U.S. patent application number 12/908831 was filed with the patent office on 2012-04-26 for rotary machine having spacers for control of fluid dynamics.
This patent application is currently assigned to General Electric Company. Invention is credited to John McConnell Delvaux, Brian Denver Potter.
Application Number | 20120099995 12/908831 |
Document ID | / |
Family ID | 45923348 |
Filed Date | 2012-04-26 |
United States Patent
Application |
20120099995 |
Kind Code |
A1 |
Delvaux; John McConnell ; et
al. |
April 26, 2012 |
ROTARY MACHINE HAVING SPACERS FOR CONTROL OF FLUID DYNAMICS
Abstract
A system includes a rotary machine with a fluid flow path
extending along an axis of the rotary machine, a plurality of
airfoils disposed about the axis, and a plurality of spacers
disposed about the axis. Each spacer of the plurality of spacers is
disposed circumferentially between adjacent airfoils of the
plurality of airfoils to define a circumferential spacing of the
airfoils about the axis.
Inventors: |
Delvaux; John McConnell;
(Fountain Inn, SC) ; Potter; Brian Denver; (Greer,
SC) |
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
45923348 |
Appl. No.: |
12/908831 |
Filed: |
October 20, 2010 |
Current U.S.
Class: |
416/203 ;
29/889.21 |
Current CPC
Class: |
F05D 2260/961 20130101;
F05D 2240/80 20130101; F05D 2260/96 20130101; F04D 29/324 20130101;
F04D 29/544 20130101; F01D 5/30 20130101; F04D 29/666 20130101;
F05D 2240/20 20130101; Y10T 29/49321 20150115; F01D 11/008
20130101 |
Class at
Publication: |
416/203 ;
29/889.21 |
International
Class: |
F04D 29/66 20060101
F04D029/66; B21K 25/00 20060101 B21K025/00; F04D 29/34 20060101
F04D029/34 |
Claims
1. A system, comprising: a rotary machine comprising: a fluid flow
path extending along an axis of the rotary machine; a plurality of
airfoils disposed about the axis; and a plurality of spacers
disposed about the axis, wherein each spacer of the plurality of
spacers is disposed circumferentially between adjacent airfoils of
the plurality of airfoils to define a circumferential spacing of
the airfoils about the axis.
2. The system of claim 1, wherein the circumferential spacing of
the plurality of airfoils is configured to reduce resonant behavior
in the rotary machine.
3. The system of claim 1, wherein the rotary machine comprises a
turbine.
4. The system of claim 1, wherein the rotary machine comprises a
compressor.
5. The system of claim 1, wherein the rotary machine comprises a
stator and a rotor, the plurality of airfoils are coupled to the
rotor, and the plurality of spacers are coupled to the rotor.
6. The system of claim 1, wherein the rotary machine comprises a
stator and a rotor, the plurality of airfoils are coupled to the
stator, and the plurality of spacers are coupled to the stator.
7. The system of claim 1, wherein the plurality of spacers have an
equal width in a circumferential direction about the axis.
8. The system of claim 1, comprising a plurality of replacement
spacers configured to replace the plurality of spacers, wherein the
plurality of replacement spacers have a different width than the
plurality of spacers.
9. The system of claim 1, comprising a plurality of second airfoils
and a plurality of second spacers disposed about the axis, wherein
each second spacer of the plurality of second spacers is disposed
circumferentially between adjacent second airfoils of the plurality
of second airfoils to define a second circumferential spacing of
the second airfoils about the axis.
10. The system of claim 9, wherein the circumferential spacing of
the plurality of airfoils is configured to reduce resonant behavior
in the rotary machine, and the second circumferential spacing of
the plurality of second airfoils is configured to reduce resonant
behavior in the rotary machine.
11. A system, comprising: a rotary machine comprising: a fluid flow
path; and a plurality of segments disposed in an annular
arrangement along the fluid flow path, wherein the plurality of
segments comprise spacer segments and flow control segments, the
flow control segments protrude into the fluid flow path, and each
spacer segment is disposed circumferentially between adjacent flow
control segments to define a circumferential spacing of the flow
control segments.
12. The system of claim 11, wherein the circumferential spacing of
the flow control segments is configured to reduce resonant behavior
in the rotary machine.
13. The system of claim 11, wherein the rotary machine comprises a
turbine, a compressor, or a combination thereof.
14. The system of claim 11, wherein the plurality of segments are
stationary, and the flow control segments comprise stationary
vanes.
15. The system of claim 11, wherein the plurality of segments are
rotatable, and the flow control segments comprise rotatable
blades.
16. The system of claim 11, wherein the spacer segments have an
equal width in a circumferential direction about the annular
arrangement.
17. The system of claim 11, comprising replacement spacer segments
configured to replace the spacer segments, wherein the replacement
spacer segments have a different width than the spacer
segments.
18. A method, comprising: mounting a plurality of airfoil segments
in a rotary machine along a fluid flow path; and spacing the
plurality of airfoil segments in a circumferential spacing with a
plurality of spacer segments.
19. The method of claim 18, comprising reducing resonant behavior
in the rotary machine by adjusting a number of the plurality of
airfoil segments and by adjusting a width and number of the
plurality of spacer segments.
20. The method of claim 19, wherein mounting comprising removably
attaching the plurality of airfoil segments and the plurality of
spacer segments in a turbine, a compressor, or a combination
thereof.
Description
BACKGROUND OF THE INVENTION
[0001] The subject matter disclosed herein relates to rotary
machines and, more particularly, turbines and compressors
susceptible to resonant behavior in a fluid flow.
[0002] Turbines and compressors exchange energy between a fluid and
a rotor. For example, a turbine generates energy in response to a
fluid flow acting on a plurality of blades, whereas a compressor
uses energy to drive a plurality of blades to compress a gas.
Unfortunately, the rotation of the blades can create wake and bow
waves, which can excite other rotating and stationary structures
upstream and downstream from the blades. For example, the wake and
bow waves may cause vibration, premature wear, and damage of vanes,
blades, nozzles, airfoils, rotors, and other structures in the
fluid flow.
BRIEF DESCRIPTION OF THE INVENTION
[0003] Certain embodiments commensurate in scope with the
originally claimed invention are summarized below. These
embodiments are not intended to limit the scope of the claimed
invention, but rather these embodiments are intended only to
provide a brief summary of possible forms of the invention. Indeed,
the invention may encompass a variety of forms that may be similar
to or different from the embodiments set forth below.
[0004] In a first embodiment, a system includes a rotary machine
with a fluid flow path extending along an axis of the rotary
machine, a plurality of airfoils disposed about the axis, and a
plurality of spacers disposed about the axis. Each spacer of the
plurality of spacers may be disposed circumferentially between
adjacent airfoils of the plurality of airfoils to define a
circumferential spacing of the airfoils about the axis.
