Note: Descriptions are shown in the official language in which they were submitted.
GAS TURBINE ENGINE TIP CLEARANCE CONTROL
TECHNICAL FIELD
The present invention generally relates to gas turbine engine thermal
devices, and more particularly, but not exclusively, to tip clearance control
of the
gas turbine engine.
BACKGROUND
Providing tip clearance in gas turbine engines remains an area of interest.
Some existing systems have various shortcomings relative to certain
applications. Accordingly, there remains a need for further contributions in
this
area of technology.
CA 2862644 2018-11-14
SUMMARY
One embodiment of the present invention is a unique tip clearance control
system. Other embodiments include apparatuses, systems, devices, hardware,
methods, and combinations for controlling tip clearance. Further embodiments,
forms, features, aspects, benefits, and advantages of the present application
shall
become apparent from the description and figures provided herewith.
In accordance with an aspect of the present invention there is provided an
apparatus comprising: a gas turbine engine comprising a gas turbine engine
flow
path wall forming a boundary for the flow of a working fluid through a
turbomachinery
component having an airfoil shaped component during operation of said gas
turbine
engine; a first thermoelectric device in thermal communication with the gas
turbine
engine; a second thermoelectric device in thermal communication with the gas
turbine engine flow path wall; and a control module structured to regulate the
second
thermoelectric device, on basis of a sensed clearance derived from a proximity
sensor operating according to one of capacitive principles or optical
principles, to
influence a thermally induced gap between the gas turbine engine flow path
wall and
the airfoil shaped component, wherein the second thermoelectric device is
powered
by the first thermoelectric device.
In accordance with another aspect of the present invention there is provided a
method comprising: operating a gas turbine engine to produce a flow stream
through a turbomachinery component of the gas turbine engine; moving a bladed
row of airflow members in the turbomachinery component, the flow stream
traversing
through the bladed row; determining a tip clearance to aid in the changing a
tip
clearance with a sensor that operates according to one of capacitive or
optical
principles; receiving an electrical current from a first thermoelectric device
in thermal
communication with the gas turbine engine; flowing the electrical current
across a
junction of two dissimilar materials of a second thermoelectric device in
thermal
communication with a gas turbine engine flow path wall to produce a heating
response; changing a clearance between said wall and the tips of the bladed
row in
proximity with the wall using said heating response.
2
CA 2862644 2018-11-14
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 depicts an embodiment of a gas turbine engine having a tip
clearance control system.
FIG. 2 depicts an embodiment of a tip clearance control system.
FIG. 3 depicts an embodiment of a tip clearance control system.
FIG. 4 depicts another embodiment of a tip clearance control system.
FIG. 5 depicts an embodiment of a tip clearance control system.
FIG. 6 depicts an arrangement of thermoelectric devices.
3
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
For the purposes of promoting an understanding of the principles of the
invention, reference will now be made to the embodiments illustrated in the
drawings and specific language will be used to describe the same. It will
nevertheless be understood that no limitation of the scope of the invention is
thereby intended. Any alterations and further modifications in the described
embodiments, and any further applications of the principles of the invention
as
described herein are contemplated as would normally occur to one skilled in
the
art to which the invention relates.
With reference to FIG. 1, a gas turbine engine 50 is shown having a
number of turbomachinery components useful in the generation of power, such
as but not limited to providing power for an aircraft 52. As used herein, the
term
"aircraft" includes, but is not limited to, helicopters, airplanes, unmanned
space
vehicles, fixed wing vehicles, variable wing vehicles, rotary wing vehicles,
unmanned combat aerial vehicles, tailless aircraft, hover crafts, and other
airborne and/or extraterrestrial (spacecraft) vehicles. Further, the present
inventions are contemplated for utilization in other applications that may not
be
coupled with an aircraft such as, for example, industrial applications, power
generation, pumping sets, naval propulsion, weapon systems, security systems,
perimeter defense/security systems, and the like known to one of ordinary
skill in
the art.
