Note: Descriptions are shown in the official language in which they were submitted.
ACTIVELY COOLED COMPONENT
TECHNICAL FIELD
[0001/2] The present examples relate generally to heat exchanger designs, and
more
particularly, to heat exchanger designs that use film cooling and/or
convective cooling, for
example, an airfoil or other component of a gas turbine engine such as a
turbine blade or
nozzle guide vane.
BACKGROUND
[0003] Gas turbine engine airfoils, particularly those that require cooling,
remain an area of
interest. Some existing systems have various shortcomings, drawbacks, and
disadvantages
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relative to certain applications. Accordingly, there remains a need for
further contributions in
this area of technology.
SUMMARY
100041 The disclosed embodiments relate to an actively cooled component, for
example, an
airfoil in a gas turbine engine.
100051 In one example, the component may have a body comprising at least one
internal channel
adapted for a flow of a cooling media therein. The internal channel may have
two side walls
separating a cold inner surface and a hot inner surface. The cold inner
surface may have two
impingement holes in fluid communication with a cooling media source, allowing
for ingress of
the cooling media into the internal channel. The hot inner surface may have
one angled film hole
in fluid communication with a hot outer surface, allowing for egress of the
cooling media out of
the internal channel. The first and second side walls may enclose a length of
the internal channel
along which the angled film hole is located between the two impingement holes.
The angled
film hole may be considered a first angled film hole, and the hot inner
surface may further
comprise a second angled film hole also in fluid communication with the hot
outer surface.
Furthermore, the two side walls may enclose a length of the channel along
which the first
impingement hole is located between the first and second angled film holes.
[0006] In another example, the actively cooled component may further comprise
a plurality of
impingement holes and a plurality of angled film holes. The plurality of
impingement holes may
be aligned along a first axis and the plurality of angled film holes may be
aligned along a second
axis parallel to the first axis.
[0007] In another example, the impingement holes may direct the cooling media
at the hot inner
surface to create a turbulent flow, and the angled film hole may be angled to
direct the cooling
media along the hot outer surface to create a laminar film. The angled film
hole may be at an
acute angle less than or equal to 45 degrees relative to the hot outer
surface. In another
example, the plurality of film holes 260 may be clocked in any direction, for
example, the film
holes 260 may align with the gas path flow field. The film holes 260 may not
necessarily point
in the same direction and can be individually tailored.
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[0008] In another example, the actively cooled component may further comprise
a plurality of
pairs of impingement holes. Each pair of impingement holes may comprise an "L"
impingement
hole aligned along a first axis, and an "R" impingement hole aligned along a
second axis parallel
to the first axis. The actively cooled component may further comprise a
plurality of angled film
holes which may be aligned along a third axis parallel to the first and second
axes. The third axis
may be located between the first and second axes.
[0009] In a further example, the actively cooled component may further
comprise a plurality of
impingement holes and a plurality of angled film holes. There may be at least
twice as many
impingement holes as angled film holes. The component may further comprise a
plurality of
internal channels, each having only one angled film hole and at least two
impingement holes.
The actively cooled component may be located at a leading edge of an airfoil.
[0010] In another example, at least one side wall may have two concave
portions relative to the
internal channel that intersect with one another to form a convex intersection
point. Each
concave portion may have a unique radius of curvature different. A second side
wall may be
.. substantially symmetrical to the first side wall.
[0011] In another example, the actively cooled component may further comprise
a plurality of
impingement holes and a plurality of angled film holes. The internal channel
may have a first
portion with a ratio of impingement holes to angled film holes of at least two-
to-one, and may
have a second portion with a ratio of impingement holes to angled film homes
of one-to-one.
[0012] In another example, a first impingement hole may be located closer to a
first side wall
than a second side wall, while a second impingement hole may be located closer
to the second
side wall than the first side wall. Furthermore, the first impingement hole
may be located closer
to the first angled film hole than the second angled film hole, and the second
impingement hole
may be located closer to the second angled film hole than the first angled
film hole.
.. [0013] The methods and systems disclosed herein are nonlimiting and may be
applied to other
actively cooled components. Other systems, methods, features and advantages of
the invention
will be, or will become, apparent to one with skill in the art upon
examination of the following
figures and detailed description. It is intended that all such additional
systems, methods, features
3
and advantages be within the scope of the invention, and be encompassed by the
following
claims.
[0013a] In another example, an actively cooled component comprises: a body
comprising an
internal channel adapted for a flow of a cooling media therein, said internal
channel
comprising first and second side walls separating a cold inner surface and a
hot inner surface,
wherein the cold inner surface comprises a first impingement hole and a second
impingement
hole both in fluid communication with a cooling media source for ingress of
the cooling
media into the internal channel, wherein the hot inner surface comprises a
first angled film
hole and a second angled film hole each in fluid communication with a hot
outer surface for
egress of the cooling media out of the internal channel, wherein the first and
second side
walls enclose a length of the internal channel along which the first
impingement hole and the
second impingement hole are between the first and second angled film holes,
wherein the
first side wall comprises first and second concave portions relative to the
internal channel that
intersect with one another to form a convex intersection point, wherein the
first impingement
hole is located closer to the first side wall than the second side wall and
closer to the first
angled film hole than the second angled film hole, and wherein the second
impingement hole
is located closer to the second side wall than the first side wall and closer
to the second
angled film hole than the first angled film hole.