[0005] In a second embodiment, a system includes a rotary machine
with a fluid flow path and a plurality of segments disposed in an
annular arrangement along the fluid flow path. The plurality of
segments include spacer segments and flow control segments. The
flow control segments protrude into the fluid flow path. Each
spacer segment is disposed circumferentially between adjacent flow
control segments to define a circumferential spacing of the flow
control segments.
[0006] In a third embodiment, a method includes mounting a
plurality of airfoil segments in a rotary machine along a fluid
flow path, and spacing the plurality of airfoil segments in a
circumferential spacing with a plurality of spacer segments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] These and other features, aspects, and advantages of the
present invention will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0008] FIG. 1 is a sectional view of an embodiment of a gas turbine
engine sectioned through a longitudinal axis;
[0009] FIG. 2 is a front view of an embodiment of a rotor with a
non-uniform spacing of blades;
[0010] FIG. 3 is a front view of an embodiment of a rotor with a
non-uniform spacing of blades;
[0011] FIG. 4 is a front view of an embodiment of a rotor with a
non-uniform spacing of blades;
[0012] FIG. 5 is a perspective view of an embodiment of three
rotors, wherein each rotor has a different non-uniform spacing of
blades;
[0013] FIG. 6 is a partial front view of an embodiment of a rotor
with differently sized spacers between blades;
[0014] FIG. 7 is a top view of an embodiment of a rotor with
differently sized spacers between blades;
[0015] FIG. 8 is a top view of an embodiment of a rotor with
differently sized spacers between blades;
[0016] FIG. 9 is a front view of an embodiment of a blade having a
T-shaped geometry;
[0017] FIG. 10 is a partial front view of an embodiment of a rotor
with blades having differently sized bases;
[0018] FIG. 11 is a top view of an embodiment of a rotor with
blades having differently sized bases;
[0019] FIG. 12 is a top view of an embodiment of a rotor with
blades having differently sized bases;
[0020] FIG. 13 is a partial front view of an embodiment of a stator
with differently sized spacers between vanes;
[0021] FIG. 14 is a partial front view of an embodiment of a stator
with vanes having differently sized bases;
[0022] FIG. 15 is a partial front view of an embodiment of a rotor
with uniform large spacers between blades;
[0023] FIG. 16 is a partial front view of an embodiment of a rotor
with uniform medium spacers between blades;
[0024] FIG. 17 is a partial front view of an embodiment of a rotor
with uniform small spacers between blades;
[0025] FIG. 18 is a graph illustrating resonant frequency of
stators and rotors with differently sized spacers with respect to
the rotational speed of the engine;
[0026] FIG. 19 is a partial front view of an embodiment of a stator
with uniform large sized spacers between vanes;
[0027] FIG. 20 is a partial front view of an embodiment of a stator
with uniform medium spacers between vanes; and
[0028] FIG. 21 is a partial front view of an embodiment of a stator
with uniform small spacers between vanes.
DETAILED DESCRIPTION OF THE INVENTION
[0029] One or more specific embodiments of the present invention
will be described below. In an effort to provide a concise
description of these embodiments, all features of an actual
implementation may not be described in the specification. It should
be appreciated that in the development of any such actual
implementation, as in any engineering or design project, numerous
implementation-specific decisions must be made to achieve the
developers' specific goals, such as compliance with system-related
and business-related constraints, which may vary from one
implementation to another. Moreover, it should be appreciated that
such a development effort might be complex and time consuming, but
would nevertheless be a routine undertaking of design, fabrication,
and manufacture for those of ordinary skill having the benefit of
this disclosure.
[0030] When introducing elements of various embodiments of the
present invention, the articles "a," "an," "the," and "said" are
intended to mean that there are one or more of the elements. The
terms "comprising," "including," and "having" are intended to be
inclusive and mean that there may be additional elements other than
the listed elements.
[0031] The disclosed embodiments are directed toward tuning of
fluid dynamics in rotary machines, such as a turbine or a
compressor, via an adjustment of the spacing between rotating
blades or stationary vanes and/or an adjustment of the count of
rotating blades or stationary vanes. In particular, the disclosed
embodiments adjust the spacing and/or count of blades or vanes to
control the frequency of wake and bow waves formed by the rotating
blades, stationary vanes, or other structures in the fluid flow.
For example, a non-uniform spacing or modified count of rotating
blades or stationary vanes may reduce the possibility of resonant
behavior, vibration, and undesirable fluid dynamics in the turbine
or compressor. In other words, the non-uniform spacing or modified
count of rotating blades or stationary vanes may reduce or
eliminate the ability of the wake and bow waves to cause resonance
in structures along the fluid flow path. Instead, the non-uniform
spacing or modified count of rotating blades or stationary vanes
may dampen and reduce the response of structures in the fluid flow
path by changing the frequency of the wake and bow waves. The
non-uniform spacing or modified count may be achieved with spacers,
modified mounting structures, mounting adapters, modified stators,
modified rotors, or some combination thereof.
[0032] For example, the non-uniform spacing of the blades or vanes
may be achieved with differently sized spacers between adjacent
blades or vanes, differently sized bases of adjacent blades or
vanes, or any combination thereof. The non-uniform spacing of the
blades or vanes may include both non-uniform spacing of the blades
about a circumference of a particular stage (e.g., turbine or
compressor stage), non-uniform spacing of the blades from one stage
to another, or a combination thereof. The non-uniform spacing
effectively reduces and dampens the wake and bow waves generated by
the rotating blades, thereby reducing the possibility of vibration,
premature wear, and damage caused by such wake and bow waves on
stationary and rotating structures.
[0033] By further example, the modified count of blades or vanes
may be achieved by uniformly spacing a greater or smaller count of
blades or vanes via spacers, modified mounting bases, or a
combination thereof. In certain embodiments employing spacers, a
first set of spacers (e.g., large spacers) may be used to provide a
first uniform spacing of blades or vanes, a second set of spacers
(e.g., medium spacers) may be used to provide a second uniform
spacing of blades or vanes, a third set of spacers (e.g., small
spacers) may be used to provide a third uniform spacing of blades
or vanes, and so forth. Similarly, in certain embodiments employing
modified bases, a first set of blades or vanes with a first
mounting base size (e.g., large mounting base) may be used to
provide a first uniform spacing of blades or vanes, a second set of
blades or vanes with a second mounting base size (e.g., medium
mounting base) may be used to provide a second uniform spacing of
blades or vanes, a third set of blades or vanes with a third
mounting base size (e.g., small mounting base) may be used to
provide a third uniform spacing of blades or vanes, and so forth.
In each embodiment, the blade or vane count may be increased or
decreased to change the frequency of wake and bow waves at specific
rotational speeds of the rotary machine. Thus, the modified count
is configured to change the frequency of the wake and bow waves to
avoid the resonant frequency of the structures in the fluid flow
path at specific rotational speeds.