The gas turbine engine 50 includes a compressor 54, combustor 56, and
turbine 58 which together operate to produce the power. Air or other suitable
working fluid enters to the compressor 54 whereupon it is compressed and
routed to the combustor 56 to be mixed with a fuel. The combustor 56 is
capable
of combusting the mixture of fuel and working fluid. The turbine 58 extracts
work
from the products of combustion that result from the combustion of fuel and
working fluid. In some forms the flow stream exiting the turbine can be routed
to
a nozzle to produce thrust.
4
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
The gas turbine engine 50 can take a variety of forms other than that
depicted in the illustrated embodiment. For example, though the embodiment is
shown as a single spool engine, other embodiments can include greater numbers
of spools. The gas turbine engine 50, furthermore, can take the form of a
turbojet, turboprop, turboshaft, or turbofan engine and can be a variable
cycle
and/or adaptive cycle engine. The gas turbine engine 50 is also depicted in
the
illustrated embodiment as an axial flow engine, but in other embodiments it
can
be a radial flow engine and/or a mixed radial/axial flow engine. In short, any
variety of forms are contemplated for the gas turbine engine 50.
The gas turbine engine 50 can be coupled with a tip clearance control
system 60 which can be use to control a clearance between a tip of an airflow
member, such as a moving blade in a turbomachinery component like the
compressor 54, and a wall that forms a flow path through the turbomachinery
component that is in proximity to the tip of the airflow member. The
discussion
that follows will often refer to a blade of the turbomachinery component which
is
but one embodiment of the present application. Therefore, no limitation is
hereby
intended as to the type of air flow member that the tip clearance control
system
60 can be used with. For example, the tip clearance control system could also
be used with a vane of the gas turbine engine 50, such as but not limited to a
variable vane. Thus, unless stated to the contrary, the term blade and vane
can
be used interchangeably to identify an air flow member disposed within the
turbomachinery component. In one form the tip clearance control system 60 can
be used to regulate a temperature of the wall thus changing the thermal growth
of the wall to affect a clearance between the airflow member and the wall. The
tip clearance control system 60 can be active during all or portions of
operation of
the gas turbine engine and in one form is capable of anticipating transient
events
to avoid and/or mitigate a clearance or contact between the blade and the
wall.
The controller 60 can be comprised of digital circuitry, analog circuitry, or
a
hybrid combination of both of these types. Also, the controller 60 can be
programmable, an integrated state machine, or a hybrid combination thereof.
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
The controller 60 can include one or more Arithmetic Logic Units (ALUs),
Central
Processing Units (CPUs), memories, limiters, conditioners, filters, format
converters, or the like which are not shown to preserve clarity. In one form,
the
controller 60 is of a programmable variety that executes algorithms and
processes data in accordance with operating logic that is defined by
programming instructions (such as software or firmware). Alternatively or
additionally, operating logic for the controller 60 can be at least partially
defined
by hardwired logic or other hardware. In one particular form, the controller
60 is
configured to operate as a Full Authority Digital Engine Control (F/ADEC);
however, in other embodiments it may be organized/configured in a different
manner as would occur to those skilled in the art. It should be appreciated
that
controller 60 can be exclusively dedicated to tip clearance control, or may
further
be used in the regulation/control/activation of one or more other subsystems
or
aspects of aircraft 52.
The aircraft 52 and/or gas turbine engine 50 can be capable of operating
at a variety of conditions in which the tip clearance control system 60 may be
exercised. In the illustrated embodiment a sensor 62 is included that can be
used to measure/estimate/assess/etc a number of conditions/states/etc. In one
form the sensor 62 can be used to measure aircraft flight condition such as
speed and altitude, to set forth just two non-limiting examples. The sensor 62
can output any variety of data whether sensed or calculated. For example, the
sensor 62 can sense and output conditions such as static temperature, static
pressure, total temperature, and/or total pressure, among possible others. In
addition, the sensor 62 can output calculated values such as, but not limited
to,
equivalent airspeed, altitude, and Mach number. Any number of other sensed
conditions or calculated values can also be output.