[0013b] In another example, an airfoil comprises: a first side wall and a
second side wall
forming a length of a convective cooling passage and separating a cold surface
and a hot
surface, wherein the cold surface comprises first and second impingement holes
for ingress of
a cooling media into the convective cooling passage, wherein the hot surface
comprises first
and second angled film holes for egress of the cooling media out of the
convective cooling
passage, wherein the first and second impingement holes and the first and
second angled film
holes are all located between the first and the second side walls of the
convective cooling
passage, wherein the convective cooling passage comprises a segment along a
length of the
convective cooling passage from the first impingement hole to the second
impingement hole,
wherein the first impingement hole and the second impingement hole are between
the first
and second angled film holes along the length, wherein the first side wall
comprises first and
second concave portions relative to the convective cooling passage that
intersect with one
another to form a convex intersection point, wherein the first impingement
hole is located
closer to the first side wall than the second side wall and closer to the
first angled film hole
than the second angled film hole, and wherein the second impingement hole is
located closer
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Date Recue/Date Received 2022-08-04
to the second side wall than the first side wall and closer to the second
angled film hole than
the first angled film hole.
[0013c] In another example, a method of actively cooling a component
comprises: providing
a pressure differential to drive a flow of a coolant media; driving the flow
of coolant media
through a plurality of apertures in a cold wall of the component, into a
channel comprising a
plurality of angled film holes and a plurality of impingement holes, wherein
the flow of
coolant media impinges on an inner surface of a hot wall of the component, and
wherein a
first side wall and a second side wall form a segment of the channel and
separate the cold
wall and the hot wall; driving the flow of coolant media through the channel;
transferring
heat energy from the hot wall to the coolant media; driving the flow of
coolant media along
the segment of the channel from a first aperture of the plurality of apertures
to a second
aperture of the plurality of apertures, wherein a first impingement hole and a
second
impingement hole of the plurality of impingement holes are between a first
angled film hole
and a second angled film hole of the plurality of angled film holes along the
segment of the
channel, wherein the first impingement hole is located closer to the first
side wall than the
second side wall and closer to the first angled film hole than the second
angled film hole,
wherein the second impingement hole is located closer to the second side wall
than the first
side wall and closer to the second angled film hole than the first angled film
hole, and
wherein the first side wall comprises first and second concave portions
relative to the channel
that intersect with one another to form a convex intersection point; and
driving the flow of
coolant media through the plurality of angled film holes, such that at least a
portion of the
coolant media forms a laminar film on an outer surface of the hot wall of the
component.
[0013d] In another example, an actively cooled component of a gas turbine
engine comprises:
a body comprising at least one internal channel adapted for a flow of a
cooling media therein,
said internal channel comprising first and second side walls separating a cold
inner surface
and a hot inner surface, wherein the cold inner surface comprises a first
impingement hole
and a second impingement hole both in fluid communication with a cooling media
source for
ingress of the cooling media into the internal channel, wherein the hot inner
surface
comprises an angled film hole in fluid communication with a hot outer surface
for egress of
the cooling media out of the internal channel, wherein the first and second
side walls enclose
a length of the channel along which the angled film hole is located between
the first and
second impingement holes, and wherein the first side wall as first and second
concave
portions relative to the internal channel that intersect with one another to
form a convex
intersection point.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention can be better understood with reference to the following
drawings and
description. The components in the figures are not necessarily to scale,
emphasis instead being
placed upon illustrating the principles of the invention. Moreover, in the
figures, like referenced
numerals designate corresponding parts throughout the different views.
[0015] FIG. 1 is a side view of a gas turbine engine with internal components
shown.
[0016] FIG. 2 illustrates a perspective view of one example of an airfoil of a
gas turbine engine.
[0017] FIG. 3 illustrates a cutaway perspective view of an example airfoil.
[0018] FIG. 4 illustrates a cross-sectional view of one of the example
internal channels of an
to airfoil shown in FIG. 3.
[0019] FIG. 5 illustrates a cross-sectional view of one of the example
internal channels of an
airfoil shown in FIG. 3.
[0020] FIG. 6 illustrates a perspective view of an example of a plurality of
internal channels of
an airfoil.
[0021] FIG. 7 illustrates a cross-sectional view of an example of an internal
channel of an airfoil.
[0022] FIGS. 8-9 illustrate perspective views of the example of an internal
channel of an airfoil
shown in FIG. 7.
[0023] FIG. 10 illustrates a cross-sectional view of another example of
internal channels of an
airfoil.
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DETAILED DESCRIPTION
ACTIVE COOLING
[0025] Gas turbine engines of the axial flow type may include turbines that
are made up of
axially alternate annular arrays of radially extending stator airfoil vanes
and rotary airfoil blades.
The demands of modern gas turbine engines may require that the gases that flow
through, and
thereby drive, the turbine are at extremely high temperature. As the gases
flow through the
turbine, their temperature progressively falls as they drive the turbine.
However,
notwithstanding this, the gas temperatures in the higher pressure regions of
the turbine may be so
high that some form of airfoil cooling may be required.
[0026] Turbine airfoils, both blades and vanes, may be cooled internally with
a gas or a liquid,
such as air that has been tapped from the gas turbine engine's compressor.
Using engine
compressor air in this manner may, however, carry a penalty in terms of the
overall operating
efficiency of the engine. Thus, cooling of the components of the gas turbine
engine is preferably
accomplished with a minimum amount of cooling media, since the cooling media
may be a
working fluid, which has been extracted from the compressor, and its loss from
the gas flow may
rapidly reduce engine efficiency. Generally speaking, the larger the
percentage of air taken from
the compressor, the greater the adverse effect there is upon overall engine
operating efficiency.
