U.S. patent application number 10/923120 was filed with the patent office on 2006-02-23 for film effectiveness enhancement using tangential effusion.
This patent application is currently assigned to Honeywell International Inc.. Invention is credited to Rodolphe Dudebout, Robert S. Reynolds.
Application Number | 20060037323 10/923120 |
Document ID | / |
Family ID | 35908366 |
Filed Date | 2006-02-23 |
United States Patent
Application |
20060037323 |
Kind Code |
A1 |
Reynolds; Robert S. ; et
al. |
February 23, 2006 |
Film effectiveness enhancement using tangential effusion
Abstract
Film effectiveness enhancement is provided by a plurality of
tangentially angled effusion holes in a combustor liner. The
effusion holes positioned in the initial flow region at the start
of the panel have a tangential angle between about 75.degree. and
about 90.degree. to the combustor axis. The tangential angle of the
effusion holes positioned downstream from the initial flow region
is gradually reduced to a value corresponding to the bulk swirl of
the combustor internal flow or to zero so that the effusion hole
orientation at the end of the panel corresponds to that of
convention effusion.
Inventors: |
Reynolds; Robert S.; (Tempe,
AZ) ; Dudebout; Rodolphe; (Phoenix, AZ) |
Correspondence
Address: |
Honeywell internaitonal, Inc.;Law Dept. AB2
P.O. Box 2245
Morristown
NJ
07962-9806
US
|
Assignee: |
Honeywell International
Inc.,
Morristown
NJ
|
Family ID: |
35908366 |
Appl. No.: |
10/923120 |
Filed: |
August 20, 2004 |
Current U.S.
Class: |
60/754 |
Current CPC
Class: |
Y02T 50/675 20130101;
Y02T 50/60 20130101; F23R 2900/03041 20130101; F23R 3/06
20130101 |
Class at
Publication: |
060/754 |
International
Class: |
F23R 3/06 20060101
F23R003/06 |
Claims
1. An apparatus for an effusion cooled component comprising: a
plurality of initial effusion hole openings positioned in an
initial flow region of said effusion cooled component, at least one
of said initial effusion hole openings positioned such that a
longitudinal line of said effusion cooled component and a
centerline of said at least one initial effusion hole opening forms
an initial hole tangential angle of between about 75' and about
90.degree.; and a plurality of transition openings positioned
downstream from said initial effusion hole openings, at least one
of said transition openings positioned such that a longitudinal
line of said effusion cooled component and a centerline of said at
least one transition opening forms a transition hole tangential
angle, said transition hole tangential angle having a value less
than a value of said initial hole tangential angle.
2. (canceled)
3. The apparatus of claim 1, wherein said transition hole
tangential angle is inversely proportional to a distance between
said transition opening and an upstream end of said effusion cooled
component.
4. The apparatus of claim 1, wherein said plurality of transition
openings comprises between about five and about ten circumferential
rows of transition openings.
5. The apparatus of claim 1, wherein said effusion cooled component
comprises a combustor.
6. The apparatus of claim 5, wherein said combustor comprises an
annular combustor liner.
7. The apparatus of claim 1, wherein said plurality of initial
effusion hole openings comprises between about five and about ten
circumferential rows of initial effusion hole openings.
8. The apparatus of claim 1, wherein each said initial effusion
hole opening has a diameter between about 0.015 and about 0.030
inches.
9. The apparatus of claim 1, wherein said initial hole tangential
angle is between about 75.degree. and about 85.degree..
10. The apparatus of claim 1, wherein said initial hole tangential
angle is between about 80.degree. and about 90.degree..
11. An effusion array for a component comprising: a plurality of
effusion hole openings through said component, said plurality of
effusion hole openings positioned such that (i) a plurality of
initial effusion hole openings are formed in an initial flow region
of said component and (ii) at least five circumferential rows of
transition openings are formed in a transition region of said
component, said plurality of initial effusion hole openings capable
of providing an effusion flow at a tangential angle of between
about 75.degree. and about 90.degree. to an axis of said component,
said at least five circumferential rows of transition openings
capable of providing an effusion flow at a tangential angle of less
than that of said plurality of initial effusion hole openings.
