nozzle extension to limit the
leakage flow therethrough; and directing the leakage flow exiting
the axial gap in a direction of a main flow.
16. A flow deflector system, comprising: a bucket deflector
positioned about a bucket; a nozzle deflector positioned about a
nozzle; and a nozzle abradable positioned about the nozzle
deflector and/or a bucket abradable positioned about the bucket
deflector.
17. The flow deflector system of claim 16, wherein the bucket
deflector comprises an upstream extension and/or a downstream
extension.
18. The flow deflector system of claim 16, wherein the nozzle
deflector comprises an upstream extension and/or downstream
extension
19. The flow deflector system of claim 16, wherein the flow
deflector system is mounted within a turbine.
20. The flow deflector system of claim 16, wherein the flow
deflector system is mounted within a compressor.
Description
TECHNICAL FIELD
[0001] The present application and the resultant patent relate
generally to turbo-machinery and more particularly relate to a
steam turbine with a flow deflector system having extensions to
restrict leakage flow in both axial and radial directions for
improved efficiency.
BACKGROUND OF THE INVENTION
[0002] Generally described, turbo-machinery such as steam turbines,
gas turbines, and the like include alternating rows of rotating
airfoils or buckets and rows of stationary airfoils or nozzles.
Each row of rotating airfoils may be attached to a rotor for
rotation therewith. Each row of stationary airfoils may be attached
at one end to a casing with each of the stationary airfoil
extending radially inward toward a packing ring and the rotor. The
packing ring may have seal strips extending from both the rotating
and stationary surfaces so as to form a clearance therebetween.
Other configurations may be used.
[0003] In operation, the rotating and the stationary airfoils
expand the flow of fluid therethrough. As the fluid passes axially
through the turbine, the pressure of the fluid decreases. For
example, the fluid pressure on the downstream side of a row of
stationary airfoils is less than the pressure on the upstream side
of the same row. The fluid will seek the path of least resistance
such that leakage may occur through the packing ring clearance
between the stationary airfoil and the rotor. This leakage flow may
enter radially into the main flow path upstream of the rotating
airfoil. The leakage flow may mix randomly with the mainstream flow
and cause increase mixing or intrusion losses. Both the random
mixing of the clearance flow with the main flow caused by intrusion
and the higher packing ring clearance flow losses will degrade
overall turbine performance and efficiency.
[0004] There is therefore a desire for improved turbo-machinery so
as to limit both intrusion losses and overall clearance leakage
flows so as to improve overall efficiency. Limiting such leakage
flow results in more of the working fluid producing useful work.
Preferably, such clearance leakage flow improvements may be
provided without the use of expensive and complex brush seals or
other types of components subject to wear and tear.
SUMMARY OF THE INVENTION
[0005] The present application and the resultant patent thus
provide a turbo-machine. The turbo-machine may include a number of
buckets, a number of nozzles, and a flow deflector system. The flow
deflector system may include a bucket deflector and a nozzle
deflector so as to limit leakage flow losses therethrough so as to
improve overall efficiency.
[0006] The present application and the resultant patent further
provide a method of limiting leakage flow losses in a turbine. The
method may include the steps of flowing a leakage flow through a
nozzle clearance, placing a bucket extension into an axial gap
between a bucket and a nozzle adjacent to the nozzle clearance,
overlapping the bucket extension in the axial gap with a nozzle
extension so as to limit the leakage flow therethrough, and
directing the leakage flow exiting the axial gap in a direction of
a main flow.
[0007] The present application and the resultant patent further
provide a flow deflector system. The flow director system may
include a bucket deflector positioned about a bucket, a nozzle
deflector positioned about a nozzle, and a nozzle abradable
positioned about the nozzle deflector and/or a bucket abradable
positioned about the bucket deflector.
[0008] These and other features and improvements of the present
application and the resultant patent will become apparent to one of
ordinary skill in the art upon review of the following detailed
description when taken in conjunction with the several drawings and
the appended claims. The several embodiments shown herein are by
way of example only.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic view of a section of a turbine.
[0010] FIG. 2 is a schematic view of a portion of a turbine with a
flow deflector system as may be described herein.
[0011] FIG. 3 is a partial side cross-sectional view of the flow
deflector system of FIG. 2.
[0012] FIG. 4 is a partial side cross-sectional view of an
alternative embodiment of a flow deflector system as may be
described herein.
