U.S. patent application number 12/755932 was filed with the patent office on 2011-10-13 for turbofan engine performance recovery system and method.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. Invention is credited to Ramakumar Venkata Naga Bommisetty, Jwala Singh, Costas Vogiatzis.
Application Number | 20110250046 12/755932 |
Document ID | / |
Family ID | 44761041 |
Filed Date | 2011-10-13 |
United States Patent
Application |
20110250046 |
Kind Code |
A1 |
Vogiatzis; Costas ; et
al. |
October 13, 2011 |
TURBOFAN ENGINE PERFORMANCE RECOVERY SYSTEM AND METHOD
Abstract
Methods and apparatus are provided for improving engine
performance in a turbofan gas turbine engine following foreign
object ingestion in turbofan gas turbine engines that include an
intake fan that includes a plurality of fan blades, and that is
disposed within and surrounded by a fan case. The occurrence of a
foreign object ingestion by the turbofan gas turbine engine is
detected and, upon detecting that a foreign object has been
ingested, air is bled from a region proximate the blades of the
intake fan through a slot in the fan case.
Inventors: |
Vogiatzis; Costas; (Gilbert,
AZ) ; Bommisetty; Ramakumar Venkata Naga; (Bangalore,
IN) ; Singh; Jwala; (Bangalore, IN) |
Assignee: |
HONEYWELL INTERNATIONAL
INC.
Morristown
NJ
|
Family ID: |
44761041 |
Appl. No.: |
12/755932 |
Filed: |
April 7, 2010 |
Current U.S.
Class: |
415/1 ;
415/116 |
Current CPC
Class: |
F01D 21/14 20130101;
F02C 6/08 20130101; F02C 7/05 20130101 |
Class at
Publication: |
415/1 ;
415/116 |
International
Class: |
F04D 27/02 20060101
F04D027/02; F04D 31/00 20060101 F04D031/00 |
Claims
1. A turbofan engine intake assembly, comprising: a fan case
adapted to be mounted in an engine nacelle assembly, the fan case
including an inner surface and an outer surface; an intake fan
mounted within the fan case and including a plurality of radially
extending fan blades; a slot extending through the fan case between
the inner and outer surfaces, the slot at least partially extending
around the fan case proximate the fan blades; and an annulus
coupled to the outer surface and including an inner surface that
defines an annular plenum, the annular plenum in fluid
communication with the slot and atmosphere outside the fan
case.
2. The turbofan engine intake assembly of claim 1, further
comprising: a discharge conduit coupled to the annulus and
including an inlet port and an outlet port, the inlet port in fluid
communication with the annular plenum, the outlet port in fluid
communication with the atmosphere outside the fan case.
3. The turbofan engine intake assembly of claim 2, further
comprising: a valve mounted on the discharge conduit and movable to
a plurality of valve positions.
4. The turbofan engine intake assembly of claim 3, further
comprising: a valve actuator coupled to the valve, the valve
actuator adapted to receive valve actuator commands and configured,
upon receipt of the valve actuator commands, to selectively move
the valve to one of the plurality of valve positions.
5. The turbofan engine intake assembly of claim 1, wherein: each
fan blade includes a leading edge and a trailing edge; and the slot
is disposed between the leading edge and trailing edge of each fan
blade.
6. A turbofan engine system, comprising: a nacelle assembly; an
intake section, a compressor section, a combustion section, and a
gas turbine section mounted in the nacelle assembly, the intake
section comprising: a fan case mounted in the nacelle assembly, the
fan case including an inner surface and an outer surface; an intake
fan mounted within the fan case and including a plurality of
radially extending fan blades; a slot extending through the fan
case between the inner and outer surfaces, the slot at least
partially extending around the fan case proximate the fan blades;
and an annulus coupled to the outer surface and including an inner
surface that defines an annular plenum, the annular plenum in fluid
communication with the slot and atmosphere outside the fan
case.
7. The turbofan engine intake assembly of claim 6, further
comprising: a discharge conduit coupled to the annulus and
including an inlet port and an outlet port, the inlet port in fluid
communication with the annular plenum, the outlet port in fluid
communication with the atmosphere outside the fan case.