[0034] The disclosed embodiments of non-uniform spacing or modified
count of rotating blades or stationary vanes may be utilized in any
suitable rotary machine, such as turbines, compressors, and rotary
pumps. However, for purposes of discussion, the disclosed
embodiments are presented in context of a gas turbine engine. FIG.
1 is a cross-sectional side view of an embodiment of a gas turbine
engine 150. As described further below, a non-uniform spacing or
modified count of rotating blades or stationary vanes may be
employed within the gas turbine engine 150 to reduce and/or dampen
periodic oscillations, vibration, and/or harmonic behavior of wake
and bow waves in the fluid flow. For example, a non-uniform spacing
or modified count of rotating blades or stationary vanes may be
used in a compressor 152 and a turbine 154 of the gas turbine
engine 150. Furthermore, the non-uniform spacing or modified count
of rotating blades or stationary vanes may be used in a single
stage or multiple stages of the compressor 152 and the turbine 154,
and may vary from one stage to another.
[0035] In the illustrated embodiment, the gas turbine engine 150
includes an air intake section 156, the compressor 152, one or more
combustors 158, the turbine 154, and an exhaust section 160. The
compressor 152 includes a plurality of compressor stages 162 (e.g.,
1 to 20 stages), each having a plurality of rotating compressor
blades 164 and stationary compressor vanes 166. The compressor 152
is configured to intake air from the air intake section 156 and
progressively increase the air pressure in the stages 162.
Eventually, the gas turbine engine 150 directs the compressed air
from the compressor 152 to the one or more combustors 158. Each
combustor 158 is configured to mix the compressed air with fuel,
combust the fuel air mixture, and direct hot combustion gases
toward the turbine 154. Accordingly, each combustor 158 includes
one or more fuel nozzles 168 and a transition piece 170 leading
toward the turbine 154. The turbine 154 includes a plurality of
turbine stages 172 (e.g., 1 to 20 stages), such as stages 174, 176,
and 178, each having a plurality of rotating turbine blades 180 and
stationary nozzle assemblies or turbine vanes 182. In turn, the
turbine blades 180 are coupled to respective turbine wheels 184,
which are coupled to a rotating shaft 186. The turbine 154 is
configured to intake the hot combustion gases from the combustors
158, and progressively extract energy from the hot combustion gases
to drive the blades 180 in the turbine stages 172. As the hot
combustion gases cause rotation of the turbine blades 180, the
shaft 186 rotates to drive the compressor 152 and any other
suitable load, such as an electrical generator. Eventually, the gas
turbine engine 150 diffuses and exhausts the combustion gases
through the exhaust section 160.
[0036] As discussed in detail below, a variety of embodiments of
non-uniform spacing or modified count of rotating blades or
stationary vanes may be used in the compressor 152 and the turbine
154 to tune the fluid dynamics in a manner that reduces undesirable
behavior, such as resonance and vibration. For example, as
discussed with reference to FIGS. 2-14, a non-uniform spacing of
the compressor blades 164, the compressor vanes 166, the turbine
blades 180, and/or the turbine vanes 182 may be selected to reduce,
dampen, or frequency shift the wake and bow waves created in the
gas turbine engine 150. Similarly, as discussed with reference to
FIGS. 15-21, a modified count (e.g., modified uniform spacing) of
the compressor blades 164, the compressor vanes 166, the turbine
blades 180, and/or the turbine vanes 182 may be selected to reduce,
dampen, or frequency shift the wake and bow waves created in the
gas turbine engine 150. In these various embodiments, the
non-uniform spacing or modified count of rotating blades or
stationary vanes is specifically selected to reduce the possibility
of resonance and vibration, thereby improving the performance and
increasing the longevity of the gas turbine engine 150.
[0037] FIG. 2 is a front view of an embodiment of a rotor 200 with
non-uniformly spaced blades. In certain embodiments, the rotor 200
may be disposed in a turbine, a compressor, or another rotary
machine. For example, the rotor 200 may be disposed in a gas
turbine, a steam turbine, a water turbine, or any combination
thereof. Furthermore, the rotor 200 may be used in multiple stages
of a rotary machine, each have the same or different arrangement of
the non-uniformly spaced blades.
[0038] The illustrated rotor 200 has non-uniformly spaced blades
208, which may be described by dividing the rotor 200 into two
equal sections 202 and 204 (e.g., 180 degrees each) via an
intermediate line 206. In certain embodiments, each section 202 and
204 may have a different number of blades 208, thereby creating
non-uniform blade spacing. For example, the illustrated upper
section 202 has three blades 208, while the illustrated lower
section 204 has six blades 208. Thus, the upper section 202 has
half as many blades 208 as the lower section 204. In other
embodiments, the upper and lower sections 202 and 204 may differ in
the number of blades 208 by approximately 1 to 1.005, 1 to 1.01, 1
to 1.02, 1 to 1.05, or 1 to 3. For example, the percentage of
blades 208 of the upper section 202 relative to the lower section
204 may range between approximately 50 to 99.99 percent, 75 to
99.99 percent, 95 to 99.99, or 97-99.99 percent. However, any
difference in the number of blades 208 between the upper and lower
sections 202 and 204 may be employed to reduce and dampen wake and
bow waves associated with rotation of the blades 208 on stationary
airfoils or structures.
[0039] In addition, the blades 208 may be evenly or unevenly spaced
within each section 202 and 204. For example, in the illustrated
embodiment, the blades 208 in the upper section 202 are evenly
spaced from one another by a first circumferential spacing 210
(e.g., arc lengths), while the blades 208 in the lower section 204
are evenly spaced from one another by a second circumferential
spacing 212 (e.g., arc lengths). Although each section 202 and 204
has equal spacing, the circumferential spacing 210 is different
from the circumferential spacing 212. In other embodiments, the
circumferential spacing 210 may vary from one blade 208 to another
in the upper section 202 and/or the circumferential spacing 212 may
vary from one blade 208 to another in the lower section 204. In
each of these embodiments, the non-uniform blade spacing is
configured to reduce the possibility of resonance on stationary
airfoils and structures due to periodic generation of wake and bow
waves by rotating airfoils or structures. The non-uniform blade
spacing may effectively dampen and reduce the wake and bow waves
due to their non-periodic generation by the non-uniform rotating
airfoils or structures. In this manner, the non-uniform blade
spacing is able to lessen the impact of wake and bow waves on
various downstream components, e.g., vanes, nozzles, stators,
airfoils, etc.
[0040] FIG. 3 is a front view of an embodiment of a rotor 220 with
non-uniformly spaced blades. In certain embodiments, the rotor 220
may be disposed in a turbine, a compressor, or another rotary
machine. For example, the rotor 220 may be disposed in a gas
turbine, a steam turbine, a water turbine, or any combination
thereof. Furthermore, the rotor 220 may be used in multiple stages
of a rotary machine, each have the same or different arrangement of
the non-uniformly spaced blades.
