U.S. patent application number 12/536869 was filed with the patent office on 2011-02-10 for turbine airfoil cooling system with pin fin cooling chambers.
Invention is credited to John J. Marra, Nicholas F. Martin, Melissa Seco-Soley.
Application Number | 20110033311 12/536869 |
Document ID | / |
Family ID | 43534962 |
Filed Date | 2011-02-10 |
United States Patent
Application |
20110033311 |
Kind Code |
A1 |
Martin; Nicholas F. ; et
al. |
February 10, 2011 |
Turbine Airfoil Cooling System with Pin Fin Cooling Chambers
Abstract
A cooling system for a turbine airfoil having at least one pin
fin with a dimpled outer surface is disclosed. The dimpled outer
surface increases the cooling efficiency of the pin fin, which
creates numerous efficiencies, including thermal efficiencies,
manufacturing efficiencies and the like. The dimples may be formed
from shapes including, but not limited to, circular, oval,
racetrack, and hemispherical. The dimples may be aligned in a
variety of configurations.
Inventors: |
Martin; Nicholas F.; (Winter
Park, FL) ; Marra; John J.; (Winter Springs, FL)
; Seco-Soley; Melissa; (Orlando, FL) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Family ID: |
43534962 |
Appl. No.: |
12/536869 |
Filed: |
August 6, 2009 |
Current U.S.
Class: |
416/97R |
Current CPC
Class: |
F05D 2260/22141
20130101; F01D 5/187 20130101; F05D 2250/60 20130101; F05D 2240/304
20130101; F05D 2260/2212 20130101; F05D 2240/122 20130101 |
Class at
Publication: |
416/97.R |
International
Class: |
F01D 5/18 20060101
F01D005/18 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0001] Development of this invention was supported in part by the
United States Department of Energy, Contract No. DE-FC26-05NT42644,
H2 Advanced Hydrogen Turbine Development, Phase 2. Accordingly, the
United States Government may have certain rights in this invention.
Claims
1. A turbine airfoil, comprising: a generally elongated, hollow
airfoil having a leading edge, a trailing edge, a tip section at a
first end, a root coupled to the airfoil at an end generally
opposite the first end for supporting the airfoil and for coupling
the airfoil to a disc, and a cooling system formed from at least
one cavity in the elongated, hollow airfoil; an outer wall forming
the generally elongated airfoil; wherein the cooling system
includes at least one pin fin having an outer surface with at least
one dimple.
2. The turbine airfoil of claim 1, wherein the at least one dimple
has a generally circular shape at an intersection with the outer
surface of the at least one dimple.
3. The turbine airfoil of claim 1, wherein the at least one dimple
has a generally oval shape at an intersection with the outer
surface of the at least one dimple.
4. The turbine airfoil of claim 1, wherein the at least one dimple
has a generally racetrack shape with two curved ends and two
generally linear sides at an intersection with the outer surface of
the at least one dimple.
5. The turbine airfoil of claim 1, wherein the at least one dimple
has a generally hemispherical shape.
6. The turbine airfoil of claim 1, wherein the outer surface of the
pin fin includes a plurality of dimples.
7. The turbine airfoil of claim 6, wherein the dimples are aligned
into horizontal rows that are offset from dimples in adjacent
rows.
8. The turbine airfoil of claim 1, wherein the at least one dimple
extends into the pin fin between about 1/2 percent to about 20
percent of the width of the pin fin.
9. The turbine airfoil of claim 1, wherein the outer surface of the
at least one pin fin includes dimples covering between about 20
percent and about 100 percent of the outer surface of the at least
one pin fin.
10. A turbine airfoil, comprising: a generally elongated, hollow
airfoil having a leading edge, a trailing edge, a tip section at a
first end, a root coupled to the airfoil at an end generally
opposite the first end for supporting the airfoil and for coupling
the airfoil to a disc, and a cooling system formed from at least
one cavity in the elongated, hollow airfoil; an outer wall forming
the generally elongated airfoil; wherein the cooling system
includes a plurality of pin fins having an outer surface with a
plurality of dimples.