8. The turbofan engine system of claim 7, further comprising: a
valve mounted on the discharge conduit and movable to a plurality
of valve positions.
9. The turbofan engine system of claim 8, further comprising: a
valve actuator coupled to the valve, the valve actuator further
coupled to receive valve actuator commands and configured, upon
receipt of the valve actuator commands, to selectively move the
valve to one of the plurality of valve positions.
10. The turbofan engine system of claim 8, further comprising: a
pump mounted on the conduit and configured to selectively pump air
from the annulus.
11. The turbofan engine system of claim 6, further comprising: an
engine control coupled to, and configured to selectively supply the
valve actuator commands to, the valve actuator.
12. The turbofan engine system of claim 11, wherein the engine
control is further configured to detect a foreign object ingestion
event.
13. The turbofan engine system of claim 12, wherein the engine
control is further configured to supply the valve actuator commands
upon detecting the foreign object ingestion event.
14. The turbofan engine system of claim 6, wherein: each fan blade
includes a leading edge and a trailing edge; and the slot is
disposed between the leading edge and trailing edge of each fan
blade.
15. A method of improving engine performance in a turbofan gas
turbine engine following foreign object ingestion, the turbofan gas
turbine engine comprising an intake fan and a fan case, the intake
fan disposed within and surrounded by the fan case and including a
plurality of fan blades, the method comprising the steps of:
detecting when a foreign object has been ingested by the turbofan
gas turbine engine; and upon detecting that a foreign object has
been ingested, bleeding air from a region proximate the blades of
the intake fan through a slot in the fan case.
16. The method of claim 15, wherein the step of detecting comprises
detecting performance degradation of the turbofan gas turbine
engine.
17. The method of claim 15, wherein the step of detecting comprises
detecting a change in air pressure around the intake fan.
18. The method of claim 15, wherein the step of bleeding air
comprises opening a valve that allows air from the region to flow
to atmosphere.
19. The method of claim 18, wherein the valve is opened
automatically upon detecting that a foreign object has been
ingested.
20. The method of claim 15, wherein the step of bleeding air
comprises pumping air from the region.
Description
TECHNICAL FIELD
[0001] The present invention generally relates to turbofan jet
engines, and more particularly relates to performance recovery
systems and methods for turbofan jet engines.
BACKGROUND
[0002] Aircraft propulsion engines can be susceptible to foreign
object ingestion events. Such events include, for example,
ingestion of one or more birds by the engine intake section. The
intake section includes an intake fan having a plurality of blades.
Following an ingestion event, the fan blades have the potential to
be deformed or damaged. Deformed or damaged fan blades may result
in relatively large flow separation on the fan case. This can cause
flow blockage and reduced engine performance, including undesirable
engine thrust reduction.
[0003] To mitigate the likelihood of post-ingestion thrust
reductions in aircraft propulsion engines, some government
regulatory agencies mandate that certain aircraft propulsion
engines be able to produce a minimum level of thrust after certain
foreign object ingestion events, such as ingesting multiple birds.
This mandated robustness is currently achieved passively by making
certain fan components relatively stiffer than what may be
necessary, thereby undesirably increasing engine weight, and thus
overall operating costs.
[0004] Hence, there is a need for a system and method that
mitigates the potential deleterious effects of a foreign object
ingestion event. The present invention addresses at least this
need.
BRIEF SUMMARY
[0005] In one embodiment, a turbofan engine intake assembly
includes a fan case, an intake fan, a slot, and an annulus. The fan
case is adapted to be mounted in an engine nacelle assembly, and
includes an inner surface and an outer surface. The intake fan is
mounted within the fan case and includes a plurality of radially
extending fan blades. The slot extends through the fan case between
the inner and outer surfaces, and at least partially extends around
the fan case proximate the fan blades. The annulus is coupled to
the outer surface and includes an inner surface that defines an
annular plenum that is in fluid communication with the slot and
atmosphere outside the fan case.
