U.S. patent application number 11/775523 was filed with the patent office on 2009-01-15 for systems and methods involving variable vanes.
This patent application is currently assigned to UNITED TECHNOLOGIES CORP.. Invention is credited to Michael G. McCaffrey.
Application Number | 20090016871 11/775523 |
Document ID | / |
Family ID | 39830181 |
Filed Date | 2009-01-15 |
United States Patent
Application |
20090016871 |
Kind Code |
A1 |
McCaffrey; Michael G. |
January 15, 2009 |
Systems and Methods Involving Variable Vanes
Abstract
Systems and methods involving vanes are provided. In this
regard, a representative method for modifying the throat area
between vanes of a gas turbine engine includes: directing a gas
flow path of the gas turbine engine between a first vane and a
second vane, wherein each of the first vane and the second vane has
an outer surface and an interior; and emitting pressurized air from
outlet ports communicating between the outer surface and the
interior of the first vane, wherein the emitted pressurized air
from the first vane modifies a throat area between the first vane
and the second vane.
Inventors: |
McCaffrey; Michael G.;
(Windsor, CT) |
Correspondence
Address: |
THOMAS, KAYDEN, HORSTEMEYER & RISLEY, LLP
600 GALLERIA PARKWAY, S.E., STE 1500
ATLANTA
GA
30339-5994
US
|
Assignee: |
UNITED TECHNOLOGIES CORP.
East Hartford
CT
|
Family ID: |
39830181 |
Appl. No.: |
11/775523 |
Filed: |
July 10, 2007 |
Current U.S.
Class: |
415/115 |
Current CPC
Class: |
F01D 5/148 20130101;
F01D 5/146 20130101; F01D 5/145 20130101; F05D 2270/17 20130101;
F01D 9/04 20130101 |
Class at
Publication: |
415/115 |
International
Class: |
F01D 5/14 20060101
F01D005/14 |
Claims
1. A gas turbine engine defining a gas flow path, the gas turbine
engine comprising: a first vane extending into the gas flow path
and having: an interior operative to receive pressurized air; an
outer surface; and outlet ports communicating between the outer
surface and the interior of the first vane, the outlet ports being
operative to receive the pressurized air from the interior and emit
the pressurized air into the gas flow path such that a throat area
defined, at least in part, by the first vane is modified.
2. The turbine engine of claim 1, wherein the throat area is
modified by moving the throat area upstream.
3. The turbine engine of claim 1, wherein the first vane further
comprises film cooling ports operative to receive cooling
pressurized air at a pressure lower than that provided to the
outlet ports and to emit the cooling pressurized air from the first
vane such that the first vane is film cooled.
4. The turbine engine of claim 1, further comprising a valve
assembly operative to regulate the pressurized air emitted by the
ports.
5. The turbine engine of claim 1, further comprising a second vane,
the throat area being defined by the first vane and the second
vane.
6. The turbine engine of claim 5, further comprising a valve
assembly operative to control the pressurized air emitted by the
first vane and the second vane.
7. The turbine engine of claim 6, further comprising a second
throat area defined, at least in part, by the second vane, wherein
the throat area and the second throat area are modified
independently by the valve assembly.
8. The turbine engine of claim 1, wherein the valve assembly is
operative to intermittently provide the pressurized air to the
ports.
9. The turbine engine of claim 1, wherein the engine is a
turbofan.
10. A vane assembly comprising: a first vane having: an outer
surface; an interior defining a cavity operative to receive
pressurized air; and outlet ports communicating between the outer
surface and the cavity, the outlet ports being operative to receive
the pressurized air from the cavity and emit the pressurized air
through the outer surface a valve assembly operative to regulate
the pressurized air emitted by the first vane.
11. The vane assembly of claim 10, further comprising a control
assembly operative to control the valve assembly.
12. The vane assembly of claim 10, further comprising: a second
vane operative to define a throat area between the first vane and
the second vane, wherein the pressurized air emitted from the
outlet ports of the first vane is operative to modify the throat
area between the first vane and the second vane.
13. The vane assembly of claim 10, wherein the first vane further
comprises film cooling ports operative to receive cooling
pressurized air at a pressure lower than that provided to the
outlet ports and to emit the cooling pressurized air from the first
vane such that the first vane is film cooled.
14. The vane assembly of claim 10, wherein the valve assembly
comprises a piston and a solenoid, the piston and the solenoid
being operative to increase the pressure of air provided to the
valve assembly.