12. (canceled)
13. The effusion array of claim 13, wherein each said transition
opening has a diameter between about 0.01 and about 0.05
inches.
14. The effusion array of claim 13, wherein said at least five
circumferential rows of transition openings comprise between about
5 and about 10 circumferential rows of transition openings.
15. The effusion array of claim 11, wherein said plurality of
initial effusion hole openings comprises between about 5 and about
10 circumferential rows of initial effusion hole openings.
16. The effusion array of claim 11, wherein said plurality of
initial effusion hole openings are capable of providing an effusion
flow at a tangential angle of between about 75.degree. and about
85.degree. to an axis of said component.
17. The effusion array of claim 11, wherein said component
comprises a combustor.
18. The effusion array of claim 11, wherein said component
comprises an annular combustor liner.
19. The effusion array of clam 11, wherein a density of said
initial effusion hole openings is between about 10 and about 100
holes/in.sup.2.
20. A component requiring cooling comprising: at least two
circumferential rows of initial effusion hole openings through said
component, each said initial effusion hole opening positioned such
that a longitudinal line of said component and a centerline of said
initial effusion hole opening forms an initial hole tangential
angle of between about 80.degree. and about 90.degree.; and at
least five circumferential rows of transition openings positioned
downstream from said initial effusion hole openings, each said
transition opening positioned such that a longitudinal line of said
component and a centerline of said transition opening forms a
transition hole tangential angle, said transition hole tangential
angle having a value less than a value of said initial hole
tangential angle.
21. The apparatus of claim 20, wherein said at least two
circumferential rows of initial effusion hole openings comprise
between about 5 and about 10 circumferential rows of initial
effusion hole openings.
22. The apparatus of claim 20, wherein said at least five
circumferential rows of transition openings comprise between about
5 and about 10 circumferential rows of transition openings.
23. A combustor for a gas turbine engine comprising: an inner
liner; an outer liner positioned radially outward from said inner
liner, said outer liner having at least about two circumferential
rows of initial effusion hole openings there through and at least
about five circumferential rows of transition openings downstream
from said at least about two circumferential rows of initial
effusion hole openings, said initial effusion hole openings having
a tangential angle between about 75.degree. and about 90.degree. to
an axis of said gas turbine engine; and a dome positioned between
and connected to said inner liner and said outer liner.
24. The combustor of claim 23, wherein said inner liner comprises
an annular combustor liner.
25. (canceled)
26. The combustor of claim 23, wherein said outer liner has at
least about five circumferential rows of transition openings there
through, each transition opening having a tangential angle
inversely proportional to a distance between said transition
opening and an upstream end of said outer liner.
27. An effusion array for an annular combustor liner comprising: at
least three circumferential rows of initial effusion hole openings
positioned in an initial flow region of said annular combustor
liner, each initial effusion hole opening positioned such that a
longitudinal line of said annular combustor liner and a centerline
of said initial effusion hole opening forms an initial hole
tangential angle of between about 75.degree. and about 90.degree.,
each initial effusion hole opening having a diameter between about
0.015 and about 0.030 inches, each initial effusion hole opening
forming an axial angle of between about 15.degree. and about
30.degree. with a surface of said annular combustor liner; and at
least five circumferential rows of transition openings positioned
downstream from said initial effusion hole openings, each said
transition opening positioned such that longitudinal line of said
annular combustor liner and a centerline of said transition opening
forms a transition hole tangential angle, said transition hole
tangential angle having a value of less than a value of said
initial hole tangential angle.
28. A method of enhancing the film effectiveness for an effusion
cooled component comprising the step of: passing a first portion of
effusion flow through a plurality of initial effusion hole openings
in an initial flow region of said effusion cooled component, at
least one said initial effusion hole opening positioned such that a
longitudinal line of said effusion cooled component and a a
centerline of said at least one initial effusion hole opening forms
an initial hole tangential angle of between about 75.degree. and
about 90.degree.; and passing a second portion of effusion flow
through a plurality of transition openings in a transition region
of said effusion cooled component, at least one transition opening
positioned such that longitudinal line of said effusion cooled
component and a centerline of said at least one transition opening
forms a transition hole tangential angle, said transition hole
tangential angle less than said initial hole tangential angle.
