U.S. patent application number 13/514621 was filed with the patent office on 2012-09-27 for arrangement and method for closed flow cooling of a gas turbine engine component.
Invention is credited to Anders Hellgren, Hans Martensson.
Application Number | 20120243970 13/514621 |
Document ID | / |
Family ID | 44167536 |
Filed Date | 2012-09-27 |
United States Patent
Application |
20120243970 |
Kind Code |
A1 |
Hellgren; Anders ; et
al. |
September 27, 2012 |
ARRANGEMENT AND METHOD FOR CLOSED FLOW COOLING OF A GAS TURBINE
ENGINE COMPONENT
Abstract
An arrangement for cooling a gas turbine engine component
includes a gas turbine engine component provided with at least one
cooling channel through which a cooling medium is intended to flow
during operation of the arrangement, a feeding system configured to
supply cooling medium to the cooling channel, a cooling channel
inlet, and a cooling channel outlet. The feeding system is arranged
in flow communication with both the inlet and the outlet of the
cooling channel such as to form a closed flow system. A gas turbine
engine provided with such a component and a method for cooling such
a component are also provided.
Inventors: |
Hellgren; Anders;
(Trollhattan, SE) ; Martensson; Hans;
(Trollhattan, SE) |
Family ID: |
44167536 |
Appl. No.: |
13/514621 |
Filed: |
December 17, 2009 |
PCT Filed: |
December 17, 2009 |
PCT NO: |
PCT/SE09/00526 |
371 Date: |
June 8, 2012 |
Current U.S.
Class: |
415/1 ;
415/178 |
Current CPC
Class: |
F05D 2260/205 20130101;
Y02T 50/673 20130101; F01K 27/02 20130101; F01D 25/12 20130101;
F01D 9/041 20130101; F01K 7/16 20130101; Y02T 50/60 20130101; Y02T
50/676 20130101; F01D 25/162 20130101; F01D 5/187 20130101; F02C
7/16 20130101; F01D 9/06 20130101 |
Class at
Publication: |
415/1 ;
415/178 |
International
Class: |
F01D 25/12 20060101
F01D025/12 |
Claims
1. Arrangement for cooling a gas turbine engine component, the
arrangement comprising: a gas turbine engine component provided
with at least one cooling channel through which a cooling medium is
intended to flow during operation of the arrangement, a feeding
system configured to supply cooling medium to the cooling channel,
a cooling channel inlet, and a cooling channel outlet, wherein the
feeding system is arranged in flow communication with both the
inlet and the outlet of the cooling channel such as to form a
closed flow system.
2. Arrangement according to claim 1, the comprising a heat
extraction device configured to extract thermal energy from the
cooling medium.
3. Arrangement according to claim 2, wherein the heat extraction
device is a heat exchanger arranged to transfer heat from the
cooling medium to a second medium.
4. Arrangement according to claim 3, wherein the second medium is
arranged to form a second closed flow system, wherein the second
medium is allowed to evaporate in the heat exchanger when the heat
is transferred from the cooling medium, wherein the second closed
flow system comprises a steam engine arranged to be driven by the
evaporated second medium.
5. Arrangement according to claim 4, wherein the second closed flow
system comprises, in flow order from an inlet to an outlet of the
heat exchanger: a turbine in which second medium that has
evaporated during or after its transport through the heat exchanger
is allowed to expand and thereby drive the turbine, a condenser in
which the second medium is condensed to a liquid form, and a pump
for feeding second medium in liquid form to the heat exchanger
inlet, wherein the turbine is operatively connected to a generator
capable of generating electricity.
6. Arrangement according to claim 2, wherein the heat extraction
device is a steam engine configured to be driven by evaporated
cooling medium.
7. Arrangement according to claim 1, characterized in that the
feeding system comprises, in flow order from cooling channel outlet
to inlet: a cooling medium turbine in which cooling medium that has
evaporated during or after its transport through the cooling
channel is allowed to expand and thereby drive the cooling medium
turbine, a condenser in which the cooling medium is condensed to a
liquid form, and a pump for feeding cooling medium in liquid form
to the cooling channel inlet, wherein the cooling medium turbine is
operatively connected to a generator capable of generating
electricity.
8. Arrangement according to claim 1, wherein the gas turbine engine
component is provided with a plurality of cooling channels and that
the arrangement comprises an inlet manifold provided with the
cooling channel inlet wherein the inlet manifold is arranged to
provide a fluid communication between the cooling channel inlet and
the plurality of cooling channels.