11. The turbine airfoil of claim 10, wherein at least one of the
plurality of dimples has a generally circular shape at an
intersection with the outer surface of the dimple.
12. The turbine airfoil of claim 10, wherein at least one of the
plurality of dimples has a generally oval shape at an intersection
with the outer surface of the dimple.
13. The turbine airfoil of claim 10, wherein at least one of the
plurality of dimples has a generally racetrack shape with two
curved ends and two generally linear sides at an intersection with
the outer surface of the dimple.
14. The turbine airfoil of claim 10, wherein at least one of the
plurality of dimples has a generally hemispherical shape.
15. The turbine airfoil of claim 10, wherein the dimples are
aligned into horizontal rows that are offset from dimples in
adjacent rows.
16. The turbine airfoil of claim 10, wherein the at least one
dimple extends into the pin fin between about 1/2 percent to about
20 percent of the width of the pin fin.
17. The turbine airfoil of claim 10, wherein the outer surface of
the at least one pin fin includes dimples covering between about 20
percent and about 100 percent of the outer surface of the at least
one pin fin.
18. A turbine airfoil, comprising: a generally elongated, hollow
airfoil having a leading edge, a trailing edge, a tip section at a
first end, a root coupled to the airfoil at an end generally
opposite the first end for supporting the airfoil and for coupling
the airfoil to a disc, and a cooling system formed from at least
one cavity in the elongated, hollow airfoil; an outer wall forming
the generally elongated airfoil; wherein the cooling system
includes a plurality of generally cylindrical pin fins having an
outer surface with a plurality of concave dimples that are aligned
into horizontal rows that are offset from dimples in adjacent
rows.
19. The turbine airfoil of claim 18, wherein at least one of the
plurality of dimples has a generally oval shape at an intersection
with the outer surface of the dimple.
20. The turbine airfoil of claim 18, wherein at least one of the
plurality of dimples has a generally racetrack shape with two
curved ends and two generally linear sides at an intersection with
the outer surface of the dimple.
Description
FIELD OF THE INVENTION
[0002] This invention is directed generally to turbine airfoils,
and more particularly to cooling systems in hollow turbine
airfoils.
BACKGROUND
[0003] Typically, gas turbine engines include a compressor for
compressing air, a combustor for mixing the compressed air with
fuel and igniting the mixture, and a turbine blade assembly for
producing power. Combustors often operate at high temperatures that
may exceed 2,500 degrees Fahrenheit. Typical turbine combustor
configurations expose turbine blade assemblies to these high
temperatures. As a result, turbine blades must be made of materials
capable of withstanding such high temperatures. In addition,
turbine blades often contain cooling systems for prolonging the
life of the blades and reducing the likelihood of failure as a
result of excessive temperatures.
[0004] Typically, turbine blades are formed from a root portion
having a platform at one end and an elongated portion forming a
blade that extends outwardly from the platform coupled to the root
portion. The blade is ordinarily composed of a tip opposite the
root section, a leading edge, and a trailing edge. The inner
aspects of most turbine blades typically contain an intricate maze
of cooling channels forming a cooling system. The cooling channels
in a blade receive air from the compressor of the turbine engine
and pass the air through the blade. The cooling channels often
include multiple flow paths that are designed to maintain all
aspects of the turbine blade at a relatively uniform temperature.
However, centrifugal forces and air flow at boundary layers often
prevent some areas of the turbine blade from being adequately
cooled, which results in the formation of localized hot spots.
Localized hot spots, depending on their location, can reduce the
useful life of a turbine blade and can damage a turbine blade to an
extent necessitating replacement of the blade. Thus, a need exists
for a cooling system capable of providing sufficient cooling to
turbine airfoils.
SUMMARY OF THE INVENTION
[0005] This invention relates to improvements in a turbine airfoil
cooling system for a turbine airfoil used in turbine engines. In
particular, the turbine airfoil cooling system includes a plurality
of internal cavities positioned between outer walls of the turbine
airfoil. The cooling system may include one or more pin fins having
one or more dimples on outer surfaces of the pin fins. The dimpled
pin fins may more efficiently remove heat from the turbine airfoil
than conventional cooling systems.
