U.S. patent application number 13/453388 was filed with the patent office on 2013-10-24 for high pressure muffling devices.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is Christopher Jon POTOKAR. Invention is credited to Christopher Jon POTOKAR.
Application Number | 20130277142 13/453388 |
Document ID | / |
Family ID | 49262376 |
Filed Date | 2013-10-24 |
United States Patent
Application |
20130277142 |
Kind Code |
A1 |
POTOKAR; Christopher Jon |
October 24, 2013 |
HIGH PRESSURE MUFFLING DEVICES
Abstract
Some example muffling devices may include an inner flow
conditioner shaped as a generally conical frustrum and a generally
cylindrical an exhaust can around the inner flow conditioner. A
ratio of a downstream end wall area of the inner flow conditioner
to a downstream end annular area between the downstream end wall
and the exhaust can may be about 0.12 to about 0.97. A ratio of the
downstream end annular area to the downstream end wall area may be
proportional, by a factor of about 0.8 to about 1.9, to a ratio of
an effective area of the inner flow conditioner sidewall holes to
an effective area of the inner flow conditioner downstream end wall
holes. A ratio of a dissipation distance between the inner flow
conditioner downstream end wall and the exhaust screen to the inner
flow conditioner downstream end wall hole diameter may be greater
than about 10.
Inventors: |
POTOKAR; Christopher Jon;
(Loveland, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
POTOKAR; Christopher Jon |
Loveland |
OH |
US |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
49262376 |
Appl. No.: |
13/453388 |
Filed: |
April 23, 2012 |
Current U.S.
Class: |
181/212 |
Current CPC
Class: |
Y02T 50/60 20130101;
F02C 6/08 20130101; F05D 2260/96 20130101; F02K 3/075 20130101;
Y02T 50/672 20130101; F05D 2250/232 20130101; F01D 17/105
20130101 |
Class at
Publication: |
181/212 |
International
Class: |
F01N 5/00 20060101
F01N005/00 |
Claims
1. A muffling device, comprising: an inner flow conditioner shaped
as a generally conical frustum comprising an upstream base and a
downstream base, a diameter of the upstream base being larger than
a diameter of the downstream base, the inner flow conditioner
comprising an inlet approximate the upstream base, a generally
circular inner flow conditioner downstream end wall having an inner
flow conditioner downstream end wall area, the inner flow
conditioner downstream end wall being generally orthogonal to a
longitudinal axis of the conical frustum and comprising a plurality
of generally longitudinally oriented inner flow conditioner
downstream end wall holes, and an inner flow conditioner sidewall
shaped generally as a truncated cone, the inner flow conditioner
sidewall tapering inwardly from approximate the upstream base to
approximate the inner flow conditioner downstream wall, the inner
flow conditioner sidewall comprising a plurality of generally
laterally oriented inner flow conditioner sidewall holes; and an
exhaust can disposed substantially around the inner flow
conditioner and shaped as a generally circular cylinder, the
exhaust can comprising a generally annular upstream end wall
disposed approximate the upstream base of the inner flow
conditioner and substantially circumscribing the upstream base of
the inner flow conditioner, a generally circular exhaust screen
comprising a plurality of exhaust screen holes, and a generally
circular exhaust can sidewall extending from approximate the
upstream end wall to approximate the exhaust screen; wherein the
inner flow conditioner and the exhaust can are configured to
conduct a fluid inward through the inlet into the inner flow
conditioner, through the inner flow conditioner downstream end wall
discharge openings and the inner flow conditioner sidewall
discharge openings into the exhaust can, and outward through the
exhaust screen discharge openings; wherein the exhaust can and the
inner flow conditioner downstream end wall at least partially
define a downstream end annular area therebetween; and wherein a
ratio of the inner flow conditioner downstream end wall area to the
downstream end annular area is about 0.12 to about 0.97.
2. The muffling device of claim 1, wherein the ratio of the inner
flow conditioner downstream end wall area to the downstream end
annular area is about 0.16 to about 0.28.
3. The muffling device of claim 1, wherein the ratio of the inner
flow conditioner downstream end wall area to the downstream end
annular area is about 0.17 to about 0.20.
4. The muffling device of claim 1, wherein a ratio of the
downstream end annular area to the downstream end wall area is
proportional, by a factor of about 0.8 to about 1.9, to a ratio of
an effective area of the inner flow conditioner sidewall holes to
an effective area of the inner flow conditioner downstream end wall
holes.