29. (canceled)
30. The method of claim 28, wherein said step of passing a first
portion of effusion flow provides a cooling film capable of
protecting said initial flow region from a hot combustion flow
through said effusion cooled component.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention generally relates to gas turbine
engines and, more particularly, to effusion cooled components, such
as combustor liners.
[0002] An important component of any gas turbine engine is the
combustor. Because of the high temperatures (>3500.degree. F.)
generated inside the combustor and because metals used in combustor
construction are limited to 1700-1800.degree. F., cooling must be
provided for the combustor liner walls.
[0003] Effusion cooling is a widely used technique for protecting
gas turbine combustor liner walls from hot combustion gases. This
cooling technique involves covering the combustor wall with a
matrix of small holes. A supply of cooling air is passed through
the holes from the cooler surface of the combustor wall to the
surface exposed to higher temperatures. The cooling air actively
cools the liner by convection as it passes through the hole and
after the cooling air is discharged.
[0004] The holes are usually 0.015 to 0.030 inches in diameter and
angled so that the centerline of the hole forms a 15 to 30 degree
angle with respect to the liner surface. This small angle increases
the length of the hole through the liner wall thus increasing the
surface area from which the effusion flow can extract heat from the
liner material. The small angle also allows the effusion flow to
enter the combustor nearly parallel to the panel surface so that a
cooling film is generated on the inside of the combustor liner.
Conventional effusion holes are oriented in an axial plane such
that they discharge into the combustor in a purely axial direction,
however sometimes a tangential component is added to the holes
corresponding to the tangential component of the bulk flow inside
the combustor. Although conventional effusion cooling may be
sufficient for cooling some areas of the combustor liners, other
areas of the liner are not cooled sufficiently and require
additional cooling.
[0005] In U.S. Pat. No. 6,408,629, wall cooling in hot spot areas,
such as dilution hole wake regions, is increased by altering the
orientation of the effusion holes in the vicinity of those regions.
The effusion holes between adjacent dilution holes are angled in a
circumferential direction opposite to the circumferential direction
of the upstream effusion holes. Although these groups of oppositely
directed effusion holes may be useful in cooling hot spot areas
caused by cooling film disruption, they are not useful in cooling
all hot spot areas of the liner.
[0006] In U.S. Pat. No. 5,261,23 rectangular film starting holes
are positioned downstream of the dilution holes. The rectangular
film starting holes are slanted at an angle corresponding to the
swirl angle of the flow, usually between 30 and 65 degrees with
respect to the downstream direction of the flow. Although these
rectangular holes may increase cooling in the cooling film shadow
area caused by the dilution holes, they may not provide sufficient
cooling in the initial flow region at the forward end of the
liner.
[0007] One characteristic of effusion cooling is that the film
effectiveness is low at the start of a panel (initial flow region)
and increases as one travels along the panel. The initial low film
effectiveness is because conventional effusion requires 5-10 rows
of effusion holes for the cooling film to develop such that the
combustor wall is protected from the hot combustion gases. Each
individual effusion row by itself provides little protection, but
it is only when the effect of a number of rows are superimposed on
each other that sufficient thermal protection is provided.
[0008] Because of this characteristic, some form of cooling
augmentation is usually required in the initial flow region of an
effusion panel in order to protect the wall while the effusion film
is developing. This augmentation typically takes the form of a
starter film cooling skirt located at the beginning of the effusion
panel. The necessity of using starter skirts complicates the
construction of combustors and increases their cost. Also, in
situations where the geometry does not permit the use of a starter
skirt or where the effusion panel is very short, the usefulness of
effusion cooling is greatly reduced.
[0009] As can be seen, there is a need for increased cooling in the
initial region of an effusion panel. Further, cooling augmentation
is needed for applications where a starter film cooling skirt
cannot be used.
SUMMARY OF THE INVENTION
[0010] In one aspect of the present invention, an apparatus for an
effusion cooled component comprises a plurality of initial effusion
hole openings positioned in an initial flow region of the effusion
cooled component, at least one initial effusion hole opening
positioned such that a longitudinal line of the effusion cooled
component and a centerline of the initial effusion hole forms an
initial hole tangential angle of between about 75.degree. and about
90.degree..
