U.S. patent application number 12/706777 was filed with the patent office on 2010-06-10 for turbine blade with reverse cooling air film hole direction.
Invention is credited to Brandon W. Spangler.
Application Number | 20100143132 12/706777 |
Document ID | / |
Family ID | 39267819 |
Filed Date | 2010-06-10 |
United States Patent
Application |
20100143132 |
Kind Code |
A1 |
Spangler; Brandon W. |
June 10, 2010 |
TURBINE BLADE WITH REVERSE COOLING AIR FILM HOLE DIRECTION
Abstract
A gas turbine engine includes turbine blades having film cooling
holes at an outer face of an airfoil wherein the film cooling holes
are designed to be better filled with air. In a disclosed
embodiment, the film cooling holes include a meter section
extending along a direction having a main component extending from
a blade tip to a blade root. In addition, a diffused section
communicates with the meter section at a face of the airfoil. The
diffused section is spaced toward the blade tip from the meter
section. In this manner, centrifugal force ensures the diffused
section is also filled with air.
Inventors: |
Spangler; Brandon W.;
(Vernon, CT) |
Correspondence
Address: |
CARLSON, GASKEY & OLDS/PRATT & WHITNEY
400 WEST MAPLE ROAD, SUITE 350
BIRMINGHAM
MI
48009
US
|
Family ID: |
39267819 |
Appl. No.: |
12/706777 |
Filed: |
February 17, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11651226 |
Jan 9, 2007 |
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12706777 |
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Current U.S.
Class: |
416/95 |
Current CPC
Class: |
F01D 5/186 20130101;
F05D 2250/52 20130101 |
Class at
Publication: |
416/95 |
International
Class: |
F01D 5/08 20060101
F01D005/08 |
Claims
1. A turbine blade comprising: a root, and an airfoil extending
away from the root to a tip; a plurality of film cooling holes on
an outer face of the airfoil, said airfoil having at least one
internal cooling passage for receiving air from a source, and
delivering air to said film cooling holes; and said film cooling
holes receiving air from said cooling passage through meter
sections extending with a component in a direction from the tip
towards the root.
2. The turbine blade as set forth in claim 1, wherein a diffused
section of an outer end of said film cooling holes extending
towards said tip from said meter section.
3. The turbine blade as set forth in claim 2, wherein said diffused
section is formed along an angle having a lesser component in the
direction from said tip toward said root than said meter
section.
4. The turbine blade as set forth in claim 2, wherein said meter
sections extend at a first angle, with an extension of said meter
section extending through to an outer wall of said airfoil, and
said diffused section extending at a different angle than said
meter section.
5. The turbine blade as set forth in claim 1, wherein said
plurality of film holes being formed in an array, with there being
film holes spaced at different locations in a direction between a
trailing edge and a leading edge of the airfoil, and also at
different locations between the root and the tip of the
airfoil.
6. The turbine blade as set forth in claim 1, wherein said meter
section extends from said cooling passage initially at said
direction.
7. The turbine blade as set forth in claim 10, wherein said meter
section extends along a single angle from said cooling passage to
said outer wall of said outer face of the airfoil.
8. The turbine blade as set forth in claim 1, wherein said array of
cooling holes is formed on a pressure side of said airfoil.
9. A turbine blade comprising: a root, and an airfoil extending
away from the root toward a tip; a plurality of film cooling holes
on an outer face of said airfoil, said airfoil having at least one
internal cooling passage for receiving air from a source, and
delivering air to said film cooling holes; and said film cooling
holes receiving air from said internal cooling passage through
meter sections, and an diffused section of an outer end of said
film cooling holes communicates with said meter section, said
diffused section extending towards said tip from said meter
section.
10. The turbine blade as set forth in claim 9, wherein said
diffused section is formed along an angle having a lesser component
in the direction from said tip toward said root than said meter
section.
11. The turbine blade as set forth in claim 9, wherein said meter
section extends from said cooling passage initially at said
direction.
12. The turbine blade as set forth in claim 11, wherein said meter
sections each extend along a single angle from said cooling passage
to said outer wall of said outer face of the airfoil.
13. The turbine blade as set forth in claim 9, wherein said array
of cooling holes is formed on a pressure side of said airfoil.
Description
RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/651,226, which was filed Jan. 9, 2007.
BACKGROUND OF THE INVENTION
[0002] This application relates to a turbine blade, wherein the
meter sections of film cooling holes extend at an angle and in a
direction toward a blade root from the blade tip. In addition, a
diffused section of a film cooling hole extends toward the blade
tip from a meter section to receive air driven by centrifugal
force.
[0003] Gas turbine engines are known, and include a plurality of
sections which are typically mounted in series. Typically a fan
delivers air to a compressor. Air is compressed in the compressor
and delivered downstream to be mixed with fuel and combusted in a
combustor section. Products of combustion move downstream over
turbine rotors. The turbine rotors include a plurality of removable
blades which rotate with the rotors, and are driven by the products
of combustion. The turbine rotors drive components within the gas
turbine engine, including the fan and compressor.
[0004] The turbine blades become quite hot from the products of
combustion. Thus, it is known to pass cooling air through internal
cooling passages within the turbine blades. In one known cooling
technique, air is passed outwardly through holes on an outer face
of an airfoil of the turbine blade, such that the cool air passes
along the outer face. These film cooling holes are designed to
maximize the coverage surface area on the blade, which receives the
air and also to maximize the time cooling air is kept on a face of
the blade.