[0041] The illustrated rotor 220 has non-uniformly spaced blades
234, which may be described by dividing the rotor 220 into four
equal sections 222, 224, 226, and 228 (e.g., 90 degrees each) via
intermediate lines 230 and 232. In certain embodiments, at least
one or more of the sections 222, 224, 226, and 228 may have a
different number of blades 234 relative to the other sections,
thereby creating non-uniform blade spacing. For example, the
sections 222, 224, 226, and 228 may have 1, 2, 3, or 4 different
numbers of blades 234 in the respective sections. In the
illustrated embodiment, each section 222, 224, 226, and 228 has a
different number of blades 234. Section 222 has 3 blades equally
spaced from one another by a circumferential distance 236, section
224 has 6 blades equally spaced from one another by a
circumferential distance 238, section 226 has 2 blades equally
spaced from one another by a circumferential distance 240, and
section 228 has 5 blades equally spaced from one another by a
circumferential distance 242. In this embodiment, sections 224 and
226 have an even yet different number of blades 234, while sections
222 and 228 have an odd yet different number of blades 234. In
other embodiments, the sections 222, 224, 226, and 228 may have any
configuration of even and odd numbers of blades 234, provided that
at least one section has a different number of blades 234 relative
to the remaining sections. For example, the sections 222, 224, 226,
and 228 may vary in the number of blades 234 with respect to each
other by approximately 1 to 1.005, 1 to 1.01, 1 to 1.02, 1 to 1.05,
or 1 to 3.
[0042] In addition, the blades 234 may be evenly or unevenly spaced
within each section 222, 224, 226, and 228. For example, in the
illustrated embodiment, the blades 234 in the section 222 are
evenly spaced from one another by the first circumferential spacing
236 (e.g., arc lengths), the blades 234 in the section 224 are
evenly spaced from one another by the second circumferential
spacing 238 (e.g., arc lengths), the blades 234 in the section 226
are evenly spaced from one another by the third circumferential
spacing 240 (e.g., arc lengths), and the blades 234 in the section
228 are evenly spaced from one another by the fourth
circumferential spacing 242 (e.g., arc lengths). Although each
section 222, 224, 226, and 228 has equal spacing, the
circumferential spacing 236, 238, 240, and 242 varies from one
section to another. In other embodiments, the circumferential
spacing may vary within each individual section. In each of these
embodiments, the non-uniform blade spacing is configured to reduce
the possibility of resonance due to periodic generation of wake and
bow waves. Furthermore, the non-uniform blade spacing may
effectively dampen and reduce the response of stationary airfoils
or structures by the rotating airfoils or structure's wake and bow
waves due to their non-periodic generation by the blades 234. In
this manner, the non-uniform blade spacing is able to lessen the
impact of wake and bow waves on various downstream components,
e.g., vanes, nozzles, stators, airfoils, etc.
[0043] FIG. 4 is a front view of an embodiment of a rotor 250 with
non-uniformly spaced blades. In certain embodiments, the rotor 250
may be disposed in a turbine, a compressor, or another rotary
machine. For example, the rotor 250 may be disposed in a gas
turbine, a steam turbine, a water turbine, or any combination
thereof. Furthermore, the rotor 250 may be used in multiple stages
of a rotary machine, each have the same or different arrangement of
the non-uniformly spaced blades.
[0044] The illustrated rotor 250 has non-uniformly spaced blades
264, which may be described by dividing the rotor 250 into three
equal sections 252, 254, and 256 (e.g., 120 degrees each) via
intermediate lines 258, 260, and 262. In certain embodiments, at
least one or more of the sections 252, 254, and 256 may have a
different number of blades 264 relative to the other sections,
thereby creating non-uniform blade spacing. For example, the
sections 252, 254, and 256 may have 2 or 3 different numbers of
blades 264 in the respective sections. In the illustrated
embodiment, each section 252, 254, and 256 has a different number
of blades 264. Section 252 has 3 blades equally spaced from one
another by a circumferential distance 266, section 254 has 6 blades
equally spaced from one another by a circumferential distance 268,
and section 256 has 5 blades equally spaced from one another by a
circumferential distance 270. In this embodiment, sections 252 and
256 have an odd yet different number of blades 264, while section
254 has an even number of blades 264. In other embodiments, the
sections 252, 254, and 256 may have any configuration of even and
odd numbers of blades 264, provided that at least one section has a
different number of blades 264 relative to the remaining sections.
For example, the sections 252, 254, and 256 may vary in the number
of blades 264 with respect to each other by approximately 1 to
1.005, 1 to 1.01, 1 to 1.02, 1 to 1.05, or 1 to 3.
[0045] In addition, the blades 264 may be evenly or unevenly spaced
within each section 252, 254, and 256. For example, in the
illustrated embodiment, the blades 264 in the section 252 are
evenly spaced from one another by the first circumferential spacing
266 (e.g., arc lengths), the blades 264 in the section 254 are
evenly spaced from one another by the second circumferential
spacing 268 (e.g., arc lengths), and the blades 264 in the section
256 are evenly spaced from one another by the third circumferential
spacing 270 (e.g., arc lengths). Although each section 252, 254,
and 256 has equal spacing, the circumferential spacing 266, 268,
and 270 varies from one section to another. In other embodiments,
the circumferential spacing may vary within each individual
section. In each of these embodiments, the non-uniform blade
spacing is configured to reduce the possibility of resonance due to
periodic generation of wake and bow waves. Furthermore, the
non-uniform blade spacing may effectively dampen and reduce the
response of stationary airfoils or structures by the rotating
airfoils or structure's wake and bow waves due to their
non-periodic generation by the blades 264. In this manner, the
non-uniform blade spacing is able to lessen the impact of wake and
bow waves on various downstream components, e.g., vanes, nozzles,
stators, airfoils, etc.
[0046] FIG. 5 is a perspective view of an embodiment of three
rotors 280, 282, and 284, wherein each rotor has a different
non-uniform spacing of blades 286. For example, the illustrated
rotors 280, 282, and 284 may correspond to three stages of the
compressor 152 or the turbine 154 as illustrated in FIG. 1. As
illustrated, each of the rotors 280, 282, and 284 has non-uniform
spacing of blades 286 between respective upper sections 288, 290,
and 292 and respective lower sections 294, 296, and 298. For
example, the rotor 280 includes three blades 286 in the upper
section 288 and five blades 286 in the lower section 294, the rotor
282 includes four blades 286 in the upper section 290 and six
blades 286 in the lower section 296, and the rotor 284 includes
five blades 286 in the upper section 292 and seven blades 286 in
the lower section 298. Thus, the upper sections 280, 282, and 284
have a greater number of blades 286 relative to the lower sections
294, 296, and 298 in each respective rotor 280, 282, and 284. In
the illustrated embodiment, the number of blades 286 increases by
one blade 286 from one upper section to another, while also
increasing by one blade 286 from one lower section to another. In
other embodiments, the upper and lower sections may differ in the
number of blades 286 by approximately 1 to 1.005, 1 to 1.01, 1 to
1.02, 1 to 1.05, or 1 to 3 within each individual rotor and/or from
one rotor to another. In addition, the blades 286 may be evenly or
unevenly spaced within each section 288, 290, 292, 294, 296, and
298.