[0011] In another aspect of the present invention, an effusion
array for a component comprises a plurality of effusion hole
openings through the component, the plurality of effusion hole
openings positioned such that a plurality of initial effusion hole
openings are formed in an initial flow region of the component, the
plurality of initial effusion hole openings capable of providing an
effusion flow at a tangential angle of between about 75.degree. and
about 90.degree. to an axis of the component.
[0012] In still another aspect of the present invention, a
component requiring cooling comprises at least two circumferential
rows of initial effusion hole openings through the component, each
initial effusion hole opening positioned such that a longitudinal
line of the component and a centerline of the initial effusion hole
opening forms an initial hole tangential angle of between about
80.degree. and about 90.degree.; and at least five circumferential
rows of transition openings positioned downstream from the initial
effusion hole openings, each transition opening positioned such
that a longitudinal line of the component and a centerline of the
transition opening forms a transition hole tangential angle, the
transition hole tangential angle having a value less than a value
of the initial hole tangential angle.
[0013] In yet another aspect of the present invention, a combustor
for a gas turbine engine comprises an inner liner; an outer liner
positioned radially outward from the inner liner, the outer liner
having at least about two circumferential rows of initial effusion
hole openings there through, the initial effusion hole openings
having a tangential angle between about 75.degree. and about
90.degree. to an axis of the gas turbine engine; and a dome
positioned between and connected to the inner liner and the outer
liner.
[0014] In another aspect of the present invention, an effusion
array for an annular combustor liner comprises at least three
circumferential rows of initial effusion hole openings positioned
in an initial flow region of the annular combustor liner, each
initial effusion hole opening positioned such that a longitudinal
line of the annular combustor liner and a centerline of the initial
effusion hole opening forms an initial hole tangential angle of
between about 75.degree. and about 90.degree., each initial
effusion hole opening having a diameter between about 0.015 and
about 0.030 inches, each initial effusion hole opening forming an
axial angle of between about 15.degree. and about 30.degree. with a
surface of said annular combustor liner; and at least five
circumferential rows of transition openings positioned downstream
from the initial effusion hole openings, each transition opening
positioned such that a longitudinal line of the annular combustor
liner and a centerline of the transition opening forms a transition
hole tangential angle, the transition hole tangential angle having
a value of less than the value of the initial hole tangential
angle.
[0015] In a further aspect of the present invention, a method of
enhancing the film effectiveness for an effusion cooled component
comprises the step of passing a first portion of effusion flow
through a plurality of initial effusion hole openings in an initial
flow region of said effusion cooled component, at least one initial
effusion hole opening positioned such that a longitudinal line of
the effusion cooled component and a centerline of the initial
effusion hole opening forms an initial hole tangential angle of
between about 75.degree. and about 90.degree..
[0016] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1a is a front side perspective view of a combustor
according to one embodiment of the present invention;
[0018] FIG. 1b is a back side perspective view of the combustor of
FIG. 1a;
[0019] FIG. 2 is a perspective view of a portion of a combustor
liner according to one embodiment of the present invention;
[0020] FIG. 3 is a perspective view of a portion of a combustor
liner according to another embodiment of the present invention;
[0021] FIG. 4 is a plot of film effectiveness as a function of
distance from start of effusion panel according to one embodiment
of the present invention;
[0022] FIG. 5 is a plot of maximum liner wall temperature as a
function of combustor discharge temperature according to one
embodiment of the present invention; and
[0023] FIG. 6 is a flow chart of a method of enhancing the film
effectiveness for an effusion cooled component according to an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The following detailed description is of the best currently
contemplated modes of carrying out the invention. The description
is not to be taken in a limiting sense, but is made merely for the
purpose of illustrating the general principles of the invention,
since the scope of the invention is best defined by the appended
claims.
[0025] The present invention generally provides film effectiveness
enhancement for effusion cooled components, such as combustor
liners, and methods for producing the same. The film effectiveness
enhancement according to the present invention may find beneficial
use in many industries including aerospace, automotive, and
electricity generation. The present invention may be beneficial in
applications including manufacturing and repair of aerospace
components. This invention may be useful in any effusion cooled
component application.
