U.S. patent application number 14/077873 was filed with the patent office on 2015-05-14 for turbomachine airfoil erosion determination.
This patent application is currently assigned to General Electric Company. The applicant listed for this patent is General Electric Company. Invention is credited to Kelsey Elizabeth Beach, Alexander James Pistner, Jacob Andrew Salm, Birol Turan.
Application Number | 20150132127 14/077873 |
Document ID | / |
Family ID | 51897142 |
Filed Date | 2015-05-14 |
United States Patent
Application |
20150132127 |
Kind Code |
A1 |
Salm; Jacob Andrew ; et
al. |
May 14, 2015 |
TURBOMACHINE AIRFOIL EROSION DETERMINATION
Abstract
A system may include at least one computer device configured to
attain a two-dimensional used profile of a leading edge at a
specified radial position on a turbomachine airfoil after use. The
system aligns opposing substantially straight alignment portions of
the two-dimensional used profile with opposing substantially
straight alignment portions of a previously attained,
two-dimensional, baseline profile of the turbomachine airfoil. The
alignment portions of each profile are in substantially identical
radial locations of the turbomachine airfoil. Comparing the used
profile to the baseline profile determines whether the leading edge
at the specified radial position of the used turbomachine airfoil
has erosion. The system may also include a laser profiler for
measuring the turbomachine airfoil.
Inventors: |
Salm; Jacob Andrew;
(Taylors, SC) ; Beach; Kelsey Elizabeth;
(Marietta, GA) ; Pistner; Alexander James;
(Atlanta, GA) ; Turan; Birol; (Kocaeli,
TR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
51897142 |
Appl. No.: |
14/077873 |
Filed: |
November 12, 2013 |
Current U.S.
Class: |
416/1 ;
416/61 |
Current CPC
Class: |
G01M 5/0016 20130101;
F01D 21/003 20130101; G01M 5/0033 20130101; G01M 5/0075 20130101;
G01B 11/24 20130101 |
Class at
Publication: |
416/1 ;
416/61 |
International
Class: |
F01D 21/00 20060101
F01D021/00 |
Claims
1. A system comprising: at least one computer device configured to
perform the steps of: attaining a two-dimensional used profile of a
leading edge at a specified radial position on a turbomachine
airfoil after use; aligning opposing substantially straight
alignment portions of the two-dimensional used profile with
opposing substantially straight alignment portions of a previously
attained two-dimensional, baseline profile of the turbomachine
airfoil, the alignment portions of each profile being in
substantially identical radial locations of the turbomachine
airfoil; and comparing the used profile to the baseline profile to
determine whether the leading edge at the specified radial position
of the used turbomachine airfoil has erosion.
2. The system of claim 1, wherein the at least one computer device
is configured to perform attaining the baseline profile, including:
receiving a raw baseline profile of the leading edge of the
turbomachine airfoil as measured by a profiler; normalizing the raw
baseline profile to attain the baseline profile by: identifying
opposing substantially straight alignment portions of the raw
baseline profile at a specified depth range from the leading edge
of the raw baseline profile; determining a compare angle of each
opposing alignment portion relative to an axis centered at the
leading edge of the raw baseline profile, and extending each
alignment portion past the leading edge to identify an intersection
point; and attaining the baseline profile by translating the raw
baseline profile to place the intersection point on the axis and
rotating the raw baseline profile to make the compare angles of
each alignment portion equal relative to the axis.
3. The system of claim 2, wherein the attaining of the used profile
includes: receiving a raw, two-dimensional used profile of the
leading edge at the specified radial position on the turbomachine
airfoil after use; identifying the opposing substantially straight
alignment portions of the raw used profile by performing a linear
regression; and attaining the used profile by performing any
translating and rotating of the raw used profile necessary to allow
aligning of the opposing substantially straight alignment portions
of the raw used profile with the opposing substantially straight
alignment portions of the baseline profile.
4. The system of claim 2, wherein the raw baseline profile of the
leading edge of the turbomachine airfoil is measured by a profiler
prior to use of the turbomachine airfoil.
5. The system of claim 1, wherein the attaining includes attaining
a plurality of two-dimensional used profiles of the leading edge at
a plurality of specified radial positions on the turbomachine
airfoil; and the at least one computer device is further configured
to perform the steps of: aligning and comparing each
two-dimensional used profile to a previously attained,
two-dimensional, baseline profile of the leading edge at a
respective specified radial position on the turbomachine airfoil to
determine whether the leading edge at the respective specified
radial position has erosion.
6. The system of claim 1, wherein the attaining includes attaining
a two-dimensional used profile of a leading edge at a specified
radial position on a plurality of circumferentially adjacent
turbomachine airfoils after use; and the at least one computer
device is further configured to perform the steps of: aligning and
comparing each two-dimensional used profile to a previously
attained two-dimensional, baseline profile of the leading edge at
the specified radial position of a respective turbomachine airfoil
to determine whether the leading edge at the specified radial
position of each turbomachine airfoil has erosion.
7. The system of claim 6, wherein the at least one computer device
is further configured to performs the steps of determining a trend
in the two-dimensional used profiles of the plurality of
turbomachine airfoils, and predicting a need for replacement or
repair of at least one turbomachine airfoil.