[0047] In each of these embodiments, the non-uniform blade spacing
is configured to reduce the possibility of resonance due to
periodic generation of wake and bow waves. Furthermore, the
non-uniform blade spacing may effectively dampen and reduce the
response of stationary airfoils or structures by the rotating
airfoils or structure's wake and bow waves due to their
non-periodic generation by the blades 286. In this manner, the
non-uniform blade spacing is able to lessen the impact of wake and
bow waves on various downstream components, e.g., vanes, nozzles,
stators, airfoils, etc. In the embodiment of FIG. 5, the
non-uniform blade spacing is provided both within each individual
rotor 280, 282, and 284, and also from one rotor to another (e.g.,
one stage to another). Thus, the non-uniformity from one rotor to
another may further reduce the possibility of resonance caused by
periodic generation of wake and bow waves in a rotary machine.
[0048] FIG. 6 is a section of a front view of an embodiment of a
rotor 310 with differently sized spacers 312 between bases 314 of
blades 316. In particular, the differently sized spacers 312 enable
implementation of a variety of non-uniform blade spacing
configurations with equally sized bases 314 and/or blades 316,
thereby reducing manufacturing costs of the blades 316. Although
any number and size of spacers 312 may be used to provide the
non-uniform blade spacing, the illustrated embodiment includes
three differently sized spacers 312 for purposes of discussion. The
illustrated spacers 312 include a small spacer labeled as "S", a
medium spacer labeled as "M", and a large spacer labeled as "L."
The size of the spacers 312 may vary in a circumferential
direction, as indicated by dimension 318 for the small spacer,
dimension 320 for the medium spacer, and dimension 322 for the
large spacer. In certain embodiments, a plurality of spacers 312
may be disposed between adjacent bases 314, wherein the spacers 312
are either of equal or different sizes. In other words, the
differently sized spacers 312 may be either a one-piece
construction or a multi-piece construction using a plurality of
smaller spacers to generate a greater spacing. In either
embodiment, the dimensions 318, 320, and 322 may progressively
increase by a percentage of approximately 1 to 1000 percent, 5 to
500 percent, or 10 to 100 percent. In other embodiments, the rotor
310 may include more or fewer differently sized spacers 312, e.g.,
2 to 100, 2 to 50, 2 to 25, or 2 to 10. The differently sized
spacers 312 (e.g., S, M, and L) also may be arranged in a variety
of repeating patterns, or they may be arranged in a random
order.
[0049] FIG. 7 is a top view of an embodiment of a rotor 322 with
differently sized spacers 324 between bases 326 of blades 328.
Similar to the embodiment of FIG. 6, the differently sized spacers
324 enable implementation of a variety of non-uniform blade spacing
configurations with equally sized bases 326 and/or blades 328,
thereby reducing manufacturing costs of the blades 328. Although
any number and size of spacers 324 may be used to provide the
non-uniform blade spacing, the illustrated embodiment includes
three differently sized spacers 324 for purposes of discussion. The
illustrated spacers 324 include a small spacer labeled as "S", a
medium spacer labeled as "M", and a large spacer labeled as "L."
The size of the spacers 324 may vary in a circumferential
direction, as discussed above with reference to FIG. 5. The
differently sized spacers 324 (e.g., S, M, and L) also may be
arranged in a variety of repeating patterns, or they may be
arranged in a random order.
[0050] In the illustrated embodiment, the spacers 324 interface
with the bases 326 of the blades 328 at an angled interface 330.
For example, the angled interface 330 is oriented at an angle 332
relative to a rotational axis of the rotor 322, as indicated by
line 334. The angle 332 may range between approximately 0 to 60
degrees, 5 to 45 degrees, or 10 to 30 degrees. The illustrated
angled interface 330 is a straight edge or flat surface. However,
other embodiments of the interface 330 may have non-straight
geometries.
[0051] FIG. 8 is a top view of an embodiment of a rotor 340 with
differently sized spacers 342 between bases 344 of blades 346.
Similar to the embodiment of FIGS. 6 and 8, the differently sized
spacers 342 enable implementation of a variety of non-uniform blade
spacing configurations with equally sized bases 344 and/or blades
346, thereby reducing manufacturing costs of the blades 346.
Although any number and size of spacers 342 may be used to provide
the non-uniform blade spacing, the illustrated embodiment includes
three differently sized spacers 342 for purposes of discussion. The
illustrated spacers 342 include a small spacer labeled as "S", a
medium spacer labeled as "M", and a large spacer labeled as "L."
The size of the spacers 342 may vary in a circumferential
direction, as discussed above with reference to FIG. 6. The
differently sized spacers 342 (e.g., S, M, and L) also may be
arranged in a variety of repeating patterns, or they may be
arranged in a random order.
[0052] In the illustrated embodiment, the spacers 342 interface
with the bases 344 of the blades 346 at a non-straight interface
350. For example, the interface 350 may include a first curved
portion 352 and a second curved portion 354, which may be the same
or different from one another. However, the interface 350 also may
have other non-straight geometries, such as multiple straight
segments of different angles, one or more protrusions, one or more
recesses, or a combination thereof. As illustrated, the first and
second curved portions 352 and 354 curve in opposite directions
from one another. However, the curved portions 352 and 354 may
define any other curved geometry.
[0053] FIG. 9 is a front view of an embodiment of a blade 360
having a T-shaped geometry 361, which may be arranged in a
non-uniform blade spacing in accordance with the disclosed
embodiments. The illustrated blade 360 includes a base portion 362
and a blade portion 364, which may be integral with one another
(e.g., one-piece). The base portion 362 includes a first flange
366, a second flange 368 offset from the first flange 366, a neck
370 extending between the flanges 366 and 368, and opposite slots
372 and 374 disposed between the flanges 366 and 368. During
assembly, the flanges 366 and 368 and slots 372 and 374 are
configured to interlock with a circumferential rail structure about
the rotor. In other words, the flanges 366 and 368 and slots 372
and 374 are configured to slide circumferentially into place along
the rotor, thereby securing the blade 360 in the axial and radial
directions. In the embodiments of FIGS. 6-8, these blades 360 may
be spaced apart in the circumferential direction by a plurality of
differently sized spacers having a similar base portion, thereby
providing a non-uniform blade spacing of the blades 360.