15. A method for modifying the throat area between vanes of a gas
turbine engine comprising: directing a gas flow path of the gas
turbine engine between a first vane and a second vane, wherein each
of the first vane and the second vane has an outer surface and an
interior; and emitting pressurized air from outlet ports
communicating between the outer surface and the interior of the
first vane, wherein the emitted pressurized air from the first vane
modifies a throat area between the first vane and the second
vane.
16. The method of claim 15, further comprising film cooling the
first vane using lower pressure air than the emitted pressurized
air used to modify the throat area.
17. The method of claim 15, wherein the step of emitting the
pressurized air from outlet ports further comprises emitting the
pressurized air in pulses.
18. The method of claim 15, further comprising emitting pressurized
air from outlet ports communicating between the outer surface of
the second vane and the interior of the second vane such that the
emitted pressurized air from the second vane also modifies the
throat area between the first vane and the second vane.
19. The method of claim 15, wherein the step of emitting the
pressurized air from outlet ports further comprises emitting the
pressurized air in a direction corresponding to the flow of the gas
flow path.
20. The method of claim 15, wherein the step of emitting the
pressurized air from ports further comprises emitting the
pressurized air to reduce engine resonance.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The invention relates to gas turbine engines.
[0003] 2. Description of the Related Art
[0004] Gas turbine engines use compressors to compress gas for
combustion. In particular, a compressor typically uses alternating
sets of rotating blades and stationary vanes to compress gas. Gas
flowing through such a compressor is forced between the sets and
between adjacent blades and vanes of a given set. Similarly, after
combustion, hot expanding gas drives a turbine that has sets of
rotating blades and stationary vanes.
SUMMARY
[0005] Systems and methods involving vanes are provided. In this
regard, an exemplary embodiment of a gas turbine engine defining a
gas flow path comprises: a first vane extending into the gas flow
path and having: an interior operative to receive pressurized air;
an outer surface; and outlet ports communicating between the outer
surface and the interior of the first vane, the outlet ports being
operative to receive the pressurized air from the interior and emit
the pressurized air into the gas flow path such that a throat area
defined, at least in part, by the first vane is modified.
[0006] An exemplary embodiment of a vane assembly comprises: a
first vane having: an outer surface; an interior defining a cavity
operative to receive pressurized air; and outlet ports
communicating between the outer surface and the cavity, the outlet
ports being operative to receive the pressurized air from the
cavity and emit the pressurized air through the outer surface a
valve assembly operative to regulate the pressurized air emitted by
the first vane.
[0007] An exemplary embodiment of a method for modifying the throat
area between vanes of a gas turbine engine comprises: directing a
gas flow path of the gas turbine engine between a first vane and a
second vane, wherein each of the first vane and the second vane has
an outer surface and an interior; and emitting pressurized air from
outlet ports communicating between the outer surface and the
interior of the first vane, wherein the emitted pressurized air
from the first vane modifies a throat area between the first vane
and the second vane.
[0008] Other systems, features, and/or advantages will be or may
become apparent to one with skill in the art upon examination of
the following drawings and detailed description. It is intended
that all such additional systems, features, and/or advantages be
included within this description and protected by the accompanying
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic side cutaway view illustrating an
exemplary embodiment of a turbine section of a gas turbine
engine.
[0010] FIG. 2 is a side cutaway view of an exemplary embodiment of
a vane.
[0011] FIG. 3 is a top cutaway view of an exemplary embodiment of
vanes in a gas flow path.
[0012] FIG. 4 is a top cutaway view of another exemplary embodiment
of vanes in a gas flow path.
[0013] FIG. 5 is a top cutaway view of another exemplary embodiment
of vanes in a gas flow path.
DETAILED DESCRIPTION
[0014] Systems and methods involving vanes of gas turbine engines
are provided. In this regard, several exemplary embodiments will be
described. Notably, gas passing through a gas turbine engine enters
a turbine that includes rotating blades and stationary vanes. The
gas, following the gas flow path, is forced between adjacent vanes.
The vanes are often shaped like airfoils and, therefore, have
aerodynamic properties similar to airfoils. The flow of gas between
adjacent vanes results in a throat area determined by, for example,
the shape and relative position of the vanes. Often, the angle of
the vanes relative to the gas flow path may be mechanically changed
to vary the location and/or size of the throat area and alter the
efficiency of the engine. However, it may be desirable, either
additionally or alternatively, to alter the location and/or size of
the throat area aerodynamically. In some embodiments, the gas
turbine engine is configured as a turbofan.