9. Arrangement according to claim 1, wherein the gas turbine engine
component is provided with a plurality of cooling channels and that
the arrangement comprises an outlet manifold provided with the
cooling channel outlet, wherein the outlet manifold is arranged to
provide a fluid communication between the cooling channel outlet
and the plurality of cooling channels.
10. Arrangement according to claim 1, wherein the gas turbine
engine component comprises an inner ring element and an outer ring
element connected by a plurality of circumferentially spaced
elements extending in a radial direction of the ring elements.
11. Arrangement according to claim 10, wherein the at least one
cooling channel is arranged in at least one of the inner or outer
ring element and/or in at least one of the circumferentially spaced
elements.
12. Arrangement according to claim 10, wherein the outer ring
element comprises an outer annular part and an inner annular part
which outer and inner parts are connected by, in relation to the
gas turbine engine component, radially and axially extending
load-carrying wall elements, wherein axially extending cooling
channels are formed between the wall elements.
13. Arrangement according to claim 1, wherein the gas turbine
engine component is arranged to transmit load or thrust from a main
shaft to a casing of a gas turbine engine.
14. Arrangement according to claim 1, wherein the gas turbine
component defines a gas channel for a main gas flow through a gas
turbine engine.
15. Arrangement according to claim 1, wherein the gas turbine
component is arranged an a turbine region of a gas turbine
engine.
16. Arrangement according to claim 5, wherein the cooling
arrangement is arranged in association with a gas turbine engine
that, during operation of the engine, generates i) a first main gas
flow that passes at an inside of an annular inner casing through
e.g. a turbine of the engine and ii) a second main gas flow that
passes at an outside of the annular casing, such as a turbojet
engine, wherein the condenser is arranged in relation to the second
main gas flow in such a way that the second main gas flow is
allowed to cool and condense the second medium or the cooling
medium.
17. Gas turbine engine, comprising a cooling arrangement according
to claim 1.
18. Method for cooling a gas turbine engine component, comprising
the step of: supplying cooling medium to an inlet of a cooling
channel arranged in the gas turbine engine component, characterized
in that the method further comprises the steps of: re-circulating
the cooling medium from an outlet of the cooling channel to the
inlet such as to form a closed flow system, and cooling the cooling
medium by extracting thermal energy from the cooling medium.
19. Method according to claim 18, comprising: using the extracted
thermal energy for driving a steam machine.
20. Method according to claim 18, comprising: using the extracted
thermal energy for producing electricity.
21. Method according to claim 20, comprising: evaporating a medium
using heat absorbed by the cooling medium, expanding the evaporated
medium in a turbine, and generating electricity by a generator
operatively connected to the turbine.
22. Method according to claim 21, comprising: condensing evaporated
medium in a condenser, and feeding medium in liquid form from the
condenser.
23. Method according to claim 22, wherein the medium evaporated is
the cooling medium.
24. Method according to claim 22, comprising: evaporating a second
medium by transferring thermal energy from the cooling medium to
the second medium using a heat exchanger, wherein the second medium
is arranged to form a second closed flow system.
Description
BACKGROUND AND SUMMARY
[0001] This invention relates to an arrangement for cooling a gas
turbine engine component. In particular, the invention relates to a
load-carrying ring-structured component arranged to guide a main
engine gas flow in a hot turbine part of a gas turbine engine. The
invention also relates to a gas turbine engine provided with such a
component and a method for cooling such a component.
[0002] Turbine components of a gas turbine engine, such as turbine
casings, vanes and blades, are exposed to very high temperatures.
Cooling of turbine components are often required to avoid material
fatigue and failure.
[0003] Conventionally, turbine vanes comprises a load-carrying
strut or shaft and an airfoil where the strut connects an inner
structure of the gas turbine engine with an outer casing and where
the airfoil is arranged around the strut for guiding a general gas
flow through the engine. To cool such a vane, compressed air tapped
off from the compressor of the gas turbine engine is guided to the
vane and led in a radial direction through a space between the
strut and the airfoil. Thus, the airfoil and the cooling air
protect the load carrying strut from being overheated.