[0006] In another embodiment, a turbofan engine system includes a
nacelle assembly, an intake section, a compressor section, a
combustion section, and a gas turbine section mounted in the
nacelle assembly. The intake section includes a fan case, an intake
fan, a slot, and an annulus. The fan case is mounted in the engine
nacelle, and includes an inner surface and an outer surface. The
intake fan is mounted within the fan case and includes a plurality
of radially extending fan blades. The slot extends through the fan
case between the inner and outer surfaces, and at least partially
extends around the fan case proximate the fan blades. The annulus
is coupled to the outer surface and includes an inner surface that
defines an annular plenum that is in fluid communication with the
slot and atmosphere outside the fan case.
[0007] In yet another embodiment, a method of recovering engine
performance in a turbofan gas turbine engine following foreign
object ingestion is provided. The turbofan gas turbine engine
includes an intake fan and a fan case. The intake fan is disposed
within and is surrounded by the fan case and includes a plurality
of fan blades. The method includes detecting when a foreign object
has been ingested by the turbofan gas turbine engine. Upon
detecting that a foreign object has been ingested, air is bled from
a region proximate the blades of the intake fan through a slot in
the fan case.
[0008] Furthermore, other desirable features and characteristics of
the turbofan engine system performance recovery system and method
will become apparent from the subsequent detailed description of
the invention and the appended claims, taken in conjunction with
the accompanying drawings and this background of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention will hereinafter be described in
conjunction with the following drawing figures, wherein like
numerals denote like elements, and wherein:
[0010] FIG. 1 depicts a functional block diagram of an embodiment
of a turbofan gas turbine engine; and
[0011] FIG. 2 is a close-up view of a portion of the turbofan gas
turbine engine of FIG. 1, depicting an embodiment of a portion of
the engine intake section in more detail.
DETAILED DESCRIPTION
[0012] The following detailed description is merely exemplary in
nature and is not intended to limit the invention or the
application and uses of the invention. Furthermore, there is no
intention to be bound by any theory presented in the preceding
background or the following detailed description.
[0013] Turning now to FIG. 1, a functional block diagram of an
exemplary turbofan gas turbine engine is depicted. The depicted
engine 100 is a multi-spool turbofan gas turbine propulsion engine,
and includes an intake section 102, a compressor section 104, a
combustion section 106, a turbine section 108, and an exhaust
section 112. The intake section 102 includes an intake fan 114,
which is mounted in a nacelle assembly 116. The intake fan 114
draws air into the intake section 102 and accelerates it. A
fraction of the accelerated air exhausted from the intake fan 114
is directed through a bypass flow passage 118 defined between the
nacelle assembly 116 and an engine cowl 122. This fraction of air
flow is referred to herein as bypass air flow. The remaining
fraction of air exhausted from the intake fan 114 is directed into
the compressor section 104.
[0014] The compressor section 104 may include one or more
compressors 124, which raise the pressure of the air directed into
it from the intake fan 114, and direct the compressed air into the
combustion section 106. In the depicted embodiment, only a single
compressor 124 is shown, though it will be appreciated that one or
more additional compressors could be used. In the combustion
section 106, which includes a combustor assembly 126, the
compressed air is mixed with fuel supplied from a non-illustrated
fuel source. The fuel and air mixture is combusted, and the high
energy combusted fuel/air mixture is then directed into the turbine
section 108.
[0015] The turbine section 108 includes one or more turbines. In
the depicted embodiment, the turbine section 108 includes two
turbines, a high pressure turbine 128, and a low pressure turbine
132. However, it will be appreciated that the engine 100 could be
configured with more or less than this number of turbines. No
matter the particular number, the combusted fuel/air mixture from
the combustion section 106 expands through each turbine 128, 132,
causing it to rotate. As the turbines 128 and 132 rotate, each
drives equipment in the engine 100 via concentrically disposed
shafts or spools. Specifically, the high pressure turbine 128
drives the compressor 124 via a high pressure spool 134, and the
low pressure turbine 132 drives the intake fan 114 via a low
pressure spool 136. The gas exhausted from the turbine section 108
is then directed into the exhaust section 112.
[0016] The exhaust section 112 includes a mixer 138 and an exhaust
nozzle 142. The mixer 138 includes a centerbody 144 and a mixer
nozzle 146, and is configured to mix the bypass air flow with the
exhaust gas from the turbine section 108. The bypass air/exhaust
gas mixture is then expanded through the propulsion nozzle 142,
providing forward thrust.