8. The system of claim 1, further comprising a laser profiler for
measuring, during a point of non-use of the turbomachine airfoil,
the two-dimensional used profile of the leading edge at the
specified radial position on the turbomachine airfoil.
9. The system of claim 8, further comprising a mount for mounting
the laser profiler for measuring of the two-dimensional profile at
the specified radial position.
10. The system of claim 9, wherein the mount includes: a base
configured to interact with at least one of: a rotor wheel, a shank
of the turbomachine airfoil and an airfoil portion of the
turbomachine airfoil, a support for supporting the laser profiler,
and an elongated member for positioning the support relative to the
base such that the laser profiler senses at the specified radial
position.
11. A computer-implemented method comprising: attaining a
two-dimensional used profile of a leading edge at a specified
radial position on a turbomachine airfoil after use; aligning
opposing substantially straight alignment portions of the
two-dimensional used profile with opposing substantially straight
alignment portions of a previously attained, two-dimensional,
baseline profile of the turbomachine airfoil, the alignment
portions of each profile being in substantially identical radial
locations of the turbomachine airfoil; and comparing the used
profile to the baseline profile to determine whether the leading
edge at the specified radial position of the used turbomachine
airfoil has erosion.
12. The method of claim 11, further comprising attaining the
baseline profile, including: receiving a raw baseline profile of
the leading edge of the turbomachine airfoil as measured by a
profiler; normalizing the raw baseline profile to attain the
baseline profile by: identifying opposing substantially straight
alignment portions of the raw baseline profile at a specified depth
range from the leading edge of the raw baseline profile;
determining a compare angle of each opposing alignment portion
relative to an axis centered at the leading edge of the raw
baseline profile, and extending each alignment portion past the
leading edge to identify an intersection point; and attaining the
baseline profile by translating the raw baseline profile to place
the intersection point on the axis and rotating the raw baseline
profile to make the compare angles of each alignment portion equal
relative to the axis.
13. The method of claim 12, wherein the raw baseline profile of the
leading edge of the turbomachine airfoil is measured by a profiler
prior to use of the turbomachine airfoil.
14. The method of claim 12, wherein the attaining the used profile
includes: receiving a raw, two-dimensional used profile of the
leading edge at the specified radial position on the turbomachine
airfoil after use; identifying the opposing substantially straight
alignment portions of the raw used profile by performing a linear
regression; and attaining the used profile by performing any
translating and rotating of the raw used profile necessary to allow
aligning of the opposing substantially straight alignment portions
of the used profile with the opposing substantially straight
alignment portions of the baseline profile.
15. The method of claim 11, further comprising repeating the
attaining, aligning and comparing for a plurality of radial
positions on the leading edge of the turbomachine airfoil.
16. The method of claim 11, further comprising repeating the
attaining, aligning and comparing for a plurality of turbomachine
airfoils of a particular stage of the turbomachine.
17. The method of claim 16, further comprising determining a trend
in the two-dimensional used profiles of the plurality of
turbomachine airfoils, and using the trend to predict a need for
replacement or repair of the turbomachine airfoil.
18. The method of claim 11, further comprising repeating the
attaining, aligning and comparing for the turbomachine airfoil over
a period of usage of the turbomachine airfoil.
19. The method of claim 11, further comprising mounting a laser
profiler for measuring of the two-dimensional used profile at the
specified radial position using a mount configured to ensure the
laser profiler senses at the specified radial position.
20. A program product stored on a computer readable medium for
determining erosion of a turbomachine airfoil, the computer
readable medium comprising program code for performing the
following steps: attaining a two-dimensional used profile of a
leading edge at a specified radial position on a turbomachine
airfoil after use; aligning opposing substantially straight
alignment portions of the two-dimensional used profile with
opposing substantially straight alignment portions of a previously
attained, two-dimensional, baseline profile of the turbomachine
airfoil, the alignment portions of each profile being in
substantially identical radial locations of the turbomachine
airfoil; and comparing the used profile to the baseline profile to
determine whether the leading edge at the specified radial position
of the used turbomachine airfoil has erosion.
Description
BACKGROUND OF THE INVENTION
[0001] The disclosure relates generally to turbomachine airfoils
and, more particularly, to a method and system for turbomachine
airfoil erosion determination.
[0002] Turbomachine airfoils erode over time in all settings in
which they are used. For example, compressor blade erosion is of
concern with gas turbines operating with evaporative coolers, inlet
foggers, and water wash operations.
[0003] Several inspection methods for erosion on turbomachine
airfoils have been attempted. In one approach, a three-dimensional
scanner or optical system is used. These inspection systems require
line of sight to the blade being measured, preventing an in-situ
measurement. In another approach, a caliper device is used to
measure the chord length of the compressor blade. Chord length is a
length between a leading edge and a trailing edge of a turbomachine
airfoil. A change in chord length is an indicator of erosion. In
this setting, the caliper device must be positioned parallel to the
platform of the compressor blades for proper measuring. This
approach has proven to be unreliable for prediction of overall
chord loss or erosion, in part, because it is not easily
repeatable, which results in inadequate accuracy.