[0026] In one embodiment, the present invention provides film
effectiveness enhancement through a unique orientation of the
effusion hole openings for an annular combustor liner. The effusion
hole openings may comprise initial effusion hole openings
positioned in an initial flow region and transition openings
positioned in a transition region. Unlike the prior art, the
initial effusion hole openings may have a tangential angle between
about 75.degree. and about 90.degree.. The initial effusion hole
openings may direct a cooling flow tangentially such that there may
be no "beginning" to the effusion due to the cyclic nature of the
circumferential direction. This is unlike the prior art that
directs the cooling flow in an axial direction. With no beginning,
the initial region of low film effectiveness may be eliminated.
[0027] The transition openings may be positioned in a transition
region downstream from the initial effusion hole openings. The
transition openings may direct a cooling flow such that the angle
of the flow transitions from the tangential flow of the upstream
initial effusion hole openings to the axial flow of downstream
effusion holes. The tangential angle of the transition openings may
be gradually reduced to zero so that at the end of the panel the
effusion hole orientation corresponds to that of conventional
effusion. Alternatively, the tangential angle of the transition
openings may be gradually reduced to a value corresponding to the
bulk swirl of the combustor internal flow. Unlike the prior art,
the cooling protection provided by the present invention may be
essentially constant for the entire length of the effusion cooled
component.
[0028] An effusion cooled component, such as a combustor 20,
according to an embodiment of the present invention is shown in
FIGS. 1a and 1b. One of the more common combustor configuration
types, an annular combustor, is depicted. The combustor 20 may
comprise an inner liner 21 and an outer liner 22. The inner liner
21 and the outer liner 22 may be connected at an upstream end 24 by
a dome 23. A downstream end 25 may be open and may connect to a
turbine section of the engine (not shown). The upstream end 24 and
the downstream end 25 may be defined with respect to the direction
of a combustion gas flow (not shown) through the combustor 20.
[0029] A combustor liner, such as the outer liner 22, may comprise
an initial flow region 29. The initial flow region 29 may be the
area of a combustor liner that is toward the upstream end 24. The
combustor liner may comprise a transition region 35. The transition
region 35 may be the area of a combustor liner that is downstream
from and adjacent to the initial flow region 29. As depicted in
FIG. 2, the outer liner 22 may have a plurality of effusion hole
openings 26 there through. Effusion hole openings 26 is a generic
term for initial effusion hole openings 27 and transition openings
28. A plurality of initial effusion hole openings 27 may be
positioned in the initial flow region 29. A plurality of transition
openings 28 may be positioned in the transition region 35.
[0030] Each initial effusion hole opening 27 may be tangentially
angled and may be positioned in the initial flow region 29. A
longitudinal line 31 and a centerline of the initial effusion hole
opening 27 (initial hole centerline 34) may form an initial hole
tangential angle 32 of between about 75.degree. and about
90.degree.. In other words, the initial hole tangential angle 32
may be between about 75.degree. and about 90.degree. from axial. A
longitudinal line 31 may be a line from the upstream end 24 to the
downstream end 25 of the combustor liner. An initial hole
centerline 34 may be a line having the same orientation as the
initial effusion hole opening 27. For some applications, the
initial hole tangential angle 32 may be between about 75.degree.
and about 85.degree.. For some applications, the initial hole
tangential angle 32 may be between about 80.degree. and about
90.degree.. The tangential angle of the initial effusion hole
opening 27 (initial hole tangential angle 32) may allow an effusion
flow 33 (cooling flow) to capitalize on the cyclic nature of an
annular combustor panel and to more effectively cool the panel. The
initial effusion hole opening 27 may be angled with respect to the
liner surface in the same manner as known effusion holes. The
initial effusion hole opening 27 and the surface of the combustor
liner may form an angle (not shown) of between about 15.degree. and
about 30.degree..
[0031] The diameter of an initial effusion hole opening 27 may vary
with application. The initial effusion hole opening 27 may have a
diameter between about 0.01 and about 0.05 inches. For some
applications, the initial effusion hole opening 27 may have a
diameter between about 0.015 and about 0.030 inches. The initial
effusion hole openings may comprise any known effusion hole shape,
such as cylindrical and tapered.