[0004] U.S. Pat. No. 6,261,054 refers to cooling requirements for
vanes/blades of a gas turbine engine and shows an airfoil/vane
provided with radially directed cooling channels through which a
cooling medium flows. The cooling medium is in the form of air from
an off-board source, steam or compressed air from earlier stage of
gas turbine engine. The airfoil/vane is arranged between flanges
that guide and distribute the cooling medium to and from the
airfoil/vane in such a way that the cooling medium flows through
the vane in one direction and then back through the vane in an
opposite direction before being discharged. The term
"closed-circuit" is used to describe that the flow is re-directed
and passes through the vane in both directions.
[0005] Although various turbine component cooling systems presented
in the past work reasonably well there is still a need for
improvements, in particular with regard to the efficiency of the
cooling system.
[0006] It is desirable to provide means for cooling a gas turbine
engine component in a more efficient way compared to conventional
technique.
[0007] The invention, according to an aspect thereof, concerns an
arrangement for cooling a gas turbine engine component, said
arrangement comprising: a gas turbine engine component provided
with at least one cooling channel through which a cooling medium is
intended to flow during operation of the arrangement, a feeding
system configured to supply cooling medium to the cooling channel,
a cooling channel inlet, and a cooling channel outlet.
[0008] The invention, according to an aspect thereof, is
characterized in that the feeding system is arranged in flow
communication with both the inlet and the outlet of the cooling
channel such as to form a closed flow system.
[0009] With such a design, no separate source for continuous
generation of cooling medium is needed, e.g. it makes it possible
to avoid tap-off from compressor which is advantageous in that such
tap-off results in a loss of power of the gas turbine engine
associated with the inventive arrangement. Further, the inventive
arrangement makes water and other liquid media suitable as cooling
medium. Water is a much more effective cooling medium than e.g. air
that commonly is used. The invention further provides possibilities
to extract useful energy from the arrangement, e.g. by producing
useful heat or electricity from the heat extracted when cooling the
heated cooling medium. Thus, the invention enables the use of a
more energy efficient cooling system. This is in turn useful for
increasing the overall energy efficiency, i.e. for reducing fuel
consumption and/or increasing power, of an associated gas turbine
engine compared to gas turbine engines with an open cooling system
where the cooling medium e.g. is generated by tapping off air from
a compressor and where the cooling medium simply is discharged
after use (i.e. after having taken up heat).
[0010] A more efficient cooling, e.g. achieved by using water as
cooling medium, is advantageous in that it reduces the need for
additional structures (additional heat shields etc.) and reduces
the temperature of the cooled part which in turn increases the
durability and reduces the need for using high-temperature
resistant materials.
[0011] In an embodiment of the invention the feeding system
comprises a heat extraction device configured to extract thermal
energy from the cooling medium. An example of a suitable device for
this purpose is a steam engine, such as a turbine driving a
generator that produces electricity. Another example is a heat
exchanger that transfers heat from the cooling medium to a second
medium for the purpose of e.g. pre-heating fuel or producing hot
water or steam, which in turn can be used for e.g. heating or for
generating electricity. Thus, this way the heat absorbed by the
cooling medium can be used to produce useful heat or
electricity.
[0012] Electricity produced in this way and in connection to a gas
turbine engine arranged for aircraft propulsion can be used to
eliminate the need for Auxiliary Power Units (APUs) in the aircraft
and/or to reduce the power taken-off from the power take-off
shaft.
[0013] In a further embodiment of the invention the heat extraction
device is a heat exchanger arranged to transfer heat from the
cooling medium to a second medium. In a variant of this embodiment
the second medium is arranged to form a second closed flow system,
wherein the second medium is allowed to evaporate in the heat
exchanger when the heat is transferred from the cooling medium,
wherein the second closed flow system comprises a steam engine
arranged to be driven by the evaporated second medium. With such a
design the cooling medium can remain in a liquid form which
increases the freedom in the selection of compound to use as
cooling medium. Moreover, since also the second medium is arranged
in a closed system there is no waste of second medium, which
typically is water.
[0014] In this variant the second closed flow system preferably
comprises, in flow order from an inlet to an outlet of the heat
exchanger: a turbine in which second medium that has evaporated
during or after its transport through the heat exchanger is allowed
to expand and thereby drive the turbine, a condenser in which the
second medium is condensed to a liquid form, and a pump for feeding
second medium in liquid form to the heat exchanger inlet, wherein
the turbine is operatively connected to a generator capable of
generating electricity.