The sensor 62 can also take the form of a proximity sensor useful in
providing information regarding a tip clearance between a blade of the
turbonnachinery component and an adjacent wall. Such information is used by
the controller 60 in the regulation of the tip clearance between a moving
blade
6
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
and a wall of the turbomachinery component. In one form the sensor 62 provides
real time signals of the distance such that a plurality of distance values as
a
function time are generated. The sensor 62 can either provide raw sensed
information, either analog or digital, or it can provide a computed value.
Furthermore, the sensor 62 can output information in a variety of formats and
can
further be conditioned using additional electronics and/or software. In some
forms the sensor 62 can provide multiple useful signals to the controller 60
such
as a minimum distance, maximum distance, time varying distance, historical
information, etc. Alternatively and/or additionally such information can be
computed in the controller 60 or other alternative and/or additional module.
No
matter the form, content, etc, the sensor 62 is capable of providing
sufficient
information that enables the controller 60 to regulate the temperature of the
wall
such that a clearance between the wall and the blade(s) is regulated.
The proximity sensor 62 can be a capacitive sensor or optical sensor,
among potential others useful for detecting a tip clearance. The sensor 62 can
be configured to withstand elevated temperatures of a gas turbine engine 50,
whether in rotating compressor equipment or turbine components, and can be
resistant chemical attack as well as resistant to deposition of solids onto
its
exposed surfaces. Further, the sensor 62 can also be resistant to
electromagnetic interference, vibration, noise, and shock, among any number of
other characteristics.
Turning now to FIGS. 2 and 3, one form of the tip clearance control
system 60 is depicted which is coupled to a thermoelectric device 64 for
changing a temperature of a portion 66 of a turbomachinery component. The
thermoelectric device 64 can be powered by the engine 50 or a vehicle power
system such as may be coupled with an airframe of an aircraft. The temperature
of the component can determine its relative size/orientation such that in one
form
at higher temperatures the component is relatively larger than at low
temperatures. The component can be heated by the thermoelectric device to
provide a larger size component and cooled to provide a relatively smaller
sized
7
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
component. In this way the thermoelectric device can be a fully reversible
system that can either heat or cool the component. Of course, in some
embodiments the thermoelectric system can include or be supplemented with
circuitry, software logic, electrical components, etc. that provide either a
heating
or a cooling, but not both. It will be understood that such a system will
still
include at its core a thermoelectric device that can be operated in both
directions
were it not for the additional or supplemental configuration. When coupled
with
changing size/orientation of the blade and/or rotor, the tip clearance control
system can selectively heat and cool the component to affect a tip clearance
between the component and the blade.
The particular type of thermoelectric device shown in FIGS. 2 and 3
includes a configuration of alternating semiconductor materials, and
specifically
alternating p-type and n-type semiconductors. The type of device depicted in
these figures can also be used in any of the embodiments herein. Any variety
of
material types can be used to form the thermoelectric device. The
thermoelectric devices described herein can take the form of a thermoelastic
film
which can have any variety of shapes and sizes. Any variety of thermoelectric
effects, and accompanying configurations, can be employed by the
thermoelectric device to alter a temperature of the turbomachinery component
to
change a tip clearance between the wall 66 and the blade 70. To set forth just
a
few examples, thermoelectric devices that rely the Seebeck effect, Peltier
effect,
and Thomson effect, are all contemplated within the scope of the application.