[0054] FIG. 10 is a section of a front view of an embodiment of a
rotor 384 with differently sized bases 386 of blades 388. In
particular, the differently sized bases 386 enable implementation
of a variety of non-uniform blade spacing configurations with or
without spacers. If spacers are used with the differently sized
bases 386, the spacers may be equally sized or differently sized to
provide more flexibility in the non-uniform blade spacing. Although
any number of differently sized bases 386 may be used to provide
the non-uniform blade spacing, the illustrated embodiment includes
three differently sized bases 386 for purposes of discussion. The
illustrated bases 386 include a small base labeled as "S", a medium
base labeled as "M", and a large base labeled as "L." The size of
the bases 386 may vary in a circumferential direction, as indicated
by dimension 390 for the small base, dimension 392 for the medium
base, and dimension 394 for the large base. For example, these
dimensions 390, 392, and 394 may progressively increase by a
percentage of approximately 1 to 1000 percent, 5 to 500 percent, or
10 to 100 percent. In other embodiments, the rotor 384 may include
more of fewer differently sized bases 386, e.g., 2 to 100, 2 to 50,
2 to 25, or 2 to 10. The differently sized bases 386 (e.g., S, M,
and L) also may be arranged in a variety of repeating patterns, or
they may be arranged in a random order.
[0055] FIG. 11 is a top view of an embodiment of a rotor 400 with
differently sized blade bases 402 supporting blades 404. Similar to
the embodiment of FIG. 10, the differently sized bases 402 enable
implementation of a variety of non-uniform blade spacing
configurations with or without spacers. Although any number and
size of bases 402 may be used to provide the non-uniform blade
spacing, the illustrated embodiment includes three differently
sized bases 402 for purposes of discussion. The illustrated bases
402 include a small base labeled as "S", a medium base labeled as
"M", and a large base labeled as "L." The size of the bases 402 may
vary in a circumferential direction, as discussed above with
reference to FIG. 10. The differently sized bases 402 (e.g., S, M,
and L) also may be arranged in a variety of repeating patterns, or
they may be arranged in a random order.
[0056] In the illustrated embodiment, the bases 402 interface with
one another at an angled interface 406. For example, the angled
interface 406 is oriented at an angle 408 relative to a rotational
axis of the rotor 400, as indicated by line 409. The angle 408 may
range between approximately 0 to 60 degrees, 5 to 45 degrees, or 10
to 30 degrees. The illustrated angled interface 406 is a straight
edge or flat surface. However, other embodiments of the interface
406 may have non-straight geometries.
[0057] FIG. 12 is a top view of an embodiment of a rotor 410 with
differently sized blade bases 412 supporting blades 414. Similar to
the embodiment of FIGS. 10 and 12, the differently sized bases 412
enable implementation of a variety of non-uniform blade spacing
configurations with or without spacers. Although any number and
size of bases 412 may be used to provide the non-uniform blade
spacing, the illustrated embodiment includes three differently
sized bases 412 for purposes of discussion. The illustrated bases
412 include a small base labeled as "S", a medium base labeled as
"M", and a large base labeled as "L." The size of the bases 412 may
vary in a circumferential direction, as discussed above with
reference to FIG. 10. The differently sized bases 412 (e.g., S, M,
and L) also may be arranged in a variety of repeating patterns, or
they may be arranged in a random order.
[0058] In the illustrated embodiment, the bases 412 interface with
one another at a non-straight interface 416. For example, the
interface 416 may include a first curved portion 418 and a second
curved portion 420, which may be the same or different from one
another. However, the interface 416 also may have other
non-straight geometries, such as multiple straight segments of
different angles, one or more protrusions, one or more recesses, or
a combination thereof. As illustrated, the first and second curved
portions 418 and 420 curve in opposite directions from one another.
However, the curved portions 418 and 420 may define any other
curved geometry.
[0059] FIG. 13 is a section of a front view of an embodiment of a
stator 440 with differently sized spacers 442 between bases 444 of
vanes 446. In particular, the differently sized spacers 442 enable
implementation of a variety of non-uniform vane spacing
configurations with equally sized bases 444 and/or vanes 446,
thereby reducing manufacturing costs of the vanes 446. Although any
number and size of spacers 442 may be used to provide the
non-uniform vane spacing, the illustrated embodiment includes three
differently sized spacers 442 for purposes of discussion. The
illustrated spacers 442 include a small spacer labeled as "S", a
medium spacer labeled as "M", and a large spacer labeled as "L."
The size of the spacers 442 may vary in a circumferential
direction, as indicated by dimension 448 for the small spacer,
dimension 450 for the medium spacer, and dimension 452 for the
large spacer. In certain embodiments, a plurality of spacers 442
may be disposed between adjacent bases 444, wherein the spacers 442
are either of equal or different sizes. In other words, the
differently sized spacers 442 may be either a one-piece
construction or a multi-piece construction using a plurality of
smaller spacers to generate a greater spacing. In either
embodiment, the dimensions 448, 450, and 452 may progressively
increase by a percentage of approximately 1 to 1000 percent, 5 to
500 percent, or 10 to 100 percent. In other embodiments, the stator
440 may include more or fewer differently sized spacers 442, e.g.,
2 to 100, 2 to 50, 2 to 25, or 2 to 10. The differently sized
spacers 442 (e.g., S, M, and L) also may be arranged in a variety
of repeating patterns, or they may be arranged in a random
order.
[0060] FIG. 14 is a section of a front view of an embodiment of a
stator 460 with differently sized bases 462 of vanes 464. In
particular, the differently sized bases 462 enable implementation
of a variety of non-uniform vane spacing configurations with or
without spacers. If spacers are used with the differently sized
bases 462, the spacers may be equally sized or differently sized to
provide more flexibility in the non-uniform vane spacing. Although
any number of differently sized bases 462 may be used to provide
the non-uniform vane spacing, the illustrated embodiment includes
three differently sized bases 462 for purposes of discussion. The
illustrated bases 462 include a small base labeled as "S", a medium
base labeled as "M", and a large base labeled as "L." The size of
the bases 462 may vary in a circumferential direction, as indicated
by dimension 466 for the small base, dimension 468 for the medium
base, and dimension 470 for the large base. For example, these
dimensions 466, 468, and 470 may progressively increase by a
percentage of approximately 1 to 1000 percent, 5 to 500 percent, or
10 to 100 percent. In other embodiments, the stator 460 may include
more of fewer differently sized bases 462, e.g., 2 to 100, 2 to 50,
2 to 25, or 2 to 10. The differently sized bases 462 (e.g., S, M,
and L) also may be arranged in a variety of repeating patterns, or
they may be arranged in a random order.