[0015] In a further embodiment of the invention the heat extraction
device is a steam engine configured to be driven by evaporated
cooling medium. In a variant of this embodiment the feeding system
comprises, in flow order from cooling channel outlet to inlet: a
cooling medium turbine in which cooling medium that has evaporated
during or after its transport through the cooling channel is
allowed to expand and thereby drive the cooling medium turbine; a
condenser in which the cooling medium is condensed to a liquid
form, and a pump for feeding cooling medium in liquid form to the
cooling channel inlet, wherein the cooling medium turbine is
operatively connected to a generator capable of generating
electricity.
[0016] In a further embodiment of the invention the gas turbine
engine component comprises an inner ring element and an outer ring
element connected by a plurality of circumferentially spaced
elements extending in a radial direction of the ring elements,
wherein the component is arranged to transmit load or thrust from a
main shaft to a casing of a gas turbine engine. Further, the outer
ring element comprises an outer annular part and an inner annular
part which outer and inner parts are connected by, in relation to
the gas turbine engine component, radially and axially extending
load-carrying wall elements, wherein axially extending cooling
channels are formed between the wall elements. In this design the
structure of the outer ring element has a multifunction in that it
provides both a load carrying function and channels suitable for
being used as cooling channels.
[0017] In a further embodiment of the invention the cooling
arrangement is arranged in association with a gas turbine engine
that, during operation of the engine, generates i) a first main gas
flow that passes at an inside of an annular inner casing through
e.g. a turbine of the engine and ii) a second main gas flow that
passes at an outside of said annular casing, such as a turbojet
engine, wherein the condenser is arranged in relation to the second
main gas flow in such a way that the second main gas flow is
allowed to cool and condense the second medium or the cooling
medium.
[0018] Air with high velocity, as in the second main gas stream,
provides for efficient heat transfer which makes it possible to
make use of a small heat exchanger as condenser. Further, the heat
transferred from the heated medium to the second airflow increases
the thrust of a turbojet engine since increased temperature gives a
greater volume flow.
[0019] The invention also concerns a gas turbine engine provided
with a component of the above type as well as a method for cooling
such a component.
BRIEF DESCRIPTION OF DRAWINGS
[0020] In the description of the invention given below reference is
made to the following figure, in which:
[0021] FIG. 1 shows, in a schematic view, a turbo-jet engine
provided with a component according to the invention,
[0022] FIG. 2 shows, in a perspective and partly schematic view, an
embodiment of the inventive cooling arrangement,
[0023] FIG. 3 shows, in a partly sectional and partly schematic
view, another embodiment of the inventive cooling arrangement, and
FIGS. 4-9 show an alternative design of the cooling channels for
the inventive cooling arrangement.
DETAILED DESCRIPTION
[0024] FIG. 1 shows a turbojet engine. The turbojet engine
comprises a central body 1, an annular outer casing 2 (fan casing),
an annular inner casing 3 (engine casing), a fan or blower 4, a low
pressure compressor 5, a high pressure compressor 6, a combustion
chamber 7, a high pressure turbine 8 and a low pressure turbine 9.
It further comprises a set of arms 10 extending in a radial
direction from the inner casing 3 to an outer ring element 14
forming part of the outer casing 2. The arms 10 comprise
aerodynamic vanes 11 primarily provided to act as guide vanes for
air passing through the annular channel between the inner casing 3
and the outer casing 2 in an axial direction, i.e. a longitudinal
direction, of the engine. The arms 10 further comprise structural
arms or load carrying vanes 12 primarily provided to guarantee a
certain mechanical strength of the construction.
[0025] A gas turbine engine component 20 associated with a cooling
arrangement according to the invention is in this example
positioned between the high pressure turbine 8 and the low pressure
turbine 9. As shown in FIG. 2, said component 20 comprises an inner
ring element 22 and an outer ring element 24 connected by a
plurality of circumferentially spaced elements 26 (vanes) extending
in a radial direction of the ring elements 22, 24. In this example
the inner ring element 22 forms part of the central body 1 whereas
the outer ring element 24 forms part of the annular inner casing 3.
The component 20 is a load carrying structure that transmits load
from an engine shaft/bearing housing via the inner ring element 22
and the vanes 26 to the outer ring element 24.
[0026] The flow of gas through the turbojet engine is divided into
two major streams, a first one of which passes through an annular
channel between the central body 1 and the inner casing 3, and
passes the compressors 5, 6, the combustion chamber 7 and the
turbines 8, 9. Thus, the first stream passes through the component
20 in an axial direction thereof; through the spaces between the
inner and outer ring elements 22, 24 and between the vanes 26. The
component 20 thus defines a gas channel for a main gas flow through
a gas turbine engine.
