U.S. patent application number 12/054535 was filed with the patent office on 2009-10-01 for film cooling of turbine components.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Gary Michael Itzel.
Application Number | 20090246011 12/054535 |
Document ID | / |
Family ID | 41011319 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090246011 |
Kind Code |
A1 |
Itzel; Gary Michael |
October 1, 2009 |
FILM COOLING OF TURBINE COMPONENTS
Abstract
A turbine component includes a flow path surface and a trench
disposed in the flow path surface. At least one cooling through
hole is located in the trench and is capable of injecting a cooling
flow onto the flow path surface of the turbine component. The
cooling flow forms a cooling film on the flow path surface. A
method of cooling a turbine component includes injecting a cooling
flow onto a flow path surface of the turbine component through at
least one cooling through hole disposed in a trench in the turbine
component. A cooling film is formed by the cooling flow between the
flow path surface and a hot gas flow.
Inventors: |
Itzel; Gary Michael;
(Simpsonville, SC) |
Correspondence
Address: |
CANTOR COLBURN, LLP
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
41011319 |
Appl. No.: |
12/054535 |
Filed: |
March 25, 2008 |
Current U.S.
Class: |
415/208.1 |
Current CPC
Class: |
F01D 5/186 20130101;
F05D 2230/90 20130101; F05D 2250/324 20130101 |
Class at
Publication: |
415/208.1 |
International
Class: |
F01D 1/02 20060101
F01D001/02 |
Claims
1. A turbine component comprising: a flow path surface; a trench
disposed in the flow path surface; and at least one cooling through
hole disposed in the trench, the at least one cooling through hole
fluidly coupled with the flow path surface of the turbine
component, and capable of producing a cooling film on the flow path
surface.
2. The turbine component of claim 1 including at least one flow
diverter disposed downstream of the at least one cooling through
hole for spreading the cooling film over the flow path surface.
3. The turbine component of claim 2 wherein the at least one flow
diverter comprises two diverter sidewalls extending from a
downstream wall at a sidewall angle.
4. The turbine component of claim 3 wherein each diverter sidewall
extends toward an adjacent diverter sidewall of an adjacent flow
diverter.
5. The turbine component of claim 4 wherein each flow diverter is
disposed at substantially a same lateral position as a
corresponding cooling through hole.
6. The turbine component of claim 3 wherein each diverter sidewall
extends toward an adjacent diverter sidewall of the same flow
diverter.
7. The turbine component of claim 2 wherein the two diverter
sidewalls extend downstream diverging from a vertex at a sidewall
angle.
8. The turbine component of claim 7 wherein at least a portion of
the at least one flow diverter is disposed in a corresponding
cooling through hole.
9. The turbine component of claim 1 wherein the trench comprises an
upstream trench wall disposed upstream of the at least one cooling
through hole and a downstream trench surface disposed downstream of
the at least one cooling through hole.
10. The turbine component of claim 9 wherein the upstream trench
wall extends substantially radially outwardly from a trench
base.
11. The turbine component of claim 9 wherein the downstream trench
surface slopes radially outwardly from a trench base.
12. The turbine component of claim 1 wherein the at least one
cooling through hole has an elliptically shaped exit.
13. The turbine component of claim 12 wherein the at least one
cooling through hole includes a diffusion surface sloping radially
inwardly from a downstream exit portion of the at least one cooling
through hole.
14. The turbine component of claim 1 comprising a substrate layer
and a coating layer.
15. The turbine component of claim 14 wherein the at least one
cooling through hole is disposed in the substrate layer,
16. The turbine component of claim 14 wherein at least one flow
diverter is disposed in the coating layer for spreading the cooling
film over the flow path surface.
17. A method of cooling a turbine component comprising: injecting a
cooling flow onto a flow path surface of the turbine component
through at least one cooling through hole disposed in a trench in
the turbine component; and forming a cooling film between the flow
path surface and a hot gas flow.
18. The method of claim 17 comprising: flowing the cooling film
into contact with at least one flow diverter disposed downstream of
the at least one cooling through hole; and spreading the cooling
film over the flow path surface via the at least one flow
diverter.
19. The method of claim 18 comprising splitting the cooling flow
via the at least one flow diverter wherein the at least one flow
diverter is disposed at least partially within a corresponding
cooling through hole.
20. The method of claim 17 wherein injecting a cooling flow
includes urging at least a portion of the cooling flow across a
diffusion surface of the at least one cooling through hole, the
diffusion surface sloping radially inwardly from a downstream exit
portion of the at least one cooling through hole.