Engines may be designed to simultaneously operate within a specified
temperature range, while
minimizing the amount of cooling media extracted from the compressor. If these
design
parameters are not satisfied, a corresponding structural degradation of the
engine components
may result, or the efficiency of the engine may be reduced because an
excessive quantity of
cooling media was extracted from the compressor.
[0027] It is therefore advantageous to make efficient use of compressor-
derived air in the
cooling of airfoils. Methods of cooling may include convection cooling and
film cooling.
[0028] Convection cooling generally refers to a technique of transferring heat
from a surface of
an object to the environment by the movement of matter, for example, cooling
internal surfaces
of the component (e.g., airfoil) by directing a steady flow of pressurized
cooling media through a
network of internal passageways of the component. The pressurized cooling
media may enter
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the passageways via cooler inlet holes and exiting through hotter exit holes.
This may provide
for convective heat transfer from the walls of the component to the cooling
media.
[0029] Accordingly, the design of airfoils may include internal channels for
the flow of cooling
air. Such channels may provide convection cooling such that air is drawn from
a hollow airfoil
interior (e.g., reservoir of cooled air) and through small inlet holes into
the channels (e.g.,
radially extending passages or impingement holes) where the air may absorb
heat from the
surfaces of the channels. Some of the air may be exhausted through small exit
holes that provide
fluid communication between the channels and the airfoil external surface. As
the air is
exhausted from the holes, it may form a film on the airfoil external surface
that provides
to additional airfoil cooling via film cooling.
[0030] Film cooling generally refers to a technique of cooling an external
surface of the
component (e.g., airfoil) that is being heated by the high temperature gas,
and may involve
directing a flow of relatively cool media, such as air, along the component's
external surface.
The cooling media may function as an insulating layer to reduce the unwanted
heating of the
external surface of the component by the flow of high temperature gas.
GAS TURBINE ENGINE
[0031] FIG. 1 illustrates a gas turbine engine 10 which may include a
compressor, a combustor,
and a power turbine. The three components may be integrated together to
produce a flight
propulsion engine, for example, for use in helicopters, airplanes, missiles,
and any other
substantially similar devices.
[0032] More specifically, the engine 10 may include, in the flow direction, an
air inlet 11, a
fan 12 rotating inside a casing, an intermediate-pressure compressor 13, a
high-pressure
compressor 14, a combustion chamber 15, a high-pressure turbine 16, an
intermediate-pressure
turbine 17 and a low-pressure turbine 18 as well as an exhaust nozzle 19, all
of which being
arranged about a center engine axis 1.
[0033] The intermediate-pressure compressor 13 and the high-pressure
compressor 14 may each
include several stages, of which each has an arrangement extending in the
circumferential
direction of fixed and stationary guide vanes 20, generally referred to as
stator vanes and
projecting radially inwards from the engine casing 21 in an annular flow duct
through the
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compressors 13 and 14. The compressors furthermore may have an arrangement of
compressor
rotor blades 22 which project radially outwards from a rotatable drum or disk
26 linked to
hubs 27 of the high-pressure turbine 16 or the intermediate-pressure turbine
17, respectively.
100341 The turbine sections 16, 17 and 18 may have similar stages, including
an arrangement of
fixed stator vanes 23 projecting radially inwards from the casing 21 into the
annular flow duct
through the turbines 16, 17, and 18, and a subsequent arrangement of turbine
blades 24
projecting outwards from a rotatable hub 27. The compressor drum or compressor
disk 26 and
the blades 22 arranged thereon, as well as the turbine rotor hub 27 and the
turbine rotor blades 24
arranged thereon, may rotate about the engine axis 1 during operation.
io 100351 The stationary guide vanes 20, compressor rotor blades 22, fixed
stator vanes 23, and
turbine blades 24 may collectively be referred to as airfoils 100 (see FIG.
2), and hereinafter this
application will refer to blades and/or vanes as airfoils 100, unless
specifically stated otherwise
in the text. As discussed later in this application, at least a portion of the
airfoils 100 may have a
dual-wall cooling configuration to improve the cooling.
100361 Other products utilizing the present concepts are contemplated herein
including but not
limited to combustor liners, exhaust nozzles, exhaust liners, airframe wing
leading edges, and/or
other actively cooled components. Depending on configuration, additional
compressors and
turbines may be added with intercoolers connecting between the compressors and
reheat
combustion chambers may be added between the turbines.
100371 In one example, the gas turbine engine airfoils 100 are formed of a
heat resistant
superalloy composition. There are various types of superalloy compositions,
such as but not
limited to nickel based or cobalt based compositions. Most superalloy
compositions of interest
are complicated mixtures of nickel, chromium, aluminum and other select
elements. The airfoils
may be of a unitary cast configuration, and/or an assembly of cast components,
and/or an
assembly of cast and wrought components. The airfoils may have an equiax,
directionally
solidified or a single crystal alloy structure. In an example, the gas turbine
engine airfoils 100
are of a cast single crystal single structure. In other examples, the products
are formed of a
metallic material, or an intermetallic material or a ceramic material.
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AIRFOIL
[0038] FIG. 2 illustrates a perspective view of one example of an airfoil 100
of a gas turbine
engine 10. The airfoil 100 may have as principal regions an airfoil portion
102, a root
portion 104, and a shank portion 106 extending between the airfoil portion 102
and the root
portion 104. The shank portion 106 may have a central conduit (not shown)
formed therein
which is in fluid communication with a hollow cavity/passageway 210 (see also
FIG. 3) within
the airfoil 100. The hollow cavity 210 may function as an internal passageway
for receiving
cooling media from the compressor and distributing it within the airfoil 100.
