U.S. patent application number 12/852679 was filed with the patent office on 2012-02-09 for turbine blade squealer tip.
Invention is credited to Allister W. James, Anand A. Kulkarni.
Application Number | 20120034101 12/852679 |
Document ID | / |
Family ID | 45556297 |
Filed Date | 2012-02-09 |
United States Patent
Application |
20120034101 |
Kind Code |
A1 |
James; Allister W. ; et
al. |
February 9, 2012 |
TURBINE BLADE SQUEALER TIP
Abstract
A turbine blade having a squealer tip coupled to a radially
outer end of the turbine blade that is usable in a gas turbine
engine is disclosed. The squealer tip may require less cooling air
and may therefore be more efficient than conventional
configurations. The squealer tip may be formed from one or more
materials such as oxide dispersion strengthened alloys and FeCrAl
alloys. The squealer tip may be formed from a plurality of
segmented tips extending radially outward and spaced apart from
each other. For example, the squealer tip may be formed from two
rails extending radially outward and spaced apart from each other.
The two rails may be formed from outer and inner rails that each
form a continuous ring. The squealer tip may be attached to the tip
with a transient liquid phase bond or an additive manufacturing
process, such as, a selective laser melting process.
Inventors: |
James; Allister W.;
(Chuluota, FL) ; Kulkarni; Anand A.; (Oviedo,
FL) |
Family ID: |
45556297 |
Appl. No.: |
12/852679 |
Filed: |
August 9, 2010 |
Current U.S.
Class: |
416/96R ;
416/219R; 416/241R |
Current CPC
Class: |
F01D 5/20 20130101; B33Y
80/00 20141201; F05D 2230/22 20130101; F05D 2230/31 20130101; F05D
2230/234 20130101 |
Class at
Publication: |
416/96.R ;
416/241.R; 416/219.R |
International
Class: |
F01D 5/18 20060101
F01D005/18; F01D 5/30 20060101 F01D005/30; F01D 5/14 20060101
F01D005/14 |
Claims
1. A turbine blade, comprising: a generally elongated airfoil
having a leading edge, a trailing edge, a tip 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 blade to a
disc, and at least one cavity forming a cooling system in the
blade; and a squealer tip coupled to the tip at the first end,
wherein the squealer tip is formed from a material selected from
the group consisting of oxide dispersion strengthened alloys and
FeCrAl alloys.
2. The turbine blade of claim 1, wherein the oxide dispersion
strengthened alloys comprise PM2000 and ODM 751.
3. The turbine blade of claim 1, wherein the FeCrAl alloys comprise
APMT.
4. The turbine blade of claim 1, wherein the squealer tip is
comprised of a plurality of segmented tips extending radially
outward and spaced apart from each other.
5. The turbine blade of claim 1, wherein the squealer tip is
comprised of two rails extending radially outward and spaced apart
from each other.
6. The turbine blade of claim 5, wherein the two rails are formed
from outer and inner rails that each form a continuous ring.
7. The turbine blade of claim 1, wherein the squealer tip is
attached to the tip with a transient liquid phase bond.
8. The turbine blade of claim 1, wherein the squealer tip is
attached to the tip with an additive manufacturing process.
9. The turbine blade of claim 8, wherein the additive manufacturing
process is a selective laser melting process.
10. The turbine blade of claim 8, wherein the additive
manufacturing process is a direct metal laser sintering.
11. The turbine blade of claim 1, wherein the squealer tip is
attached to the tip with a mechanical attachment system.
12. The turbine blade of claim 11, wherein the mechanical
attachment system is a dovetail attachment system.
13. A turbine blade, comprising: a generally elongated blade having
a leading edge, a trailing edge, a tip 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 blade to a disc,
and at least one cavity forming a cooling system in the blade; and
a squealer tip coupled to the tip at the first end, wherein the
squealer tip is formed from two rails extending radially outward
and spaced apart from each other.
14. The turbine blade of claim 13, wherein the two rails are formed
from outer and inner rails that each form a continuous ring.
15. The turbine blade of claim 13, wherein the squealer tip is
formed from a material selected from the group consisting of oxide
dispersion strengthened alloys PM2000 and ODM 751 and FeCrAl alloys
of APMT.
16. The turbine blade of claim 13, wherein the squealer tip is
attached to the tip with a transient liquid phase bond.
17. The turbine blade of claim 13, wherein the squealer tip is
attached to the tip with an additive manufacturing process selected
from the group consisting of a selective laser melting process and
a direct metal laser sintering.
