U.S. patent application number 13/756293 was filed with the patent office on 2014-07-31 for compressor wash with air to turbine cooling passages.
This patent application is currently assigned to Solar Turbines Incorporated. The applicant listed for this patent is SOLAR TURBINES INCORPORATED. Invention is credited to John Frederick Lockyer.
Application Number | 20140209123 13/756293 |
Document ID | / |
Family ID | 51135601 |
Filed Date | 2014-07-31 |
United States Patent
Application |
20140209123 |
Kind Code |
A1 |
Lockyer; John Frederick |
July 31, 2014 |
COMPRESSOR WASH WITH AIR TO TURBINE COOLING PASSAGES
Abstract
A system and method for washing a gas turbine engine. The method
for washing the gas turbine engine includes coupling a pressurized
air supply assembly to an air supply and to a secondary air system,
cranking a compressor rotor assembly of the gas turbine engine,
supplying pressurized offline buffer air from the air supply to the
pressurized air supply assembly, and spraying a cleaner into the
compressor.
Inventors: |
Lockyer; John Frederick;
(San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SOLAR TURBINES INCORPORATED |
San Diego |
CA |
US |
|
|
Assignee: |
Solar Turbines Incorporated
San Diego
CA
|
Family ID: |
51135601 |
Appl. No.: |
13/756293 |
Filed: |
January 31, 2013 |
Current U.S.
Class: |
134/22.1 ;
134/166R |
Current CPC
Class: |
F04D 29/705 20130101;
F04D 19/02 20130101; F01D 25/002 20130101 |
Class at
Publication: |
134/22.1 ;
134/166.R |
International
Class: |
F01D 25/00 20060101
F01D025/00 |
Claims
1. A method for washing a compressor in a gas turbine engine, the
method comprising: coupling a pressurized air supply assembly to an
air supply; coupling the pressurized air supply assembly to a
cooling air path, the cooling air path leading to one or more
cooling passages of at least one turbine rotor assembly of the gas
turbine engine; coupling the pressurized air supply assembly to a
buffer air path, the buffer air path leading to one or more
buffered seals of at least one bearing assembly of the gas turbine
engine; cranking a compressor rotor assembly of the gas turbine
engine; supplying pressurized offline buffer air from the air
supply to the pressurized air supply assembly; and delivering
cleaner to the compressor.
2. The method of claim 1, further comprising: removing an injector
from an injector port; and installing a local air supply adapter to
the injector port.
3. The method of claim 2, wherein the supplying pressurized offline
buffer air from the air supply to the pressurized air supply
assembly includes keeping a combustor case bleed at least partially
closed during the delivering cleaner to the compressor.
4. The method of claim 1, wherein the cranking the compressor rotor
assembly includes operating a starter of the gas turbine engine
without fuel supplied, and further includes cranking the compressor
to at least 20 percent of a normal operating speed of the
compressor.
5. The method of claim 1, wherein the cranking the compressor rotor
assembly includes cranking the compressor such that a maximum
output pressure of the compressor is at least 0.5 psig, as gauged
off atmospheric pressure.
6. (canceled)
7. The method of claim 1, wherein the at least one bearing assembly
includes at least one end bearing assembly and at least one
intermediate bearing assembly of the gas turbine engine.
8. The method of claim 1, further comprising accessing a compressor
port, including decoupling secondary air plumbing pneumatically
coupled to the compressor port; installing a secondary air cap,
including capping off the compressor port; accessing the cooling
air path, including decoupling secondary air plumbing outside a
combustor at a mating cooling air path mounting flange; accessing
the buffer air path, including decoupling secondary air plumbing
outside a combustor at a mating buffer air path mounting flange,
the at least one bearing assembly including an intermediate bearing
assembly; removing an injector from an injector port; installing a
local air supply adapter to the injector port; wherein the coupling
the pressurized air supply assembly to a cooling air path includes
coupling the pressurized air supply assembly to the cooling air
path mounting flange; and wherein the coupling the pressurized air
supply assembly to a buffer air path includes coupling the
pressurized air supply assembly to the buffer air path mounting
flange.
9. The method of claim 8, wherein the secondary air cap includes a
bleed vent, the method further comprising: rinsing the cleaner from
the compressor; and purging the secondary air cap by opening the
bleed vent after the rinsing the cleaner from the compressor.
10. A method for washing a gas turbine engine, the gas turbine
engine including a compressor, a combustor, and a turbine, the
method comprising: shutting off fuel to the combustor; accessing a
compressor port, including decoupling secondary air plumbing
pneumatically coupled to the compressor port; installing a
secondary air cap, including capping off the compressor port, the
secondary air cap including a bleed vent; cranking the compressor
of the gas turbine engine; distributing a cleaner into the
compressor; supplying compressed air to a cooling air path of the
gas turbine engine via a secondary air system; rinsing the cleaner
from the compressor; and purging the secondary air cap by opening
the bleed vent after the rinsing the cleaner from the
compressor.
11. The method of claim 10, further comprising: removing an
injector from an injector port; installing a first air supply
pneumatic couple to the injector port; and wherein the compressed
air is supplied from the first air supply pneumatic couple.
12. The method of claim 11, further comprising: coupling a second
air supply pneumatic couple to a shop air supply, the shop air
supply being other than the gas turbine engine; supplying
compressed air to a buffered seal of an intermediate bearing
assembly of the gas turbine engine via the secondary air system;
supplying compressed air to a mixed air path of the gas turbine
engine via the secondary air system; and wherein the compressed air
is supplied from both the first air supply pneumatic couple and the
second air supply pneumatic couple.
13. The method of claim 10, wherein the cranking the compressor of
the gas turbine engine includes operating a starter of the gas
turbine engine.
14. The method of claim 10, wherein the cranking the compressor of
the gas turbine engine includes cranking the compressor to at least
20 percent of a normal operating speed of the compressor, and such
that a maximum output pressure of the compressor is at least 0.5
psig, as gauged off atmospheric pressure.
15. The method of claim 10, wherein the supplying compressed air to
the cooling air path of the gas turbine engine via the secondary
air system includes supplying compressed air such that a
differential pressure between a primary air flow path of the
turbine and the cooling air path of the gas turbine engine is at
least 0.15 psig, as gauged off the primary air flow path of the
turbine.