[0004] In another approach, a laser profiler has been used to
obtain a profile of a leading edge of a turbomachine airfoil, and a
complicated geometrical mathematical determination of a width of
the leading edge based on a centroid of the profile is performed.
The measured leading edge width is then compared to a predetermined
distance to determine whether erosion has occurred. This approach
is oftentimes unworkable because manufacturing variation in certain
turbomachine airfoils is too large to allow determination of
erosion by measuring leading edge width. More specifically, the
original airfoil profiles and, consequently, lateral edge widths
are oftentimes not manufactured with sufficient uniformity to allow
erosion determination based on a changed leading edge width after a
period of use.
BRIEF DESCRIPTION OF THE INVENTION
[0005] A first aspect of the invention is directed to a system
comprising at least one computer device configured to perform the
steps of: attaining a two-dimensional used profile of a leading
edge at a specified radial position on a turbomachine airfoil after
use; aligning opposing substantially straight alignment portions of
the two-dimensional used profile with opposing substantially
straight alignment portions of a previously attained,
two-dimensional, baseline profile of the turbomachine airfoil, the
alignment portions of each profile being in substantially identical
radial locations of the turbomachine airfoil; and comparing the
used profile to the baseline profile to determine whether the
leading edge at the specified radial position of the used
turbomachine airfoil has erosion.
[0006] A second aspect of the disclosure provides a
computer-implemented method comprising: attaining a two-dimensional
used profile of a leading edge at a specified radial position on a
turbomachine airfoil after use; aligning opposing substantially
straight alignment portions of the two-dimensional used profile
with opposing substantially straight alignment portions of a
previously attained, two-dimensional, baseline profile of the
turbomachine airfoil, the alignment portions of each profile being
in substantially identical radial locations of the turbomachine
airfoil; and comparing the used profile to the baseline profile to
determine whether the leading edge at the specified radial position
of the used turbomachine airfoil has erosion.
[0007] A program product stored on a computer readable medium for
determining erosion of a turbomachine airfoil, the computer
readable medium comprising program code for performing the
following steps: attaining a two-dimensional used profile of a
leading edge at a specified radial position on a turbomachine
airfoil after use; aligning opposing substantially straight
alignment portions of the two-dimensional used profile with
opposing substantially straight alignment portions of a previously
attained, two-dimensional, baseline profile of the turbomachine
airfoil, the alignment portions of each profile being in
substantially identical radial locations of the turbomachine
airfoil; and comparing the used profile to the baseline profile to
determine whether the leading edge at the specified radial position
of the used turbomachine airfoil has erosion.
[0008] The illustrative aspects of the present disclosure are
designed to solve the problems herein described and/or other
problems not discussed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] These and other features of this disclosure will be more
readily understood from the following detailed description of the
various aspects of the disclosure taken in conjunction with the
accompanying drawings that depict various embodiments of the
disclosure, in which:
[0010] FIG. 1 shows a schematic drawing of a system for
turbomachine airfoil erosion determination according to embodiments
of the invention.
[0011] FIG. 2 shows a perspective view of a laser profiler of the
system of FIG. 1 according to embodiments of the invention.
[0012] FIG. 3 shows a graphical representation of a comparison
between two-dimensional profiles of a leading edge and a base line
profile of the same turbomachine airfoil according to embodiments
of the invention.
[0013] FIG. 4 shows a flow diagram of a process of determining
erosion according to embodiments of the invention.
[0014] FIGS. 5-9 show graphical representations of a process of
determining erosion in a turbomachine airfoil according to
embodiments of the invention.
[0015] It is noted that the drawings of the disclosure are not to
scale. The drawings are intended to depict only typical aspects of
the disclosure, and therefore should not be considered as limiting
the scope of the disclosure. In the drawings, like numbering
represents like elements between the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0016] As indicated above, the disclosure provides for erosion
determination of a turbomachine airfoil. The teachings of the
invention may be applied to any variety of turbomachine airfoil
including but not limited to blades or nozzles of: a compressor,
gas turbine, steam turbine, jet engine, etc. In general terms, a
system, method or program product according to embodiments of the
invention attains a two-dimensional used profile of a leading edge
at a specified radial position on a turbomachine airfoil after use,
e.g., using a laser profiler. Opposing substantially straight
alignment portions of the two-dimensional used profile are aligned
with opposing substantially straight alignment portions of a
previously attained, two-dimensional, baseline profile of the
turbomachine airfoil. The alignment portions of each profile are in
substantially identical radial locations of the turbomachine
airfoil. A comparison of the used profile to the baseline profile
then determines whether the leading edge at the specified radial
position of the used turbomachine airfoil has erosion.
[0017] As will be appreciated by one skilled in the art, the
present invention may be embodied as a system, method or computer
program product. Accordingly, the present invention may take the
form of an entirely hardware embodiment, an entirely software
embodiment (including firmware, resident software, micro-code,
etc.) or an embodiment combining software and hardware aspects that
may all generally be referred to herein as a "circuit," "module" or
"system." Furthermore, the present invention may take the form of a
computer program product embodied in any tangible medium of
expression having computer-usable program code embodied in the
medium.