[0027] A second stream passes through the annular channel between
the inner casing 3 and the outer casing 2. A temperature of the
second stream is in operation lower than a temperature of the first
stream, but the second stream substantially increases the thrust of
the turbojet engine. An engine mount (not shown in FIG. 1) is
arranged onto the outer ring element 14 by means of which the
turbojet engine is attached to and held in position in relation to
an aircraft.
[0028] FIG. 2 shows in a perspective and partly schematic view, an
embodiment of the inventive cooling arrangement. The cooling
arrangement comprises the above mentioned gas turbine component 20
that in turn comprises the inner and outer ring elements 22, 24
connected by the circumferentially spaced elements 26 (vanes)
extending in the radial direction of the ring elements 22, 24. The
component 20 is further provided with a system of cooling channels
that can be arranged in different ways inside the component 20 (see
FIGS. 3-10). A cooling medium in the form of water flows through
the cooling channels during operation of the arrangement.
[0029] The arrangement further comprises a main cooling channel
inlet 27 configured to provide an inlet for the cooling medium to
the cooling channels arranged in the component 20, and a main
cooling channel outlet 28 configured to provide an outlet for the
(heated) cooling medium from the cooling channels arranged in the
component 20. In this example the main inlet 27 is arranged at an
annular inlet manifold 30 that extends in a circumferential
direction around the component 20 along the outer ring element 24
and that distributes cooling medium from the main inlet 27 to a
plurality of cooling channels arranged inside the component 20 (see
FIG. 3). Similarly, the main outlet 28 is arranged at an annular
outlet manifold 31 that extends in a circumferential direction
around the component 20 along the outer ring element 24 and that
guides cooling medium from the plurality of cooling channels
arranged inside the component 20 to the main outlet 28 (see FIG.
3).
[0030] The annular inlet and outlet manifolds 30, 31 are arranged
at a distance from each other as seen in an axial direction of the
component 20. As shown in FIG. 3, this allows cooling channels to
be arranged in an axial direction in fluid communication with both
manifolds 30, 31. Also the manifolds 30, 31 may be regarded as
cooling channels.
[0031] An internal wall section 25 forms a closing end section in
each of the manifolds and prevents the cooling medium from taking a
short-cut from the inlet 27 to the outlet 28. The wall section 25
forces the cooling medium to pass almost 360.degree. around the
component 20.
[0032] The arrangement further comprises a feeding system 40
configured to supply cooling medium to the system of cooling
channels. In particular, the feeding system 40 is arranged in flow
communication with both the main inlet 27 and the main outlet 28 of
the cooling channel system such as to form a closed flow system.
This means that the cooling medium, in this case the water, that
flows out through the main outlet 28 is re-circulated such as to
also flow in through the main inlet 27.
[0033] The arrangement is designed in such a way that the cooling
water evaporates while flowing through the cooling channels. Thus,
the water is generally in liquid form when passing the main inlet
27 and generally in gas form when passing the main outlet 28.
Various designs may be suitable depending on e.g. the type of
component, where the component is positioned in the gas turbine
engine and type of engine. For a given component in a given engine,
the degree of evaporation can be adjusted by adjusting the mass
flow rate of the cooling medium.
[0034] As shown in FIG. 2, the feeding system 40 further comprises,
in flow order from cooling channel outlet to inlet 28, 27,: a
cooling medium turbine 41 in which cooling medium that has
evaporated during its transport through the cooling channel and
manifolds 30, 31 is allowed to expand and thereby drive the cooling
medium turbine 41; a condenser 42 in which the cooling medium is
condensed to a liquid form, and a pump 43 for feeding cooling
medium in liquid form to the cooling channel inlet 27. The cooling
medium turbine 41 is operatively connected to a generator 44 for
generating electricity.
[0035] Accordingly, the feeding system 40 comprises a heat
extraction device in the form of a turbine 41 configured to extract
thermal energy from the cooling medium. The turbine 41 converts
this thermal energy to kinetic (rotational) energy which in turn is
converted to electricity by the generator 44. This electricity can,
for instance, be used in electric systems of an aircraft provided
with the inventive arrangement and the associated gas turbine
engine as to replace electricity generated by an on-board APU or by
the gas turbine engine (via the power take-off shaft). The turbine
41 and the generator 44 together forms an energy conversion device
configured to convert cooling medium thermal energy to another
(useful) form of energy, in this case electricity.