[0017] Though not visible in FIG. 1, the intake fan 114 is disposed
within and surrounded by a fan case that is coupled to nacelle
assembly 116. A close-up view of a portion of the intake section
102 in more detail is depicted in FIG. 2, and with reference
thereto will now be described.
[0018] In addition to the intake fan 114, the depicted intake
section 102 includes a fan case 202, a slot 204, and an annulus
206. The fan case 202, at least in the depicted embodiment, is
mounted in the nacelle assembly 116 (not illustrated in FIG. 2),
and includes an inner surface 208 and an outer surface 212. The
depicted embodiment additionally includes a containment casing 214
and abradable lining 216, both of which are coupled to the fan case
outer surface 212. It will be appreciated that the intake section
could be implemented without one or both of the containment casing
214 and abradable lining 216, and that the depicted configuration
of these elements, when included, is merely exemplary of one
particular embodiment.
[0019] The intake fan 114 is mounted within the fan case 202 and
includes a plurality of radially extending fan blades 218. It will
be appreciated, however, that for clarity only a single fan blade
218 is depicted in FIG. 2. As is generally known, each fan blade
218 has a leading edge 222 and a trailing edge 224. The fan blades
218 are contoured between the leading edges 222 and trailing edges
224 to facilitate the above-described functionality of the intake
fan 114; namely, to draw air into the intake section 102 and
accelerate the air for subsequent use downstream.
[0020] The slot 204 is formed in, and extends through, the fan case
202 between the inner and outer surfaces 208 and 212. The slot 204
preferably extends circumferentially around the fan case 202 and
thus circumferentially surrounds the fan blades 218. It will be
appreciated, however, that the slot 204 could extend only partially
around the fan case 202. Moreover, the slot 204 need not extend
continuously around the fan case 202, but may be interrupted by
various support structure, such as, for example, struts. The slot
204 is preferably disposed at least proximate the fan blades 218.
In a particular preferred embodiment, the slot 204 is disposed
between the leading edge 222 and trailing edge 224 of each fan
blade 218. The specific location between the leading edges 222 and
trailing edges 224 may vary depending, for example, on engine type.
For example, in some embodiments the slot 204 may be located midway
between the leading edges 222 and trailing edges 224, whereas in
other embodiments the slot 204 may be disposed closer to either the
leading edges 222 or trailing edges 224. It will be appreciated
that the slot 204 may also be disposed slight upstream of the
leading edges 224 or slight downstream of the trailing edges. The
width of the slot 204 may also vary to meet desired
performance.
[0021] No matter the specific location and width of the slot 204,
the annulus 206 is coupled to the outer surface 212 of the fan case
202 at the location of the slot 204. The annulus 206 may be
variously shaped and configured, but includes at least an inner
surface 226 that defines an annular plenum 228. The annulus 206 is
also configured such that the annular plenum 228 is in fluid
communication with the slot 204, and at least selectively in fluid
communication with the atmosphere 232 outside of the fan case 202.
It will be appreciated that the annular plenum 228 may be
selectively placed in fluid communication with the atmosphere 232
using any one of numerous techniques. In the depicted embodiment,
however, a conduit 234 and a valve 236 are used.
[0022] The conduit 234 includes an inlet port 238 and an outlet
port 242. The inlet port 238 is in fluid communication with the
annular plenum 228, and the outlet port 242 in fluid communication
with the atmosphere 232. The valve 236 is mounted on the conduit
234 between the inlet port 238 and the outlet port 242, and is
movable to a plurality of valve positions. The valve positions
include a closed position and a plurality of open positions. In the
closed position the valve 236 fluidly isolates the conduit inlet
port 238 and outlet port 242, and thereby prevents (or at least
substantially prevents) air from flowing through the slot 204, into
the annular plenum 228, and out the conduit 234 to the atmosphere
228. In any one of the open positions the conduit inlet port 238
and outlet port 242 are in fluid communication, which allows air to
flow through the slot 204, into the annular plenum 228, and out the
conduit 234 to the atmosphere 228.