5. The muffling device of claim 1, wherein a ratio of the
downstream end annular area to the downstream end wall area is
proportional, by a factor of about 0.97 to about 1.26, to a ratio
of an effective area of the inner flow conditioner sidewall holes
to an effective area of the inner flow conditioner downstream end
wall holes.
6. The muffling device of claim 1, wherein the inner flow
conditioner downstream end wall holes have an inner flow
conditioner downstream end wall hole diameter; wherein the inner
flow conditioner downstream end wall is spaced from the exhaust
screen by a dissipation distance; and wherein a ratio of the
dissipation distance to the inner flow conditioner downstream end
wall hole diameter is greater than about 10.
7. The muffling device of claim 1, wherein the inner flow
conditioner downstream end wall holes have an inner flow
conditioner downstream end wall hole diameter; wherein the inner
flow conditioner downstream end wall is spaced from the exhaust
screen by a dissipation distance; and wherein a ratio of the
dissipation distance to the inner flow conditioner downstream end
wall hole diameter is greater than about 20.
8. A muffling device, comprising: an inner flow conditioner shaped
as a generally conical frustum comprising an upstream base and a
downstream base, a diameter of the upstream base being larger than
a diameter of the downstream base, the inner flow conditioner
comprising an inlet approximate the upstream base, a generally
circular inner flow conditioner downstream end wall having an inner
flow conditioner downstream end wall area, the inner flow
conditioner downstream end wall being generally orthogonal to a
longitudinal axis of the conical frustum and comprising a plurality
of generally longitudinally oriented inner flow conditioner
downstream end wall holes, and an inner flow conditioner sidewall
shaped generally as a truncated cone, the inner flow conditioner
sidewall tapering inwardly from approximate the upstream base to
approximate the inner flow conditioner downstream wall, the inner
flow conditioner sidewall comprising a plurality of generally
laterally oriented inner flow conditioner sidewall holes; and an
exhaust can disposed substantially around the inner flow
conditioner and shaped as a generally circular cylinder, the
exhaust can comprising a generally annular upstream end wall
disposed approximate the upstream base of the inner flow
conditioner and substantially circumscribing the upstream base of
the inner flow conditioner, a generally circular exhaust screen
comprising a plurality of exhaust screen holes, and a generally
circular exhaust can sidewall extending from approximate the
upstream end wall to approximate the exhaust screen; wherein the
inner flow conditioner and the exhaust can are configured to
conduct a fluid inward through the inlet into the inner flow
conditioner, through the inner flow conditioner downstream end wall
discharge openings and the inner flow conditioner sidewall
discharge openings into the exhaust can, and outward through the
exhaust screen discharge openings; wherein the exhaust can and the
inner flow conditioner downstream end wall at least partially
define a downstream end annular area therebetween; and wherein a
ratio of the downstream end annular area to the downstream end wall
area is proportional, by a factor of about 0.8 to about 1.9, to a
ratio of an effective area of the inner flow conditioner sidewall
holes to an effective area of the inner flow conditioner downstream
end wall holes.
9. The muffling device of claim 8, wherein the ratio of the
downstream end annular area to the downstream end wall area is
proportional, by a factor of about 0.88 to about 1.58, to the ratio
of the effective area of the inner flow conditioner sidewall holes
to the effective area of the inner flow conditioner downstream end
wall holes.
10. The muffling device of claim 8, wherein the ratio of the
downstream end annular area to the downstream end wall area is
proportional, by a factor of about 0.97 to about 1.26, to the ratio
of the effective area of the inner flow conditioner sidewall holes
to the effective area of the inner flow conditioner downstream end
wall holes.
11. The muffling device of claim 8, wherein a ratio of the inner
flow conditioner downstream end wall area to the downstream end
annular area is about 0.17 to about 0.20.
12. The muffling device of claim 8, wherein the inner flow
conditioner downstream end wall holes have an inner flow
conditioner downstream end wall hole diameter; wherein the inner
flow conditioner downstream end wall is spaced from the exhaust
screen by a dissipation distance; and wherein a ratio of the
dissipation distance to the inner flow conditioner downstream end
wall hole diameter is greater than about 10.