[0036] Cooling water can be kept in liquid form during its
transport through the cooling channels by keeping the pressure
sufficiently high. Evaporation can in such a case be brought about
by decreasing the pressure before the water reaches the turbine 41,
e.g. by letting the cooling water pass a release valve arranged
between the outlet 28 and the turbine 41.
[0037] The condenser 42 is a heat exchanger, and thus also a form
of heat extraction device, where a secondary cooling medium is used
to cool and condense the primary cooling medium used to cool the
component 20. In the embodiment shown here the condenser 42 is
arranged in the annular channel between the inner casing 3 and the
outer casing 2 such that the second (colder) gas stream works as
the secondary cooling medium. Air with high velocity, as in the
second gas stream, provides for efficient heat transfer which makes
it possible to make use of a small heat exchanger as condenser.
Further, the heat transferred from the (primary) cooling medium to
the second airflow increases the thrust of the turbojet engine
since increased temperature gives a greater volume flow. The
condenser/heat exchanger 42 can form part of or be integrated in
the fan outlet guide vanes or other already existing static fan
structure.
[0038] Alternatively, outdoor air can be used as secondary cooling
medium for cooling/condensing the primary cooling medium in the
condenser 42.
[0039] FIG. 3 shows, in a partly sectional and partly schematic
view, another embodiment of the inventive cooling arrangement. This
embodiment is in principle similar to the embodiment shown in FIG.
2 and therefore the same reference numbers has been used for the
majority of parts involved. The gas turbine component has been
given reference number 200 as compared to 20 in FIG. 2 as to
indicate that the cooling arrangement exemplified in FIG. 3
concerns only a circumferential section of the outer ring element
24, i.e. the section delimited by wall sections 25a and 25b. This
section can, in principal, have any length in the circumferential
direction of the outer ring element 24, which means that the
section e.g. can extend 360.degree. around the outer ring element
24 such that the wall sections 25a and 25b coincide and such that
the embodiment in FIG. 3 becomes similar to the embodiment shown in
FIG. 2.
[0040] As shown in FIG. 3 the outer ring element 24 of the gas
turbine component 200 is provided with a plurality of parallel and,
in relation to the component 200, axially extending cooling
channels 50 separated by wall elements 55. The outer ring element
24 is a load carrying structure comprising an outer annular part
and an inner annular part which outer and inner parts are connected
by the radially (and axially) extending wall elements 55. The
cooling channels 50 are thus formed between the load carrying wall
elements 55. The structure of the outer ring element 24 thus
provides both a load carrying function and channels suitable for
being used as cooling channels.
[0041] In similarity to what is described in relation to FIG. 2, an
inlet manifold 30 provided with a main inlet 27 is arranged at an
inlet side of the cooling channels 50 and an outlet manifold 31
provided with a main outlet 28 is arranged at an outlet side of the
cooling channels 50. Each cooling channel 50 is arranged in fluid
communication with the inlet and outlet manifolds 30, 31 by means
of inlet openings 51 and outlet opening 52, respectively.
[0042] The closed flow system for the cooling medium is indicated
with an arrowed line and can be described in the following way: The
cooling medium, in this case water, flows through the main inlet 27
and enters the inlet manifold 30. While flowing inside the inlet
manifold 30 along its direction of extension (circumferentially
along the outer ring element 24) a fraction of the flow is
distributed to each of the cooling channels 50 via inlet opening
51. During operation of the gas turbine engine associated with the
cooling arrangement the gas turbine component 200 becomes heated by
the hot gases flowing through the component 200. Heat absorbed by
(the section of) the outer ring element 24 is transferred to the
cooling water flowing through the cooling channels 50 which in this
case results in that the water evaporates. The cooling medium, now
in the form of steam, enters the outlet manifold 31 via outlet
opening 52. The steam flows inside the inlet manifold 30 along its
direction of extension (circumferentially along the outer ring
element 24) until it reaches the main outlet 28 at the end of the
outlet manifold 31.
[0043] From the main outlet 31 the steam flows to and drives the
turbine 41 that in turn drives the generator 44 that generates
electricity. In the condenser 42 the steam is condensed to water
which is forced to the main inlet 27 by means of the pump 43.