The cooling media
may be a compressible fluid such as air.
Jo [0039] The airfoil 100 may have a leading edge 120, a trailing edge 122,
and an outer
surface 124 extending therebetween. Hereinafter, the term spanwise will
indicate an orientation
between a tip 126 and a platform 128; and the term streamwise will indicate an
orientation
between the leading edge 120 and the trailing edge 122. The leading edge 120
may face in an
upstream direction with respect to the approaching fluid flow and the trailing
edge 122 may face
in a downstream direction. The airfoil 100 may include a concave pressure side
130 and an
opposite convex suction side 132. Arranged along the outer surface 124 of the
airfoil 100 may
be a plurality of cooling media exit holes 140 that may allow for the
discharge of cooling media
across the outer surface 124.
[0040] One example of the cooling scheme includes a plurality of cooling media
exit holes 140
(e.g., plurality of angled film holes 260) along the outer surface 124 of the
pressure side 130.
The suction side 132 may also have a plurality of exit holes (not shown). The
exit holes 140 may
be arranged in a closely-spaced array to help compensate for the heat load on
the airfoil 100
related to the high temperature working fluid flowing thereover. It is
understood that the
airfoil 100 illustrated in FIG. 2 is not intended to be limiting and other
airfoil and airfoil cooling
designs are contemplated herein. The location, size, and quantity of cooling
media exit openings
may be driven by the design parameters of a specific application.
AIRFOIL CROSS-SECTION: WALLS/HOLES
[0041] FIG. 3 illustrates a cutaway perspective view of an example airfoil
100. Airfoil 100 may
have a cover member 150, a spar member 160, and a hollow cavity/passageway 210
extending
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therethrough (see also FIG. 2). The hollow cavity 210 may be in fluid
communication with the
central conduit of the shank portion 106, which itself may be in fluid
communication with
cooling media from the compressor. These connected passageways may act as a
cooling media
reservoir.
[0042] Cooling media from the hollow cavity 210 may deliver cooling media to
one or more
internal channels 240 within the airfoil 100 via one or more apertures 220 in
the spar
member 160. The internal channel 240 may be positioned between the cover
member 150 and
spar member 160 such that the internal channel 240 is adjacent to the
perimeter of the airfoil 100.
The cover member 150 may be exposed to the high temperature working fluid
flowing, and thus
may have a hot outer surface 152 forming at least a portion of the outer
surface 124 of the airfoil,
and a hot inner surface forming at least a portion of a hot inner surface 154
of the internal
channel 240. The spar member 160 may be exposed to the cold hollow cavity 210,
and thus have
a cold outer surface 162 forming at least a portion of a surface of the hollow
cavity 210, and a
cold inner surface forming at least a portion of a cold inner surface 164 of
the internal
channel 240. The internal channel 240 may have a first side wall 250 and a
second side
wall 252, both separating the cold inner surface 164 and the hot inner surface
154 of the spar
member 160 and cover member 150, respectively. The spar member 160 may further
comprise a
plurality of impingement holes 230 in fluid communication with the internal
channel 240 and the
cold outer surface 162 of the spar member 150 (including hollow cavity 210 and
apertures 220).
The cover member 150 may further comprise a plurality of angled film holes 260
(e.g., exit
holes 140) in fluid communication with the internal channel 240 and the hot
outer surface 152 of
the cover member 150 (e.g., outer surface 124 of airfoil 100).
[0043] In an example, the cover member 150 may be a thin walled member, and
may have a wall
thickness in the range of about 0.35 millimeters to 0.65 millimeters. In
another example the
cover member 150 may have a wall thickness of about 0.51 millimeters. However,
other wall
thicknesses are contemplated herein.
[0044] The thickness of the cover member 150 may be related to the dimensions
of the plurality
of angled film holes 260 (e.g., exit holes 140). Each of the plurality of
angled film holes 260
may have a length "L" and a diameter "D", where the ratio of L/D is greater
than one. The L/D
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ratio greater than one may encourage film cooling by allowing the cooling
media to achieve a
less turbulent flow as it progresses through the plurality of angled film
holes 260 and is directed
onto the hot outer surface 152 of the cover member 150. While in the examples
illustrated herein
the internal channels 240 may be illustrated without cooling pedestals, other
examples are
considered herein where the internals channels 240 may have at least one
cooling pedestal.
[0045] As shown in FIG. 3, there may be a plurality of internal channels 240
positioned around
the perimeter of the airfoil 100. The internal channels 240 may be closely
arranged to help
compensate for the heat load on the airfoil 100. Each internal channel 240 may
comprise a
plurality of apertures 220, a plurality of impingement holes 230, and a
plurality of angled film
io holes 260 (e.g., a plurality of exit holes 140). The plurality of
apertures 220 and impingement
holes 230 may be formed through the spar member 160 to allow the flow of
pressurized cooling
media into the plurality of internal channels 240. The cooling media may flow
through the
internal channel 240 and absorb heat via convection from the hot inner surface
154 of the cover
member 150 and the side walls 250 and 252. In some examples, the cooling media
may also
absorb heat via convection cooling from the cold inner surface 164 of the
cover member 160.