13. The muffling device of claim 8, wherein the inner flow
conditioner downstream end wall holes have an inner flow
conditioner downstream end wall hole diameter; wherein the inner
flow conditioner downstream end wall is spaced from the exhaust
screen by a dissipation distance; and wherein a ratio of the
dissipation distance to the inner flow conditioner downstream end
wall hole diameter is greater than about 20.
14. A muffling device, comprising: an inner flow conditioner shaped
as a generally conical frustum comprising an upstream base and a
downstream base, a diameter of the upstream base being larger than
a diameter of the downstream base, the inner flow conditioner
comprising an inlet approximate the upstream base, a generally
circular inner flow conditioner downstream end wall having an inner
flow conditioner downstream end wall area, the inner flow
conditioner downstream end wall being generally orthogonal to a
longitudinal axis of the conical frustum and comprising a plurality
of generally longitudinally oriented inner flow conditioner
downstream end wall holes, and an inner flow conditioner sidewall
shaped generally as a truncated cone, the inner flow conditioner
sidewall tapering inwardly from approximate the upstream base to
approximate the inner flow conditioner downstream wall, the inner
flow conditioner sidewall comprising a plurality of generally
laterally oriented inner flow conditioner sidewall holes; and an
exhaust can disposed substantially around the inner flow
conditioner and shaped as a generally circular cylinder, the
exhaust can comprising a generally annular upstream end wall
disposed approximate the upstream base of the inner flow
conditioner and substantially circumscribing the upstream base of
the inner flow conditioner, a generally circular exhaust screen
comprising a plurality of exhaust screen holes, and a generally
circular exhaust can sidewall extending from approximate the
upstream end wall to approximate the exhaust screen; wherein the
inner flow conditioner and the exhaust can are configured to
conduct a fluid inward through the inlet into the inner flow
conditioner, through the inner flow conditioner downstream end wall
discharge openings and the inner flow conditioner sidewall
discharge openings into the exhaust can, and outward through the
exhaust screen discharge openings; wherein the exhaust can and the
inner flow conditioner downstream end wall at least partially
define a downstream end annular area therebetween; wherein the
inner flow conditioner downstream end wall holes have an inner flow
conditioner downstream end wall hole diameter; wherein the inner
flow conditioner downstream end wall is spaced from the exhaust
screen by a dissipation distance; and wherein a ratio of the
dissipation distance to the inner flow conditioner downstream end
wall hole diameter is greater than about 10.
15. The muffling device of claim 14, wherein a ratio of the
dissipation distance to the inner flow conditioner downstream end
wall hole diameter is greater than about 15.
16. The muffling device of claim 14, wherein a ratio of the
dissipation distance to the inner flow conditioner downstream end
wall hole diameter is greater than about 20.
17. The muffling device of claim 14, wherein a ratio of the inner
flow conditioner downstream end wall area to the downstream end
annular area is about 0.16 to about 0.28.
18. The muffling device of claim 14, wherein a ratio of the inner
flow conditioner downstream end wall area to the downstream end
annular area is about 0.17 to about 0.20.
19. The muffling device of claim 14, wherein a ratio of the
downstream end annular area to the downstream end wall area is
proportional, by a factor of about 0.88 to about 1.58, to a ratio
of an effective area of the inner flow conditioner sidewall holes
to an effective area of the inner flow conditioner downstream end
wall holes.
20. The muffling device of claim 14, wherein a ratio of the
downstream end annular area to the downstream end wall area is
proportional, by a factor of about 0.97 to about 1.26, to a ratio
of an effective area of the inner flow conditioner sidewall holes
to an effective area of the inner flow conditioner downstream end
wall holes.
Description
BACKGROUND
[0001] The subject matter disclosed herein relates generally to
muffling systems, and, more specifically, to muffling devices
capable of inducing high pressure drops and desirable flow
properties.
[0002] In a gas turbine engine, air is pressurized in a compression
module during operation. The air channeled through the compression
module is mixed with fuel in a combustor and ignited, generating
hot combustion gases which flow through turbine stages that extract
energy therefrom for powering the fan and compressor rotors and
generate engine thrust to propel an aircraft in flight or to power
a load, such as an electrical generator.