[0005] In the prior art, the film cooling holes have a meter
section that typically extend at an angle to the outer face. The
angle includes a major component in a direction extending from a
blade root and toward a blade tip. In addition, a diffused section
extends back from this meter section towards the blade root. This
type of film cooling holes is known as shaped or flared holes. The
purpose of the diffused section is to slow the speed of the cooling
air down as it reaches the face of the blade, such that the air
would be less likely to move away from the face, and more likely to
move along the face.
[0006] However, in the prior art, a centrifugal force applied as
the blade rotates, moves the cooling air radially outwardly and
toward the blade tip. Thus, the diffused section tends not to be
filled with air. This centrifugal force and flow momentum drives
the air into the radially outer portions of the holes spaced toward
the tip, and leaves the diffused section less filled. Thus, the air
exits the film cooling hole at a greater velocity, and does not
stay on the face of the blade as long as would be desired.
SUMMARY OF THE INVENTION
[0007] In a disclosed embodiment of this invention, the meter
section of film cooling holes in a turbine blade extend with a
major component in a direction from the blade tip toward the blade
root. A diffused section is formed to enlarge a film cooling hole
at the outer face of the blade. The diffused section extends toward
the blade tip from the meter section.
[0008] As the blade rotates, and cooling air exits the film cooling
hole, centrifugal force forces some of the cooling air into the
diffused section and the diffused section is relatively full
compared to the prior art. Thus, the air exits the film cooling
hole at a lower velocity than in the prior art, tends to stay on
the face of the turbine blade longer, and cover a greater surface
area.
[0009] These and other features of the present invention can be
best understood from the following specification and drawings, the
following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic view of a gas turbine engine.
[0011] FIG. 2A is a view of a prior art turbine blade.
[0012] FIG. 2B is an enlarged view of a portion of the FIG. 2A
turbine blade.
[0013] FIG. 2C is another view of the FIG. 2A blade.
[0014] FIG. 3 is a view similar to FIG. 2C, but showing the
inventive blade.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] A gas turbine engine 10 circumferentially disposed about an
engine centerline, or axial centerline axis 12 is shown in FIG. 1.
The engine 10 includes a fan 14, a compressor 16, a combustion
section 18 and a turbine 11. As is well known in the art, air
compressed in the compressor 16 is mixed with fuel and burned in
the combustion section 18 and expanded in turbine 11. The turbine
11 includes rotors 22 which rotate in response to the expansion,
driving the compressor 16 and fan 14. The turbine 11 comprises
alternating rows of rotary airfoils or blades 24 and static
airfoils or vanes 26. In fact, this view is quite schematic, and
blades 24 and vanes 26 are actually removable. It should be
understood that this view is included simply to provide a basic
understanding of the sections in a gas turbine engine, and not to
limit the invention. This invention extends to all types of turbine
engines for all applications.
[0016] FIG. 2A shows a prior art turbine blade 24. As known, a
platform 32 and blade root form a base for an airfoil 34. The
airfoil 34 includes a plurality of film cooling holes 36. As can be
appreciated, the holes 36 are formed on the pressure side 198 of
the turbine blade. The holes are in an array, with holes being
spaced in several columns and rows extending between the root of
the airfoil and the tip, and from the trailing edge 197 toward the
leading edge 199. As an example, there are several columns 200,
201, and 202 spaced between the trailing edge 197 and the leading
edge 199. In addition, there are holes 202 that are closer to the
root than other holes 205 or 207.
[0017] As shown in FIG. 2B, the film cooling holes 36 have a meter
section 38, and a diffused section 40.
[0018] As shown in FIG. 2C, the meter section 38 extends along a
non-parallel angle relative to a radial axis, and with a component
extending from the blade root to the blade tip. The air from an
internal cooling passage 42 passes through this meter section 38 to
an outer face of the airfoil 34. As can be seen in FIG. 2C, this
diffused section extends from the meter section 38 and closer to
the blade root than the blade tip. Now, as the turbine blade 24
rotates, centrifugal forces force air from the meter section 38
radially outwardly, and away from the diffused section 40. Thus,
the diffused section 40 is not always filled.
[0019] As shown in FIG. 3, in an inventive turbine blade 50, a
meter section 52 extends with a main component of its direction
from the blade tip to the blade root. A diffused section 54 extends
toward the blade tip from the meter section 52. As can be seen, the
diffused section 54 may be at an angle having a lesser component in
the direction from the tip towards the root. As can be appreciated
from FIG. 2, the enlarged portions 40 and 54 may not extend
directly, or solely, towards the root and tip respectively. Still,
they extend with a major component in those directions. As is
clearly shown in FIG. 3, the meter sections 52 extend from cooling
passage 42 at an angle that is initially from the blade tip toward
the blade root, and at a single angle to an outer face of the
airfoil. While holes 52 are shown along a single column, it should
be appreciated that these holes would be utilized in an array such
as shown in FIG. 2A or 2B.
[0020] When centrifugal force acts on the air in the meter section
52, the air is driven into the diffused section 54. Flow momentum
will ensure that the meter section 52 is still full. Thus, the
present invention ensures the cooling air is delivered to the outer
face 51 across the entirety of the film cooling holes. As can be
appreciated from FIG. 2B, the diffused sections 40 and 54 may not
extend directly, or solely, towards the root and tip respectively.
Still, they extend with a major component in those directions. It
should be noted that the flow in the internal cooling passage 42
can flow in any direction and does not necessarily have to flow
from blade root to blade tip.
[0021] In fact, the meter section can extend in the reverse
direction or any direction with the diffused section extending
toward the tip. Flow momentum will still fill the meter section
while centrifugal force will fill the diffused section.
[0022] Although a preferred embodiment of this invention has been
disclosed, a worker of ordinary skill in this art would recognize
that certain modifications would come within the scope of this
invention. For that reason, the following claims should be studied
to determine the true scope and content of this invention.
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