The plurality of angled film holes 260 (e.g., exit holes 140) may be formed
through the cover
member 150 to allow the flow of the cooling media to exit the internal channel
240. The
plurality of angled film holes 260 may be angled such that the cooling media
is directed towards
the outer surface 124 of the airfoil 100, forming a laminar film thereon.
SINGLE COLD-FEED EXAMPLE
[0046] FIG. 4 illustrates a cross-sectional view of one of the example
internal channels 240 of an
airfoil 100 shown in FIG. 3. The first side wall 250 and second side wall 252
may both separate
the cold inner surface 164 and the hot inner surface 154 of the spar member
160 and cover
member 150, respectively (see FIG. 3). The apertures 220 in the cold inner
surface 164 may
comprise a first impingement hole 231 and a second impingement hole 232 both
in fluid
communication with the hollow cavity 210 (e.g., cooling media source) for
ingress of the cooling
media into the internal channel 240. The exit holes 140 in the hot inner
surface 154 may
comprise a first angled film hole 261 in fluid communication with the hot
outer surface 152 of
the cover member 150 for egress of the cooling media out of the internal
channel 240. The first
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and second side walls 250 and 252, respectively, may enclose a length of the
channel along
which the first angled film hole 261 is located between the first and second
impingement
holes 231 and 232, respectively. As shown, the impingement holes 230, 231, and
232 may
appear circular, whereas the angled film holes 260, 261, and 262 may appear
elliptical. This may
.. be a result of the cross-sectional view, wherein the angled film holes are
oriented at an acute
angle such that they appear elliptical while the impingement holes are
oriented at an orthogonal
angle such that they appear circular.
100471 The first side wall 250 and second side wall 252 may have a variety of
shapes and
contours. For example, the first side wall 250 may have a first concave
portion 254 relative to
the internal channel 240. The first side wall 250 may also have a second
concave portion 256
intersecting the first concave portion 254, forming a convex intersection
point 258 relative to the
internal channel 240. The first concave portion 254 may have a first radius of
curvature, and the
second concave portion 256 may have a second radius of curvature different
from the first radius
of curvature. The second side wall 252 may be substantially symmetrical to the
first side
wall 250, for example, having substantially symmetrical concave portions,
convex portions, and
respective radii of curvature.
100481 The cooling media may flow from the hollow cavity 210, through the
apertures 220,
through first and second impingement holes 231 and 232, respectively, such
that the cooling
media enters the internal channel 240 and impinges on the hot inner surface
154 (see FIG. 3).
Primarily driven by a pressure gradient, the cooling media may then flow
through the internal
channel 240 between the first and second side walls 250 and 252, respectively.
The shape of the
first and second side walls 250 and 252 may cause turbulence in the cooling
media flow, for
example, caused by the first concave portion 254 with the first radius of
curvature, the second
concave portion 256 having the second radius of curvature, the convex
intersection point 258,
and any shapes that may be present on the second side wall 252, for example,
the second side
wall 252 may be symmetrical to the first side wall 250. The cooling media may
exit the internal
channel 240 through the first angled film hole 261, which may direct the
cooling media onto the
hot outer surface 152 of the cover member 150 of the airfoil 100 (see FIG. 3).
As the cooling
media flows within the internal channel 240, it may absorb heat via convective
heat transfer from
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any surface having a higher temperature than the cooling media itself,
including the hot inner
surface 154, the first side wall 250, the second side wall 252, and the cold
inner surface 164.
[0049] Continuing with this example, the internal channel 240 may further
comprise a second
angled film hole 262 in fluid communication with the hot outer surface 152 of
cover
member 150. The first and second side walls 250 and 252, respectively, may
enclose a length of
the internal channel 240 along which the first impingement hole 231 is located
between the first
and second angled film holes 261 and 262, respectively. Thus, along this
length of the internal
channel 240 is an alternating pattern, wherein the first impingement hole 231
is spaced between
two angled film holes, and the first angled film hole is spaced between two
impingement holes.
to As a result, there is a one-to-one ratio of impingement holes to angled
film holes.
[0050] As shown in FIG. 4, internal channels 240 of the airfoil 100 may
further comprise a
plurality of impingement holes 230 and a plurality of angled film holes 260.
The of
impingement holes may be aligned along a first impingement hole axis 236, and
wherein the
plurality of angled film holes may be aligned along a first angled film hole
axis 266. The first
.. impingement hole axis 236 may be parallel to the first angled film hole
axis 266. In some
examples, as shown in FIG. 4, the first impingement hole axis 236 may be
identical to the first
angled film hole axis 266.
[0051] The plurality of impingement holes 230 and angled film holes 260 may
facilitate cooling.
As the cooling media impinges on the hot inner surface 154 and flows within
the internal
channel 240, the concave and convex shape of the side walls 250 and 252 may
create a turbulent
flow. This turbulent flow may encourage mixing of the cooling media and
increased heat
transfer. As a result, the cooling media may remain in the internal channel
240 for a longer
duration, increasing heat transfer from the surfaces of the internal channels
240. This may result
in increased engine efficiency by reducing the amount of cooling media
extracted from the
compressor to cool the airfoil 100. Additionally, the turbulent flow and
increased mixing of the
cooling media may decrease the fraction of cooling media that enters through a
given
impingement hole and exits through the next angled film hole, again increasing
heat transfer and
engine efficiency.