[0018] Any combination of one or more computer usable or computer
readable medium(s) may be utilized. The computer-usable or
computer-readable medium may be, for example but not limited to, an
electronic, magnetic, optical, electromagnetic, infrared, or
semiconductor system, apparatus, device, or propagation medium.
More specific examples (a non-exhaustive list) of the
computer-readable medium would include the following: an electrical
connection having one or more wires, a portable computer diskette,
a hard disk, a random access memory (RAM), a read-only memory
(ROM), an erasable programmable read-only memory (EPROM or Flash
memory), an optical fiber, a portable compact disc read-only memory
(CD-ROM), an optical storage device, a transmission media such as
those supporting the Internet or an intranet, or a magnetic storage
device. Note that the computer-usable or computer-readable medium
could even be paper or another suitable medium upon which the
program is printed, as the program can be electronically captured,
via, for instance, optical scanning of the paper or other medium,
then compiled, interpreted, or otherwise processed in a suitable
manner, if necessary, and then stored in a computer memory. In the
context of this document, a computer-usable or computer-readable
medium may be any medium that can contain, store, communicate,
propagate, or transport the program for use by or in connection
with the instruction execution system, apparatus, or device. The
computer-usable medium may include a propagated data signal with
the computer-usable program code embodied therewith, either in
baseband or as part of a carrier wave. The computer usable program
code may be transmitted using any appropriate medium, including but
not limited to wireless, wireline, optical fiber cable, RF,
etc.
[0019] Computer program code for carrying out operations of the
present invention may be written in any combination of one or more
programming languages, including an object oriented programming
language such as Java, Smalltalk, C++ or the like and conventional
procedural programming languages, such as the "C" programming
language or similar programming languages. The program code may
execute entirely on the user's computer, partly on the user's
computer, as a stand-alone software package, partly on the user's
computer and partly on a remote computer or entirely on the remote
computer or server. In the latter scenario, the remote computer may
be connected to the user's computer through any type of network,
including a local area network (LAN) or a wide area network (WAN),
or the connection may be made to an external computer (for example,
through the Internet using an Internet Service Provider).
[0020] The present invention is described below with reference to
flowchart illustrations and/or block diagrams of methods, apparatus
(systems) and computer program products according to embodiments of
the invention. It will be understood that each block of the
flowchart illustrations and/or block diagrams, and combinations of
blocks in the flowchart illustrations and/or block diagrams, can be
implemented by computer program instructions. These computer
program instructions may be provided to a processor of a general
purpose computer, special purpose computer, or other programmable
data processing apparatus to produce a machine, such that the
instructions, which execute via the processor of the computer or
other programmable data processing apparatus, create means for
implementing the functions/acts specified in the flowchart and/or
block diagram block or blocks. These computer program instructions
may also be stored in a computer-readable medium that can direct a
computer or other programmable data processing apparatus to
function in a particular manner, such that the instructions stored
in the computer-readable medium produce an article of manufacture
including instruction means which implement the function/act
specified in the flowchart and/or block diagram block or
blocks.
[0021] The computer program instructions may also be loaded onto a
computer or other programmable data processing apparatus to cause a
series of operational steps to be performed on the computer or
other programmable apparatus to produce a computer implemented
process such that the instructions which execute on the computer or
other programmable apparatus provide processes for implementing the
functions/acts specified in the flowchart and/or block diagram
block or blocks.
[0022] Referring now to FIGS. 1-2, embodiments of the invention
will now be described in detail. FIG. 1 shows a schematic drawing
of a computer system 100 for determining turbomachine airfoil
erosion; and FIG. 2 shows a perspective view of a laser profiler
130 of the system of FIG. 1. Referring to FIG. 1, system 100
includes a computer infrastructure 102 that can perform the various
process steps described herein for turbomachine airfoil erosion
determination. In particular, computer infrastructure 102 is shown
including a computing device 104 that comprises an erosion
determination system 106, which enables computing device 104 to
determine turbomachine airfoil erosion by performing the process
steps of the disclosure.
[0023] Computing device 104 is shown including a memory 112, a
processor (PU) 114, an input/output (I/O) interface 116, and a bus
118. Further, computing device 104 is shown in communication with
an external I/O device/resource 120 and a storage system 122. As is
known in the art, in general, processor 114 executes computer
program code, such as erosion determination system 106, that is
stored in memory 112 and/or storage system 122. While executing
computer program code, processor 114 can read and/or write data,
such as turbomachine airfoil erosion determination, to/from memory
112, storage system 122, and/or I/O interface 116. Bus 118 provides
a communications link between each of the components in computing
device 104. I/O device 120 can comprise any device that enables a
user to interact with computing device 104 or any device that
enables computing device 104 to communicate with one or more other
computing devices. Input/output devices (including but not limited
to keyboards, displays, pointing devices, etc.) can be coupled to
the system either directly or through intervening I/O
controllers.
[0024] Computing device 104 can comprise any general purpose
computing article of manufacture capable of executing computer
program code installed by a user (e.g., a personal computer,
server, handheld device, etc.). However, it is understood that
computing device 104 and erosion determination system 106 are only
representative of various possible equivalent computing devices
that may perform the various process steps of the disclosure. To
this extent, in other embodiments, computing device 104 can
comprise any specific purpose computing article of manufacture
comprising hardware and/or computer program code for performing
specific functions, any computing article of manufacture that
comprises a combination of specific purpose and general purpose
hardware/software, or the like. In each case, the program code and
hardware can be created using standard programming and engineering
techniques, respectively.