[0013] FIG. 5 is a partial side plan view of an alternative
embodiment of a flow deflector system as may be described
herein.
[0014] FIG. 6 is a partial side plan view of an alternative
embodiment of a flow deflector system as may be described
herein
[0015] FIG. 7 is a partial side plan view of an alternative
embodiment of a flow deflector system as may be described
herein.
[0016] FIG. 8 is a partial side plan view of an alternative
embodiment of a flow deflector system as may be described
herein.
[0017] FIG. 9 is a partial side plan view of an alternative
embodiment of a flow deflector system as may be described
herein.
[0018] FIG. 10 is a partial side plan view of an alternative
embodiment of a flow deflector system as may be described
herein
[0019] FIG. 11 is a partial side plan view of an alternative
embodiment of a flow deflector system as may be described
herein.
[0020] FIG. 12 is a schematic view of a portion of a compressor
with a flow deflector system as may be described herein.
DETAILED DESCRIPTION
[0021] Referring now to the drawings, in which like numerals refer
to like elements throughout the several views, FIG. 1 shows a
portion of a turbo-machine 10. In this example, the turbo-machine
10 may be a steam turbine 15. A gas turbine and other
configurations and types of turbo-machinery also may be used
herein. As described above, the steam turbine 15 includes a number
of rotating airfoils or buckets 20. The rotating airfoils 20 may be
attached to a rotor 25 for rotation therewith. The rotating
airfoils 20 may be positioned between rows of a number of
stationary airfoils or nozzles 30. The stationary airfoils 30
extend from a casing 35 on one end to a packing ring 40 on the
other. The packing ring 40 may have a number of seal strips 45
positioned on both the stationary airfoil 30 and the rotor 25. A
packing ring clearance 50 may extend between the stationary airfoil
30 and the rotor 25. A leakage flow 55 may extend therethrough. The
nature of the leakage flow 55 may vary. Other components and other
configurations may be used herein.
[0022] FIG. 2 shows a portion of a turbo-machine 100 as may be
described herein. As above, the turbo-machine 100 may be a steam
turbine 110. Gas turbines and other turbo-machinery also may be
used herein. The steam turbine 110 may include a number of rotating
airfoils or buckets 120. The buckets 120 may be attached to a rotor
130 and a disk 140. Likewise, the steam turbine 110 may include a
number of stationary airfoils or nozzles 150. The nozzles 150 may
extend radially towards the rotor 130 and a packing ring 160 on one
end thereof. A packing ring clearance 170 may extend between the
packing ring 160 and the rotor 130. While a main flow 180 may pass
between the buckets 120 and the nozzles 150, a leakage flow 190 may
seek to escape via the packing ring clearance 170 and into an axial
gap 195 between the buckets 120 and the nozzles 150.
[0023] The steam turbine 110 also may include a leakage flow
deflector system 200. The leakage flow deflector system 200 may
include a bucket deflector 210. The bucket deflector 210 may
include an upstream bucket extension 220 on an upstream side 230
thereof and a downstream bucket extension 240 on a downstream side
thereof. The bucket extensions 220, 240 may extend from the disk
140 beneath the bucket 120 and extend into the axial gap 195.
Although the bucket extensions 220, 240 are shown as having a
largely rectangular, blunted shape 260 any desired size or shape
may be used herein.
[0024] The flow deflector system 200 also may include a nozzle
deflector 270 positioned about each nozzle 150. The nozzle
deflector 270 may include an upstream nozzle extension 280
positioned on an upstream side 290 thereof and a downstream nozzle
extension positioned on a downstream side 310 thereof. The nozzle
extensions 280, 300 may extend into the axial gap 195. The blade
extensions 220, 240 and the nozzle extensions 280, 300 may overlap
each other to a varying extent. Although the nozzle extensions 280,
300 are shown as having a rectangular blunt shape 320, any size or
shape may be used herein. Likewise, although the blade extensions
220, 240 are shown on top of the nozzle extensions 280, 300, the
nozzle extensions 280, 300 may be on top and/or one blade extension
220, 240 may be on top and one nozzle extension 280, 300 may be on
top in any configuration.