[0044] FIGS. 4-9 show, for a component similar to what is described
above, an alternative design of the cooling channels for the
inventive cooling arrangement where cooling channels are provided
not only in the outer ring element 24 but also in the vanes 26 and
in the inner ring element 22.
[0045] FIG. 4 shows a load-carrying vane 260, the shape of which is
only schematic, provided with first and second inlet cooling
channels 261, 262 arranged at a leading edge and a trailing edge,
respectively, thereof. First and second outlet cooling channels
263, 264 are arranged along both sides (i.e. pressure and suction
sides) of the vane 260. All of these cooling channels extend
through the vane 260 from one end to the other in a radial
direction with reference to the annular component in which the vane
260 is intended to be arranged. The vane 260 is further provided
with centrally located channels 265, in this case three in number,
for leading e.g. oil to a bearing of the gas turbine engine.
[0046] FIG. 5 shows the vane 260 arranged and extending radially
between an inner ring element 220 and an outer ring element 240.
The vane 260 and the parts of the inner and outer ring elements
220, 240 shown in FIG. 5 form a part of a gas turbine engine
component similar to the component shown in FIGS. 1-3. The outer
ring element 240 has a flange 241 for attachment to adjacent
components in the gas turbine engine and an engine mount 242 for
mounting of the engine to e.g. an aircraft.
[0047] FIG. 5 further shows two main inlets 270 each of which forms
a passage for a cooling medium to an inlet manifold 300. The
component also comprises two main outlets 280 in fluid
communication with outlet manifolds 310. As will be described
below, there are in this example two partly separated cooling
channel systems arranged inside the component, and therefore there
are two main inlets 270 and two main outlets 280. The partly
separated systems may be combined in different ways if only one
inlet and one outlet is desired.
[0048] A feeding system (not shown), similar to the feeding system
40 described above, is arranged in flow communication with the main
inlets 270 and the main outlets 280 of the cooling channel system
such as to form a closed flow system. The flows of cooling medium
through the two separate cooling channel systems are combined
outside of the component so that one combined flow of cooling
medium is supplied to and from the feeding system. Alternatively it
is possible to combine the two flows inside the component or to
make use of two feeding systems, one for each inlet-outlet
pair.
[0049] As indicated with the arrowed line in FIG. 5 the cooling
medium enters the inlet manifold 300 via the main inlet 270 and
flows further through the trailing (or leading) edge of the vane
towards the inner ring element 220.
[0050] FIG. 6 shows, with arrows, how the cooling medium flows via
the inlet manifolds 300 to the first or second inlet cooling
channels 261, 262 arranged at the leading and trailing edge,
respectively, of the vane 260. Thus, relatively cool cooling medium
is guided to the leading edge of the vane 260 which is an advantage
since the leading edge is likely to be the part of the vane 260
that requires the most efficient cooling during operation of the
gas turbine engine. FIG. 6 also shows how the cooling medium leaves
the first and second outlet cooling channels 263, 264 of the vane
260 and enters the outlet manifolds 310.
[0051] FIG. 7 shows that a first cavity 222 is arranged in the
inner ring element 220 below the vane 260 at a position where the
second inlet cooling channel 262 ends such that cooling medium
flowing through the second inlet channel 262 can enter the first
cavity 222. An opening 224 provides a further fluid communication
to inner ring cooling channels 225 arranged in the inner ring
element 220. A further opening 228 provides for fluid communication
between the inner ring cooling channels 225 and a second cavity 226
arranged below and in fluid communication with the first outlet
cooling channel 263 of the vane 260.
[0052] A still further opening 223 can be arranged between the
first and second cavities 222, 226 as to (partly) bypass the inner
ring cooling channels 225.
[0053] According to FIG. 7 one of the two partly separated flows of
cooling medium through the annular component can be described like
this: The cooling medium enters the inlet manifold 300 via the
inlet 270 and flows in a radial direction through the second inlet
cooling channel 262 of the vane 260 and further via the first
cavity 222 and opening 224 into the inner ring cooling channels
225. Via the further opening 228 the cooling medium enters the
second cavity 226 and flows further in a radial direction through
the second outlet cooling channel 263 of the vane 260. This channel
263 ends at the outlet manifold 310 which guides the cooling medium
to the outlet 280. At this stage the cooling medium is, in this
example, in evaporated form. The medium then enters the feeding
system where its heat is utilized, in this case for generating
electricity as described above. Finally, the cooling medium, in
liquid form, is fed back to the inlet 270.