[0003] In some gas turbine engines, a portion of the high-pressure
air, such as, for example, bleed air from a compressor, may be
extracted or bled from the compressor for various needs. These
needs include, for example, compressor flow bleeding which may be
used in order to improve operability as well as to provide turbine
cooling, pressurize bearing sumps, purge air or provide aircraft
environment control. The air may be bled off from the compressor
using bleed slots located over specific portions or stages of the
compressor.
[0004] The problem: In least some gas turbine engines, during
engine operation occurring in some operating conditions, the
compressor may pump more air than is required for needs including
the combustion process. In order to manage operability of the
engine and combustion performance, a portion of the excess bleed
air from the compressor may be routed through bleed conduits and
exhausted into the by-pass flow stream, engine exhaust, or to
ambient. The pressure and temperature of the air stream bled from
the compressor may be very high. For example, bleed air pressure
may be greater than about 1375 kPa and the bleed air temperature
may be greater than about 538 degrees C. A transient bleed valve
system (TBV) system is sometimes used for bleeding and exhausting
the air removed from the compressor. Certain conventional designs
for bleed exhaust systems use large and/or heavy muffling devices
to reduce the generated noise. For example, the exhaust area of
some conventional bleed systems may be set to lower the flow
velocity at the exhaust location to a level below that required to
meet the acoustic limits for the application. The exhaust area, as
well as the relatively gently expansions between the source
pressure and exhaust, may contribute to the relatively large size
and/or weight of these systems. In some applications (e.g.,
aircraft), it may be undesirable to use large and/or heavy
components.
[0005] In addition, some conventional exhaust designs on aircraft
may require extensive thermal shielding on other components near
the exhaust location, once the exhaust velocities that meet the
acoustic limits are achieved. Due to the nature of the high
temperature air, once it is over-expanded to achieve lower
velocities, the air it mixes with may overwhelm the bleed air,
causing it to "lay down" on the surrounding structure around the
engine. In some aircraft the surrounding structure may be made of
lightweight composite material or of other metallic material with
lesser temperature capability.
BRIEF DESCRIPTION OF THE INVENTION
[0006] At least one solution for the above-mentioned problem(s) is
provided by the present disclosure to include example embodiments,
provided for illustrative teaching and not meant to be
limiting.
[0007] An example muffling device according to at least some
aspects of the present disclosure may include an inner flow
conditioner shaped as a generally conical frustum including an
upstream base and a downstream base. A diameter of the upstream
base may be larger than a diameter of the downstream base. The
inner flow conditioner may include an inlet approximate the
upstream base, a generally circular inner flow conditioner
downstream end wall having an inner flow conditioner downstream end
wall area, the inner flow conditioner downstream end wall being
generally orthogonal to a longitudinal axis of the conical frustum
and comprising a plurality of generally longitudinally oriented
inner flow conditioner downstream end wall holes, and an inner flow
conditioner sidewall shaped generally as a truncated cone, the
inner flow conditioner sidewall tapering inwardly from approximate
the upstream base to approximate the inner flow conditioner
downstream wall, the inner flow conditioner sidewall comprising a
plurality of generally laterally oriented inner flow conditioner
sidewall holes. The muffling device may include an exhaust can
disposed substantially around the inner flow conditioner and shaped
as a generally circular cylinder. The exhaust can may include a
generally annular upstream end wall disposed approximate the
upstream base of the inner flow conditioner and substantially
circumscribing the upstream base of the inner flow conditioner, a
generally circular exhaust screen comprising a plurality of exhaust
screen holes, and a generally circular exhaust can sidewall
extending from approximate the upstream end wall to approximate the
exhaust screen. The inner flow conditioner and the exhaust can may
be configured to conduct a fluid inward through the inlet into the
inner flow conditioner, through the inner flow conditioner
downstream end wall discharge openings and the inner flow
conditioner sidewall discharge openings into the exhaust can, and
outward through the exhaust screen discharge openings. The exhaust
can and the inner flow conditioner downstream end wall may at least
partially define a downstream end annular area therebetween. A
ratio of the inner flow conditioner downstream end wall area to the
downstream end annular area may be about 0.12 to about 0.97.