[0025] The nozzle deflector 270 also may include a honeycomb or an
amount of abradable material positioned under the nozzle extensions
280, 300 and in line with the bucket extensions 220, 240 as a
nozzle abradable 330. The use of the abradable material prevents
possible damage to the blade extensions 220, 240. The abradable
material may be of a conventional nature. The nozzle abradable 330
may have different sizes and shapes. The abradable material may be
applied directly to the nozzle cavity or attached to a plate that
may be positioned within the nozzle cavity. Other types of
attachment methods may be used herein.
[0026] In use, the leakage flow 190 may pass through the packing
ring clearance 170. As the leakage flow 190 reaches the downstream
side 310 of the nozzle 150, the overlap of the downstream nozzle
extension 300 and the upstream bucket extension 220 creates
resistance to the leakage flow 190 passing into the axial gap 195.
Such increased resistance thus limits the leakage flow 190
therethrough. Further, the leakage flow 190 that does pass
therethrough is now directed in the same direction as the main flow
180. As a result, intrusion losses caused by random mixing between
the leakage flow 190 and the main flow 180 may be reduced. The
reduction in both the volume of the leakage flow 190 and the random
mixing caused by the intrusion of the leakage flow 190 into the
main flow 180 thus promotes overall turbo-machine efficiency.
[0027] Various modifications and embodiments may be used herein. As
is shown in FIG. 3, for example, the blade extensions 220, 240 may
extend in close proximity to the nozzle abradable 330 of the
nozzles 150. Alternatively, the spacing of the blade extensions 220
and the nozzle abradable 330 may be increased as is shown in FIG. 4
so as to provide for an extension gap 340 therebetween. Different
sizes, spacings, and configurations may be used herein.
[0028] Likewise, the extensions themselves may have different
shapes. As is shown in FIG. 5, the blade extensions 220, 240 may
extend to a sharp tip 350 (similar to FIG. 9). As is shown in FIG.
6, a vertical tip 355 also may be used. The vertical tip 355 may
extend upwardly or downwardly. Likewise, the blade extensions 220,
240 also may use a blade abradable 360 thereon as is shown in FIG.
7 (similar to FIG. 12). Similarly, the nozzles 150 may include a
nozzle cavity 370 instead of the use of the nozzle abradable 330.
Likewise, the nozzle extensions 280, 300 may extend into a downward
flange 380 as is shown in FIG. 8, a blunt tip 390 as is shown in
FIG. 9, a sharp vertical tip 400 (upward or downward) as shown in
FIG. 10, or a sharp tip 410 as shown in FIG. 11. Many different
configurations and designs may be used herein.
[0029] The flow deflector system 200 thus reduces the total leakage
flow 190 and the losses caused by the intrusion of the leakage flow
190 into the main flow 180. Such reductions provide an increase in
overall system efficiency without the use of expensive or complex
brush seals. The flow deflector system 200 limits both radial and
axial clearances and redirects the leakage flow 190 in the
direction of the main flow 180. Moreover, overall blade loading may
be improved. The flow deflector system 200 may be used with high
pressure, intermediate pressure, and/or low pressure sections of
the steam turbine 110 and otherwise. The flow deflector system 200
also may be used with any type of turbo-machinery 100.
[0030] FIG. 12 shows a further embodiment of a turbo-machine 100 as
may be described herein. In this example, the turbo-machine 100 may
be in the form of a compressor 420. The compressor 420 may use the
flow deflection system 200 as described above with the bucket
deflector 210 and the nozzle deflector 270. In this case, the
nozzle 150 includes the upstream nozzle extension 280, the
downstream nozzle extension 300, and the nozzle abradable 330.
Likewise, the bucket deflector 210 includes the upstream bucket
extension 220, the downstream bucket extension 240, and the bucket
abradable 360.
[0031] In this example, the main flow 180 is compressed such that
the pressure is increased as the flow moves downstream. The leakage
flow 190 thus is leaked from the downstream side 250 of the bucket
120 and heads toward the upstream side 290. The leakage flow 190
thus may be blocked by the upstream nozzle extension 280 in
combination with the downstream bucket extension 240 and the bucket
abradable 360. Other components and other configurations may be
used herein.
[0032] It should be apparent that the foregoing relates only to
certain embodiments of the present application and the resultant
patent. Numerous changes and modifications may be made herein by
one of ordinary skill in the art without departing from the general
spirit and scope of the invention as defined by the following
claims and the equivalents thereof.
* * * * *