[0015] Referring now in detail to the drawings, FIG. 1 is a
schematic side view illustrating an exemplary embodiment of a
turbine section 100 of a gas turbine engine. In turbine section
100, rotating blades 104 are attached to a disk that is rotated by
a shaft 106. Stationary vanes 108 are attached to the casing of the
engine between the blades 104. In operation, gas enters the turbine
section along gas flow path 102 and drives the blades 104. The gas
exits the turbine section 100 along gas flow path 102.
[0016] FIG. 2 is a simplified, side cutaway view of vane assembly
200 that includes a vane airfoil 202 and a valve assembly 208. Note
that vane airfoil 202 typically is mounted to and spans between an
outer diameter vane platform and an inner diameter vane platform,
neither of which is depicted in FIG. 2.
[0017] In the embodiment of FIG. 2, valve assembly 208 includes a
piston 204 and solenoid 220, which is used to actuate the piston.
Inlet ports 218 provide gas to the valve assembly so that actuation
of the piston pressurizes the received gas.
[0018] Vane airfoil 202 includes an interior cavity 214 that
receives pressurized air from the inlet ports via the piston, and
outlet ports 216 that are used to emit the pressurized air into the
gas flow path. In particular, the gas emitted by the outlet ports
216 affects the throat area formed between vane airfoil 202 and an
adjacent vane airfoil. This is in contrast to emission of
pressurized gas from ports of a vane airfoil for performing film
cooling. Notably, the pressure of the pressurized gas emitted from
the outlet ports 216 is greater than that used for performing film
cooling. As such, the pressurized gas from the outlet ports 216
urges the gas flow path, which flows about the vane airfoil during
operation of the gas turbine engine, away from the exterior surface
of the vane airfoil to a greater extent than that caused by
pressurized gas involved in film cooling. In fact, in those
embodiments that additionally include film cooling, the boundary
layer formed by the film-cooling air also is urged away from the
exterior of the vane airfoil. Typically, the pressure of the gas
required to alter the throat is not available from the compressor
alone. Thus, piston 204 is used in the embodiment of FIG. 2 to
increase the pressure of the gas provided to the outlet ports. In
other embodiments, various other mechanisms could be used to
increase the gas pressure.
[0019] The shape of the vane assembly 200 illustrated in FIG. 2 is
merely an illustration of but one possible embodiment. The shape of
the vane assembly 200 may vary depending on a variety of factors
including, but not limited to, the component to which the vane
assembly 200 is attached, the location of the vane assembly 200 in
the gas turbine engine, the gas flow path around the vane assembly
200 at particular gas flow velocities, desired design
characteristics of the gas turbine engine, and materials used in
the fabrication of the gas turbine engine.
[0020] In FIG. 2, a controller 212 also is provided. The controller
212 is used to open and close the valve assembly 208. In one mode
of operation, the valve assembly 208 is left open such that the
outlet ports 216 emit a constant flow of pressurized air.
Additionally, or alternatively, the valve assembly 208 may be
opened and closed intermittently. In this mode of operation, the
pressurized air may be emitted from the outlet ports 216 in pulses.
Notably, operation in a pulsed mode allows the pressure of the
pressurized air to increase prior to being emitted into a gas flow
path. In some of these embodiments, the controller 212 may be set
to control the frequency of the pulses of emitted pressurized air.
Controlling the frequency of the pulses may be desirable because a
change in the throat area based on a frequency of pulses may allow
the aerodynamic characteristics of the engine to be adjusted.
[0021] Specifically, the frequencies of the pulses may be
controlled to modify one or more throat areas in a specific region
of an engine to control local pressure ratios and/or local
temperatures. The pulse frequencies may also be timed to adjust for
resonance in the engine that may result in vane and blade
vibrations. These pulses may be used to add a canceling frequency
that may effectively cancel engine resonance, for example.
[0022] FIG. 3 is a top cutaway view of a pair of vanes in an
embodiment of a gas turbine engine. As shown in FIG. 3, gas is
forced between the vanes 300 along gas flow path 302, forming a
throat area 304. The shape of the adjacent vanes 300, their
proximity to each other, and the angle of incidence to the gas flow
path 302 are possible factors that can influence the location and
size of the throat area 304.