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[0052] Cooling media may flow through at least one of plurality of angled film
holes 260
(including the first and second angled film holes 261 and 262). The angled
film hole(s) may be
angled to direct the cooling media along the hot outer surface 152 to create a
laminar film for
film cooling. This laminar film of cooling media may function as an insulating
layer to reduce
the unwanted heating of the hot outer surface 152 of the cover member 150 (and
thus the outer
surface 124 of the airfoil 100) by the flow of high temperature gas. The angle
of the angled film
hole(s) may be an acute angle, for example, less than or equal to 45 degrees
relative to the hot
outer surface 152. In some examples, this angle may be between 25-35 degrees.
The optimal
angle may differ based on engine and airfoils designs, however, in general the
cooling media
forms a suitable boundary layer to insulate the hot outer surface 152. In
another example, the
plurality of film holes 260 may be clocked in any direction, for example, the
film holes 260 may
align with the gas path flow field. The film holes 260 may not necessarily
point in the same
direction and can be individually tailored.
DUAL COLD-FEED EXAMPLE (CONTINUOUS CHANNEL)
[0053] FIG. 5 illustrates a cross-sectional view of one of the example
internal channels 240 of an
airfoil 100 shown in FIG. 3. The internal channel 240 may further comprise a
plurality of pairs
of impingement holes 235, wherein each pair of impingement holes comprises an
impingement hole 238 and an "R" impingement hole 239. The plurality of "L"
impingement
holes 238 may be aligned along a first impingement hole axis 236. The
plurality of "R"
impingement holes 239 may be aligned along a second impingement hole axis 237.
The first and
second impingement hole axes 236 and 237, respectively, may be parallel to one
another. The
internal channel 240 may further comprise a plurality of angled film holes 260
aligned along a
first angled film hole axis 266. The first angled film hole axis 266 may be
parallel to the first
and second impingement hole axes 236 and 237, respectively. The first angled
film hole
axis 266 may be located between the first and second impingement hole axes 236
and 237,
respectively. As discussed above with respect to FIG. 4, the impingement holes
may appear
circular, whereas the angled film holes may appear elliptical due to their
acute angle.
[0054] As shown in FIG. 5, there may be at least twice as many impingement
holes as angled
film holes. In the illustrated example, this is because each of the plurality
of pairs of
14
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impingement holes 235 may have just one corresponding angled film hole in the
plurality of
angled film holes 260, resulting in a two-to-one ratio. The first and second
side walls 250
and 252 may enclose a length of the channel along which the first and second
impingement
holes 231 and 232 are located between the first and second angled film holes
261 and 262. The
first impingement hole 231 may be located closer to the first side wall 250
than the second side
wall 252, while the second impingement hole 232 may be located closer to the
second side
wall 252 than the first side wall 250. Furthermore, the first impingement hole
231 may be
located closer to the first angled film hole 261 than the second angled film
hole 262, while the
second impingement hole 232 may be located closer to the second angled film
hole 262 than the
first angled film hole 261. The result may be a tortuous "zig-zag" shape of
the internal
channel 240.
[0055] Other ratios are possible for other designs and configurations. For
example, there could
be a three-to-one ratio of impingement holes to angled film holes (not shown).
[0056] Similar to FIG. 4, the first and second side walls 250 and 252 may have
a variety of
is shapes and contours. For example, the first side wall 250 may have a
first concave portion 254
relative to the internal channel 240. The first side wall 250 may also have a
second concave
portion 256 intersecting the first concave portion 254, forming a convex
intersection point 258
relative to the internal channel 240. The first concave portion 254 may have a
first radius of
curvature, and the second concave portion 256 may have a second radius of
curvature different
from the first radius of curvature. The second side wall 252 may also have
concave portions,
convex portions, and respective radii of curvature.
[0057] The additional tortuosity ("zig-zag") of the internal channel 240 and
the increased
number of impingement holes may both facilitate additional cooling, while
retaining the cooling
properties of the plurality of impingement holes 230 and angled film holes
260. "Zig-zag" may
be defined as a path that changes direction at regular intervals, for example,
alternating ninety-
degree turns to the left and right at fixed intervals. Other angles may also
fall within this
definition, as well as varying intervals.
[0058] As the cooling media impinges on the hot inner surface 154 (see FIG. 3)
and flows within
the internal channel 240, the cooling media may flow from an "L" impingement
hole 238,
CA 2967099 2017-05-11
towards an "R" impingement hole 239, and towards the next "L" impingement hole
238, towards
the next "R" impingement hole 239, and so on. This "zig-zag" pattern of
tortuous flow may
further increase the turbulent flow of cooling media with the internal channel
240 in addition to
the turbulence caused by the concave and convex shape of the side walls 250
and 252. This
.. increased turbulent flow may further increase mixing of the cooling media
and increased heat
transfer. As a result, the cooling media may remain in the internal channel
240 for a longer
duration, increasing heat transfer as well as engine efficiency. Additionally,
the turbulent flow
and increased mixing of the cooling media may decrease the fraction of cooling
media that enters
through a given impingement hole and exits through the next angled film hole,
again increasing
heat transfer and engine efficiency. As described above, the plurality of
angled film holes 260
may be angled to direct the cooling media along the hot outer surface 152 to
create a laminar
film that may function as an insulating layer for film cooling. In another
example, the plurality
of film holes 260 may be clocked in any direction, for example, the film holes
260 may align
with the gas path flow field. The film holes 260 may not necessarily point in
the same direction
and can be individually tailored.
HYBRID EXAMPLE
[0059] FIG. 6 illustrates a perspective view of another example of a plurality
of internal
channels 240 of an airfoil 100. As shown, different examples of internal
channels 240 may be
adjacent to one another within a given airfoil 100. For example, the right-
most channel has a
ratio of impingement holes to angled film holes of one-to-one, whereas the
adjacent channel has
a higher ratio.