[0008] An example muffling device according to at least some
aspects of the present disclosure may include an inner flow
conditioner shaped as a generally conical frustum including an
upstream base and a downstream base. A diameter of the upstream
base may be larger than a diameter of the downstream base. The
inner flow conditioner may include an inlet approximate the
upstream base, a generally circular inner flow conditioner
downstream end wall having an inner flow conditioner downstream end
wall area, the inner flow conditioner downstream end wall being
generally orthogonal to a longitudinal axis of the conical frustum
and comprising a plurality of generally longitudinally oriented
inner flow conditioner downstream end wall holes, and an inner flow
conditioner sidewall shaped generally as a truncated cone, the
inner flow conditioner sidewall tapering inwardly from approximate
the upstream base to approximate the inner flow conditioner
downstream wall, the inner flow conditioner sidewall comprising a
plurality of generally laterally oriented inner flow conditioner
sidewall holes. The muffling device may include an exhaust can
disposed substantially around the inner flow conditioner and shaped
as a generally circular cylinder. The exhaust can may include a
generally annular upstream end wall disposed approximate the
upstream base of the inner flow conditioner and substantially
circumscribing the upstream base of the inner flow conditioner, a
generally circular exhaust screen comprising a plurality of exhaust
screen holes, and a generally circular exhaust can sidewall
extending from approximate the upstream end wall to approximate the
exhaust screen. The inner flow conditioner and the exhaust can may
be configured to conduct a fluid inward through the inlet into the
inner flow conditioner, through the inner flow conditioner
downstream end wall discharge openings and the inner flow
conditioner sidewall discharge openings into the exhaust can, and
outward through the exhaust screen discharge openings. The exhaust
can and the inner flow conditioner downstream end wall may at least
partially define a downstream end annular area therebetween. A
ratio of the downstream end annular area to the downstream end wall
area may be proportional, by a factor of about 0.8 to about 1.9, to
a ratio of an effective area of the inner flow conditioner sidewall
holes to an effective area of the inner flow conditioner downstream
end wall holes.
[0009] An example muffling device according to at least some
aspects of the present disclosure may include an inner flow
conditioner shaped as a generally conical frustum including an
upstream base and a downstream base. A diameter of the upstream
base may be larger than a diameter of the downstream base. The
inner flow conditioner may include an inlet approximate the
upstream base, a generally circular inner flow conditioner
downstream end wall having an inner flow conditioner downstream end
wall area, the inner flow conditioner downstream end wall being
generally orthogonal to a longitudinal axis of the conical frustum
and comprising a plurality of generally longitudinally oriented
inner flow conditioner downstream end wall holes, and an inner flow
conditioner sidewall shaped generally as a truncated cone, the
inner flow conditioner sidewall tapering inwardly from approximate
the upstream base to approximate the inner flow conditioner
downstream wall, the inner flow conditioner sidewall comprising a
plurality of generally laterally oriented inner flow conditioner
sidewall holes. The muffling device may include an exhaust can
disposed substantially around the inner flow conditioner and shaped
as a generally circular cylinder. The exhaust can may include a
generally annular upstream end wall disposed approximate the
upstream base of the inner flow conditioner and substantially
circumscribing the upstream base of the inner flow conditioner, a
generally circular exhaust screen comprising a plurality of exhaust
screen holes, and a generally circular exhaust can sidewall
extending from approximate the upstream end wall to approximate the
exhaust screen. The inner flow conditioner and the exhaust can may
be configured to conduct a fluid inward through the inlet into the
inner flow conditioner, through the inner flow conditioner
downstream end wall discharge openings and the inner flow
conditioner sidewall discharge openings into the exhaust can, and
outward through the exhaust screen discharge openings. The exhaust
can and the inner flow conditioner downstream end wall may at least
partially define a downstream end annular area therebetween. The
inner flow conditioner downstream end wall holes may have an inner
flow conditioner downstream end wall hole diameter. The inner flow
conditioner downstream end wall may be spaced from the exhaust
screen by a dissipation distance. A ratio of the dissipation
distance to the inner flow conditioner downstream end wall hole
diameter may be greater than about 10.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The subject matter for which patent claim coverage is sought
is particularly pointed out and claimed herein. The subject matter
and embodiments thereof, however, may be best understood by
reference to the following description taken in conjunction with
the accompanying drawing figures in which:
[0011] FIG. 1 is a schematic cross-sectional view of an example gas
turbine engine assembly including an example bleed system including
an example muffling device;
[0012] FIG. 2 is a perspective view of an example bleed system
including an example muffling device;
[0013] FIG. 3 is a cross-sectional view of an example muffling
device; and
[0014] FIG. 4 is a partial-cutaway, perspective view of an example
muffling device, all in accordance with at least some aspects of
the present disclosure.