[0032] The effusion hole openings 26 may comprise a plurality of
initial effusion hole openings 27. The effusion hole openings 26
may comprise at least about two circumferential rows of initial
effusion hole openings 27. A circumferential row may comprise a
plurality of about equally spaced openings along a circumference of
an effusion-cooled component. The effusion hole openings 26 may
comprise between about five and about ten circumferential rows of
initial effusion hole openings 27. The number of circumferential
rows of initial effusion hole openings 27 may depend on factors
including the dimensions and composition of the effusion-cooled
component, dimensions of the initial effusion hole openings 27, and
the temperature of the combustion gases.
[0033] A plurality of transition openings 28 may be positioned
downstream from the initial effusion hole openings 27. At least
one, and desirably each, transition opening 28 may be a
tangentially angled effusion hole and may be positioned in the
transition region 35. A longitudinal line 31 and a centerline of
the transition opening 28 (transition hole centerline 36) may form
a transition hole tangential angle 37, as depicted in FIG. 2. A
transition hole centerline 36 may be a line having the same
orientation as the transition opening 28. The transition hole
tangential angle 37 may be less than the initial hole tangential
angle 32. The tangential angle of the transition openings 28
(transition hole tangential angle 37) may be gradually reduced as
the distance from the initial flow region 29 is increased. For
example, the tangential angle of a transition opening 28 adjacent
to the initial flow region 29 may be about 70.degree. and the
tangential angle of a transition opening 28 further downstream may
be about 60.degree.. The transition hole tangential angle 37 may be
inversely proportional to a distance 30 between the transition
opening 28 and the upstream end 24. For some applications, the
tangential angle of the transition openings 28 may be gradually
reduced to zero so that the orientation of the transition openings
28 furthest downstream correspond to the orientation of axial
effusion. Alternatively, the tangential angle of the transition
openings 28 may be gradually reduced to a value corresponding to
the bulk swirl of the combustor internal flow. The bulk swirl of
the combustor internal flow may be the orientation of a flow of
combustion gases through the combustor 20 and may depend on the
configuration of the combustor 20. For example, for some annular
combustors, the bulk swirl of the combustor internal flow may be
about 30.degree. and the tangential angle of the transition
openings 28 may be gradually reduced to about 30.degree..
[0034] The transition opening 28 may be angled with respect to the
liner surface in the same manner as known effusion holes. The
transition opening 28 and the surface of the combustor liner may
form an axial angle (not shown) of between about 15.degree. and
about 30.degree.. Any known effusion hole shape, such as
cylindrical and tapered, may be useful with the present invention.
The diameter of a transition opening 28 may vary with application
and may depend on factors including, the diameter of the combustor
20, the temperature of the combustion gases, and the velocity of
the cooling air. The transition opening 28 may have a diameter
between about 0.01 and about 0.05 inches. For some applications,
the transition opening 28 may have a diameter between about 0.015
and about 0.030 inches. The effusion hole openings 26 may comprise
at least about five circumferential rows of transition openings 28.
The number of circumferential rows of transition openings 28 may
depend on factors including the dimensions of the combustor 20, the
diameter of the transition openings 28, and the temperature of the
combustion gases. The effusion hole openings 26 may comprise
between about five and about ten circumferential rows of transition
openings 28. The number of circumferential rows of transition
openings 28 may depend on the tangential angle of the transition
opening 28 furthest downstream. For example, there may be a greater
number of circumferential rows of transition openings 28 for an
application where the tangential angle of the transition openings
28 is gradually reduced to zero than for an application where the
tangential angle of the transition openings 28 is gradually reduced
to about 30.degree..
[0035] The number of rows of initial effusion hole openings 27 and
transition openings 28 may vary with application and may depend on
factors including the dimensions of the combustor 20 and the
temperature of the combustion gases. For example, there may be
about 7 rows of initial effusion hole openings 27 and about 11 rows
of transition openings 28 for an annular combustor liner
application. Computational fluid dynamic (CFD) analysis may be
useful in determining the desired number of rows and array
configuration for a particular application. The effusion hole
openings 26 may comprise a plurality of initial effusion hole
openings 27 and a plurality of transition openings 28. The effusion
hole openings 26 may comprise a plurality of initial effusion hole
openings 27.