[0060] Furthermore, channel design may differ within a given internal channel
240, forming a
hybrid internal channel 242. For example, as shown in FIG. 6, the two left-
most channels are
hybrid channels 242, each having at least one portion where the ratio of
impingement holes to
.. angled film holes is two-to-one and at least one portion where the ratio is
one-to-one. For
viewing purposes, the angled film holes are not shown in FIG. 6, though they
are understood to
be present.
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DUAL COLD-FEED EXAMPLE (ISOLATED CHANNELS)
100611 FIGS. 7-9 illustrate a cross-sectional view and two perspective views,
respectively, of
another example of an internal channel 240 of an airfoil 100. In FIG. 8, the
cover member 150
obstructs the view of certain internal channels 240, while in FIG. 9 the cover
member 150 has
been hidden from view for illustration purposes. Additionally, in FIG. 9 all
but four of the
plurality of angled film holes 260 have also been hidden for illustration
purposes. The internal
channel 240 may further comprise a plurality of pairs of impingement holes 235
and a plurality
of angled film holes 260. There may be at least twice as many impingement
holes as angled film
holes. The airfoil 100 may further comprise a plurality of internal channels
240.
10062] Each pair of impingement holes 235 may comprise an "L" impingement hole
238 and an
"R" impingement hole 239. The plurality of "L" impingement holes 238 may be
aligned along a
first impingement hole axis 236. The plurality of "R" impingement holes 239
may be aligned
along a second impingement hole axis 237. The first and second impingement
hole axes 236
and 237, respectively, may be parallel to one another. The internal channel
240 may further
comprise a plurality of angled film holes 260 aligned along a first angled
film hole axis 266. The
first angled film hole axis 266 may be parallel to the first and second
impingement hole axes 236
and 237, respectively. The first angled film hole axis 266 may be located
between the first and
second impingement hole axes 236 and 237, respectively. As discussed above
with respect to
FIGS. 4-5, the impingement holes may appear circular, whereas the angled film
holes may
appear elliptical due to their acute angle.
100631 As shown in FIGS. 7-9, there may be at least twice as many impingement
holes as angled
film holes. In the illustrated example, this is because each of the plurality
of pairs of
impingement holes 235 may have just one corresponding angled film hole in the
plurality of
angled film holes 260, resulting in a two-to-one ratio. The first and second
side walls 250
and 252 may enclose a length of the channel along which the first angled film
hole 261 is located
between the first and second impingement holes 231 and 232.
10064] Similar to FIGS. 3-6, the first and second side walls 250 and 252 may
have a variety of
shapes and contours. For example, the first side wall 250 may have a first
concave portion 254
relative to the internal channel 240. The first side wall 250 may also have a
second concave
17
CA 2967099 2017-05-11
portion 256 intersecting the first concave portion 254, forming a convex
intersection point 258
relative to the internal channel 240. The first concave portion 254 may have a
first radius of
curvature, and the second concave portion 256 may have a second radius of
curvature different
from the first radius of curvature. The second side wall 252 may also have
concave portions,
convex portions, and respective radii of curvature.
[0065] Additionally, the angles of the plurality of angled film holes 260 may
not be identical for
each of the plurality of internal channels 240. For example, as shown in FIGS.
7-9, the angles of
the plurality of angled film holes 260 may alternate such that the angles of
the film holes of
adjacent channels may be perpendicular to one another. This may provide
targeted film cooling
on the outer surface 124 of the airfoil 100. In another example, the plurality
of film holes 260
may be clocked in any direction, for example, the film holes 260 may align
with the gas path
flow field. The film holes 260 may not necessarily point in the same direction
and can be
individually tailored.
[0066] As shown in FIGS. 7-9, each of the plurality of internal channels 240
may be limited to
only one angled film hole. As such, the cooling media within each of the
plurality of internal
channels 240 is "isolated" because it can only flow within the channel and out
of a single angled
film hole. While the flow within the plurality of internal channels 240 may be
turbulent, the lone
angled film hole and shorter length in a given internal channel means the
cooling media may
spend less time mixing. As a result, this channel design and configuration may
be ideal for a
hotter region of the airfoil 100, for example the leading edge 120, where the
higher temperature
means that the cooling media absorbs the requisite amount of heat in a shorter
time. This may
compensate for the reduced mixing time since the heat may be absorbed at a
faster rate. Other
examples (not shown) may include additional impingement holes.
DUAL COLD-FEED WITH PEDESTAL EXAMPLE
[0067] FIG. 10 illustrates a cross-sectional view of an example including dual
cold-feed internal
channels 240 of an airfoil 100 where the channels 240 have at least one
pedestal-like obstruction.
The first side wall 250 and second side wall 252 may both separate the cold
inner surface 164
(not shown) and the hot inner surface 154 (not shown) of the spar member 160
and cover
member 150, respectively (see e.g., FIG. 3). The apertures 220 in the cold
inner surface 164 may
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CA 2967099 2017-05-11
comprise a first impingement hole 231 and a second impingement hole 232 both
in fluid
communication with the hollow cavity 210 (e.g., cooling media source) for
ingress of the cooling
media into the internal channel 240. The exit holes 140 in the hot inner
surface 154 may
comprise a first angled film hole 261 in fluid communication with the hot
outer surface 152 of
the cover member 150 for egress of the cooling media out of the internal
channel 240. The first
and second side walls 250 and 252, respectively, may enclose a length of the
channel along
which the first angled film hole 261 is located between the first and second
impingement
holes 231 and 232, respectively. As shown, the impingement holes 230, 231, and
232 may
appear circular, whereas the angled film holes 260, 261, and 262 may appear
elliptical. This may
be a result of the cross-sectional view, wherein the angled film holes are
oriented at an acute
angle such that they appear elliptical while the impingement holes are
oriented at an orthogonal
angle such that they appear circular.