DETAILED DESCRIPTION
[0015] In the following detailed description, reference is made to
the accompanying drawings, which form a part hereof. In the
drawings, similar symbols typically identify similar components,
unless context dictates otherwise. The illustrative embodiments
described in the detailed description, drawings, and claims are not
meant to be limiting. Other embodiments may be utilized, and other
changes may be made, without departing from the spirit or scope of
the subject matter presented here. It will be readily understood
that the aspects of the present disclosure, as generally described
herein, and illustrated in the figures, can be arranged,
substituted, combined, and designed in a wide variety of different
configurations, all of which are explicitly contemplated and make
part of this disclosure.
[0016] The present disclosure includes, inter alia, muffling
systems, and more specifically muffling devices capable of inducing
high pressure drops and desirable flow properties.
[0017] The present disclosure contemplates that modern, highly
efficient turbofan engines may use high-pressure/high-temperature
bleed from the aft compressor stages to improve operability and
performance. This bleed air may be directed into the fan duct or
other locations, which may generate additional noise during some
phases of engine operation.
[0018] Some example embodiments according to the present disclosure
provide a compact, lightweight transient/operability bleed exhaust
muffling device (which may be referred to generally as a
"pepperpot") that has minimal acoustic impact. Acoustic benefit for
the high pressure/temperature compressor discharge bleed may be
achieved at a high exhaust velocity into the fan duct and, in some
example embodiments, may use only a single flow conditioning
element (which may be referred to as an "inner flow conditioner")
within the pepperpot body (which may be referred to as an "exhaust
can"). Some such embodiments may be referred to as "single stage"
muffling devices. The present disclosure contemplates that some
"single stage" muffling devices are described in U.S. Provisional
Patent Application No. 61/580,675, titled COMPACT HIGH-PRESSURE
EXHAUST MUFFLING DEVICES, filed Dec. 28, 2011, and U.S. patent
application Ser. No. 13/347,728, titled COMPACT HIGH-PRESSURE
EXHAUST MUFFLING DEVICES, filed Jan. 11, 2012, which are
incorporated herein by reference. The present disclosure
contemplates that some other acoustic pepperpots may utilize
multiple (e.g., three to five or more) inner flow conditioning
elements, which may add weight to the engine.
[0019] In addition, the present disclosure contemplates that some
other acoustically friendly pepperpots may necessitate extensive
shielding on the thrust reverser structure to address thermal
concerns. Some example embodiments according to the present
disclosure may reduce or eliminate the need for such shielding by
directing at least a substantial portion of the high-temperature
bleed air generally to the middle of the cool fan duct flow, which
may allow the hot plume to exit the fan duct without substantially
impinging on thrust reverser or other aircraft surfaces.
[0020] FIG. 1 is a schematic cross-sectional view of an example gas
turbine engine assembly 10 including an example bleed system 40
including an example muffling device 50, according to at least some
aspects of the present disclosure. FIG. 2 is a perspective view of
bleed system 40 including muffling device 50, according to at least
some aspects of the present disclosure. The gas turbine engine
assembly 10 includes a core gas turbine engine 12 that includes a
high-pressure compressor 14, a combustor 16, and a high-pressure
turbine 18. In the example embodiment shown in FIG. 1, the gas
turbine engine assembly 10 also includes a low-pressure turbine 20
coupled axially downstream from core gas turbine engine 12 and a
fan assembly 22 coupled axially upstream from core gas turbine
engine 12. Fan assembly 22 includes an array of fan blades 24 that
extend radially outward from a rotor disk. In the exemplary
embodiment shown in FIG. 1, gas turbine engine assembly 10 has an
intake side 28 and an exhaust side 29. Core gas turbine engine 12,
fan assembly 22, and low-pressure turbine 20 are coupled together
by a first rotor shaft 31, and high-pressure compressor 14 and
high-pressure turbine 18 are coupled together by a second rotor
shaft 32.
[0021] In operation, air flows through fan blades 24 and is
supplied to high-pressure compressor 14. The air discharged from
fan assembly 22 is channeled to high-pressure compressor 14 where
the airflow is further compressed and channeled to combustor 16.