16-20. (canceled)
21. A method for washing a compressor in a gas turbine engine, the
method comprising: coupling a pressurized air supply assembly to an
air supply; removing an injector from an injector port; installing
a local air supply adapter to the injector port; coupling the
pressurized air supply assembly to a cooling air path, the cooling
air path leading to one or more cooling passages of at least one
turbine rotor assembly of the gas turbine engine; cranking a
compressor rotor assembly of the gas turbine engine; delivering
cleaner to the compressor; and supplying pressurized offline buffer
air from the air supply to the pressurized air supply assembly
including keeping a combustor case bleed at least partially closed
during the delivering cleaner to the compressor.
22. The method of claim 21, wherein the supplying pressurized
offline buffer air from the air supply to the pressurized air
supply assembly includes keeping a combustor case bleed at least
partially closed during the delivering cleaner to the
compressor.
23. The method of claim 21, wherein the cranking the compressor
rotor assembly includes operating a starter of the gas turbine
engine without fuel supplied, and further includes cranking the
compressor to at least 20 percent of a normal operating speed of
the compressor.
Description
TECHNICAL FIELD
[0001] The present disclosure generally pertains to a water wash
system for a gas turbine engine, and is more particularly directed
toward an offline crank wash system for a gas turbine engine.
BACKGROUND
[0002] Over a period of operating time the compressor section of a
gas turbine engine may accumulate deposits of ingested material and
consequently become dirty. Dirt build up in the compressor will
reduce its efficiency; this results in a poorer overall engine
efficacy and therefore power output. Accordingly, the compressor
requires periodic cleaning (sometimes referred to as "water wash").
There are primarily three types of wash systems: on-line wash
system, offline crank wash system, and manual wash system. On-line
washing basically consists of a process where by a cleaning fluid
is sprayed into the air intake of the engine while running at full
speed and loaded. Here, demineralized water is used and the
droplets are sized to be large enough so that the drag forces are
dominated by the inertia forces that tend to cause the droplets to
impinge on the hardware of the compressor and provide the cleaning
action. Offline washing is wherein the gas turbine engine spun by
an external crank. Manual washing is where the gas turbine engine
is shut down, and the gas turbine engine's components are washed
manually.
[0003] U.S. Pat. No. 6,659,715 issued to Kuesters et al. on Dec. 9,
2003 shows an axial compressor and method of cleaning an axial
compressor. In particular, the disclosure of Kuesters et al. is
directed toward an axial compressor that includes a nozzle for
injecting a cleaning fluid. The cleaning fluid is injected through
the nozzles in a flow duct during operation, so that rear blading
rows are also cleaned.
[0004] The present disclosure is directed toward overcoming known
problems and/or problems discovered by the inventors.
SUMMARY OF THE DISCLOSURE
[0005] A method for washing a compressor in a gas turbine engine.
The method for washing the compressor in the gas turbine engine
includes coupling a pressurized air supply assembly to an air
supply and a cooling air path, cranking a compressor rotor assembly
of the gas turbine engine, supplying pressurized offline buffer air
from the air supply to the pressurized air supply assembly, and
spraying a cleaner into the compressor. According to one
embodiment, a method for washing a gas turbine engine is also
disclosed herein. The method for washing the gas turbine engine
includes shutting off fuel to a combustor, cranking a compressor of
the gas turbine engine, distributing a cleaner into the compressor,
and supplying compressed air to a cooling air path of the gas
turbine engine via a secondary air system. According to another
embodiment, a system for washing a compressor in a gas turbine
engine is also disclosed herein. The system for washing a
compressor in the gas turbine engine includes a sprayer configured
to deliver a cleaner into the compressor, a crank configured to
rotate a compressor rotor assembly, a secondary air cap configured
to interface with and cap off a secondary air compressor port, and
a pressurized air supply assembly including an air supply pneumatic
couple, an air conduit, and a secondary air system pneumatic couple
configured to couple with a cooling air path of a secondary air
system of the gas turbine engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 illustrates a portion of a wash system for washing a
compressor in a gas turbine engine, including a cut away side view
of an exemplary gas turbine engine.
[0007] FIG. 2 illustrates a portion of the wash system of FIG. 1,
where the gas turbine engine is configured for angled
injectors.
[0008] FIG. 3 illustrates a portion of the wash system of FIG. 1,
where the gas turbine engine is configured for straight
injectors.
[0009] FIG. 4 illustrates a portion of the wash system of FIG. 1,
including an axial view of the combustor region of FIG. 3.
[0010] FIG. 5 is a flow chart of an exemplary method for washing a
gas turbine engine.
DETAILED DESCRIPTION
[0011] The present disclosure relates to an air buffering system
for a compressor water wash operation of a gas turbine engine. The
compressor water wash is a maintenance operation performed to clean
deposits from the compressor for improved efficiency. The present
disclosure provides an air buffering system that taps into the
compressor air from the compressor through the injector ports in
the combustor. The compressed air is generated and supplied to the
combustor chamber as a result of the compressor being cranked (at a
fraction of operating speed) during the wash. The compressed air is
then rerouted to the bearing assemblies' buffer lines and to the
cooling passages through the secondary air system. The high volume
of air can enable the buffering of multiple bearing assemblies and
turbine cooling passages, and can mitigate the need for shop air on
site.
[0012] FIG. 1 schematically illustrates a portion of a wash system
for washing a compressor in a gas turbine engine, including a cut
away side view of an exemplary gas turbine engine. In particular,
the wash system 800 for washing a compressor in a gas turbine
engine integrates with, and makes use of, features of the gas
turbine engine 100 itself. As such, several exemplary features of
the gas turbine engine 100 will be initially discussed for context.
In addition, here and in other figures, some of the surfaces have
been left out, repositioned, simplified, and/or exaggerated for
clarity and ease of explanation.
[0013] Also, the present disclosure may use the gas turbine engine
100 for orientation purposes. In particular, the disclosure may
reference a center axis 95 of rotation of the gas turbine engine
100, which may be generally defined by the longitudinal axis of its
shaft 120. Thus, all references to radial, axial, and
circumferential directions and measures refer to the center axis
95, unless specified otherwise, and terms such as "inner" and
"outer" generally indicate a lesser or greater radial distance from
the center axis 95, wherein a radial 96 may be in any direction
perpendicular and radiating outward from center axis 95.
Furthermore, the disclosure may generally reference a forward and
an aft direction, where references to "forward" and "aft" are
associated with the axial flow direction of primary air 11 (i.e.,
air used in the combustion process), unless specified otherwise.
For example, forward is "upstream" relative to the flow of primary
air 11, and aft is "downstream" relative to the flow of primary air
11.