[0054] The other partly separated flow of cooling medium through
the component is in this example in principal similar to the flow
described above but makes instead use of e.g. the first inlet
cooling channel 261, a third cavity 222' corresponding to the first
cavity 222, second inner ring cooling channels 225' and the second
outlet cooling channel 264 of the vane 260. This other partly
separated flow also flows through a further cavity corresponding to
the second cavity 226. The two flows are mixed in the two second
cavities 226.
[0055] FIG. 8 shows part of what is described above and also that
the flow that leaves the third cavity 222' is split so that half
the flow goes through the second inner ring cooling channels
225'and the other half through similar channels arranged on the
other (left and nearer) side of the position of the vane 260.
[0056] The outlet manifold 310 may be arranged as to combine the
flows exiting the first and second outlet cooling channels 263, 264
of the vane 260 and may be provided with only one outlet 280.
Further, the outlet manifold 310 may extend circumferentially along
the outer ring 240 such as to receive flows from several vanes 260.
Also the inlet manifolds 300 may extend along the outer ring 240
and be arranged such as to feed several vanes 26 with a flow of
cooling medium.
[0057] FIG. 9 shows some of the parts described above but in
another view. FIG. 9 also shows a load-carrying structure 316 that
connects a bearing house 317 to the inner ring element 220. The
bearing house 317 is arranged in association with a main shaft of
the gas turbine engine. Thus, FIG. 9 visualizes that the gas
turbine engine component is arranged to transmit load or thrust
from the engine shaft to e.g. an aircraft via the bearing house
317, the load-carrying structure 316, the inner ring element 220,
the vane 260 (not shown in FIG. 9), the outer ring element 240 and
the engine mount 242.
[0058] An advantage of the inventive cooling arrangement according
to FIGS. 4-9 compared to the traditional solution with a two-part
turbine vane structure that includes a first load-carrying part and
a second heat-protecting/air-guiding part, is that only one part
(with at least one cooling channel) is needed which provides for a
more cost-efficient production.
[0059] Typically, the gas turbine component of the present
invention is a gas turbine engine housing component located in the
turbine region of the engine. Such a component must be configured
to withstand a high thermal load from a passing gas flow during
operation of the gas turbine engine. The typical component can also
be described as a gas turbine component that defines a gas channel
for a main gas flow through a gas turbine engine or as a gas
turbine component that is configured so that an external surface of
the gas turbine component is in direct contact with a passing main
gas flow through a gas turbine engine. Since such a main gas flow
has its highest temperature in the region of the turbine
(downstream of the combustion chamber) said component is typically
arranged in the turbine region of a gas turbine engine.
[0060] By controlling the temperature of the cooling medium in the
cooling channels arranged in the outer ring element 24, 240, it is
possible to control the diameter of the outer ring element 24,
240.
[0061] The invention is not limited by the embodiments described
above but can be modified in various ways within the scope of the
claims. For instance, in an alternative arrangement the cooling
medium can be pressurized so that no evaporation of cooling medium
occurs. Heat can in such a case be extracted from the cooling
medium by using a heat exchanger that is arranged to transfer heat
from the cooling medium to a second medium. Preferably, such a heat
exchanger is arranged in association with a flow connection between
the between the inlet 27, 270 and outlet 28, 280.
[0062] This second medium can be air (e.g. by using the second gas
stream as the second medium as described above for the condenser 42
or by using another flow of air for the purpose of heating the
cabin space) or fuel (for preheating purposes) or another
medium.
[0063] In a variant of this alternative arrangement the second
medium is arranged to form a second closed flow system wherein the
second medium is evaporated in the heat exchanger when the heat is
transferred from the cooling medium. Further, in this variant the
second closed flow system comprises, in flow order from heat
exchanger outlet to inlet, the turbine 41 (and the generator 44),
the condenser 42 and the pump 43, which work in the same way as
described above but where the second medium, instead of the cooling
medium, drives the turbine etc. The closed cooling flow system
preferably comprises a cooling medium pump for circulating the
cooling medium.
[0064] In said variant the second medium is suitably water. The
cooling medium that is to flow through the cooling channels of the
component, which cooling medium in this variant is not intended to
evaporate, can be water but other substances may now be used, such
as oil.
[0065] In the embodiments and variants described above the turbine
41 and generator 44 can be replaced by another form of steam
engine.
* * * * *