[0025] Similarly, computer infrastructure 102 is only illustrative
of various types of computer infrastructures for implementing the
disclosure. For example, in one embodiment, computer infrastructure
102 may comprise two or more computing devices (e.g., a server
cluster) that communicate over any type of wired and/or wireless
communications link, such as a network, a shared memory, or the
like, to perform the various process steps of the disclosure. When
the communications link comprises a network, the network can
comprise any combination of one or more types of networks (e.g.,
the Internet, a wide area network, a local area network, a virtual
private network, etc.). Network adapters may also be coupled to the
system to enable the data processing system to become coupled to
other data processing systems or remote printers or storage devices
through intervening private or public networks. Modems, cable modem
and Ethernet cards are just a few of the currently available types
of network adapters. Regardless, communications between the
computing devices may utilize any combination of various types of
transmission techniques.
[0026] As shown in FIG. 1, system 100 may also include a laser
profiler 130 (i.e., as a particular type of I/O device 120). Laser
profiler 130 (also referred to as a sensor) may include any laser
measurement device capable of measuring a two-dimensional profile
of a turbomachine airfoil, as illustrated, for example, in FIG. 3.
As illustrated in FIG. 3, a two-dimensional profile includes a
two-dimensional representation of an airfoil's shape, as a partial,
lateral cross-section. FIG. 3 shows four (4) two-dimensional
profiles: a baseline profile 124 of the airfoil prior to use, and
three (3) used profiles 125, 126, 127 of the airfoil at various
stages of use. One example laser profiler 130 may include a model
HS730LE from Origin Technologies, but other laser profilers may
also be employed.
[0027] With reference to FIG. 2, laser profiler 130 is shown
positioned relative to a turbomachine airfoil 132 for measurement
thereof at a specified radial position R during a point of non-use
(rotational movement) of the turbomachine airfoil. In this setting,
the particular turbomachine airfoil is a blade 132 of a compressor.
As noted herein, the turbomachine airfoil may take a variety of
forms. As known in the art, adjacent blades 134 are arranged
circumferentially adjacent to blade 132 about a rotor 136, and
rotate with the rotor during operation. Stationary nozzle vanes 138
are positioned circumferentially about rotor 136 and axially
adjacent blades 132, 134 to direct the operative fluid towards the
blades. Laser profiler 130 measures a two-dimensional profile of
the leading edge at a specified radial position R on the
turbomachine airfoil. The specified radial position R is
predetermined prior to use of system 100. The radial position may
be selected, for example, to evaluate a position having known
higher erosion issues for the particular stage, airfoil, airfoil
section, etc., of the turbomachine. As will be described herein, a
number of specified radial positions may be used during use of
system 100.
[0028] System 100 may also include a mount 140 for mounting laser
profiler 130 for measuring of the two-dimensional profile at
specified radial position R. Mount 140 allows system 100 to operate
accurately and in a repetitive fashion at the selected radial
position, which is especially advantageous for newer turbomachine
airfoils that have extreme tapers. In one embodiment, mount 140
positions laser profiler 130 between a pair of vanes 138 of a
nozzle stage adjacent to the turbomachine airfoil 132 at issue,
e.g., in the form of a compressor blade. Mount 140 may take a
variety of forms capable of positioning laser profiler 130 at the
specified radial position R. In one embodiment, mount 140 includes:
a base 142 configured to interact with at least one of: a rotor
wheel 144, a shank 146 of turbomachine airfoil 132 and an airfoil
portion 148 of the turbomachine airfoil; a support 150 for
supporting the laser profiler 130, and an elongated member 152 for
positioning the support relative to the base such that the laser
profiler senses at the specified radial position. In one
embodiment, base 142 may be magnetized to adhere to the particular
part(s) and immobilize the base. However, other manners of
immobilizing the base may be employed, e.g., shaping the base so as
not to move when interacting with the particular part(s). Elongated
member 152 may be length adjustable if desired using any now known
or later developed manner. Base 142 may be constructed for a
particular stage of turbomachine airfoil in order to immovably
position laser profiler 130 at the specified radial position for a
plurality of airfoils in the particular stage. Mount 140 may be
provided in sets to accommodate system 100 uses for a variety of
stages, airfoils and turbomachines having different dimensions.
[0029] Returning to FIG. 1, as previously mentioned and discussed
further herein, erosion determination system 106 enables computing
infrastructure 102 to determine turbomachine airfoil erosion. To
this extent, erosion determination system 106 is shown including an
attainer 160, a normalizer 162, an aligner 164, a comparator 166
and a trend module 168. Operation of each of these systems/modules
is discussed further below. It is understood that some of the
various systems shown in FIG. 1 can be implemented independently,
combined, and/or stored in memory for one or more separate
computing devices that are included in computer infrastructure 102.
Further, it is understood that some of the systems and/or
functionality may not be implemented, or additional systems and/or
functionality may be included as part of system 100.