[0014] Regarding the exemplary gas turbine engine 100, generally,
the gas turbine engine 100 includes an inlet 110, a compressor 200,
a combustor 300, a turbine 400, an exhaust 500, and a power output
coupling 600. The compressor 200 includes one or more rotating
compressor rotor assemblies 220 populated with compressor blades.
The turbine 400 includes one or more rotating turbine rotor
assemblies 420 populated with turbine blades.
[0015] The gas turbine engine 100 may also includes a starter
configured to rotate the rotating components without combustion.
The starter may be mechanically coupled to the shaft 120 at the
power output coupling 600, or at any other convenient location.
[0016] One or more of the rotating components are coupled to each
other and driven by one or more shafts 120. The one or more shafts
120 are supported by a plurality of bearing assemblies 150, which
may be identified in any convenient manner. For example, the gas
turbine engine 100 may include a number one bearing assembly 151, a
number two bearing assembly 152, a number three bearing assembly
153, a number four bearing assembly 154, and a number five bearing
assembly 155. One or more of the bearing assemblies 150 may include
dry seals such as buffered labyrinth seals 170 (see FIG. 2), which
use a combination of a tortuous escape path and pressurized buffer
air (secondary air 13) to inhibit lubricants from escaping their
designated "wet" areas (i.e., the lubricated side of the lubricant
seal).
[0017] As illustrated, the combustor 300 may include a combustor
case 310, an internal combustor strut ("strut") 312, a bearing
housing 315, a diffuser 320, an injector 350 and a combustion
chamber 390 or "liner". In addition, the combustor 300 may include
a combustor case bleed 370 and a combustor case bleed valve 372
(see FIG. 2). When the combustor case bleed valve 372 is open
(e.g., during engine start up) the combustor case bleed 370 acts as
a turbine bypass that ducts primary air 11 from the combustor 300
directly to the exhaust 500, relieving back pressure on the
compressor 200. For clarity and illustration purposes, only one
injector 350 is shown here in the installed position and only one
combustor case bleed 370 is shown. Also, here, and in other
figures, the struts 312 and injectors 350 have been rotated and/or
repositioned to align with the view, for clarity and ease of
explanation.
[0018] Depending on its configuration, the combustor 300 may
include one or more of the above components. For example, the
combustor 300 may include a plurality of injectors 350 annularly
distributed around the center axis 95 (see FIG. 4). Similarly, the
combustor 300 may be configured to include a several, annularly
distributed struts 312, the struts 312 radially extending between
the bearing housing 315 and the combustor case 310.
[0019] In operation, air 10 enters the gas turbine engine 100 via
its inlet 110 as a "working fluid", and is compressed by the
compressor 200. In the compressor 200, the working fluid is
compressed by the series of compressor rotor assemblies 220. In
particular, the air 10 is compressed in numbered "stages", the
stages being associated with each compressor rotor assembly 220.
For example, "4th stage air" may be associated with the 4th
compressor rotor assembly 220 in the downstream or "aft" direction.
While only five stages are illustrated here, the compressor 200 may
include many more stages.
[0020] When compressed, air 10 may be used as needed: for
combustion, for cooling, for pressurization, etc. In particular,
the compressed air 10 may be divided into primary air 11 and
secondary air 13. Primary air 11 is used in the combustion process.
Primary air 11 is discharged from the compressor 200, enters the
combustor 300 for combustion, drives the turbine 400, and exits the
gas turbine engine 100 from the exhaust 500 as exhaust gas 90.
[0021] Secondary air 13 is air provided throughout gas turbine
engine 100 via a secondary air system 700 (or "bleed system") for
auxiliary uses such as internal cooling, pressurized buffer
sealing, etc. In particular, the secondary air system 700 may tap
one or more stages of compressor 200 and route the pressurized
secondary air 13 via any combination of ducting, internal
passageways, interstices between components, and any other air
channels or secondary air plumbing 707.
[0022] To illustrate, secondary air system 700 may include one or
more compressor ports 705 that tap the compressor at one or more
locations. The compressor ports 705 are pneumatically coupled to
the secondary air plumbing 707. The secondary air plumbing 707 can
then distribute secondary air 13 as needed. For example, secondary
air plumbing 707 may pneumatically couple with a strut bleed tube
external flange assembly 710 and provide compressed secondary air
13 into one or more struts 312 of combustor 300. Also for example,
secondary air plumbing 707 may pneumatically couple with one or
more buffer air fittings 708 and provide compressed secondary air
13 the "end" bearing assemblies (e.g., number one, four, and five
bearing assemblies 151, 154, 155).
[0023] The secondary air system 700 may further include a network
of air flow paths configured to distribute and deliver secondary
air 13 at different pressure levels. For example, intermediate
pressure secondary air 13 may be ported from an intermediate stage
(e.g., 6th stage air) of the compressor 200 via intermediate
pressure secondary air plumbing 707. In addition, high pressure
secondary air 13 may be ported from a subsequent or final stage of
the compressor 200 via high pressure or PCD (pressure at compressor
discharge) secondary air plumbing 707. Different and/or additional
stages may be tapped as a compressed air supply.
[0024] Furthermore, secondary air 13 may be used for a first
purpose, and subsequently recovered and/or reused for a second
purpose. In particular, the secondary air system 700 may recover
"mixed air" (i.e., air that has been "used" or otherwise exposed to
lubricants and/or other "contaminants") from air passageways
throughout the gas turbine engine 100 for post-processing, reuse,
etc. For example, used seal buffer air (mixed air) may be captured
within or proximate the bearing housing 315, and routed out of the
combustor 300 via one or more strut 312 to the turbine 400 (e.g.,
for cooling or buffering).
[0025] Turning to the system for washing a compressor in a gas
turbine engine, the wash system 800 includes a sprayer 810 and a
crank 820. In particular, the sprayer 810 introduces cleaner 818
into the compressor 200 and the crank 820 rotates the compressor
rotor assemblies 220. The wash system 800 may further include one
or more secondary air caps 830 and/or a waste trap 840.
[0026] The sprayer 810 may include one or more nozzles 812
configured to deliver the cleaner 818 into the compressor 200. The
cleaner 818 may include a chemical cleaner (e.g., solvent) and/or a
physical cleaner (e.g., water with predetermined droplet size). The
one or more nozzles 812 may be configured to meter the quantity
and/or quality (i.e., droplet size, spray angle, cleaner-to-air
ratio, etc.) of the cleaner 818 introduced to the compressor 200.
Also, the one or more nozzles 812 may deliver the cleaner 818 into
the compressor 200 via applied pressure or resultant pressure
(i.e., lowered pressure at the outlet of the nozzle 812, venturi
effect).
[0027] According to one embodiment, the sprayer 810 may be
configured to deliver the cleaner 818 into the compressor 200 via
the inlet 110 of the gas turbine engine 100. Moreover, the sprayer
810 may be configured to extend into the inlet 110 downstream of an
air filter. For example, the sprayer 810 may include an elongated
member configured to extend one or more nozzles 812 into the inlet
110. Also, for example, the sprayer 810 may include an extension
tube that is generally linear, and which can be conveniently
inserted into an access port 111 of the inlet 110 and manipulated
so as to distribute the cleaner 818 throughout the inlet 110.
[0028] According to one embodiment, the sprayer 810 may be fixed to
the inlet 110. In particular, the sprayer 810 may be attached to
the inlet 110 such that user manipulation is not required. In
addition, the sprayer 810 may be removable or integrated into the
inlet 110. For example, the sprayer 810 may include a tube having
multiple nozzles 812 strategically positioned in and attached to
the inlet 110. The tube may be ring-shaped or otherwise shaped to
conform to the inlet 110, extending the entire circumference or a
part thereof. Also for example, the sprayer 810 may include
multiple nozzles 812 integrated directly into, and distributed
throughout the inlet 110 and/or the compressor 200.
[0029] According to one embodiment, the sprayer 810 may be
configured to deliver a rinse. In particular, the sprayer 810 may
also introduce a rinsing agent into the compressor 200 via the
inlet 110 of the gas turbine engine 100. The rinse may be water
that is demineralized, or otherwise purified, and selected so as to
rinse the cleaner 818 and/or any residue. The sprayer 810 may
deliver the rinse using the same delivery path as the cleaner 818
or a separate path. For example, the sprayer 810 may include a
selectable feed where cleaner 818 and rinse can be alternately
delivered via one or more nozzles 812. Also, for example, the
sprayer 810 may include an independent delivery path and nozzles
812 for the cleaner 818, and for the rinse. Finally, the cleaner
818 and the rinse may differ only in the timing of their
delivery.
[0030] The crank 820 includes a drive couple 822 to the compressor
rotor assemblies 220 and a driver 824 configured to rotate the
compressor rotor assemblies 220 via the drive couple 822. In
particular, the crank 820 rotates the compressor rotor assemblies
220 without combustion in the combustion chamber 390 or fuel
delivery to the injectors 350. Also, the drive couple 822 need not
be directly connected to the compressor rotor assemblies 220. For
example, the drive couple 822 may be coupled to an intermediated
drive member such as the power output coupling 600, the shaft 120,
etc.
[0031] According to one embodiment, the crank 820 may be a starter
motor of the gas turbine engine 100. In particular, the starter
motor may be used to crank the gas turbine engine 100 as part of an
offline wash. As such, the starter motor of the gas turbine engine
100 may be operated to rotate the compressor rotor assemblies 220
while the fuel supply is shut off, or otherwise inhibited. In
addition, the starter motor of the gas turbine engine 100 may be
configured to selectably operate in both an offline wash mode and
in an engine start-up mode.
[0032] Alternately, the crank 820 may include a driver 824 separate
from the gas turbine engine 100. In particular, the driver 824 may
be independent of the starter of the gas turbine engine 100, but
otherwise mechanically coupled to the compressor rotor assemblies
220. For example, the crank 820 may include a driver 824 coupled to
the compressor rotor assemblies 220 via the power output coupling
600 and/or the shaft 120.
[0033] The driver 824 may be an electric motor, a pneumatic motor,
or any convenient driving device. Moreover, the driver 824 may
separable from the gas turbine engine 100, and only used as part of
the wash system 800. Alternately, the driver 824 may be
persistently coupled to the gas turbine engine 100, such as a
system normally driven by the power output coupling 600 (e.g., an
electric generator re-configured to operate as an electric
motor).
[0034] The one or more secondary air caps 830 are caps configured
to interface with and cap off the one or more compressor ports 705,
one or more ports of the strut bleed tube external flange assembly
710, and/or other openings of the secondary air plumbing 707 made
upon the removal of the secondary air plumbing 707 for engine wash.
Accordingly, the one or more secondary air caps 830 may include the
same or similar interface fitting of the removed secondary air
plumbing 707.
[0035] According to one embodiment, one or more of the secondary
air caps 830 may include a bleed vent 832. In particular, the
secondary air cap 830 configured to cap off the compressor port 705
may include a bleed vent 832. For example, the bleed vent 832 may
be a quick release type. Moreover, the bleed vent 832 may be
configured to cap off the compressor port 705 yet be opened and
closed while pressurized and/or unpressurized.
[0036] The waste trap 840 collects and/or redirects used cleaner
818 from the wash system 800. For example, the waste trap 840 may
include an exhaust collector 841 and waste separator 842. In
particular, exhaust collector 841 may be any convenient duct, such
as a hood configured to direct flow from the exhaust 500 to the
waste separator 842. Also for example, the waste separator 842 may
be any convenient catch, such as an open fluid container configured
to receive waste and/or rinse liquid, and permit gas to escape.
Alternately, the wash system 800 may use existing exhaust paths to
direct flow from the exhaust 500, for example when the cleaner 818
is water.
[0037] FIG. 2 illustrates a portion of the wash system of FIG. 1.
In particular, buffer air portions are shown. Moreover, the wash
system 800 integrates with the secondary air system 700 of the gas
turbine engine 100 providing compressed air from onboard and/or off
board the gas turbine engine 100. As such, exemplary aspects of the
secondary air system 700 and the injectors 350 will be initially
discussed for context. Note, for clarity, repeated or similar
components may only be called out at in a single location in the
figure.
[0038] Although other types of injectors may be used, here, the gas
turbine engine 100 is configured for angled injectors. In
particular, the injectors 350 are 90-degree injectors, radially
entering the combustor 300. For example, the injectors 350 may be
radially distributed around the center axis 95, and mounted at one
end to the combustor case 310 and at the other end to the
combustion chamber 390. Here, and in other figures, the injectors
350 have been removed and/or repositioned to align with the view
for clarity and ease of explanation.
[0039] As discussed above, combustor 300 may include a plurality of
struts 312, providing radial support between the bearing housing
315 and the combustor case 310. As illustrated, struts 312 may be
placed in the air stream of diffuser 320, radially distributed, and
positioned between adjacent gas turbine injectors 350. For example,
each strut 312 may be radially distributed such that radially
adjacent struts 312 are separated by two injectors.
[0040] In addition to providing radial support, struts 312 provide
internal passageways traversing the pressurized flow regions inside
combustor 300, shielded from interaction with primary air 11. In
particular, one or more passageways may be provided within the
walls of strut 312 for carrying secondary air 13, mixed air,
lubricants, and/or other media between the outside of the combustor
case 310 and the internal regions of the gas turbine engine 100
(e.g., inside or nearby the bearing housing 315). Accordingly,
portions of the secondary air system 700 may pass through one or
more struts 312.
[0041] As illustrated, the secondary air system 700 of the gas
turbine engine 100 may include a buffer air path 720, a cooling air
path 730, and/or a mixed air path 740. In normal operation, the
buffer air path 720 delivers compressed secondary air 13 to one or
more dry seals (e.g., buffered labyrinth seals 170). The buffer air
inhibits the undesired travel of lubricant from "wet" areas. Also,
in normal operation, the cooling air path 730 delivers compressed
secondary air 13 to one or more cooling passages (e.g., cooling
passages traversing the various turbine rotor assemblies 420).
Also, in normal operation, the mixed air path 740 collects mixed
air (e.g., proximate a bearing seal) and routes it away.
[0042] As discussed above, the secondary air system 700 may include
one or more strut bleed tube external flange assemblies 710. In
particular, the strut bleed tube external flange assemblies 710
interface with combustor 300 such that the secondary air plumbing
707 may transmit secondary air 13 and/or mixed air to/from the
buffer air path 720, the cooling air path 730, and/or the mixed air
path 740 during normal operation.
[0043] Turning to the compressor wash, the wash system 800 further
includes a pressurized air supply assembly 850. The pressurized air
supply assembly 850 generally includes one or more of an air supply
pneumatic couple and a secondary air system pneumatic couple 853
coupled to each end of an air conduit 852. The pressurized air
supply assembly 850 is configured to provide offline buffer air 16
to one or more areas of the gas turbine engine 100. The offline
buffer air 16 may come from "shop air" (i.e., an air supply other
than the gas turbine engine 100), "local air" (i.e., primary air 11
compressed by the gas turbine engine 100), or a combination
thereof. The offline buffer air 16 may be used to buffer against
egress of lubricants or ingress of contaminants, as described
below.
[0044] The air supply pneumatic couple may include any convenient
pneumatic coupling configured to join with the source of offline
buffer air 16. In particular, where the offline buffer air supply
is "shop air", the air supply pneumatic couple may be a
standardized air fitting (not shown). For example, the air supply
pneumatic couple may be a quick-disconnect hand operable air-line
fitting. In addition, when configured to receive "shop air" the air
supply pneumatic couple may include a one-to-many or many-to-one
manifold, and or multiple air supply pneumatic couples.
[0045] Alternately, where the offline buffer air supply is the gas
turbine engine 100 ("local air"), the air supply pneumatic couple
may include a local air supply adapter 851 configured to interface
with an opening downstream of the compressor 200. In particular,
the local air supply adapter 851 pneumatically couples with the
primary air flow path. For example, the local air supply adapter
851 may include ported plug that inserts into a preexisting port of
the combustor 300, such as an injector port, starter torch port,
combustor case bleed port, etc.
[0046] According to one embodiment, the local air supply adapter
851 may interface with an injector port and include an injector
port flange 854 and a conduit mount 855. In particular, the
injector port flange 854 and the conduit mount 855 may form a
structure that fits and attaches in the place of a removed injector
350 and provides an air path to the air conduit 852. For example,
the injector port flange 854 may be a cap, shaped substantially
similar to the mounting flange of the removed injector 350, but
including one or more air passageways passing through the cap and
terminating at the conduit mount 855. The conduit mount 855 may be
an interface and/or a fitting, configured to mate with the air
conduit 852 in a permanent or removable manner.
[0047] According to one embodiment, the local air supply adapter
851 may include a plurality of conduit mounts 855. In particular,
where offline buffer air 16 is routed in various locations
throughout the secondary air system 700, a single injector port
flange 854 may include a plurality of conduit mounts 855 to support
each path. For example, as illustrated the air local air supply
adapter 851 may include three conduit mounts 855, having different
sizes and coupling to three different air conduits 852. The three
different air conduits 852 of the illustrated local air supply
adapter 851 may route offline buffer air 16 to various locations of
the buffer air path 720.
[0048] The air conduit 852 may include pneumatic conduit of any
convenient shape or configuration. In addition, the air conduit 852
may be of a fixed shape or may be flexible. For example, the air
conduit 852 may be a flexible air-line with smooth Teflon bore.
Also for example, the air conduit 852 may additional environmental
features such as mesh shielding.
[0049] Moreover, where multiple air conduits 852 are used, each may
have varying lengths and inner diameters. In particular, each air
conduit 852 may have a different length and/or inner diameter,
depending on which part of the secondary air system 700 it is
integrating with. For example, the air conduits 852 may include
air-lines of different lengths, going to the "end" bearing
assemblies, and air-lines going into the combustor 300 via one or
more struts 312.
[0050] According to one embodiment, the air conduits 852 may have
varying inner diameters different from one another. In particular,
the air conduits 852 integrating with buffer air paths 720, and/or
mixed air paths 740 may have different inner diameters than those
integrating with cooling air paths 730. For example, the air
conduits 852 integrating with buffer air paths 720, and/or mixed
air paths 740 may have a first inner diameter and those integrating
with cooling air paths 730 may have a second inner diameter larger
than the first. Also, for example, the first inner diameter may be
0.75 inch (19 mm) and the second inner diameter may be 1.25 inch
(32 mm).
[0051] The secondary air system pneumatic couple 853 may include
any convenient pneumatic fitting or adapter configured to attach to
the part of the secondary air system 700 it is integrating with. In
particular, secondary air system pneumatic couple 853 may include
multiple attachments of differing sizes, coupling to different
secondary air paths. Moreover, the inner diameter of each secondary
air system pneumatic couple 853 may vary with each air conduit 852
coupled to it, as described above. In addition, each secondary air
system pneumatic couple 853 may be shaped substantially similar to
the mounting flange of the part of the removed secondary air
plumbing.
[0052] As discussed above, the secondary air system 700 may
conveniently include one or more strut bleed tube external flange
assemblies 710. Accordingly, with one or more sections of the
secondary air plumbing 707 removed, the pressurized air supply
assembly 850 may pneumatically couple with the corresponding
secondary air system interface. In particular, the secondary air
system pneumatic couple 853 may be joined to the strut bleed tube
external flange assembly 710, using any convenient attachment.
[0053] According to one embodiment, secondary air system pneumatic
couples 853 may include attachments for one or more different air
paths of the secondary air system 700. In particular, secondary air
system pneumatic couple 853 may include a buffer air path
attachment 856 configured to couple with the buffer air path 720, a
cooling air path attachment 857 configured to couple with the
cooling air path 730, and/or a mixed air path attachment 858
configured to couple with the mixed air path 740.
[0054] For example, the buffer air path attachment 856 may couple
with a port of the strut bleed tube external flange assembly 710
associated with buffered labyrinth seals 170 of the "intermediate"
bearing assemblies 150 (e.g., number two and three bearing
assemblies 152, 153 in the bearing housing 315). The buffer air
path attachment 856 may also couple with the buffer air fittings
708 (see FIG. 1) for the buffered labyrinth seals 170 of the end
bearing assemblies 150. Also for example, the cooling air path
attachment 857 may couple with a port of the strut bleed tube
external flange assembly 710 associated with cooling to the turbine
400. Also for example, the mixed air path attachment 858 may couple
with a port of the strut bleed tube external flange assembly 710
associated with mixed air leaving the bearing housing 315.
[0055] FIG. 3 illustrates a portion of the wash system 800, where
the gas turbine engine 100 is configured for straight injectors. In
particular, the combustor 300 is configured for 180-degree
injectors entering the combustor 300 in a generally axial
direction. As with the 90-degree injectors, the 180-degree
injectors may be radially distributed around the center axis 95.
Also, the 180-degree injectors may be mounted at one end to the
combustor case 310, and at the other end to the combustion chamber
390.
[0056] According to one embodiment, the wash system 800 may draw
offline buffer air 16 from within the compressor 200, and/or
provide a more tortuous path for wash contaminants to enter the
pressurized air supply assembly 850. In particular, the pressurized
air supply assembly 850 may further include an air supply extension
859. The air supply extension 859 begins at the injector port
flange 854 and extends into the combustor 300. For example, the air
supply extension 859 may be a tube, of any cross section extending
into the combustor 300 from the injector port flange 854.
[0057] According to one embodiment, the air supply extension 859
may extend to or into the combustion chamber 390. In particular,
the air supply extension 859 may extend to and mates with an
injector opening in the combustion chamber 390. For example, the
air supply extension 859 may have a substantially the same shape
and interface dimensions of a removed injector. Moreover, the air
supply extension 859 may be fit up or otherwise configured to
require offline buffer air 16 to first enter the combustion chamber
390 in order to enter the air supply extension 859.
[0058] FIG. 4 illustrates a portion of the wash system 800 of FIG.
1, including an axial view of the combustor region of FIG. 3. In
particular, the view includes the combustor 300 looking aft (from
the compressor side). As illustrated and discussed above, the
struts 312 and the injectors 350 annularly distributed around the
center axis 95. Here, however, the gas turbine engine 100 is
configured for straight injectors. While this configuration differs
from that of angled injectors (entering radially), the illustrated
embodiments apply to both.
[0059] According to one embodiment, the local air supply adapter
851 may include a plurality of injector port flanges 854 and/or
conduit mounts 855. In particular, where a plurality of injectors
350 are removed, each injector port may be capped and tapped. For
example, as illustrated, the local air supply adapter 851 may
include a first injector port flange 854 and a second injector port
flange 854. Moreover, the first injector port flange 854 and a
second injector port flange 854 may be coupled to injector ports in
the upper half of the combustor 300. For example and as
illustrated, the first injector port flange 854 and a second
injector port flange 854 may be installed in the two uppermost
injector ports of the combustor 300.
[0060] According to one embodiment, the local air supply adapter
851 may route the offline buffer air 16 to various locations with
each injector port flange 854 including a plurality of conduit
mounts 855. In particular, each injector port flange 854 may
include a plurality of independent air paths. For example, the
first and second injector port flange 854 may include two and three
conduit mounts 855, respectively, having various sizes and coupling
to five different air conduits 852. The five different air conduits
852 may then route offline buffer air 16 to buffer air paths 720 of
the end and intermediate bearing assemblies 150, to the cooling air
path 730, and to the mixed air path 740.
INDUSTRIAL APPLICABILITY
[0061] The present disclosure generally pertains to a wash system
for a gas turbine engine, and is applicable to the use, operation,
maintenance, repair, and improvement of gas turbine engines. The
wash system embodiments described herein may be suited for gas
turbine engines any number of industrial applications, such as, but
not limited to, various aspects of the oil and natural gas industry
(including transmission, gathering, storage, withdrawal, and
lifting of oil and natural gas), power generation industry,
aerospace and transportation industry, to name a few examples.
[0062] Furthermore, the described embodiments are not limited to
use in conjunction with a particular type of compressor or gas
turbine engine. There are numerous gas turbine engine
configurations and types that are applicable here. For example, the
compressor may be an axial compressor, a centrifugal compressor,
etc., having one or more compression stages. Also for example, the
gas turbine engine may be single shaft, multi-shaft, having any
number of bearing assemblies, any type of combustor configuration,
and/or may operate on one or more different fuels. The gas turbine
engine is not limited in size or output, and may be rated at 3000
kW power output or greater. In addition, compressor wash system may
be used in any the gas turbine engine having a secondary air
system.
[0063] Generally, embodiments of the presently disclosed wash
system are applicable to the use, operation, maintenance, repair,
and improvement of gas turbine engines, and may be used in order to
improve performance and efficiency, decrease maintenance and
repair, and/or lower costs. In addition, embodiments of the
presently disclosed compressor wash system may be applicable at any
stage of the gas turbine engine's life, from design to prototyping
and first manufacture, and onward to end of life.
[0064] FIG. 5 is a flow chart of an exemplary method for washing a
gas turbine engine. In particular, the compressor and/or any other
components in the primary air flow path may be washed using the
following method 900, the above description, or a combination
thereof. As illustrated (and with reference to FIG. 1 through FIG.
4), the components in the primary air flow path may be washed and
rinsed while the gas turbine is offline by operating the disclosed
wash system.
[0065] The method 900 begins with setting up the wash system. In
particular, the wash system may include the wash system 800
described above. Also, setting up the wash system includes
accessing the secondary air system of the gas turbine engine at
step 910 and installing wash system hardware at step 920.
[0066] Accessing the secondary air system of the gas turbine engine
910 may include accessing a compressor port at step 911, accessing
a buffer air path at step 912, accessing a cooling air path at step
913, and/or accessing a mixed air path at step 914. In particular,
the steps of accessing the compressor port 911, accessing the
buffer air path 912, accessing the cooling air path 913, and/or
accessing the mixed air path 914 may include removing secondary air
plumbing, or otherwise obtaining pneumatic access to the compressor
port, the buffer air path, the cooling air path and the mixed air
path, respectively. For example, removing secondary air plumbing
may provide both access to the underlying port or air path and a
mating mounting flange.
[0067] Moreover, accessing each port or air path above may be made
at one or more locations. For example, accessing the compressor
port at step 911 may include decoupling secondary air plumbing at
multiple compressor stages and/or at multiple compressor ports
distributed around the compressor. Also for example, accessing the
buffer air path at step 912 may include decoupling secondary air
plumbing for seals at each bearing assembly, including end bearing
assemblies and intermediate bearing assemblies. Similarly,
accessing the cooling air path at step 913 or the mixed air path at
step 914 may include decoupling secondary air plumbing at a
convenient location, such as outside the combustor at one or more
strut tube external flange assemblies.
[0068] Installing wash system hardware at step 920 may include the
steps of installing a sprayer 921, installing a crank 922,
installing a secondary air cap 923, installing a waste trap 924,
and/or installing a pressurized air supply assembly 930. One or
more of each of this hardware may be installed. In addition, one or
more of these may be preinstalled. For example, as discussed above
the sprayer or the crank may be integrated into, or persistently
installed on the gas turbine engine. Similarly, the waste trap may
be integrated into or persistently installed on the gas turbine
engine.
[0069] Installing the secondary air cap 923 includes capping off
one or more compressor ports. In particular, air is prevented from
advancing in the secondary air system beyond the secondary air cap.
For example, where the compressor includes one or more compressor
ports, as described above, each port may be capped off with a
secondary air cap. Alternately, one or more secondary air caps may
be installed at a more convenient downstream location.
[0070] According to one embodiment, the one or more secondary air
caps may be installed downstream of a flow juncture or reducing
manifold. In particular, where there are multiple ports off the
compressor pneumatically joined via a gallery or other flow
junction and pneumatically reduced to fewer outputs, the fewer
outputs may be capped rather than the multiple ports. This may be
beneficial in reducing the number of secondary air cap,
installation time expended, and for ease of installation.
[0071] The step 930 of installing the pressurized air supply
assembly may include the steps of coupling the pressurized air
supply assembly to an air supply 931, coupling the pressurized air
supply assembly to the buffer air path 932, coupling the
pressurized air supply assembly to the cooling air path 933, and/or
coupling the pressurized air supply assembly to the mixed air path
934. Coupling the pressurized air supply assembly to each air path
932, 933, 934 may include coupling one or more secondary air system
pneumatic couples to each accessed air path, or otherwise
pneumatically coupling the pressurized air supply assembly to each
air path 932, 933, 934. For example, one or more secondary air
system pneumatic couples may be mated with each previously accessed
mounting flange associated with each air path to be coupled
with.
[0072] Coupling the pressurized air supply assembly to an air
supply a step 931 may include coupling to "shop air" 935 and/or
coupling to "local air" 936. In particular, coupling to "shop air"
935 may include coupling an air supply pneumatic couple such as a
standardized air fitting to an air supply other than the gas
turbine engine, as described above. According to embodiment, the
"shop air" may be depressurized at the time of coupling, and
subsequently pressurized.
[0073] The step coupling to "local air" 936 may include coupling an
air supply pneumatic couple such as a local air supply adapter
configured to interface with an opening downstream of the
compressor, as described above. In particular, coupling to "local
air" 936 may include removing an injector from an injector port 937
and installing the local air supply adapter to the injector port
938. Installing the local air supply adapter to the injector port
938 may include installing an injector port flange, as described
above, to the open injector port. According to another embodiment,
more than one injector may be removed and more than one local air
supply adapter may be installed.
[0074] According to one embodiment, installing the local air supply
adapter to the injector port 938 may further include installing the
local air supply adapter into a combustion chamber. For example,
the local air supply adapter may include an air supply extension,
as described above, and installing local air supply adapter into a
combustion chamber may include extending the air supply extension
into an injector opening in the combustion chamber.
[0075] According to one embodiment, coupling to "local air" 936 may
include selecting an upper injector port for the air supply. In
particular, when removing the injector from the injector port 937
and installing the local air supply adapter to the injector port
938, the injector port 938 may at an uppermost position, as viewed
axially (see FIG. 4). Moreover, where a plurality of injector ports
are utilized, the plurality of injector ports may likewise be the
uppermost injector ports in the combustor.
[0076] Next, the method 900 includes washing the gas turbine
engine. In particular, washing the gas turbine engine includes
cranking a compressor rotor assembly 940, pressurizing the offline
buffer air 945, and spraying cleaner 950. Cranking the compressor
rotor assembly 940 may include cranking all compressor rotor
assemblies or cranking the compressor in general. Moreover,
cranking the compressor rotor assembly 940, may include installing
and operating a crank as described above, and/or operating a
preinstalled crank (e.g. operating a starter without fuel supplied,
operating a reconfigured electric generator, etc.), as described
above. Also, cranking the compressor rotor assembly 940 may include
first shutting off fuel to the combustor and then cranking the
compressor. The compressor may be cranked sufficiently to draw
cleaner through the gas turbine engine when the cleaner is
sprayed.
[0077] According to one embodiment, the step 945 of pressurizing
the offline buffer air may include supplying compressed air to the
secondary air system. In particular, pressurizing the offline
buffer air may include supplying compressed air to the buffer air
path, the cooling air path, and/or the mixed air path of the
secondary air system. For example, pressurizing the offline buffer
air may include supplying compressed air to a seal of an
intermediate and/or an end bearing assembly of the gas turbine
engine via a secondary air system.
[0078] As discussed above, "local air" and "shop air" may be used
separately or in combination. Where "local air" is used, cranking
the compressor may further include cranking the compressor
sufficiently to supply offline buffer air at pressure. In
particular, the compressor may be cranked to a minimum
predetermined rotation speed and/or output pressure (gauged off
atmospheric pressure). For example, the compressor may be cranked
to at least 20 percent of its normal operating speed. Also for
example, the compressor may be cranked such that its maximum output
pressure (PCD) is at least 0.5 psig (3.44 kPa). Also for example,
the compressor may be cranked such that its maximum output pressure
is at least 1.0 psig (6.89 kPa). Also for example, the compressor
may be cranked such that its maximum output pressure is between 0.5
psig and 1.0 psig (3.44 kPa and 6.89 kPa).