18. The turbine blade of claim 13, wherein the squealer tip is
attached to the tip with a mechanical attachment system.
19. A turbine blade, comprising: a generally elongated blade having
a leading edge, a trailing edge, a tip at a first end, a root
coupled to the blade at an end generally opposite the first end for
supporting the blade and for coupling the blade to a disc, and at
least one cavity forming a cooling system in the blade; and a
squealer tip coupled to the tip at the first end, wherein the
squealer tip is formed from a material selected from the group
consisting of oxide dispersion strengthened alloys and FeCrAl
alloys; wherein the squealer tip is attached to the tip with a
transient liquid phase bond.
20. The turbine blade of claim 19, wherein the oxide dispersion
strengthened alloys comprise PM2000 and ODM 751, and the FeCrAl
alloy comprises APMT.
21. The turbine blade of claim 19, wherein the squealer tip is
comprised of a plurality of segmented tips extending radially
outward and spaced apart from each other.
Description
FIELD OF THE INVENTION
[0001] This invention is directed generally to turbine blades, and
more particularly to tip sealing systems for turbine blades.
BACKGROUND
[0002] 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.
[0003] Typically, turbine blades are formed from a root portion at
one end and an elongated portion forming an airfoil that extends
outwardly from a platform coupled to the root portion at an
opposite end of the turbine blade. The blade is ordinarily composed
of a tip opposite the root section, a leading edge, and a trailing
edge. The tip of a turbine blade often has a tip seals to reduce
the gap between ring segments and blades in the gas path of the
turbine. The tip seals are often referred to as squealer tips and
are frequently incorporated onto the tips of blades to help reduce
pressure losses between turbine stages. These features are designed
to minimize the gap between the blade tip and the ring segment. The
material at the tip is exposed to the hot gas path because there is
not a ceramic thermal barrier coating on the squealer tips.
Squealer tips are integrally cast with the turbine blade. Turbine
engines are being run at higher and higher temperatures in an
effort to create increasing amounts of power from the engines.
These higher temperatures are creating increased thermal stress
levels on the turbine airfoils.
[0004] The inner aspects of most turbine blades typically contain
an intricate maze of cooling channels forming a cooling system. 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.
SUMMARY OF THE INVENTION
[0005] A turbine blade having a squealer tip coupled to a radially
outer end of the turbine blade that is usable in a gas turbine
engine is disclosed. The squealer tip may be configured such that
the squealer tip requires less cooling fluids than conventional
squealer tips, therefore increasing the efficiency of the turbine
engine in which the squealer tip is used. In at least one
embodiment, the squealer tip may use about 1.5 percent less cooling
fluids than conventional turbine blades. In addition, the squealer
tip may also be configured to be used in turbine engines that are
designed to operate at higher operating temperatures than
conventional turbine engines. The squealer tip may be formed from a
material that is different than the material forming the turbine
blade.
[0006] The turbine blade may be formed from a generally elongated
blade having a leading edge, a trailing edge, a tip wall at a first
end, a root coupled to the blade at an end generally opposite the
first end for supporting the blade and for coupling the blade to a
disc, and at least one cavity forming a cooling system in the
blade. The squealer tip may be coupled to the tip at the first end.
The squealer tip may be formed from a material selected from the
group consisting of oxide dispersion strengthened alloys and FeCrAl
alloys. The oxide dispersion strengthened alloys may include, but
are not limited to, PM2000 and ODM 751, and the FeCrAl alloy may
include, but are not limited to, APMT.
[0007] The squealer tip may be formed from a plurality of segmented
tips extending radially outward and spaced apart from each other to
relieve thermal stress at the tip. To relieve thermal stress in the
squealer tip, the squealer tip may be formed from two rails
extending radially outward and spaced apart from each other. The
two rails may be formed from outer and inner rails that each form a
continuous ring.
[0008] The squealer tip may be attached to the tip using a joining
method such as transient liquid phase bonding. Alternatively, the
squealer tip may be attached to the tip with an additive
manufacturing process. The additive manufacturing process may be a
selective laser melting process or a direct metal laser sintering
process.
[0009] An advantage of this invention is that the squealer tip may
enable turbine blade tips to be exposed to higher temperatures
without an increased risk of failure.
[0010] Another advantage of this invention is that the squealer tip
may be made with materials that would reduce cooling requirements
at the tip and improve blade clearance while increasing the
operating efficiency of the turbine engine by about 1/2
percent.