Products of combustion from combustor 16 are utilized to drive
high-pressure turbine 18 and low-pressure turbine 20, and turbine
20 drives fan assembly 22 via shaft 31.
[0022] In an example gas turbine engine assembly 10, at certain
operating conditions, a portion of the compressed air may be routed
through the bleed system 40, thereby becoming bleed air 2. Bleed
air 2 from high-pressure compressor 14 may enter a bleed flow
conduit 44. Bleed air 2 may pass through the bleed flow conduit 44
and enter muffling device 50 that directs bleed air 2 into a flow
path, such as the bypass flow path 4 and mixes that air with
another flow, such as a fan flow stream 1. Flow through bleed flow
conduit 44 may be controlled by a bleed air valve 45. Bleed flow
conduit 44 may be made from a variety of materials, such as a
metal, which may be selected to be capable of withstanding a bleed
air 2 flow that is relatively hot and at high pressure.
[0023] Muffling device 50, described in more detail herein below,
may be in flow communication with bleed flow conduit 44 such that
the bleed air 2 is discharged as exit flow stream 5 into by-pass
flow path 4, facilitating a reduction of the noise generated by the
mixing of the exit flow stream 5 and fan flow stream 1.
[0024] As shown in FIG. 2, bleed flow conduit 44 may convey bleed
air 2 from bleed air valve 45 to muffling device 50. In some
example embodiments according to at least some aspects of the
present disclosure, some or all of the acoustic improvements
provided by this device occur within muffling device 50, which may
allow the use of relatively small diameter and lightweight ducting
to direct the flow to a location very close to the exhaust can.
[0025] FIG. 3 is a cross-sectional view of an example muffling
device 50, according to at least some aspects of the present
disclosure. FIG. 4 is a partial-cutaway, perspective view of an
example muffling device 50, according to at least some aspects of
the present disclosure. Muffling device 50 may comprise an exhaust
can 102, which may include an exhaust screen 104 (which may be
generally circular) at a downstream end, an upstream end wall 126
(which may be generally annular), and a sidewall 128 (which may be
generally circular). Exhaust can 102 may be generally in the form
of a hollow circular cylinder arranged about a central axis 124
with a diameter 130. Exhaust screen 104 may include a plurality of
holes 106 through which air may be discharged from an interior 108
of exhaust can 102. In some example embodiments, exhaust screen 104
may be outwardly curved.
[0026] In some example embodiments according to at least some
aspects of the present disclosure, an inner flow conditioner 110
may be disposed within exhaust can 102. Inner flow conditioner 110
may be generally in the form of a hollow, conical frustum arranged
coaxially with exhaust can 102 about central axis 124. Inner flow
conditioner 110 may include an inwardly tapering sidewall 112 and a
downstream end wall 114, which may be generally circular. Sidewall
112 may be shaped generally as a truncated cone. Downstream end
wall 114 may be generally orthogonal to central axis 124. Inner
flow conditioner 110 may taper inwardly from an upstream base 136
(which may be substantially circumscribed by upstream end wall 126)
to a downstream base 138 (which may be proximate downstream end
wall 114). Sidewall 112 and downstream end wall 114 may at least
partially define an interior 116 of inner flow conditioner 110.
Sidewall 112 may include a plurality of generally laterally
oriented holes 120 and/or downstream end wall 114 may include a
plurality of generally axially oriented holes 122 through which
pressurized air may be discharged into interior 108 of exhaust can
102. Inner flow conditioner 110 may be arranged to receive
pressurized air from bleed flow conduit 44 through an inlet 118
(which may be proximate upstream base 136). Inner flow conditioner
110 may have an upstream base diameter 132 proximate inlet 118
and/or downstream base diameter 134 proximate downstream end wall
114. Upstream base diameter 132 may be larger than downstream base
diameter 134. Inner flow conditioner 110 may be attached inside
exhaust can 102 such that inlet 118 is disposed within upstream end
wall 126 of exhaust can 102.