Description
BACKGROUND
[0001] The subject invention relates to turbines. More
particularly, the subject invention relates to film cooling of
turbine components.
[0002] Components in the hot gas path of turbines, for example, gas
turbines, are subjected to high temperatures which leads to low
cycle fatigue cracking, creep rupture, and/or oxidation and the
like which causes premature failure of the components. One or more
methods are often employed to cool the hot gas path components to
extend their useful lives. One such method is film cooling. Film
cooling is accomplished by injecting air through holes in the
surface of the component, from a source such as compressor bleed
flow which bypasses a combustor. The relatively cooler air enters
the hot gas path and forms an insulating layer between the hot gas
and the component and reduces heat flux into the component.
[0003] An increase in the volume of air bled from the compressor,
however, has a negative impact on an overall turbine efficiency. It
is therefore desirable to increase an effectiveness of film cooling
such that less air needs to be bled from the compressor and
injected through the holes in order to achieve an acceptable amount
of cooling.
BRIEF DESCRIPTION OF THE INVENTION
[0004] A turbine component includes a flow path surface and a
trench disposed in the flow path surface. At least one cooling
through hole is located in the trench and is capable of injecting a
cooling flow onto the flow path surface of the turbine component.
The cooling flow forms a cooling film on the flow path surface.
[0005] A method of cooling a turbine component includes injecting a
cooling flow onto a flow path surface of the turbine component
through at least one cooling through hole disposed in a trench in
the turbine component. A cooling film is formed by the cooling flow
between the flow path surface and a hot gas flow.
[0006] These and other advantages and features will become more
apparent from the following description taken in conjunction with
the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The subject matter which is regarded as the invention is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
objects, features, and advantages of the invention are apparent
from the following detailed description taken in conjunction with
the accompanying drawings in which:
[0008] FIG. 1 is a partial perspective view of an embodiment of a
turbine component having flow diverters for film cooling;
[0009] FIG. 2 is a cross-sectional view of the turbine component of
FIG. 1;
[0010] FIG. 3 is an axial cross-sectional view of the turbine
component of FIG. 1;
[0011] FIG. 4 is a partial perspective view of another embodiment
of a turbine component having flow diverters for film cooling;
[0012] FIG. 5 is a partial perspective view of an alternative
embodiment of the turbine component of FIG. 4; and
[0013] FIG. 6 is a partial perspective view of yet another
embodiment of a turbine component having flow diverters for film
cooling.
[0014] The detailed description explains embodiments of the
invention, together with advantages and features, by way of example
with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0015] A partial view of a turbine component, for example, a
turbine airfoil 10 is shown in FIG. 1. Hot gas flow 12 proceeds
across an outer surface 14 of the turbine airfoil 10 in a flow
direction 16. At least one trench 18 is disposed in the turbine
airfoil 10 and is defined by an upstream trench wall 20 which, in
some embodiments extends substantially radially outward from the
turbine airfoil 10, and at least one downstream trench surface 22.
At least one cooling through hole 24 is disposed in the trench 18.
In FIG. 1, a plurality of cooling through holes 24 are arranged
substantially in a line extending radially along the trench 18, but
other arrangements of cooling through holes 24 in the trench 18 are
contemplated within the scope of the present disclosure. The
cooling through holes 24 may have an elliptical opening as shown in
FIG. 1, or may have circular or other-shaped openings depending on
desired flow from the cooling through holes 24. Further, as shown
in FIG. 2, the cooling through holes 24 may have an axis 26 which
is not perpendicular to the outer surface 14, to facilitate
smoother flow through the cooling through holes 24.