[0011] Yet another advantage of this invention is that the squealer
tip may be formed from segmented tips to alleviate thermal stress
in the squealer tip.
[0012] These and other embodiments are described in more detail
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] 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.
[0014] FIG. 1 is a perspective view of a turbine blade having
features according to the instant invention.
[0015] FIG. 2 is top view of the turbine blade.
[0016] FIG. 3 is a detailed, side view of a squealer tip.
[0017] FIG. 4 is a partial side of a squealer tip being formed in a
mechanical attachment system.
[0018] FIG. 5 is a partial side view of a squealer tip attached to
a tip of the turbine blade.
DETAILED DESCRIPTION OF THE INVENTION
[0019] As shown in FIGS. 1-5, this invention is directed to a
turbine blade 10 having a squealer tip 12 for use in turbine
engines. The squealer tip 12 may be configured such that the
squealer tip 12 requires less cooling fluids than conventional
squealer tips, thereby increasing the efficiency of the turbine
engine in which the squealer tip 12 is used. In at least one
embodiment, the squealer tip 12 may use about 1.5 percent less
cooling fluids than conventional turbine blades. In addition, the
squealer tip 12 may also be configured to be used in turbine
engines that are designed to operate at higher operating
temperatures than conventional turbine engines without an increased
risk of failure.
[0020] The squealer tip 12 may be attached to a radially outward
tip 14 of a turbine blade 10. The turbine blade 10 may be formed
from a generally elongated airfoil 16 having a leading edge 18, a
trailing edge 20, the tip 14 at a first end 24, a root 26 coupled
to the blade 10 at an end 28 generally opposite the first end 24
for supporting the blade 10 and for coupling the blade 10 to a
disc, and one or more cavities forming a cooling system in the
blade 10. The cooling system may have any appropriate configuration
within internal aspects of the elongated blade 16.
[0021] The squealer tip 12 may be coupled to the tip 14 at the
first end 24. The squealer tip 12 may be formed from a material
having high temperature oxidation and corrosion properties. The
squealer tip 12 may be formed from materials that are different
from the turbine blade 10. The material may be, but is not limited
to, an oxide dispersion strengthened alloy, such as, but not
limited to, PM2000 and ODM 751. The material may also be an
advanced dispersion strengthened powder metallurgy FeCrAl alloy,
such as, but not limited to Kanthal APMT. These materials are
capable of withstanding temperatures in excess of 1200 degrees
Celsius in an uncoated condition.
[0022] The squealer tip 12 may be configured such that the squealer
tip 12 is formed from a plurality of segmented tips 32 extending
radially outward and spaced apart from each other, as shown FIG. 3.
The tips 32 may include channels 34 between each adjacent tip 32.
The segments tips 32 may be aligned with each other or otherwise
positioned. The channels 34 may extend any appropriate depth into
the squealer tip 12 but not completely through the squealer tip 12
and into the tip 14 of the turbine blade 10. The channels 34 may be
square, rectangular, or have any other appropriate cross-sectional
configuration.
[0023] In one embodiment, as shown in FIG. 2, the squealer tip 12
may be formed from two rails 36, 38 extending radially outward and
spaced apart from each other. The rails 36, 38 may be formed from
inner and outer rails 36, 38 that each form a continuous ring.
[0024] The squealer tip 12 may be formed using powder manufacturing
systems that enable easy buildup of different structures on the tip
14 of the turbine blade 10. The squealer tip 12 may be manufactured
using an additive manufacturing technique such as selective laser
melting (SLM), direct metal laser sintering (DMLS) or via the
attachment of a preform by techniques such as transient liquid
phase (TLP) bonding. Such a system enables multiple rails, such as
rails 36, 38, to be formed, which may have increased efficiencies.
In particular, these manufacturing systems enable the formation of
the inner and outer rails 36, 38 that follow the exterior shape of
the turbine blades 10.
[0025] As shown in FIGS. 4 and 5, the squealer tip 12 may be
attached to the tip 14 via a mechanical attachment system 36. The
mechanical attachment system 36 may be any cavity having a ledge
under which the squealer tip 12 may be attached. As shown in FIG.
4, a powder may be placed in a cavity and sintered therein to build
the squealer tip 12. As shown in FIG. 5, the squealer tip 12 may
extend radially outward from the tip 14. The mechanical attachment
system 36 may be a dovetail attachment system 38, as shown in FIG.
5.
[0026] 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.
* * * * *