[0030] Referring to FIGS. 1 and 2 along with the flow diagram of
FIG. 4 and the graphical representations of FIGS. 5-9, operation of
system 100 will now be described.
[0031] As a preliminary step S10, attainer 160 (FIG. 1) may attain
a two-dimensional baseline profile of turbomachine airfoil 132,
i.e., where the baseline profile is not already attained and stored
in memory 112 or 122 (FIG. 1). In contrast to conventional
techniques, the use of a baseline profile of the turbomachine
airfoil to determine erosion eliminates concerns relative to
manufacturing variation/non-uniformity since an ideal turbomachine
airfoil is being used for comparison. Two-dimensional baseline
profile 172 (FIG. 6) may be attained in a number of ways. In one
embodiment, described in greater detail herein, baseline profile
may be attained by actually measuring a turbomachine airfoil prior
to use. In another embodiment, also described in greater detail
herein, baseline profile 172 (FIG. 6) may be attained by measuring
the turbomachine airfoil being evaluated after some amount of use
(i.e., a lesser amount of use then when being evaluated for
erosion). In another embodiment, the baseline profile may be
attained from a nominal model, e.g., based on a CAD based
definition of the blade profile.
[0032] Turning to the situations in which baseline profile 172
(FIG. 6) is attained by measuring an actual turbomachine airfoil
(e.g., prior to use or after some amount of use), preliminary step
S10 may include attaining an actual baseline profile by mounting
laser profiler 130 for measuring of a raw, two-dimensional baseline
profile 170 (FIG. 5) at the specified radial position using mount
140. As described relative to FIG. 1, mount 140 is configured to
ensure laser profiler 130 senses at the specified radial position
R. The preliminary attaining step S10 may also include attainer 160
(FIG. 1) receiving a raw baseline profile 170 (FIG. 5) of the
leading edge of the turbomachine airfoil (e.g., prior to use or
after some use) as measured by laser profiler 130 (or receiving it
from memory or another device if already stored).
[0033] As shown in FIG. 5, raw baseline profile 170 represents a
partial, lateral cross-section of the turbomachine airfoil and
indicates a substantially smooth, rounded leading edge with no
erosion. (It is understood that while FIGS. 5-9 illustrate
processing relative to a rounded leading edge, turbomachine airfoil
132 may have a variety of differently shaped leading edges (see,
e.g., the flatter leading edge of FIG. 3)). As illustrated in FIG.
5, raw baselines profile 170 may be askew relative to an origin (of
the X-Y axis) centered at a maximum measured point of the profile.
This translation/rotation of raw baseline profile 170 is due to the
angle at which a turbomachine airfoil twists, tapers, etc. To
accommodate further processing, preliminary attaining step S10 may
also include attainer 160 calling on normalizer 162 (FIG. 1) to
normalize raw baseline profile 170 to attain baseline profile 172,
as shown in FIG. 6. The normalization includes
re-positioning/re-configuring raw baseline profile 170 in a
standardized fashion such that two-dimensional profiles of the
airfoil after use (192, FIG. 8) can be similarly normalized and
thus uniformly compared to the baseline profile, as will be
described herein. The normalizing of raw baseline profile 170 may
take a variety of now known or later developed
mathematical/geometrical calculations. In one embodiment, however,
normalizing may include, as shown in FIGS. 5-6, identifying
opposing substantially straight alignment portions 174 of raw
baseline profile 170 at a specified depth range DR from the leading
edge (at origin) of the raw baseline profile. The depth range used
for a particular turbomachine airfoil for identifying alignment
portions 174 is selected to be sufficiently deep on the airfoil so
as to substantially reduce the possibility of erosion at that
location, and thus may vary from airfoil to airfoil. In one example
airfoil, the depth range may be about 2.5 millimeters to about 5
millimeters.
[0034] As shown in FIG. 5, preliminary attaining step S10 may also
include normalizer 162 determining a compare angle (.alpha.,
.beta.) of each opposing alignment portion 174 relative to an axis
(y-axis) centered at the leading edge (at origin) of raw baseline
profile 170. Normalizer 162 identifies an intersection point
(X.sub.1, Y.sub.1) of alignment portions 174, e.g., by extending
the alignment portions 174 past the leading edge until they
intersect. (The position of intersection point (X.sub.1, Y.sub.1)
away from the Y-axis indicates how raw baseline profile 170 is
askew). Normalizer 162 may also calculate a linear representation
(e.g., y=mx+b) of each alignment portion 174 in raw baseline
profile 170 for comparison with later raw used profiles (190, FIG.
7), as described herein. As shown in FIG. 6, preliminary attaining
step S10 finally includes normalizer 162 attaining baseline profile
172 by translating raw baseline profile 170 to place the
intersection point on the axis (Y-axis) and rotating raw baseline
profile 170 to make the compare angles (now .epsilon. in FIG. 6) of
each alignment portion 174 equal relative to the axis. Baseline
profile 172 is now normalized and in a state that it can be used
for comparison to two-dimensional used profiles (192, FIG. 8) of
the turbomachine airfoil after use. The linear representation
(e.g., y=mx+b) of each alignment portion 174 of raw baseline
profile 170 along with baseline profile 172, as shown in FIG. 6,
may be saved in memory 112 or 122 (FIG. 1). Although a particular
process of normalizing a profile has been described, it is
understood that a variety of alternative processes may be
implemented for a baseline profile or a used profile. For example,
the process of normalizing a profile may be carried out with the
assistance of computer aided design modeling systems.
[0035] Preliminary attaining step S10 may include attaining
baseline profile 172 from a single turbomachine airfoil, e.g.,
prior to use, after an amount of use or based on a nominal model.
Alternatively, the step may also include attaining baseline profile
172 by averaging a plurality of two-dimensional profiles for a
plurality of turbomachine airfoils. Ideally, each turbomachine
airfoil in a particular stage of a turbomachine should be
identical. However, some manufacturing variation is normal.
Consequently, the averaging of, for example, raw baseline profiles
170 to arrive at a (combined) baseline profile 172 may be
advantageous to minimize the impact of any manufacturing variation.
The averaging may occur across a number of locations in a stage of
the turbomachine or a sub-region thereof (e.g., a quadrant). The
averaging technique can be any now known or later developed manner
of averaging point-wise along the particular raw baseline profiles
170 used. The averaging may occur prior to or after the described
normalizing. In any event, baseline profile 172 may include an
average of a plurality of two-dimensional profiles for a plurality
of turbomachine airfoils.
[0036] Returning to FIG. 4 and with reference to FIGS. 7-8, in step
S12, attainer 160 (FIG. 1) attains a two-dimensional used profile
190 (FIG. 7) of a leading edge at a specified radial position on
the turbomachine airfoil after use. Turbomachine airfoil 132 has
been in use and therefore has been exposed to the myriad of
environmental conditions that may cause erosion to a leading edge
thereof. The erosion is indicated by the presence of a rough
leading edge surface 196 (FIG. 7) and a lack of a smooth leading
edge (as in FIGS. 5-6). Step S12 may include aligner 160 carrying
out a number of sub-steps. More specifically, attainer 160 may
receive a raw, two-dimensional used profile 190 (FIG. 7) of the
leading edge at the specified radial position on the turbomachine
airfoil after use, e.g., from profiler 130 or from memory. Laser
profiler 130 measures turbomachine airfoil 132 during point of
non-operation of the turbomachine, e.g., relative to a compressor,
during a down time of the compressor and/or gas turbine system to
which it is operatively coupled. Step S12 also may include attainer
160 calling on normalizer 162 to identify opposing substantially
straight alignment portions 194 of used profile 190 by performing a
linear regression analysis of each opposing side of raw used
profile 190. The linear regression determines the location of
alignment portions 194 of used profile 190 by calculating a linear
representation thereof and comparing it the previously calculated
linear representation for raw baseline profile 170 to ensure that
alignment portions 194 (FIG. 7) correspond to alignment portions
174 (FIG. 5). That is, the slopes of raw two-dimensional used
profile 190 and raw baseline profile 170 are compared to ensure
portions 194 match portions 174. As shown in FIG. 8, attainer 160
may finally attain used profile 192 by performing any translating
and rotating of raw used profile 190 necessary to allow aligning of
the opposing substantially straight alignment portions 194 of raw
used profile 190 with opposing substantially straight alignment
portions 174 of baseline profile 172.
[0037] In step S14, as shown in FIG. 9, aligner 164 (FIG. 1) aligns
opposing substantially straight alignment portions 194 (FIGS. 7-8)
of two-dimensional used profile 190 (FIG. 6) with opposing
substantially straight alignment portions 174 (FIGS. 5-6) of a
previously attained, two-dimensional, baseline profile 172 (FIG. 6)
of the turbomachine airfoil. As alignment portions 174, 194 of each
respective profile 170, 190 are in substantially identical radial
locations of the turbomachine airfoil 132 (FIG. 2), the alignment
of the profiles indicates an amount of erosion 200 existing on the
used turbomachine airfoil. Aligner 164 may align the profiles using
any now known or later developed technique for ensuring overlap of
portions 174, 194 within an acceptable tolerance.
[0038] In step S16, comparator 166 (FIG. 1) compares used profile
190 to baseline profile 170 to determine whether the leading edge
at the specified radial position of the used turbomachine airfoil
has erosion. The determination as to when erosion exists may be
based on a number of characteristics such as erosion 200 being:
greater than a set distance, greater than a certain percentage of a
width at a certain position, etc. The comparing results provide a
measurement of leading edge erosion and therefore airfoil chord
loss.
[0039] System 100 has a technical effect in that it allows for
accurate monitoring of blade leading edge erosion which is
indicative of potential operating restrictions and limitations for
turbomachine airfoil 132. System 100 provides such results in a
repeatable fashion via the use of mount 140. Proper implementation
of the method can enable operability and provide awareness of
low/high risk airfoils. Erosion monitoring may improve turbomachine
(e.g., a gas turbine) operability and reduce costly unplanned
outages as a result of airfoil failures due to erosion and
subsequent crack propagation. In addition, system 100 may enable
asset planning for airfoils (e.g., for forward compressor stages),
extend airfoil life thus saving cost and avoiding unnecessary
outages.