[0016] Referring again to FIG. 1, the downstream trench surface 22
slopes radially outwardly from a trench floor 28. This prevents a
cooling flow 30 exiting the cooling through holes 24 from blowing
off of the outer surface 14 and into the hot gas flow 12. At least
one flow diverter 32 is disposed at the downstream trench surface
22. Each flow diverter 32 includes a downstream wall 34 which, in
the embodiment of FIG. 1, is disposed axially downstream from and
substantially perpendicular to the flow direction 16 such that
cooling flow 30 exiting the cooling through hole 24 is diverted or
split as shown in FIG. 1. In some embodiments the downstream wall
34 is disposed at a substantially same lateral position as a
corresponding cooling through hole 24. The cooling flow 30 divides
and flows laterally around the downstream wall 34 and along the
downstream trench surface 22. A portion of the cooling flow 30 may
flow radially outboard of the downstream wall 34 and proceed along
the outer surface 14. Each flow diverter 32 includes two diverter
sidewalls 36. Each diverter sidewall 36 extends from the downstream
wall 34 at a sidewall angle 38 which in some embodiments may be
toward a diverter sidewall 36 of an adjacent flow diverter 32. In
the embodiment shown in FIG. 1, the sidewall angles 38 are equal,
but it is to be appreciated that embodiments where sidewall angles
38 differ for one or more sidewalls 36 are contemplated within the
present scope. Utilizing flow diverters 32 causes the cooling flow
30 to spread over a greater portion of the turbine airfoil 10 thus
providing more effective cooling of the turbine airfoil 10. A width
40 of the downstream wall 32 and/or the sidewall angle 38 can be
varied to provide a desired amount of spread of the cooling flow
28. Further, as shown in FIG. 3, the diverter sidewalls 36 of
adjacent flow diverters form a flow channel 42 preventing hot gas
flow 12 from flowing between the cooling flow 30 and the downstream
trench surface 22 thus preventing mixing of the hot gas flow 12 and
the cooling flow 30.
[0017] Referring now to FIG. 4, in an alternative embodiment each
flow diverter 32 comprises two diverter sidewalls 36 converging at
a vertex 44 located axially downstream from, and at a substantially
same lateral position as a corresponding cooling through hole 24
such that cooling flow 30 exiting the cooling through hole 24 is
split or diverted as shown in FIG. 4. Each diverter sidewall 36 is
disposed at a sidewall angle 38 and extends toward a diverter
sidewall 36 of an adjacent flow diverter 32. The flow diverter 32
including a vertex 44 prevents a vortex from forming in the cooling
flow 30 at an exit of the cooling through hole 24, as well as
causes the cooling flow 30 to spread over a greater portion of the
turbine airfoil 10. Referring now to FIG. 5, each vertex 44 may be
disposed at least partially within a corresponding cooling through
hole 24. A flow diverter 32 of this configuration is capable of
splitting or diverting the cooling flow 30 as the cooling flow 30
exits the cooling through hole 24.
[0018] In an alternative embodiment shown in FIG. 6, each flow
diverter 32 is disposed laterally substantially between two cooling
through holes 24. As above, each flow diverter 32 includes a
downstream wall 34 and two diverter sidewalls 36 disposed at a
sidewall angle 38. In this embodiment, the sidewall angles 38 are
such that each diverter sidewall 36 extends toward convergence with
the other diverter sidewall 36 of the same flow diverter 32. In
this embodiment, the cooling flow 30 does not split upon exit from
the cooling through hole 24, but spreads across the flow channel 42
between adjacent flow diverters 32.
[0019] As stated above, the cooling through holes 24 may have a
number of shapes. The cooling through holes 24 shown in FIG. 6
include a diffusion surface 46 located at a downstream exit portion
of the cooling through hole 24 and which slopes radially inward
below the trench floor 28. Cooling through holes 24 including the
diffusion surface 46 provide additionally smooth transition of
cooling flow 30 from the cooling through holes 24 to the outer
surface 14 preventing blowing off of the cooling flow 30 into the
hot gas flow 12. In the embodiment shown in FIG. 6, an edge 48 of
the diffusion surface is coplanar with the diverter sidewall 36,
but other configurations and alignments of the edge 48 relative to
the diverter sidewall 36 are contemplated within the present
scope.
[0020] In some embodiments, the turbine airfoil 10 comprises a
substrate layer 50 and a coating layer 52, which may include a
thermal barrier coating (TBC) to provide additional thermal
protection of the substrate layer 50. As shown in FIG. 6, the
cooling through holes 24 are disposed in the substrate layer 50
while the flow diverters 32, upstream trench wall 20 and downstream
trench surface 22 are disposed in the coating layer 52 and may be
formed from TBC.
[0021] While the invention has been described in detail in
connection with only a limited number of embodiments, it should be
readily understood that the invention is not limited to such
disclosed embodiments. Rather, the invention can be modified to
incorporate any number of variations, alterations, substitutions or
equivalent arrangements not heretofore described, but which are
commensurate with the spirit and scope of the invention.
Additionally, while various embodiments of the invention have been
described, it is to be understood that aspects of the invention may
include only some of the described embodiments. Accordingly, the
invention is not to be seen as limited by the foregoing
description, but is only limited by the scope of the appended
claims.
* * * * *