[0023] FIG. 4 depicts a top cutaway view of another embodiment of a
vane assembly. In this embodiment, vanes 406 and 412 are adjacent
vanes. Vane 406 has an interior cavity 404 that is connected to a
pressurized air source (not shown). Outlet ports 410 are located on
the surface of vane 406 and are in communication with interior
cavity 404.
[0024] Pressurized air emitted from the outlet ports 410 in vane
406 defines a boundary layer 408 that has an aerodynamic effect on
the gas flow path 402. Notably, the boundary layer 408 associated
with the pressurized air from the outlet ports modifies the
location and/or size of the throat area 416. Also note that the
outlet ports of this embodiment are oriented such that the flow
from the outlet ports is generally in a direction of the gas flow
path. In other embodiments, however, the orientation can be
different, such as by providing a perpendicular (see FIG. 5) or
counter flow (not shown).
[0025] Modifying the throat area of an engine may affect the flow
of gasses through the engine. For instance, such modifying can
affect the pressure ratio of the compressor and change the
relationship between the flow and the pressure ratio. For example,
a lower flow rate can increase the pressure ratio.
[0026] FIG. 5 depicts a top cutaway view of another embodiment of a
vane assembly. In the illustrated embodiment, vane assembly 500
incorporates two adjacent vanes, a first vane 501 and a second vane
503. The first vane 501 and the second vane 503 are spaced from
each other to define a gas flow path 502. The first vane 501
includes three chambers--a film-cooling chamber 504, a suction side
chamber 505 and a pressure side chamber 507. The film-cooling
chamber 504, suction side chamber 505 and the pressure side chamber
507 include ports, such as ports 506, 509 and 511,
respectively.
[0027] In operation, the film-cooling chamber 504 receives cooling
pressurized air that is emitted from the associated ports, e.g.,
port 506. This air creates a relatively thin boundary layer 530
that is located adjacent to the exterior of the vane 501 to serve
as a barrier against the hot gas flowpath 502. The suction side
chamber 505 and the pressure side chamber 507 also receive
pressurized air, which is at a higher pressure than that provided
to chamber 504, that is emitted from associated ports, e.g., ports
509 and 511. The pressurized air emitted from chamber 507 creates a
boundary layer 513 along the pressure surface 515 of the first vane
501 that affects the throat area 550. Notably, the boundary layer
513 tends to urge the boundary layer 530 away from the pressure
surface 515, thereby causing the boundary layer 530 to dissipate
and mix with the gas of the gas flow path 502.
[0028] The second vane 503 also includes three chambers--a
film-cooling chamber 532, a suction side chamber 510 and a pressure
side chamber 512. The film-cooling chamber 532, suction side
chamber 510 and the pressure side chamber 512 include ports, such
as ports 534, 522 and 514, respectively.
[0029] In operation, the film-cooling chamber 532 receives cooling
pressurized air that is emitted from the associated ports, e.g.,
port 534. This air creates a relatively thin boundary layer 536
that is located adjacent to the exterior of the vane 503. The
suction side chamber 510 and the pressure side chamber 512 also
receive pressurized air, which is at a higher pressure than that
provided to chamber 534, that is emitted from associated ports,
e.g., ports 522 and 514. The pressurized air emitted from chamber
510 creates a boundary layer 525 along the suction surface 506 of
the vane 503 that affects the throat area 550. Notably, the
boundary layer 525 tends to urge the boundary layer 536 away from
the suction surface 506, thereby causing the boundary layer 536 to
dissipate and mix with the gas of the gas flow path 502.
[0030] The suction side chambers 505 and 510 and the pressure side
chambers 507 and 512 may be separate and unconnected to each other
so that the air emitted from each of the chambers may be controlled
independently. Alternatively, the suction side chambers 505 and 510
and the pressure side chambers 507 and 512 may be in communication,
and therefore, dependently controlled.
[0031] It should be emphasized that the above-described embodiments
are merely possible examples of implementations. Many variations
and modifications may be made to the above-described embodiments.
By way of example, although a solenoid is described with respect to
the embodiment of FIG. 2, other types of actuation could be used.
As another example, a pressurized line could be used to provide gas
to a valve assembly. All such modifications and variations are
intended to be included herein within the scope of this disclosure
and protected by the accompanying claims.
* * * * *