[0061] As discussed above, the present embodiments may tune the
fluid dynamics in a rotary machine, such as a compressor or
turbine, via an adjustment of the spacing between rotating blades
or stationary vanes and/or an adjustment of the count of rotating
blades or stationary vanes. This tuning may substantially reduce or
eliminate the possibility of resonance behavior in the rotary
machine, e.g., resonant behavior due to wakes and bow waves. The
embodiments of FIGS. 2-14 provide a non-uniform spacing of rotating
blades or stationary vanes, which may also correspond with a change
or no change in the count of the blades or vanes. The embodiments
of FIGS. 15-21 specifically modify the count of the blades or
vanes, while maintaining a uniform spacing of the blades or vanes.
As discussed in further detail below, changing the number of blades
or vanes on respective rotors and stators while maintaining uniform
spacing changes the frequency of wake and bow waves at specific
rotational speeds. For instance, altering the size of the spacers
may increase or decrease the blade count by any suitable number,
e.g., 1 to 5, 1 to 10, or 1 to 20. This frequency change may
prevent a long-lasting resonant response in structures along the
flow path (e.g., rotors, stators, etc.) at specific rotational
speeds.
[0062] FIGS. 15, 16, and 17 illustrate the use of three differently
sized spacers to provide a different uniform blade spacing and
blade count, which may be selectively used to vary the frequency of
wakes and bow waves in a rotary machine such as a turbine or a
compressor. Although FIGS. 15, 16, and 17 illustrate only three
sizes of spacers (i.e., large, medium, and small), certain
embodiments may employ any number of spacer sizes (e.g., 2 to 100
different sizes) to modify the blade spacing and count. FIG. 15 is
a section of a front view of an embodiment of a rotor 480 with
large spacers 482 between blade bases 484 supporting blades 486. In
the illustrated embodiment, the large spacers 482 have an equal
size to separate adjacent blade bases 484 by an equal distance 488
around the rotor 480. The large spacers 482 also separate the
blades 486 by an equal distance 490 around the rotor 480. Relative
to the small and medium spacers as illustrated in FIGS. 16 and 17,
the large spacers 482 decrease the number of blades 486 on the
rotor 480, thereby decreasing the frequency of the bow and wake
waves. The large spacers 482 may be used to shift the frequency of
the bow and wake waves away from a resonant frequency, e.g., if the
medium or small spacers result in a frequency too close to the
resonant frequency.
[0063] FIG. 16 is a section of a front view of an embodiment of a
rotor 500 with medium spacers 502 between blade bases 504
supporting blades 506. In the illustrated embodiment, the medium
spacers 502 have an equal size to separate adjacent blade bases 504
by an equal distance 508 around the rotor 500. The medium spacers
502 also separate the blades 506 by an equal distance 510 around
the rotor 500. Relative to the large spacers as illustrated in FIG.
15, the medium spacers 502 increase the number of blades 506 on the
rotor 500, thereby increasing the frequency of the bow and wake
waves. Relative to the small spacers as illustrated in FIG. 17, the
medium spacers 502 decrease the number of blades 506 on the rotor
500, thereby decreasing the frequency of the bow and wake waves.
The medium spacers 502 may be used to shift the frequency of the
bow and wake waves away from a resonant frequency, e.g., if the
large or small spacers result in a frequency too close to the
resonant frequency.
[0064] FIG. 17 is a section of a front view of an embodiment of a
rotor 520 with small spacers 522 between blade bases 524 supporting
blades 526. In the illustrated embodiment, the small spacers 522
have an equal size to separate adjacent blade bases 524 by an equal
distance 528 around the rotor 520. The small spacers 522 also
separate the blades 526 by an equal distance 530 around the rotor
520. Relative to the large and medium spacers as illustrated in
FIGS. 15 and 16, the small spacers 522 increase the number of
blades 526 on the rotor 520, thereby increasing the frequency of
the bow and wake waves. The small spacers 522 may be used to shift
the frequency of the bow and wake waves away from a resonant
frequency, e.g., if the large and medium spacers result in a
frequency too close to the resonant frequency.
[0065] FIG. 18 is a graph 530 illustrating a fluid oscillation
frequency or vibration frequency versus rotational speed of a
rotary machine, such as a turbine or a compressor. As illustrated
in FIG. 18, the x-axis 532 represents the rotational speed of the
rotary machine, while the y-axis 534 represents the fluid
oscillation frequency or vibration frequency of a structure in the
fluid flow. The dashed vertical line 536 represents a normal
rotational speed of the rotary machine, e.g., a design speed of a
turbine engine. A curve 538 represents a resonant frequency of a
structure in the fluid flow. For example, the curve 538 may
correspond to a resonant frequency of vibration of a stationary
structure (e.g., vane) upstream or downstream from a rotating blade
that produces wake and bow waves. Lines 540, 542, and 544 represent
the frequency of oscillations of the fluid flow (e.g., wake or bow
waves) driven by rotation of the blades, wherein each line 540,
542, and 544 represents a different count of equally spaced blades.
In particular, the line 540 represents a large count of blades
provided by a plurality of small spacers as represented by "S," the
line 542 represents a medium count of blades provided by a
plurality of medium spacers as represented by "M," and the line 544
represents a small count of blades provided by a plurality of large
spacers as represented by "L." Accordingly, the line 540 may
correspond to the embodiment of FIG. 17, the line 542 may
correspond to the embodiment of FIG. 16, and the line 544 may
correspond to the embodiment of FIG. 15.
[0066] As illustrated in FIG. 18, an increase in the blade count
corresponding to a decrease in the spacer size causes an increase
in the frequency of oscillations (e.g., wake or bow waves)
generated by the blades, whereas a decrease in the blade count
corresponding to a increase in the spacer size causes an decrease
in the frequency of oscillations (e.g., wake or bow waves)
generated by the blades. Thus, the disclosed embodiments adjust the
spacer size to alter the blade count, and thus alter the frequency
of oscillations, to avoid the resonant frequency for a particular
rotational speed. The intersections of the lines 540, 542, and 544
with the line 538 represent resonant points 546, 548, and 550 for
the different blade counts. For example, the resonant point 546
represents a first resonant frequency 552 at a first rotational
speed 554, wherein the frequency of oscillations (e.g., wake or bow
waves) generated by rotation of the blades 526 of FIG. 17 (i.e.,
small spacers; large blade count) intersects with the resonant
frequency of the structure (e.g., vane) upstream or downstream from
the blades 526. By further example, the resonant point 548
represents a second resonant frequency 556 at a second rotational
speed 558, wherein the frequency of oscillations (e.g., wake or bow
waves) generated by rotation of the blades 506 of FIG. 16 (i.e.,
medium spacers; medium blade count) intersects with the resonant
frequency of the structure (e.g., vane) upstream or downstream from
the blades 506. By further example, the resonant point 550
represents a third resonant frequency 560 at a third rotational
speed 562, wherein the frequency of oscillations (e.g., wake or bow
waves) generated by rotation of the blades 486 of FIG. 15 (i.e.,
large spacers; small blade count) intersects with the resonant
frequency of the structure (e.g., vane) upstream or downstream from
the blades 486.
