U.S. patent application number 12/222067 was filed with the patent office on 2010-02-04 for compressor blade leading edge shim and related method.
This patent application is currently assigned to General Electric Company. Invention is credited to David A. Helmick, Surinder S. Pabla, Jeffrey Roberts, Jon C. Schaeffer.
Application Number | 20100028160 12/222067 |
Document ID | / |
Family ID | 41558615 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100028160 |
Kind Code |
A1 |
Schaeffer; Jon C. ; et
al. |
February 4, 2010 |
Compressor blade leading edge shim and related method
Abstract
A method of improving an erosion resistance at the leading edge
of a compressor blade includes: a) cleaning a leading edge portion
of the compressor blade airfoil; and b) attaching one or more
erosion or corrosion-resistant shims to the leading edge
portion.
Inventors: |
Schaeffer; Jon C.;
(Simpsonville, SC) ; Pabla; Surinder S.; (Greer,
SC) ; Helmick; David A.; (Fountain Inn, SC) ;
Roberts; Jeffrey; (Simpsonville, SC) |
Correspondence
Address: |
NIXON & VANDERHYE P.C.
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
41558615 |
Appl. No.: |
12/222067 |
Filed: |
July 31, 2008 |
Current U.S.
Class: |
416/224 ;
29/889.71 |
Current CPC
Class: |
F01D 5/005 20130101;
Y10T 29/49337 20150115; F01D 5/28 20130101; F04D 29/023 20130101;
F05D 2260/95 20130101; F05D 2300/2284 20130101; F05D 2230/80
20130101; F05D 2240/303 20130101; F04D 29/324 20130101; F05D
2230/23 20130101 |
Class at
Publication: |
416/224 ;
29/889.71 |
International
Class: |
F04D 29/38 20060101
F04D029/38 |
Claims
1. A compressor blade comprising an airfoil portion and a mounting
portion; the airfoil portion having leading and trailing edges, the
leading edge having an erosion-resistant shim attached thereto.
2. The compressor blade of claim 1 wherein said shim is comprised
of a material selected from a group comprising TiN, Ti/TiN,
TiN/CrN, NiCrWC.
3. The compressor blade of claim 1 wherein the shim is composed at
least in part of a composition selected from a group comprising Cr,
Al or Ti-rich materials.
4. The compressor blade of claim 1 wherein the shim is comprised of
a metal coated with an erosion or corrosion resistant material.
5. The compressor blade of claim 1 wherein said shim is attached by
welding, brazing or soldering.
6. The compressor blade of claim 1 wherein said shim is attached by
adhesive.
7. The compressor blade of claim 1 wherein said shim comprises
plural shim segments.
8. The compressor blade of claim 1 wherein said shim is between
about 1 and about 25 mils thick.
9. The compressor blade of claim 1 wherein said shim is made of a
polymeric material.
10. The compressor blade of claim 9 wherein said polymeric material
comprises polypropylene.
11. A method of improving an erosion/corrosion resistance at the
leading edge portion of a compressor blade airfoil comprising: a)
preparing the leading edge portion of the compressor blade airfoil;
and b) attaching one or more shims to said leading edge
portion.
12. The method of claim 11 wherein step (a) is carried out by
milling, shot-peening, grit blasting, vibratory finishing or
combinations thereof.
13. The method of claim 11 wherein said shim said shim is comprised
of a material selected from a group comprising TiN, Ti/TiN,
TiN/CrN, NiCrWC.
14. The method of claim 11 wherein the shim is composed at least in
part of a composition selected from a Cr, Al or Ti-rich
material.
15. The method of claim 11 wherein the shim is comprised of a metal
coated with an erosion or corrosion resistant material.
16. The method of claim 11 wherein said shim is attached by
welding, brazing or soldering.
18. The method of claim 11 wherein said shim is attached by
adhesive.
19. The method of claim 11 wherein said shim is made of a
polyurethane tape.
20. The method of claim 11 wherein said shim is made of a polymeric
material.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to turbine technology and,
more specifically, to an article and a method for mitigating damage
caused by compressor blade leading edge erosion and/or
corrosion.
[0002] Compressor blade leading edge erosion/corrosion is a common
problem in turbine engines. Turbine blades, and particularly the
leading edges of the turbine compressor blades or airfoils, are
particularly susceptible to erosion and/or corrosion resulting from
exposure to harsh environments. Repair and/or replacement of
damaged turbine blades requires costly downtime that may not
coincide with normal service intervals.
[0003] It would be advantageous, therefore, to develop techniques
or processes to mitigate the incidence or damage caused by erosion
and/or corrosion of blade leading edges.