[0040] System 100 may gain additional accuracy and advantage by
using a plurality of two-dimensional used profiles 190 in a number
of ways. In one alternative embodiment, described with reference to
FIGS. 4-6 and step S12, attainer 160 may attain a plurality of
two-dimensional used profiles 192 of the leading edge at a
plurality of specified radial positions R (FIG. 2) on a particular
turbomachine airfoil 132 (FIG. 2). Each used profile 192 is
attained as described herein. In this case, system 100 (computer
device 104) is further configured to: align (with aligner 154) and
compare (with comparator 155) each two-dimensional used profile 192
to a previously attained, two-dimensional, baseline profile 172 of
the leading edge at a respective specified radial position on the
turbomachine airfoil to determine whether the leading edge at the
respective specified radial position has erosion. In this fashion,
a number of locations along turbomachine airfoil 132 length can be
evaluated for erosion.
[0041] In another alternative embodiment, described again with
reference to FIGS. 4-6 and step S12, system 100 may be applied
across a number of turbomachine airfoils in such a way that a trend
in erosion can be determine for, e.g., a particular stage,
sub-region of a stage or a particular turbomachine. In this
embodiment, in step S12, attainer 160 may attain a two-dimensional
used profile of a leading edge at a specified radial position on a
plurality of circumferentially adjacent turbomachine airfoils 132
after use. For example, laser profiler 130 may measure a number of
airfoils 132 within a particular stage or a sub-region (e.g.,
quadrant) of a stage. In this case, system 100 (computer device
104) may be further configured to: align (using aligner 164) and
compare (using comparator 155) each two-dimensional used profile
192 to a previously attained, two-dimensional, baseline profile 172
of the leading edge at the specified radial position R of a
respective turbomachine airfoil 132 to determine whether the
leading edge at the specified radial position of each turbomachine
airfoil has erosion. Here, system 100 can determine erosion for a
number of airfoils 132 (FIG. 2).
[0042] In addition to evaluating a number of airfoils' erosion
levels, in an alternative embodiment, system 100 may also evaluate
for trends within the erosion determinations of the various
airfoils and predict need for replacement. In particular, in
optional step S18, trend module 168 (FIG. 1) may determine a trend
in the two-dimensional used profiles 192 of the plurality of
turbomachine airfoils 132, and predict a need for replacement or
repair of at least one turbomachine airfoil. The determination of a
trend may be carried out using any now known or later developed
trend analysis technique, e.g., using regression analysis. Any form
of a trend may be determined such as accelerated erosion within a
particular quadrant, which may indicate a problem with airfoils
within that quadrant. The prediction of a need for replacement or
repair may be based on any now known or later developed knowledge
base or analytic model for a particular turbomachine, airfoil or
airfoil stage. For example, a certain percentage erosion average
over the airfoils evaluated may indicate need for replacement of
one or more of the airfoils.
[0043] Although described herein as occurring at a specific time,
it is understood that the teachings of the invention may be applied
repeatedly over a period of usage of the turbomachine airfoil(s)
132.
[0044] The flowchart and block diagrams in the Figures illustrate
the architecture, functionality, and operation of possible
implementations of systems, methods and computer program products
according to various embodiments of the present invention. In this
regard, each block in the flowchart or block diagrams may represent
a module, segment, or portion of code, which comprises one or more
executable instructions for implementing the specified logical
function(s). It should also be noted that, in some alternative
implementations, the functions noted in the block may occur out of
the order noted in the figures. For example, two blocks shown in
succession may, in fact, be executed substantially concurrently, or
the blocks may sometimes be executed in the reverse order,
depending upon the functionality involved. It will also be noted
that each block of the block diagrams and/or flowchart
illustration, and combinations of blocks in the block diagrams
and/or flowchart illustration, can be implemented by special
purpose hardware-based systems that perform the specified functions
or acts, or combinations of special purpose hardware and computer
instructions.
[0045] As used herein, various systems and components are described
as "receiving" or "obtaining" data (e.g., two-dimensional profiles
of the turbomachine airfoil, etc.). It is understood that the
corresponding data can be obtained using any solution. For example,
the corresponding system/component can generate and/or be used to
generate the data, retrieve the data from one or more data stores
(e.g., a database) or measurement devices (e.g., laser profiler
130), receive the data from another system/component, and/or the
like. When the data is not generated by the particular
system/component, it is understood that another system/component
can be implemented apart from the system/component shown, which
generates the data and provides it to the system/component and/or
stores the data for access by the system/component.
[0046] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the disclosure. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0047] The corresponding structures, materials, acts, and
equivalents of all means or step plus function elements in the
claims below are intended to include any structure, material, or
act for performing the function in combination with other claimed
elements as specifically claimed. The description of the present
disclosure has been presented for purposes of illustration and
description, but is not intended to be exhaustive or limited to the
disclosure in the form disclosed. Many modifications and variations
will be apparent to those of ordinary skill in the art without
departing from the scope and spirit of the disclosure. The
embodiment was chosen and described in order to best explain the
principles of the disclosure and the practical application, and to
enable others of ordinary skill in the art to understand the
disclosure for various embodiments with various modifications as
are suited to the particular use contemplated.
* * * * *