[0006] The turbine airfoil may be formed from any appropriate
configuration. In at least one embodiment, the turbine airfoil may
be formed from a generally elongated, hollow airfoil having a
leading edge, a trailing edge, a tip section at a first end, a root
coupled to the airfoil at an end generally opposite the first end
for supporting the airfoil and for coupling the airfoil to a disc,
and a cooling system formed from at least one cavity in the
elongated, hollow airfoil. The turbine airfoil may be formed from
an outer wall forming the generally elongated airfoil.
[0007] The cooling system may include a pin fin having an outer
surface with one or more dimples that are generally concave. The
dimple may have a generally circular shape at an intersection with
the outer surface of the at least one dimple, a generally oval
shape at an intersection with the outer surface of the at least one
dimple, a generally racetrack shape with two curved ends and two
generally linear sides at an intersection with the outer surface of
the at least one dimple, a generally hemispherical shape, or other
appropriate shape.
[0008] The pin fin may have any appropriate configuration. In at
least one embodiment, the pin fin may be generally cylindrical. The
outer surface of the pin fin may include a plurality of dimples.
The dimples may be aligned into horizontal rows that are offset
from dimples in adjacent rows. The dimples may be positioned such
that the dimples extend into the pin fin between about 1/2 percent
to about 20 percent of the width of the pin fin.
[0009] An advantage of this invention is that the dimpled pin fins
offer reduced pressure losses, increase surface area for convective
heat transfer and greater design flexibility.
[0010] Another advantage of this invention is that the dimpled pin
fins may enable a reduction in the amount of cooling fluids sent
through the turbine airfoil cooling system without compromising the
cooling capabilities of the turbine airfoil cooling system, thereby
increasing the efficiency of the turbine engine.
[0011] These and other embodiments are described in more detail
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings, which are incorporated in and
form a part of the specification, illustrate embodiments of the
presently disclosed invention and, together with the description,
disclose the principles of the invention.
[0013] FIG. 1 is a perspective view of a turbine airfoil having
features according to the instant invention.
[0014] FIG. 2 is a cross-sectional view of the turbine airfoil
shown in FIG. 1 taken along line 2-2.
[0015] FIG. 3 is a perspective view of a pin fin that is a
component of the turbine airfoil cooling system.
[0016] FIG. 4 is a perspective view of an alternative configuration
of a dimple.
[0017] FIG. 5 is a perspective view of another alternative
configuration of a dimple.
[0018] FIG. 6 is a perspective view of yet another alternative
configuration of a dimple.
DETAILED DESCRIPTION OF THE INVENTION
[0019] As shown in FIGS. 1-6, this invention is directed to
improvements in a turbine airfoil cooling system 10 for a turbine
airfoil 12 used in turbine engines. In particular, the turbine
airfoil cooling system 10 includes a plurality of internal cavities
14, as shown in FIG. 2, positioned between outer walls 16 of the
turbine airfoil 12. The cooling system 10 may include one or more
pin fins 18 having one or more dimples 20 on outer surfaces 22 of
the pin fins 18. The dimpled pin fins 18 may more efficiently
remove heat from the turbine airfoil 12 than conventional cooling
systems 10.
[0020] The turbine airfoil 12 may be a stationary turbine vane, a
rotatable turbine blade or other appropriate structure. In the
embodiment shown in FIGS. 1 and 2, the turbine airfoil 12 is a
turbine blade. The turbine airfoil 12 may be formed from a
generally elongated, hollow airfoil 28 coupled to a root 30 at a
platform 32. The turbine airfoil 12 may be formed from conventional
metals or other acceptable materials. The generally elongated
airfoil 28 may extend from the root 30 to a tip section 34 and
include a leading edge 36 and trailing edge 38. Airfoil 28 may have
an outer wall 16 adapted for use, for example, in a first stage of
an axial flow turbine engine. Outer wall 16 may form a generally
concave shaped portion forming the pressure side 24 and may form a
generally convex shaped portion forming the suction side 26. The
cavity 14, as shown in FIG. 2, may be positioned in inner aspects
of the airfoil 28 for directing one or more gases, which may
include air received from a compressor (not shown), through the
airfoil 28 to reduce the temperature of the airfoil 28. The cavity
14, and thus the turbine airfoil cooling system 10, may be arranged
in various configurations and is not limited to a particular flow
path.