[0036] For some applications, the entire length of an effusion
cooled component may have initial effusion hole openings 27 there
through, as depicted in an alternate embodiment of the present
invention shown in FIG. 3. For some applications, film
effectiveness may be low only in the initial flow region 29 of an
effusion wall. For such an application, it may not be necessary,
nor particularly desirable, to maintain the large tangential angle
of the initial effusion hole opening 27 for the entire panel as
depicted in FIG. 3 and the embodiment depicted in FIG. 2 may be
used.
[0037] The effusion hole openings 26 may be formed by conventional
drilling techniques such as electrical-discharge machining (EDM),
stationary percussion laser machining and percussion on-the-fly
laser drilling or with complex casting techniques. The density of
the effusion hole openings 26 may vary with application and may
depend on factors including the dimensions of the combustor 20, the
composition of the combustor liners, the velocity of the cooling
air, and the temperature of the combustion gases. For some
combustor applications, the density of the effusion hole openings
26 may be between about 10 and about 100 holes/in.sup.2.
[0038] The effusion cooled component, such as but not limited to
the combustor 20 discussed above, may comprise any component
exposed to high temperatures. Useful components may include gas
turbine engine components, for example combustors, vanes and
shrouds. The effusion cooled component may comprise a metal or a
metal alloy. The effusion cooled component may comprise nickel
based and cobalt based superalloys such as HA230.TM. (Haynes
International), Rene' alloy N5.TM. (General Electric), MarM247.TM.
(Martin Marietta), PWA 1422.TM. (Pratt Whitney), PWA 1480.TM.
(Pratt Whitney), PWA 1484.TM. (Pratt Whitney), Rene' 80.TM.
(General Electric), Rene' 142.TM. (General Electric), SC 180.TM.
(Honeywell), HA188.TM. (Haynes International), MarM509.TM. (Martin
Marietta) and others.
[0039] A method 40 of enhancing the film effectiveness for an
effusion cooled component is depicted in FIG. 6. The method 40 may
comprise a step 41 of passing an effusion flow 33 through at least
about two rows of initial effusion hole openings 27 in an initial
flow region of the component. The step 41 may comprise passing a
first portion of effusion flow 33 through a plurality of initial
effusion hole openings 27 in an initial flow region 29 of the
effusion cooled component. The method may comprise a further step
42 of passing an effusion flow 33 through at least about five rows
of transition openings 28 in a transition region. The step 42 may
comprise passing a second portion of effusion flow 33 through a
plurality of transition openings 28 in a transition region 35 of
said effusion cooled component.
EXAMPLE 1
[0040] The film effectiveness of a conventional effusion panel and
an effusion panel of the present invention were compared. A plot of
film effectiveness as a function of distance from start of panel is
depicted in FIG. 4. The dashed curve represents the film
effectiveness of a conventional axial orientation effusion panel.
The solid line represents the film effectiveness of an effusion
panel of the present invention. The present invention provides
greater film effectiveness at the start of the effusion panel, the
initial flow region. As can be appreciated by those skilled in the
art, the present invention may decrease liner temperatures in the
initial flow region of the panel, making starter skirts
unnecessary.
EXAMPLE 2
[0041] The impact of tangential effusion can be seen in FIG. 5,
which shows thermocouple measured liner metal temperatures for an
annular combustor. The figure plots the maximum inner wall
temperature as a function of the combustor discharge temperature.
The axial orientation effusion panel used conventional axial
effusion and generated the upper line of data. By changing to
tangential effusion according to one embodiment of the present
invention which transitioned to axial as discussed above, and
without changing the amount of cooling flow, the lower line of data
was generated which represents a reduction over 500.degree. F. in
liner temperature.
[0042] As can be appreciated by those skilled in the art, the
present invention provides improved film effectiveness at the start
of an effusion panel. This means that the complication and expense
of starter skirts can be eliminated and/or effusion cooling can be
effectively used in situations where a starter skirt is
geometrically impossible.
[0043] It should be understood, of course, that the foregoing
relates to exemplary embodiments of the invention and that
modifications may be made without departing from the spirit and
scope of the invention as set forth in the following claims.
* * * * *