BRIEF DESCRIPTION OF THE INVENTION
[0004] In accordance with one exemplary but nonlimiting embodiment,
the invention relates to a compressor blade comprising an airfoil
portion and a mounting portion; the airfoil portion having leading
and trailing edges, the leading edge having an erosion or
corrosion-resistant shim attached thereto.
[0005] In another aspect, the invention relates to a method of
improving erosion or corrosion resistance at the leading edge of a
compressor blade airfoil comprising: a) cleaning a leading edge
portion of the compressor blade airfoil; and b) attaching one or
more erosion or corrosion-resistant shims to the leading edge
portion.
[0006] The invention will now be described in more detail in
connection with the drawings identified below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of a compressor blade in
accordance with an exemplary embodiment of the invention; and
[0008] FIG. 2 is a section taken along the line 2-2 in FIG. 1, but
with the shim exaggerated in scale.
DETAILED DESCRIPTION OF THE INVENTION
[0009] With reference to FIG. 1, a vane or blade 10, e.g., a
turbine compressor blade, includes an airfoil portion 12 and a
dovetail mounting portion 14. The airfoil portion 12 has a leading
edge 16, a trailing edge 18, a pressure side 20 and a suction side
22.
[0010] It is the leading edge 16 that is most susceptible to
erosion and/or corrosion due to incoming air flow (containing, for
example, dry particles, salt fog, etc.) at the compressor
inlet.
[0011] In accordance with a non-limiting exemplary embodiment of
this invention, one or more shims 24 may be applied to the leading
edge 16 of the airfoil portion. With further reference to FIG. 2,
the shim 24 substantially encloses the leading edge 16, extending
into both the pressure and suction sides 20, 22 of the airfoil.
Note that in FIG. 2, the shim is shown in greatly exaggerated scale
simply to facilitate an understanding of the invention. One shim
may extend along part or substantially the entire length of the
leading edge, or alternatively, plural shim segments may be
employed to reduce shear strain at the airfoil/shim interface.
[0012] In a preferred configuration, the shim 24 has a thickness in
a range of from 1 to 30 mils. The shim or shims may be composed of
corrosion-resistant compositions including Cr-rich materials such
as Ni-25Cr sheet; Al-rich or Ti-rich materials. Alternatively,
hard, erosion resistant materials such as TiN, Ti/TiN, TiN/CrN,
NiCrWC, etc. may be employed. The shim or shims could also be
constructed of an erosion-resistant polymeric material such as
polypropylene, or a corrosion-resistant tape, e.g., 3M Protective
Polyurethane Tape, having a thickness of about 1-10 mils. It will
be appreciated that the shim or shims may also be constructed of a
suitable metal coated with an erosion or corrosion resistant
material, i.e., using a powder form of the compositions mentioned
above.
[0013] The shim or shims 24 in metal form may be attached to the
leading edge 16 by any of several known techniques such as, for
example, welding, brazing, soldering and/or by an adhesive film.
One suitable adhesive film is available under the name 3M
Structural Adhesive Tape. Additional adhesive material shown at 26,
28, may be applied along the edges 30, 32 of the metal shim in
order to smooth out shim edges where they interface with the
airfoil.
[0014] In any event, thermal expansion characteristics of the
airfoil and shim should be matched to the extent possible to reduce
the amount of cyclic straining, noting that in the front end of the
machine temperature swings are relatively mild, i.e., from about
70.degree. F. to about 400.degree. F. In this regard, low
temperature adhesive for attaching the metal shims, or for use as
the shims themselves, are advantageous in that no cutting is
required, thus preserving the properties of the base metal.
[0015] Prior to the attachment of one or more shims 24, surface
preparation at the leading edge 16 is required through milling,
shot-peening, grit blasting, vibratory finishing or combinations of
the above. For attachment of a shim by means of a high pressure
adhesive tape such as the 3M structural adhesive tape mentioned
above, additional preparation is required. For example, the facing
surfaces of the shim and the airfoil leading edge may be rinsed,
alkaline-degreased, etched, dried, primed and cured. After the shim
is applied by means of the adhesive tape, the blade may be placed
in an autoclave, for example, for curing the adhesive.
[0016] When utilizing a low temperature adhesive such as the 3M
Protective Polyurethane Tape as the shim, the facing surfaces
simply need to be rinsed and degreased prior to application of the
tape.
[0017] It is contemplated that the shims described herein would be
added to blades at the time of manufacture. On the other hand, they
could be retrofitted to existing blades so long as the blades are
in acceptable condition.
[0018] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *