Information
-
Patent Grant
-
6457933
-
Patent Number
6,457,933
-
Date Filed
Friday, December 22, 200023 years ago
-
Date Issued
Tuesday, October 1, 200221 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Look; Edward K.
- Kershteyn; Igor
Agents
-
CPC
-
US Classifications
Field of Search
US
- 415 1
- 415 104
- 415 105
- 415 107
- 415 1701
- 415 1741
- 415 229
- 251 326
- 251 327
- 251 328
- 251 329
- 251 193
- 251 89
- 251 95
- 251 111
- 251 112
-
International Classifications
-
Abstract
An orifice plate assembly for a gas turbine engine that facilitates extending a useful life of bearing assemblies within the gas turbine engine is described. Each orifice plate assembly is coupled in flow communication with an engine air source, and includes a first body portion and a second body portion. The first body portion includes a channel and a flow opening. The channel is sized to receive the second body portion, such that the second body portion may slide with respect to the first body portion. The orifice plate assembly is adjustable after engine shutdown to regulate bearing loading.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to gas turbine engines and, more particularly, to methods and apparatus for regulating bearing loads within gas turbine engine bearing assemblies.
Gas turbine engines include a high pressure compressor, a combustor, and a high pressure turbine. The high pressure compressor includes a rotor, and a plurality of stages. The rotor is supported with a plurality of bearing assemblies that include an inner race, an outer race, and a plurality of rolling elements between the inner and outer races. Maintaining bearing loads within pre-defined limits during engine operation facilitates extending a useful life of the bearing assembly.
To regulate the bearing load, at least some known gas turbine engines use compressor bleed air. The bleed air is routed through delivery lines including orifice plate assemblies. The orifice plate assemblies are multi-piece assemblies and each orifice plate assembly includes a discretely sized opening that limits an amount of airflow through the orifice plate assembly and thus regulates a pressure/flow from the air sources.
During engine operation, when engine parameters indicate that bearing load is exceeding pre-defined limits, engine operation is stopped and the orifice plate assembly is replaced with a different orifice plate assembly that has a different sized opening. Because each orifice plate assembly is discretely sized, a large inventory of plates is often maintained. Because of the complexity of the multi-piece orifice plate assemblies, replacing the orifice plate assemblies is often a time-consuming and costly process.
BRIEF SUMMARY OF THE INVENTION
In an exemplary embodiment, an orifice plate assembly for a gas turbine engine facilitates extending a useful life of bearing assemblies within the gas turbine engine. Each orifice plate assembly is coupled within the engine in flow communication with an engine air source, and each includes a first body portion and a second body portion. The first body portion includes a channel and a flow opening. The channel is sized to receive the second body portion, such that the second body portion may slide with respect to the first body portion. More specifically, the second body portion may be positioned to cover any portion or all of the first body portion flow opening.
During engine operation, when parameters measured indicate that bearing loads are approaching pre-defined limits, the orifice plate assembly may be adjusted after engine shutdown to regulate air pressure and flow to facilitate maintaining bearing loads within the limits. More specifically, to adjust the orifice plate assembly, the second body portion is loosened from the first body portion and is repositioned with respect to the first body portion. As the second body portion is repositioned, a cross-sectional flow area through the first body portion flow opening is changed. When bearing loads are reestablished within the pre-defined limits, the second body portion is re-secured to the first body portion. As a result, the orifice plate assembly facilitates extending a useful life of a bearing assembly in a highly reliable and cost-effective manner.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a schematic illustration of a gas turbine engine;
FIG. 2
is a cross-sectional view of a portion of the gas turbine engine shown in
FIG. 1
;
FIG. 3
is a plan view of an orifice plate assembly used with the gas turbine engine shown in
FIG. 2
; and
FIG. 4
is a side view of the orifice plate assembly shown in FIG.
2
.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1
is a schematic illustration of a gas turbine engine
10
including at least one compressor
12
, a combustor
16
, a high pressure turbine
18
, a low pressure turbine
20
, an inlet
22
, and an exhaust nozzle
24
connected serially. In one embodiment, engine
10
is an LM2500+ engine commercially available from General Electric Company, Cincinnati, Ohio. Compressor
12
and turbine
18
are coupled by a first shaft
26
. Engine
10
also includes a centerline axis of symmetry
32
.
In operation, air flows into engine inlet
22
through compressor
12
and is compressed. The compressed air is then delivered to combustor
16
where it is mixed with fuel and ignited. Airflow from combustor
16
drives rotating turbines
18
and
20
and exits gas turbine engine
10
through exhaust nozzle
24
.
FIG. 2
is a cross-sectional view of a portion of gas turbine engine
10
. Compressor
14
includes a plurality of stages
50
, and each stage
50
includes a row of rotor blades
52
and a row of stator vanes
56
. Rotor blades
52
are circumferentially spaced apart, and are typically supported by rotor spools and disks
58
connected to rotor shaft
26
. Rotor blades
52
and stator vanes
56
are coaxial with respect to engine centerline axis
32
. A row of circumferentially spaced apart stator vanes
56
extend between each row of adjacent rotor blades
52
and are supported with an annular outer engine casing
62
.
Compressor bleed air is extracted from high pressure compressor
14
from intermediate stages
66
of compressor
14
and used to regulate bearing loads of bearing assemblies
70
coupled to an engine frame
72
. In one embodiment, bearing loads of a #
4
B thrust bearing assembly are regulated using high pressure compressor recoup compressor air
78
. In another embodiment, bearing loads of a #
7
B thrust bearing assembly are regulated using stage
13
high pressure compressor bleed
76
.
More specifically, a plurality of air delivery lines
80
are coupled in flow communication to various stages of compressor
14
, and are used for supplying fluid flow for controlling bearing loads of bearing assemblies
70
and #
7
B bearing assemblies. Each air delivery line
80
includes an orifice plate assembly
82
. Orifice plate assembly
82
, described in more detail below, is adjustable and may be adjusted after engine shutdown to regulate pressure/flow through delivery lines
80
from compressor
14
.
In an exemplary embodiment, bearing assembly
70
is enclosed within a sealed annular compartment
90
radially bounded by rotor shaft
26
and support frame
72
. Bearing assembly
70
includes a paired race
91
, a plurality of rolling elements
92
, and a cage
94
. More specifically, paired race
91
includes an outer race
96
and an inner race
98
that is radially inward from outer race
96
. Each rolling element
92
is between inner race
98
and outer race
96
, and in rolling contact with inner and outer races
98
and
96
, respectively. Furthermore, rolling elements
92
are spaced circumferentially by cage
94
.
During operation, engine
10
uses high pressure compressor recoup air
78
and high pressure compressor bleed
76
supplied through delivery lines
80
to control bearing loads. More specifically, bearing loads are maintained between pre-determined limits to facilitate extending useful bearing life. Orifice plate assemblies
82
regulate the pressure/flow from compressor sources
78
and
76
. More specifically, when parameters measured during engine operation indicate that bearing loads are approaching pre-determined limits, orifice plate assemblies
82
may be adjusted after engine shutdown to control bearing loads.
FIG. 3
is a plan view of orifice plate assembly
82
that may be used with gas turbine engine
10
(shown in FIGS.
1
and
2
).
FIG. 4
is a side view of orifice plate assembly
82
. Orifice plate assembly
82
includes a first body portion
100
and a second body portion
102
. First body portion
100
includes an upper surface
104
, a lower surface
106
, and a channel
108
, and has a thickness
110
measured between upper and lower surfaces
104
and
106
, respectively. First body portion
100
also includes an inlet side
112
and a rear side
114
connected with a pair of sidewalls
116
and
118
. An axis of symmetry
119
extends from first body portion inlet side
112
to rear side
114
.
First body portion channel
108
is sized to receive second body portion
102
therein. More specifically, channel
108
extends a distance
120
into first body portion
100
towards first body portion lower surface
106
from first body portion upper surface
104
. Channel depth
120
is smaller than first body portion thickness
110
. Additionally, channel
108
has a width
122
that is smaller than a width
124
of first body portion
100
. Furthermore, channel
108
also extends inward towards first body portion rear side
114
from first body portion inlet side
112
for a length
126
. Channel length
126
is smaller than a length
128
of first body portion
100
measured between inlet and rear sides
112
and
114
, respectively.
First body portion
100
also includes a flow opening
130
and a plurality of attachment openings
132
. Flow opening
130
extends from first body portion upper surface
104
to lower surface
106
. More specifically, flow opening
130
is co-axially positioned with respect to first body portion
100
within channel
108
. A width
133
of flow opening
130
is smaller than channel width
122
, and a length
134
of flow opening
130
is smaller than channel length
126
. In one embodiment, flow opening
130
has a substantially rectangular cross-sectional profile. In another embodiment, flow opening
130
has a non-rectangular cross sectional profile.
First body portion attachment openings
132
extend through first body portion
100
from first body portion upper surface
104
to lower surface
106
. Each attachment opening
132
has a diameter
140
sized to receive a fastener (not shown) therethrough to secure each orifice plate assembly
82
to engine
10
(shown in FIGS.
1
and
2
). More specifically, attachment openings
132
extend through first body portion
100
between first body portion channel
108
and sidewalls
116
and
118
.
First body portion
100
also includes an alignment opening
144
. Alignment opening
144
is between flow opening
130
and first body portion inlet side
112
within channel
108
. Alignment opening
144
extends through first body portion
100
from first body portion upper surface
104
to lower surface
106
, and has a diameter
146
sized to receive an alignment fastener
148
therethrough. Alignment fastener
148
secures orifice plate assembly second body portion
102
in position with respect to first body portion
100
. In one embodiment, alignment fastener
148
is a threaded bolt and locking nut.
Orifice plate assembly second body portion
102
includes an upper surface
160
and a lower surface
162
, and has a thickness
164
measured between upper and lower surfaces
160
and
162
, respectively. Second body portion thickness
164
is smaller than first body portion thickness
110
. In one embodiment, orifice plate assembly second body portion thickness
164
is approximately equal first body portion channel depth
120
.
Orifice second body portion
102
also includes an inlet side
166
and a rear side
168
connected with a pair of sidewalls
170
and
172
, and an alignment slot opening
174
. Second body portion
102
also includes an axis of symmetry
176
extending from second body portion inlet side
166
to rear side
168
. Second body portion axis of symmetry
176
is substantially co
4
inear with first body portion axis of symmetry
119
.
Orifice second body portion
102
has a width
180
measured between sidewalls
170
and
172
that is smaller than orifice first body portion width
124
. Second body portion width
180
is slightly smaller than first body portion channel width
122
, such that second body portion
102
is received in slidable contact within first body portion channel
108
. In one embodiment, orifice second body portion length
182
is approximately equal first body portion channel length
126
. Accordingly, first body portion channel
108
is sized to receive second body portion
102
, such that second body portion upper surface
160
is substantially co-planar with first body portion upper surface
104
. Furthermore, first body portion channel
108
permits second body portion
102
to slide therein with respect to first body portion
100
.
Orifice second body portion alignment slot opening
174
is co-axially aligned with respect to axis of symmetry
176
. Alignment slot opening
174
has a width
186
that is approximately equal first body portion alignment opening diameter
146
. Accordingly, orifice second body portion alignment slot opening
174
is sized to receive alignment fastener
148
therethrough. Alignment slot opening
174
has a length
188
measured between an inlet end
190
and a rear end
192
.
Alignment slot inlet end
190
is a distance
194
from second body portion inlet side
166
, and alignment slot rear end
192
is a distance
196
from second body portion rear side
168
. Alignment slot opening length
188
is longer than first body portion flow opening length
134
.
A plurality of graduation lines
200
extend from second body portion sidewall
170
to sidewall
172
. More specifically, graduation lines extend from second body portion alignment slot opening
174
to each respective sidewall
170
and
172
, to provide reference indications used in aligning second body portion
102
with respect to first body portion
100
. In one embodiment, second body portion
102
also includes reference numbers (not shown) used in aligning second body portion
102
with respect to first body portion
100
.
During assembly of orifice plate assembly
82
, fasteners are inserted through first body portion attachment openings
132
to secure orifice plate assembly
82
in flow communication with a respective air delivery line
80
(shown in FIG.
2
). More specifically, orifice plate assembly
82
is secured such that first body portion flow opening
130
is in flow communication with an air delivery line
80
. Second body portion
102
is then coupled to first body portion
100
. More specifically, second body portion
102
is inserted within first body portion channel
108
such that second body portion rear side
168
initially enters first body portion channel
108
. Second body portion
102
is then slid towards first body portion rear side
114
, such that second body portion upper surface
160
is substantially co-planar with first body portion upper surface
104
.
After second body portion
102
has been slid into position with respect to first body portion
100
and is in a desired position, as indicated by second body portion graduation lines
200
, a portion
210
of first body portion flow opening
130
may be covered by second body portion
102
. Portion
210
is infinitely variable and is determined by a relative position of second body portion
102
with respect to first body portion
100
. More specifically, second body portion alignment slot opening length
188
permits second body portion to be positioned such that any percentage of flow opening
130
from approximately zero percent to approximately one hundred percent may be covered with second body portion
102
.
When a desired percentage of first body portion flow opening
130
is covered by second body portion
102
, alignment fastener
148
is extended through first body portion alignment opening
144
and second body portion alignment slot opening
174
. Alignment fastener
148
is then tightened to secure second body portion
102
in position relative to first body portion
100
.
During engine operation, when parameters measured during engine operation indicate bearing loads are approaching the pre-defined limits, orifice plate assembly may be adjusted after engine shutdown to regulate the pressure/flow to maintain bearing loads within the limits to facilitate extending bearing assembly useful life. More specifically, alignment fastener
148
is loosened and orifice plate assembly second body portion
102
is repositioned with respect to first body portion
100
to ensure a cross-sectional flow area through first body portion flow opening
130
maintains an appropriate bearing load. Because second body portion
102
is slid with respect to first body portion
100
, orifice adjustments are infinitely variable. In addition, because orifice plate assembly
82
is variably adjustable, orifice plate assembly
82
may be used for fine tuning bearing loads as performance parameters and bearing loads drift during a useful life of engine
10
.
The above-described orifice plate assembly for a gas turbine engine is cost-effective and highly reliable. The orifice plate assembly includes a second body portion that is received within a first body portion. A position of the second body portion is infinitely variable with respect to the first body portion to regulate bearing loads. Furthermore, the orifice plate assembly may be adjusted after engine shutdown. Thus, the orifice plate assembly facilitates extending a useful life of engine bearing assemblies in a cost-effective and reliable manner.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
Claims
- 1. A method for regulating bearing loads of a gas turbine engine bearing assembly using an orifice plate assembly, the orifice plate assembly including a first body portion and a second body portion, the first body portion including an opening extending therethrough, said method comprising the steps of:coupling the orifice plate assembly to the gas turbine engine in flow communication with the bearing assembly; supplying air through the orifice plate assembly first body portion opening; and coupling the orifice plate assembly second body portion to the first body portion to regulate an amount of air flowing through the orifice plate assembly first body portion opening, such that the second body portion slides with respect to the first body portion.
- 2. A method in accordance with claim 1 wherein the first body portion includes an upper surface, a channel, and a lower surface, the channel extending from the upper surface towards the lower surface, said step of coupling the orifice plate assembly second body portion to the first body portion further comprising the step of sliding the orifice plate assembly second body portion relative to the orifice first plate assembly body portion on the engine to change an amount of air flowing through the orifice plate first body portion opening.
- 3. A method in accordance with claim 1 wherein the second body portion includes an upper surface and a lower surface, the second body portion upper surface including a plurality of graduation lines, said step of coupling the orifice plate assembly second body portion to the first body portion further comprising the step of using the graduation lines to align the second body portion with respect to the first body portion.
- 4. A method in accordance with claim 3 wherein the second body portion includes an upper surface and a lower surface, said step of coupling the orifice plate assembly second body portion to the first body portion further comprising the step of inserting the second body portion within the first body portion, such that the second body portion upper surface is substantially co-planar with a first body portion upper surface.