Thermoelectric heaters/coolers can be coupled with the controller 60 in a
way that an electric state of the thermoelectric device 64 can be regulated to
control a tip clearance. The thermoelectric device 64 of the illustrated
embodiments include a radially inner substrate 78 and a radially outer
substrate
80 to which the p-type semiconductor 74 and n-type 76 are coupled. The
radially
inner substrate 78 is coupled with electrical leads 82 and 84 between which
can
be a potential difference. The leads 82 and 84 are coupled to the substrate 78
in
a way that creates a pathway for current flow through the thermoelectric
device
8
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
64. In one form the potential difference between the leads 82 and 84 can be
the
result of a waste heat being captured by the thermoelectric device and in
others
a potential difference can be applied across the leads to encourage a heat
transfer in a certain direction, such as whether to cool or heat the wall 66,
to set
forth just two non-limiting examples. In still other examples the potential
difference applied across the leads can be the result of electric power
provided
by a thermoelectric device disposed elsewhere whether associated with the
vehicle and/or gas turbine engine. In some forms the electric power can
originate from a battery that is charged using a thermoelectric device
disposed
elsewhere. In one non-limiting example, a waste heat can be captured by one
thermoelectric device and the electric power stored using a storage device
such
as but not limited to a battery. Alternativey and/or additionally the waste
heat can
be used to directly regulate power across another thermoelectric device. In
still
other forms a waste heat can be stored for purposes other than strictly tip
clearance.
Though a number of p-type 74 and n-type 76 are depicted in the illustrated
embodiment, more or fewer can also be used. The semiconductors are
alternated along the flow stream direction in a pattern that alternates
between the
types of semiconductors, but any other pattern is also contemplated. In some
cases, individual pairings of p-type 74 and n-type 76 semiconductors can be
combined with other individual pairings in any number of combinations to be
used in the thermoelectric device 64.
The thermoelectric device 64 can extend over the entire periphery of the
engine case in some embodiments, while in other embodiments the device 64
may only extend over part of the engine case. In some forms a number of
thermoelectric devices 64 can be located about the engine case at the same or
different axial stations. In still other alternative and/or additional
embodiments,
the thermoelectric devices 64 can be configured such that portions of the
device
distributed around the engine case can be selectively operated. For example, a
portion in one circumferential region can be activated to provide one level of
heat
9
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
transfer, while a portion in another circumferential region can be activated
to
provide another level of heat transfer, whether the heat transfer is a heating
or a
cooling. Various modules can also be used, which in whole or in part can be
operated similarly to provide localized heat transfer to the engine case,
again
whether that heat transfer is a heating or cooling.
Thermal transfer member 86, which in the illustrate embodiment is in the
form of fins but other embodiments need not include fins, can be used to
assist in
transferring heat between a medium 88 and the wall 66. For example, the
medium can be a flowing working fluid, such as a cooling air, to aid in heat
transfer when the thermoelectric device 64 is in operation. The thermal
transfer
fins 86 of the illustrated embodiment can take a variety of shapes and sizes
whether generally referred to as a "fin" or other device useful in
transferring heat
with the medium 88. The thermal transfer fins 86 can cover the entirety of the
thermoelectric device 64 or only a portion thereof.
Turning now to FIG. 4, another embodiment of the tip clearance control
system 60 is shown. The thermoelectric device 64 is shown located above a
compressor blade 70 just upstream of a diffuser 90. The thermoelectric device
64 can include a thermal mass 92 that assists in the transfer of heat between
the
thermoelectric device 64 and a medium in contact with the thermal mass 92. The
thermal mass can take a variety of forms such as a cold plate and/or fins. In
any
of the embodiments herein, any of the fins, cold plates,
FIG. 5 shows a view of an embodiment of the tip clearance control system
60 in which a number of thermoelectric devices in the form of modules 94 are
spaced about the circumference of a gas turbine engine case 96. The modules
94 are evenly distributed in a single row round the circumference of the case
96,
but other arrangements are also contemplated. For example, a higher
concentration of modules 94 can be located at certain circumference locations
than other. Some modules 94 can be axially offset from others, while in other
embodiments additional rows can also be added. The modules 94 can be
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
controlled individually, in clusters, or as a whole. Furthermore, the modules
94
can have different sizes, configurations, capabilities, etc even though the
illustrated embodiment depicts similar modules. In sum, any variety of
physical
and control arrangements as well as size and capabilities are contemplated.