[0067] In the illustrated embodiment, the second rotational speed
558 is generally the same as the design rotational speed 536 of the
rotary machine, and thus the line 542 corresponding to the medium
count of blades (e.g., FIG. 16) would likely result in resonant
behavior of the structure (e.g., vane) upstream or downstream from
the rotating blades 506. Accordingly, the disclosed embodiments may
employ either a greater or lesser count of blades to avoid this
resonant behavior at the design rotational speed 536 of the rotary
machine. For example, the disclosed embodiments may employ the
greater count of blades provided by smaller spacers as depicted in
FIG. 17, or the lesser count of blades provided by the larger
spacers as depicted in FIG. 15. At the design rotational speed 536,
the greater count of blades provided by smaller spacers as depicted
in FIG. 17 would result in a frequency 564 of oscillations (e.g.,
wakes or bow waves) substantially greater than the resonant
frequency 556, thereby substantially preventing any resonant
behavior in the structure (e.g., vane) upstream or downstream from
the blades. Similarly, at the design rotational speed 536, the
lesser count of blades provided by larger spacers as depicted in
FIG. 15 would result in a frequency 566 of oscillations (e.g.,
wakes or bow waves) substantially lesser than the resonant
frequency 556, thereby substantially preventing any resonant
behavior in the structure (e.g., vane) upstream or downstream from
the blades. Although FIGS. 15-18 represent only three sizes of
spacers (i.e., large 482, medium 502, and small 522), any number of
differently sized spacers may be used to adjust the count of blades
with a uniform blade spacing, thereby avoiding any resonant
behavior in the rotary machine.
[0068] Similar to the modification of blade spacing of rotating
blades as discussed above with reference to FIGS. 15-18, the
disclosed embodiments also include modification of vane spacing of
stationary vanes as discussed below with reference to FIGS. 19, 20,
and 21. FIGS. 19, 20, and 21 illustrate the use of three
differently sized spacers to provide a different uniform vane
spacing and vane count, which may be selectively used to vary the
frequency of wakes and bow waves in a rotary machine such as a
turbine or a compressor. Although FIGS. 19, 20, and 21 illustrate
only three sizes of spacers (i.e., large, medium, and small),
certain embodiments may employ any number of spacer sizes (e.g., 2
to 100 different sizes) to modify the blade spacing and count. In
each embodiment, the spacers may be selected to alter the vane
count to control the frequency of oscillations (e.g., wakes or bow
waves), thereby ensuring that the frequency of oscillations does
not coincide with a resonant frequency.
[0069] FIG. 19 is a section of a front view of an embodiment of a
stator 570 with large spacers 572 between vane bases 574 supporting
vanes 576. In the illustrated embodiment, the large spacers 572
have an equal size to separate adjacent vane bases 574 by an equal
distance 578 around the stator 570. The large spacers 572 also
separate the vanes 576 by an equal distance 580 around the stator
570. Relative to the small and medium spacers as illustrated in
FIGS. 20 and 21, the large spacers 572 decrease the number of vanes
576 on the stator 570, thereby decreasing the frequency of the bow
and wake waves. The large spacers 572 may be used to shift the
frequency of the bow and wake waves away from a resonant frequency,
e.g., if the medium or small spacers result in a frequency too
close to the resonant frequency.
[0070] FIG. 20 is a section of a front view of an embodiment of a
stator 590 with medium spacers 592 between vane bases 594
supporting vanes 596. In the illustrated embodiment, the medium
spacers 592 have an equal size to separate adjacent vane bases 594
by an equal distance 598 around the stator 590. The medium spacers
592 also separate the vanes 596 by an equal distance 600 around the
stator 590. Relative to the large spacers as illustrated in FIG.
19, the medium spacers 592 increase the number of vanes 596 on the
stator 590, thereby increasing the frequency of the bow and wake
waves. Relative to the small spacers as illustrated in FIG. 21, the
medium spacers 592 decrease the number of vanes 596 on the stator
590, thereby decreasing the frequency of the bow and wake waves.
The medium spacers 592 may be used to shift the frequency of the
bow and wake waves away from a resonant frequency, e.g., if the
large or small spacers result in a frequency too close to the
resonant frequency.
[0071] FIG. 21 is a section of a front view of an embodiment of a
stator 610 with small spacers 612 between vane bases 614 supporting
vanes 616. In the illustrated embodiment, the small spacers 612
have an equal size to separate adjacent vane bases 614 by an equal
distance 618 around the stator 610. The small spacers 612 also
separate the vanes 616 by an equal distance 620 around the stator
610. Relative to the large and medium spacers as illustrated in
FIGS. 19 and 20, the small spacers 612 increase the number of vanes
616 on the stator 610, thereby increasing the frequency of the bow
and wake waves. The small spacers 612 may be used to shift the
frequency of the bow and wake waves away from a resonant frequency,
e.g., if the large and medium spacers result in a frequency too
close to the resonant frequency.
[0072] The embodiments discussed above are directed to changing the
frequency of wake and bow waves generated by rotating blades or
stationary vanes, such that the frequency does not intersect with a
resonant frequency of various structures in the fluid flow. As
appreciated, the non-uniform spacing or modified count of rotating
blades or stationary vanes may be applied to a single stage of a
rotary machine (e.g., a turbine or a compressor), or it may be
applied to multiple stages in a similar or different configuration.
For example, each stage in a compressor or turbine may change the
non-uniform spacing or modified count of blades or vanes to address
different fluid dynamics in each particular stage. In other words,
each stage may exhibit different resonant behavior, frequencies of
wake and bow waves, and other characteristics. Thus, the disclosed
embodiments may employ a combination of non-uniform spacing and a
modified count of blades and vanes to address the different fluid
dynamics from one stage to another.
[0073] Technical effects of the disclosed embodiments include the
ability to dampen fluid oscillations (e.g., wake or bow waves)
and/or reduce resonant behavior caused by the fluid oscillations in
a rotary machine. In particular, the disclosed embodiments adjust
the spacing and/or count of blades or vanes to control the
frequency of wake and bow waves formed by the rotating blades,
stationary vanes, or other structures in the fluid flow. For
example, a non-uniform spacing of rotating blades or stationary
vanes may be achieved with differently sized spacers between
adjacent blades or vanes, differently sized bases of the blades or
vanes, or a combination thereof. By further example, a modified
count of rotating blades or vanes may be achieved with different
sets of spacers, each configured to provide a different uniform
spacing of the blades or vanes. The non-uniform spacing or modified
count of blades or vanes is able to reduce the possibility of
resonant behavior in the rotary machine, thereby reducing the
possibility of costly wear and damage of vanes, blades, and other
structures in the fluid flow path.
[0074] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal language of the claims.
* * * * *