- 5. A method in accordance with claim 1 wherein the first body portion includes an alignment opening, the second body portion includes an alignment opening, said method further comprising the step of extending a fastener through the first and second body portion alignment openings to secure the second body portion in position relative to the first body portion.
- 6. Apparatus for a gas turbine engine including a bearing assembly, said apparatus comprising an orifice plate sub-assembly comprising a first body portion and a second body portion, said first body portion comprising an opening extending therethrough, said second body portion configured to slide relative to said first body portion to regulate an amount of fluid flowing through said first body portion opening for controlling bearing load of said bearing assembly.
- 7. Apparatus in accordance with claim 6 wherein said orifice plate sub-assembly second body portion comprises an alignment opening configured to receive a fastener therethrough.
- 8. Apparatus in accordance with claim 6 wherein said orifice plate sub-assembly first body portion further comprises a first alignment opening, said orifice plate sub-assembly second body portion comprises a second alignment opening, said first alignment opening and said second alignment opening configured to receive a fastener therethrough for securing said second body portion to said first body portion.
- 9. Apparatus in accordance with claim 8 wherein said orifice plate sub-assembly second body portion second alignment opening comprises a slot.
- 10. Apparatus in accordance with claim 6 wherein said orifice plate sub-assembly first body portion comprises a channel sized to receive said second body portion therein.
- 11. Apparatus in accordance with claim 10 wherein said orifice plate sub-assembly second body portion comprises an upper surface and lower surface, said orifice plate sub-assembly first body portion comprises an upper surface and a lower surface, said first body portion channel configured to receive said second body portion, such that said second body portion upper surface substantially coplanar with said first body portion upper surface.
- 12. Apparatus in accordance with claim 6 wherein said orifice plate sub-assembly second body portion comprises a plurality of graduation lines configured to align said second body portion with respect to said orifice plate sub-assembly first body portion, said second body portion configured to be repositioned with respect to said first body portion while installed on the engine to regulate an amount of fluid flowing through said first body portion opening for controlling bearing load of said bearing assembly.
- 13. A gas turbine engine comprising:bearing assembly; and an orifice plate assembly configured to regulate a bearing load of said bearing assembly, said orifice plate assembly comprising a first body portion and a second body portion, said first body portion comprising an opening extending therethrough, said second body portion coupled to said first body portion to regulate an amount of fluid flowing through said first body portion opening for controlling bearing loading of said bearing assembly, such that said second body portion slides relative to said first body portion.
- 14. A gas turbine engine in accordance with claim 13 wherein said orifice plate assembly second body portion configured to be repositioned with respect to said first body portion while attached to said engine.
- 15. A gas turbine engine in accordance with claim 14 wherein said orifice plate assembly first body portion comprises an upper surface, a channel, and a lower surface, said channel extending from said upper surface towards said lower surface and sized to receive said orifice plate assembly second body portion therein.
- 16. A gas turbine engine in accordance with claim 15 wherein said orifice plate assembly second body portion comprises an upper surface and a lower surface, said second body portion received within said orifice plate assembly first body portion such that said second body portion upper surface substantially co-planar with said first body portion upper surface.
- 17. A gas turbine engine in accordance with claim 15 wherein said orifice plate assembly first body portion further comprises an alignment opening configured to receive a fastener therethrough.
- 18. A gas turbine engine in accordance with claim 17 wherein said orifice plate assembly second body portion further comprises an alignment opening, said first and second body portion alignment openings configured to receive a fastener therethrough to secure said second body portion in position relative to said first body portion.
- 19. A gas turbine engine in accordance with claim 18 wherein said orifice plate assembly second body portion alignment opening comprises a slot.
- 20. A gas turbine engine in accordance with claim 15 wherein said orifice plate assembly second body portion comprises a plurality of graduation lines configured to align said second body portion with respect to said first body portion.
US Referenced Citations (34)
Foreign Referenced Citations (2)
Number |
Date |
Country |
9-4248 |
Feb 1997 |
JP |
9-280388 |
Oct 1997 |
JP |