The thermoelectric devices described herein can be affixed to a casing or
other suitable gas turbine engine structure through a variety of techniques.
In
one non-limiting form the thermoelectric devices can be affixed via a
thermally
conductive bond. The thermoelectric devices can be affixed to the bond at
discrete locations around the casing or other suitable structure, or for a
full
circumferential length around the casing, etc.
The thermoelectric devices described herein can be powered using a
variety of power sources. In one non-limiting embodiment the electrical power
originates from a generator driven by the gas turbine engine 50. In other
additional and/or alternative embodiments the thermoelectric device can be
powered by an energy storage device, such as a battery. In still further
additional
and/or alternative forms the thermoelectric devices can be powered by other
thermoelectric devices, some of which can be in thermal communication with the
gas turbine engine.
FIG. 6 depicts an arrangement of thermoelectric devices used in the gas
turbine engine 50 in which one device 98, or a set of devices is used to
provide
power to another device 100, or set of devices. In the illustrated embodiment
two
separate rows of thermoelectric devices are shown in each of the compressor 54
and the turbine 58. The devices 98 shown as thermally coupled with the turbine
58 in the illustrated embodiment can be used to generate power to drive the
devices 100 shown as thermally coupled with the compressor 54. Though the
illustrated embodiment depicts flowing power from devices in a turbine area to
devices in a compressor area, other locations and directions of power transfer
are contemplated. In this way power generated using a thermoelectric devices
in
one location of the gas turbine engine can be used to power thermoelectric
11
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
devices in another location. To set forth another non-limiting example, one
embodiment would be to coupe the tip clearance control system with a set of
thermoelectric modules attached elsewhere to the engine or to hardware
mounted on the engine such as a bleed air duct.
In any of the embodiments described in the application, the tip clearance,
or gap, can be set during manufacture of the turbomachinery component and/or
gas turbine engine to favor a certain flight condition, engine operating
environment, operational demands, etc. For example, the tip clearance can be
set to accommodate a snap deceleration in which a tip clearance is typically
the
tightest owing to a faster cooling of the casing than the rotating disc and
blades.
In this case the gap can be manipulated during cruise by supplying power to
the
thermoelectric devices.
Though various of the illustrated embodiments discussed above depicts
controlling a tip clearance e of a compressor section of the gas turbine
engine,
the tip clearance control system 60 could also be used in the turbine section
as
well. The thermoelectric device is shown as being coupled at a radially outer
portion of the flow path 68 but other locations are also contemplated to
affect a
change in a tip clearance between a blade 70 and wall 66.
One aspect of the present application includes an apparatus comprising a
gas turbine engine flow path wall forming a boundary for the flow of a working
fluid through a turbomachinery component having an airfoil shaped component
during operation of a gas turbine engine, a thermoelectric device in thermal
communication with the gas turbine engine flow path wall, and a control module
structured to regulate the thermoelectric device to influence a thermally
induced
gap between the gas turbine engine flow path wall and the airfoil shaped
component.
One feature of the present application provides wherein the control
module can regulate the thermoelectric device to selectively heat the gas
turbine
12
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
engine flow path wall in a first mode of operation and selectively cool the
gas
turbine engine flow path wall in a second mode of operation.
Another feature of the present application provides wherein the
thermoelectric device is in thermal communication with protrusions that
project
into a cooling space.
Still another feature of the present application provides wherein the control
module regulates the thermoelectric device on basis of a sensed clearance
derived from a proximity sensor.
Yet still another feature of the present application provides wherein the
proximity sensor operates according to one of capacitive principles and
optical
principles.