[0079] Alternately, the compressor may be cranked such that the
offline buffer air has sufficient pressure to inhibit egress of
lubricants from "wet" areas, or ingress of contaminants during
washing. In particular, losses associated with the particular gas
turbine engine may be incorporated by cranking the compressor to a
minimum differential pressure (gauged off the non-buffered side).
For example, the compressor may be cranked such the differential
pressure across all buffered interfaces is at least 0.25 psig (1.72
kPa), at least 0.5 psig (3.44 kPa), or between 0.25-1.0 psig
(1.72-6.89 kPa). Also for example, the compressor may be cranked
such the differential pressure between the wet side of a buffered
bearing seal and its secondary air system buffer air path or
secondary air system side is at least 0.25 psig (1.72 kPa), at
least 0.50 psig (3.44 kPa), or between 0.25-1.0 psig (1.72-6.89
kPa) (gauged off the wet side). Also for example, the compressor
may be cranked such the differential pressure between the primary
air flow path of the turbine and the cooling air path of the
secondary air system is at least 0.15 psig (1.03 kPa), at least
0.25 psig (1.72 kPa), or between 0.25-1.0 psig (1.72-6.89 kPa)
(gauged off the primary air flow path side). Also for example, the
compressor may be cranked such the differential pressure between
the primary air flow path, upstream of the turbine, and a mixed air
path across a labyrinth seal is at least 0.25 psig (1.72 kPa), at
least 0.50 psig (3.44 kPa), or between 0.25-1.0 psig (1.72-6.89
kPa) (gauged off the primary air flow path side of the labyrinth
seal).
[0080] According to one embodiment, the step 945 of pressurizing
the offline buffer air may include keeping the combustor case bleed
at least partially closed during wash. In particular, the combustor
case bleed may be overridden or otherwise kept closed while
cranking the compressor rotor assembly 940. For example, where the
starter is used to crank the compressor, a command to open the
combustor case bleed valve may be bypassed, or the combustor case
bleed valve may be otherwise configured to inhibit primary air from
bypassing the turbine while washing the gas turbine engine. Also
for example, the combustor case bleed valve may be locked in a
closed position during the washing of the gas turbine engine. An
improvement on pressurizing the offline buffer air may result where
the combustor case bleed is kept closed while washing the gas
turbine engine and local air is used. Accordingly, this embodiment
may be limited to embodiments where local air is used.
[0081] Where "shop air" is used, pressurizing the offline buffer
air 945 may include supplying pressurized offline buffer air from
the air supply to the pressurized air supply assembly. For example,
a pressure control valve of the air supply may be opened, thereby
pressurizing the coupled system. In addition the offline buffer air
may be supplied at the same or similar pressure levels as above
with "local air".
[0082] Spraying cleaner 950 includes delivering cleaner to the
compressor or otherwise distributing cleaner into the compressor.
In particular, cleaner (e.g., water, solvent, etc.) may be sprayed
using the sprayer described above. For example, cleaner may be
sprayed after the offline buffer air has been pressurized. Also for
example cleaner may be sprayed after the compressor rotor assembly
has been cranked.
[0083] In addition, a rinse may be sprayed 951. In particular,
after delivering the cleaner, it may be rinsed from the compressor.
As described above, the cleaner and the rinse may differ only in
the timing of their delivery. Also, as described above, spraying
the rinse 951 may include using same sprayer for both cleaner and
rinse.
[0084] According to one embodiment, the method 900 may include
collecting waste 960. In particular, the wash system may include a
waste trap, as described above. Alternately, the gas turbine engine
may include a series of fluid drains throughout. Accordingly,
collecting waste 960 may include trapping and removing waste such
as used cleaner, rinse, and other contaminants collected in waste
trap, one or more drains, or otherwise, during washing the gas
turbine engine.
[0085] According to one embodiment, the method 900 may include
purging secondary air caps 970. In particular, the secondary air
caps may include bleed vents as described above, and the bleed
vents may be opened while under pressure. For example, at the end
of the washing the compressor may continue to rotate and the bleed
vents may be opened so as to permit debris, contaminant, rinse,
etc. to escape. According to one embodiment, purging secondary air
caps 970 may include leaving the bleed vents open while under
pressure until minimal or no water leaves the bleed vents.
[0086] Finally, the method 900 ends with disassembling the wash
system. In particular, disassembling the wash system includes
removing compressor wash system hardware 980 and returning
secondary air system to operating configuration 990. In particular,
removing compressor wash system hardware 980 is substantially the
reverse of installing the compressor wash system hardware, and
returning secondary air system to operating configuration 990 is
substantially the reverse of accessing the secondary air system. In
addition, returning secondary air system to operating configuration
990 may include removing the crank or otherwise reconfiguring the
crank. Also, returning secondary air system to operating
configuration 990 may include reinstalling one or more injectors
991.
[0087] Embodiments of the presently disclosed wash system provide
for an offline crank wash system for a gas turbine engine. In
particular, one or more secondary air passages may be buffered,
inhibiting egress of lubricants from "wet" areas, or ingress of
contaminants during washing. Moreover, by drawing offline buffer
air from the combustor, the amount of air needed (at least in
larger engines) to buffer "intermediate" bearing assemblies and the
associated cooling passages may be made practical, particularly
where adequate shop air is not available. As a result, this
buffering may reduce contamination and blockage from containments
in the water wash. Moreover, with fewer drawbacks and a "cleaner"
wash, it may be performed more frequently, improving performance
and increasing intervals between manual washes.
[0088] The preceding detailed description is merely exemplary in
nature and is not intended to limit the invention or the
application and uses of the invention. The described embodiments
are not limited to use in conjunction with a particular type of gas
turbine engine. Hence, although the present embodiments are, for
convenience of explanation, depicted and described as being
implemented in a single spool axial gas turbine engine, it will be
appreciated that it can be implemented in various other types of
gas turbine engines, and in various other systems and environments.
Furthermore, there is no intention to be bound by any theory
presented in any preceding section. It is also understood that the
illustrations may include exaggerated dimensions and graphical
representation to better illustrate the referenced items shown, and
are not consider limiting unless expressly stated as such.
* * * * *