[0027] Downstream base 138 may at least partially define a
downstream end wall area 133, which may be the generally axially
downstream facing area of downstream end wall 114. Downstream base
138 and exhaust can 102 may at least partially define a downstream
end annular area 135, which may be the generally axially downstream
facing area between downstream end wall 114 and sidewall 128 of
exhaust can 102. In some example embodiments, a ratio of downstream
end wall area 133 to downstream end annular area 135 may be about
0.12 to about 0.97. In some example embodiments, a ratio of
downstream end wall area 133 to downstream end annular area 135 may
be about 0.16 to about 0.28. In some example embodiments, a ratio
of downstream end wall area 133 to downstream end annular area 135
may be about 0.17 to about 0.20.
[0028] In operation, inner flow conditioner 110 and exhaust screen
102 may be configured to conduct pressurized air inward through
inlet 118 into interior 116 of inner flow conditioner 110, through
holes 120 and/or holes 122 of inner flow conditioner 110 into
interior 108 of exhaust can 102, and outward through holes 106 of
exhaust screen 104. In some example embodiments, interior 108 of
exhaust can 102 may be substantially devoid of flow obstructions
between holes 120 and holes 122 of inner flow conditioner and holes
106 of exhaust screen 104.
[0029] An example muffling device 50 may include holes 106, 120,
122 having individual hole sizes (e.g., diameters and/or slot
length/width) and areas. An individual hole may have an effective
area for fluid flow that differs from its measurable physical area.
A hole's effective area for fluid flow may be determined by known
methods, and may depend on the size and shape of the hole. A
plurality of holes, e.g., holes 106 of exhaust screen 104, may have
an effective area for fluid flow that may be calculated using known
methods. For example, holes 120 of sidewall 112 of inner flow
conditioner 110 may have an effective flow area and/or holes 122 of
downstream end wall 114 of inner flow conditioner 110 may have an
effective flow area.
[0030] In some example embodiments according to at least some
aspects of the present disclosure, a ratio of downstream end
annular area 135 to downstream end wall area 133 may be
proportional, by a factor of about 0.8 to about 1.9, to a ratio of
the effective area of holes 120 of sidewall 112 of inner flow
conditioner 110 to the effective flow area of holes 122 of
downstream end wall 114 of inner flow conditioner 110. Expressed
mathematically,
downstream end annular area 135 downstream end wall area 133 = F *
effective flow area of holes 120 effective flow area of holes 122
##EQU00001##
where F, in some example embodiments, may be about 0.8 to about
1.9. In some example embodiments, F may be about 0.88 to about
1.58. In some example embodiments, F may be about 0.97 to about
1.26.
[0031] In some example embodiments according to at least some
aspects of the present disclosure, a ratio of an effective flow
area of the holes (e.g., holes 120 and holes 122) of an inner flow
conditioner (e.g., inner flow conditioner 110) to an effective flow
area of an inlet (e.g., inlet 118) may be about 0.7 to about 1.2.
In some example embodiments according to at least some aspects of
the present disclosure, a ratio of an effective flow area of the
holes of the inner flow conditioner to an effective flow area of
the inlet may be about 0.76 to about 0.91.
[0032] In some example embodiments according to at least some
aspects of the present disclosure, inner flow conditioner 110 may
be disposed within an exhaust can 102 such that airflow through
holes 122 of downstream end wall 114 substantially dissipates
before it reaches exhaust screen 104 of exhaust can 102. For
example, downstream end wall 114 may be spaced from exhaust screen
104 by a dissipation distance 140. One or more holes 122 through
downstream end wall 114 may have a hole diameter 142. In some
example embodiments, a ratio of dissipation distance 140 to hole
diameter 142 may be greater than 10. In some example embodiments,
the ratio of dissipation distance 140 to hole diameter 142 may be
greater than 15. In some example embodiments, the ratio of
dissipation distance 140 to hole diameter 142 may be greater than
20.
[0033] Some example embodiments according to at least some aspects
of the present disclosure may be arranged such that air flow 144
approaching exhaust screen 104 may be substantially uniform across
diameter 130 of exhaust can 102.
[0034] Although some example embodiments have been described in
connection with discharging exit flow stream 5 into by-pass flow
path 4, it is within the scope of the disclosure to direct exit
flow stream 5 elsewhere. For example, some muffling devices
according to the present disclosure may be mounted at the engine
pylon, the turbine rear frame, and/or core nozzle/center bleed
tube. Some example embodiments may be arranged to direct exit flow
stream 5 generally behind gas turbine engine assembly 10.
[0035] 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 languages of the claims.
* * * * *