[0023] The valve 236 is preferably moved to a valve position via a
valve actuator 244, which is coupled to the valve 236 and which may
be implemented using any one of numerous types of pneumatic,
hydraulic, or electric type of actuators. No matter how it is
specifically implemented, the valve actuator 244 is coupled to
receive valve actuator commands and is configured, upon receipt of
the valve actuator commands, to selectively move the valve 236 to
one of the plurality of valve positions. The valve actuator
commands that are supplied to the valve actuator 244 may originate
from a manually actuated switch or knob 246, such as the one
depicted in phantom in FIG. 2. Alternatively, in a preferred
embodiment, the valve actuator commands originate from an engine
control 248.
[0024] Before proceeding further, it is noted that a plurality of
conduits 234 could extend between the annular plenum 228 and
atmosphere 232, each having an associated valve 236. In FIG. 2, a
second conduit 234 and second valve 236 are depicted in phantom;
however, more than two conduits 234 and valves 236 could be
included, if needed or desired. As FIG. 2 also depicts in phantom,
one or more pumps 237 (only one depicted) could be included to help
discharge air from the annular plenum 228. It will be appreciated
that a pump 237 could be associated with each conduit 234, a pump
237 could be associated with a plurality of conduits 234, and that
some conduits 234 could have an associated pump 237 while others do
not.
[0025] The engine control 248, which may be implemented as a
full-authority digital engine control (FADEC), an electronic engine
control (EEC), or any one of numerous other engine control
configurations, receives data from various sensors 252. The sensors
252 sense various parameters such as, for example, engine throttle
position, fuel flow, and various parameters within with the
turbofan gas turbine engine 100. The engine control 248, based at
least in part on these parameters, controls the operation of the
turbofan gas turbine engine 100.
[0026] In addition to the above, the depicted engine control 248 is
configured to detect a foreign object ingestion event, such as a
bird ingestion event. The engine control 248 is further configured,
upon detecting a foreign object ingestion event, to supply valve
actuator commands to the valve actuator 244 that will cause the
valve 236 to move from the closed position to an open position. The
manner in which the engine control 248 detects a foreign object
ingestion event may vary. For example, in some embodiments the
engine control 248, based on data from at least selected ones of
the sensors 252, detects a performance degradation of the turbofan
gas turbine engine 100. In other embodiments the engine control
248, based on data from at least selected ones of the sensors 252,
detects a change in the air pressure around the intake fan 114. No
matter the specific foreign object ingestion event detection scheme
that is used, when the valve 236 is subsequently moved to an open
position, air flows through the slot 204, into the annular plenum
228, and out the conduit 234 to the atmosphere 228.
[0027] It has been found that bleeding air through the slot 204,
into the annular plenum 228, and out the conduit 234 to the
atmosphere 228 following a foreign object ingestion event reduces
the size of flow separations that may be induced by the potential
damage the ingested object may have caused. As a result, engine
performance is improved relative to conventional turbofan gas
turbine engines, which do not include provisions for this flow
path. Indeed, models of pre-ingestion event and post-ingestion
event operations in a conventional turbofan gas turbine engine and
in a turbofan gas turbine engine that embodies the instant
invention show that post-ingestion event total pressure ratio and
total temperature ratio in an inventive turbofan gas turbine engine
are higher than those of conventional engine.
[0028] The system and method described herein mitigate the
potential deleterious effects of a foreign object ingestion event.
As a result, lighter intake fan components may be used to construct
aircraft propulsion engines and/or additional margin may be
provided for certain foreign object ingestion events, such as
multiple bird ingestion events.
[0029] While at least one exemplary embodiment has been presented
in the foregoing detailed description of the invention, it should
be appreciated that a vast number of variations exist. It should
also be appreciated that the exemplary embodiment or exemplary
embodiments are only examples, and are not intended to limit the
scope, applicability, or configuration of the invention in any way.
Rather, the foregoing detailed description will provide those
skilled in the art with a convenient road map for implementing an
exemplary embodiment of the invention. It being understood that
various changes may be made in the function and arrangement of
elements described in an exemplary embodiment without departing
from the scope of the invention as set forth in the appended
claims.
* * * * *