[0068] The first side wall 250 and second side wall 252 may have a series of
orthogonal or
ninety-degree (90') turns or intersections. For example, the first side wall
250 may have first and
second concave points 254 and 256 relative to the internal channel 240.
Between these two
points, the first side wall 250 may have a first convex point 258 relative to
the internal
channel 240. The second side wall 252 may be substantially symmetrical to the
first side
wall 250. The ninety-degree (90 ) turns or intersections may increase
turbulent flow of cooling
media through the channels 240.
.. 100691 The of impingement holes 230 may be aligned along a first
impingement hole axis 236,
and the angled film holes 260 may be aligned along a first angled film hole
axis 266. The first
impingement hole axis 236 may be parallel to the first angled film hole axis
266.
[00701 There may be twice as many impingement holes 230 as angled film holes
260 (dual cold-
feed). Each channel 240 may include one or more pedestal structures 300
spanning the height of
the channel. The arrows shown in the left-most channel 240 illustrate the flow
of a portion of the
cooling media from two impingement holes 230 and around one pedestal 300. The
pedestal 300
may act as an obstruction to the flow of cooling media and may create a
turbulent flow. This
turbulent flow may encourage mixing of the cooling media and increased heat
transfer. As a
result, the cooling media may remain in the internal channel 240 for a longer
duration, increasing
19
CA 2967099 2017-05-11
heat transfer from the surfaces of the internal channels 240. This may result
in increased engine
efficiency by reducing the amount of cooling media extracted from the
compressor to cool the
airfoil 100. Additionally, the turbulent flow and increased mixing of the
cooling media may
decrease the fraction of cooling media that enters through a given impingement
hole and exits
through the next angled film hole, again increasing heat transfer and engine
efficiency.
ADDITIONAL ADVANTAGES
[0071] The concepts described herein, including the designs and configurations
of internal
channels 240 of an airfoil 100, may be utilized advantageously, for example,
in large civil
engines having reduced combustor feed pressures, especially in low AP (change
in pressure)
JO locations of the airfoil 100. The advantages of these designs include,
but are not limited to,
increased thermal efficiency and increased hot-side pressure margins (change
in pressure
between hot outer surface 152 and hot inner surface 154, in particular, the
change in pressure
across one or more of the plurality of angled film holes 260). Advantages may
also include
maintaining certain design requirements, for example, maintaining minimum wall
thickness for
casting yields, maintaining minimum hole spacing to meet longevity
requirements, and
maintaining a minimum footprint to allow close hot side hole spacing for
enhanced film
effectiveness.
[0072] Another advantage is increased redundancy in the system by having
multiple
impingement holes and multiple angled film holes. If any hole becomes plugged
with debris or
otherwise becomes less effective, there are multiple other holes nearby for
cooling media to flow
through, reducing any negative effect. This may increase the lifespan of an
airfoil since regions
near any holes plugged with debris may remain within the expected range of
operational
temperatures. There may also be additional heat transfer due to unsteady
effects (e.g., flow may
be split unevenly between adjacent impingement holes wherein flow switches
rapidly during
operation, increasing heat transfer). As discussed throughout this
application, the flow of
cooling media through the internal channels 240 may also encourage the cooling
media to remain
within the channels 240 for longer (increased heat transfer), instead of
flowing out of the nearest
angled film hole.
CA 2967099 2017-05-11
100731 The examples disclosed herein and the related designs mitigate
ingestion of hot-side air
and provide increased heat transfer due to the design and configuration of the
concave
portions 254 and 256, and convex intersection point 258 (which collectively
may be referred to
as the side wall protrusions). The side wall protrusions may cause the cross-
sectional area of the
channel to advantageously vary along the length of the channel. As a result,
the cooling media
may flow faster through the narrower sections resulting in a lower pressure,
and may flow slower
through the wider sections resulting in a higher pressure. As illustrated in
FIGS. 3-9, the wider
sections (higher pressure) may be near the plurality of angled film holes 260,
resulting in a
higher pressure differential (e.g., hot side pressure margin) between the hot
outer surface 152 and
the hot inner surface 154, with the pressure higher in the internal channels
240. The higher
pressure drop across the angled film holes 260 may discourage the ingestion of
air into the
internal channels 240 from the angled film holes 260, improving engine
efficiency and cooling
efficiency due to optimized heat transfer. This may also make the airfoil 100
more robust
because the higher pressure may discourage the ingress of debris or other
outside matter into the
internal channels 240. The baseline pressurized cooling media may also
discourage such ingress
of debris and/or ingestion of hot-side air.
100741 While various embodiments of the invention have been described, the
invention is not to
be restricted except in light of the attached claims and their equivalents.
These concepts may be
applicable to other components within a jet engine, turbines, compressors, and
other actively
cooled components, not necessarily airfoils only. Moreover, the advantages
described herein are
not necessarily the only advantages of the invention and it is not necessarily
expected that every
embodiment of the invention will achieve all of the advantages described.
21