[0021] The turbine airfoil cooling system 10 may include one or
more pins fins 18 positioned in the cooling system 10. Pin fin 18
may extend through a cooling fluid flow channel generally
nonparallel to the flow of cooling fluids through the cooling fluid
flow channel. In one embodiment, the pin fin 18 may be positioned
generally. orthogonal to the flow of cooling fluids through the
cooling fluid flow channel. The pin fins 18 may have any
appropriate size. The pin fins 18 may impede flow of the cooling
fluids and increase the convective cooling of the airfoil 12. The
pin fins 18 may be positioned in any appropriate position,
alignment and configuration to enhance the cooling capabilities of
the turbine airfoil cooling system 10. The pin fins 18 may have any
appropriate size and may be formed from any appropriate material.
The pin fins 18 may extend from the an outer wall 16 at the
pressure side 24 to the outer wall 16 forming the suction side 26.
In other embodiments, the pin fins 18 may extend between other
aspects of the turbine airfoil cooling system 10. The pin fins 18
may be generally cylindrical or have other appropriate
configurations. In particular, the pin fins 18 may have
cross-sectional shapes such as, but not limited to, cylindrical,
elliptical or oval.
[0022] As shown in FIG. 3, the pin fins 18 may include one or more
dimples 20. The dimples 20 may enhance the thermal capabilities of
the pin fins 18. In particular, the dimples 20 may reduce drag,
reduce pressure loss, and increase the surface area of the pin fins
18. The dimples 20 may have any appropriate configuration and may
be generally concave in configuration. In particular, the dimples
20 may have an oval shape at an intersection with the outer surface
22, as shown in FIG. 3, a circular shape at an intersection with
the outer surface 22, as shown in FIG. 4, a racetrack shape at an
intersection with the outer surface 22, as shown in FIG. 5, a
hemispherical shape at an intersection with the outer surface 22,
as shown in FIG. 6, or another appropriate shape. The generally
racetrack shape shown in FIG. 5 includes two curved ends 40 and two
generally linear sides 42 at an intersection with the outer surface
22 of the dimple 20.
[0023] The dimples 20 may be positioned on a pin fin 18 such that
the dimples 20 are positioned randomly about the outer surface 22
of the pin fin. Alternatively, the dimples 20 may be aligned into
horizontal rows 44 that are offset from dimples 20 in adjacent rows
44, as shown in FIG. 3. The dimples 20 may be positioned in any
pattern that increases the thermal efficiency and reduces the drag
of the pin fin 18. In at least one embodiment, one or more dimples
20 may be positioned such that the dimple 20 extends into the pin
fin 18 between about 1/2 percent to about 20 percent of the width
of the pin fin 18. In one embodiment, the dimples 20 may be
positioned such that the dimples 20 cover between about 20 percent
and about 100 percent of the outer surface area of a pin fin 18.
The pin fins 18 may be manufactured with a blade core manufacturing
process referred to as Tomo Lithography Molding, by Mikro Systems,
Inc.
[0024] During operation, cooling fluids are passed through the
turbine airfoil cooling system 10 to cool the turbine airfoil 12
during turbine engine operation. A portion of the cooling fluids
may encounter the pin fins 18 positioned in the cooling system 10
and contact the pins fins 18 and the dimples 20 thereon. The
dimples 20 increase the surface area of the outer surface 22 of the
pin fins 22 and thereby increase the cooling efficiency of the pin
fins 22 and the turbine airfoil cooling system 10. The dimples 20
may also reduce the amount of pressure loss associated with
conventional pin fins 18.
[0025] The foregoing is provided for purposes of illustrating,
explaining, and describing embodiments of this invention.
Modifications and adaptations to these embodiments will be apparent
to those skilled in the art and may be made without departing from
the scope or spirit of this invention.
* * * * *