Still yet another feature of the present application provides wherein in a
first mode of operation the thermoelectric device is used to generate a
potential
difference based upon a waste heat of the gas turbine engine.
A further feature of the present application provides wherein the
thermoelectric device includes a plurality of P-Type and N-Type
semiconductors.
A still further feature of the present application provides wherein a first P-
Type semiconductor and a first N-Type semiconductors are located at different
flow stream locations, wherein the plurality of semiconductors extend around
the
full circumference of the gas turbine engine flow path wall, and wherein a
thermally conductive bond is used to coupled the thermoelectric device with
the
turbomachinery component.
Another aspect of the present application provides anapparatus
comprising a gas turbine engine flow component having a flow path defined by a
wall and in which is disposed a blade used to alter a direction of a flow
through
the component, and a tip clearance control system configured to change a
distance between the wall and the blade, the clearance control system having
an
13
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
electrical device that includes a junction between dissimilar materials in
thermal
communication with the wall wherein a potential difference across the junction
is
related to a temperature difference across the junction.
Still another feature of the present application provides wherein the tip
clearance control system is structured to regulate a voltage across the
electrical
device to perform one of heating the gas turbine engine flow component and
cooling the gas turbine engine flow component.
Yet still another feature of the present application further includes a sensor
in feedback relation with the tip clearance control system, the sensor
operable to
provide a regulation variable such that the distance between the wall and the
rotatable blade is controlled.
Still yet another feature of the present application provides wherein the
sensor generates a signal representative of a distance between the wall and at
least one of the blades.
A further feature of the present application provides wherein the proximity
sensor includes one of a capacitor and an optical sensor.
A still further feature of the present application provides wherein during
operation of the tip clearance control system, waste heat from the gas turbine
engine is used to power the thermoelectric device.
A yet still further feature of the present application further includes an
energy storage device to harvest potential difference generated by the waste
heat.
Still another aspect of the present application provides an apparatus
comprising a gas turbine engine having rotatable blade and an end wall, and
means for thermoelectrically changing a distance between the blade and the end
wall.
14
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
Yet still another aspect of the present application provides a method
comprising operating a gas turbine engine to produce a flow stream through a
turbomachinery component of the gas turbine engine, moving a bladed row of
airflow members in the turbomachinery component, the flow stream traversing
through the bladed row;, flowing an electrical current across a junction of
two
dissimilar materials to produce a heating response, changing a clearance
between a wall and the tips of the bladed row in proximity with the wall.
A feature of the present application provides wherein the flowing occurs as
a result of a thermoelectric phenomena, and the flowing results in a cooling
of a
wall member of the turbomachinery component.
Another feature of the present application further includes changing a tip
clearance of the turbomachinery component.
Still another feature of the present application further includes determining
a tip clearance to aid in the changing a tip clearance.
Yet still another feature of the present application provides wherein the
determining includes sensing the tip clearance with a sensor that operates
according to one of capacitive or optical principles.
While the invention has been illustrated and described in detail in the
drawings and foregoing description, the same is to be considered as
illustrative
and not restrictive in character, it being understood that only the preferred
embodiments have been shown and described and that all changes and
modifications that come within the spirit of the inventions are desired to be
protected. It should be understood that while the use of words such as
preferable, preferably, preferred or more preferred utilized in the
description
above indicate that the feature so described may be more desirable, it
nonetheless may not be necessary and embodiments lacking the same may be
contemplated as within the scope of the invention, the scope being defined by
the claims that follow. In reading the claims, it is intended that when words
such
CA 02862644 2014-06-30
WO 2013/141937
PCT/US2012/072133
as "a," "an," "at least one," or "at least one portion" are used there is no
intention
to limit the claim to only one item unless specifically stated to the contrary
in the
claim. When the language "at least a portion" and/or "a portion" is used the
item
can include a portion and/or the entire item unless specifically stated to the
contrary.
16
