U.S. patent application number 13/545842 was filed with the patent office on 2014-01-16 for turbine engine fan housing abradable material removal tool and method of abradable material removal.
This patent application is currently assigned to HONDA MOTOR CO., LTD.. The applicant listed for this patent is Michael J. Edmonson, Richard James Gritter. Invention is credited to Michael J. Edmonson, Richard James Gritter.
Application Number | 20140017980 13/545842 |
Document ID | / |
Family ID | 49914370 |
Filed Date | 2014-01-16 |
United States Patent
Application |
20140017980 |
Kind Code |
A1 |
Edmonson; Michael J. ; et
al. |
January 16, 2014 |
TURBINE ENGINE FAN HOUSING ABRADABLE MATERIAL REMOVAL TOOL AND
METHOD OF ABRADABLE MATERIAL REMOVAL
Abstract
Devices and methods by which an amount of an abradable material
may be removed from the housing of a gas turbine engine. A device
of the invention is generally comprised of an abradable material
removal tool having a curved abradable material contacting base
with a handle or other gripping portion extending therefrom. An
abrasive material, such as a sheet of sand paper, may be associated
with a contacting surface of the base. The base is dimensioned and
provided with a shape that permits its insertion between adjacent
leading and trailing fan blades of an engine fan. A manual
back-and-forth rotation of the fan while the abradable material
removal tool is positioned between the fan blades and depressed
against the surface of the abradable material will result in a
controlled removal of abradable material along a path traced by the
tips of the fan blades.
Inventors: |
Edmonson; Michael J.;
(Pleasant Garden, NC) ; Gritter; Richard James;
(Kernersville, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Edmonson; Michael J.
Gritter; Richard James |
Pleasant Garden
Kernersville |
NC
NC |
US
US |
|
|
Assignee: |
HONDA MOTOR CO., LTD.
Tokyo
JP
|
Family ID: |
49914370 |
Appl. No.: |
13/545842 |
Filed: |
July 10, 2012 |
Current U.S.
Class: |
451/28 ;
451/540 |
Current CPC
Class: |
F05D 2230/70 20130101;
F01D 25/285 20130101; B24D 15/023 20130101 |
Class at
Publication: |
451/28 ;
451/540 |
International
Class: |
B24B 1/00 20060101
B24B001/00; B24B 7/00 20060101 B24B007/00 |
Claims
1. A gas turbine engine abradable material removal tool,
comprising: a base having a curved profile that substantially
mimics the curvature of an abradable material lining of a gas
turbine engine of interest, the base having a leading end with a
tapered edge, a trailing end, and an abradable material contacting
surface adapted for association with an abrasive material; and a
rib extending upward from the base.
2. The abradable material removal tool of claim 1, wherein the base
is comprised of a rigid material that retains the curved profile
without assistance.
3. The abradable material removal tool of claim 1, wherein the base
is comprised of a semi-rigid material and the curved profile
thereof is retained with assistance from the rib.
4. The abradable material removal tool of claim 1, wherein the rib
is attached to the base.
5. The abradable material removal tool of claim 1, wherein the rib
and the base are a unitary molded structure.
6. The abradable material removal tool of claim 1, wherein the rib
includes at least one cutout for facilitating use of the rib as a
handle.
7. The abradable material removal tool of claim 1, further
comprising an abrasive material affixed to one side of a carrier
sheet, an opposite side of the carrier sheet removably affixed to
the abradable material contacting surface of the base.
8. The abradable material removal tool of claim 7, wherein the
abrasive material and carrier sheet are parts of a sheet of
sandpaper.
9. The abradable material removal tool of claim 8, wherein the
shape of the sheet of sandpaper is substantially duplicative of the
planform shape of the base.
10. The abradable material removal tool of claim 1, further
comprising a texture on the contacting surface of the base that
serves as the abrasive material.
11. The abradable material removal tool of claim 1, further
comprising an abrasive material embedded in the contacting surface
of the base.
12. The abradable material removal tool of claim 1, wherein the
base is dimensioned to fit between adjacent blades of a fan of a
gas turbine engine of interest.
13. The abradable material removal tool of claim 12, wherein the
taper along the leading end of the base will substantially lie on
an imaginary line between leading tips of the fan blades when the
tool is properly located between adjacent fan blades of the
fan.
14. A tool for removing an amount of an abradable material lining
located within an engine housing and surrounding a fan of a
turbofan jet engine, comprising: a rigid base having a curved
profile that substantially mimics the curvature of the abradable
material lining, the base having a leading end with a tapered edge,
a trailing end, and an abradable material contacting surface
adapted for association with an abrasive medium; a rib extending
upward from the base to act as a handle for gripping and
manipulating the tool; and an abrasive material associated with and
exposed along the abradable material contacting surface of the
base; wherein the base is dimensioned to fit between adjacent
blades of a fan of a gas turbine engine of interest and shaped such
that the taper along the leading end of the base will substantially
lie on an imaginary line between leading tips of adjacent fan
blades when the tool is properly located between adjacent fan
blades of the fan.
15. The abradable material removal tool of claim 14, wherein the
rib is attached to the base and the curvature of the rib along the
line of attachment is substantially the same as the curvature of
the base.
16. The abradable material removal tool of claim 1, wherein the
abrasive material is a sheet of sandpaper that is removably affixed
to the abradable material contacting surface of the base, the sheet
of sandpaper having substantially the same planform shape as the
base.
17. A method of selectively removing an amount of an abradable
material lining located within an engine housing and surrounding a
fan of a turbofan jet engine, comprising: providing an abradable
material removal tool, the abradable material removal tool further
comprising: a base having a curved profile that substantially
mimics the curvature of the abradable material lining of the
turbofan engine of interest, the base having a leading end with a
tapered edge, a trailing end, and an abradable material contacting
surface substantially covered with an exposed abrasive material,
and a rib extending upward from the base, the rib acting as a
handle for gripping and manipulating the tool; locating the tool
between adjacent blades of the turbofan engine fan such that the
abrasive material is in contact with the abradable material lining;
orienting the tool such that the taper along the leading end of the
base will substantially lie on an imaginary line between leading
tips of the adjacent fan blades; if the selected adjacent fan
blades between which the tool is located are not already located in
an area of desired abradable material removal, manually rotating
the fan to so that the blades and tool are so located; pressing the
tool against the abradable material lining with some amount of
force; and manually rotating the fan back-and-forth through an arc
sufficient to pass the tool over a desired area of abradable
material removal while maintaining pressure on the tool.
18. The method of claim 17, wherein the exposed abrasive material
of the abradable material removal tool is a sheet of sandpaper that
is removably affixed to the abradable material contacting surface
of the base.
19. The method of claim 17, wherein the base of the abradable
material removal tool is comprised of a rigid material that retains
the curved profile without assistance.
20. The method of claim 17, wherein the abradable material removal
tool is pressed against the abradable material lining of the engine
during fan rotation by the finger(s) of a user.
Description
BACKGROUND
[0001] A number of gas turbine engines are known and would be
familiar to one of skill in the art. Three common types of jet
aircraft gas turbine engines are the turboprop, the turbojet and
the turbofan, although more exotic and application-specific
embodiments also exist. Each engine achieves the desired end result
of generating thrust that may be used to propel an aircraft, albeit
in a somewhat different manner.
[0002] All gas turbine engines generally include a forward intake
section for capturing and feeding air to the engine. The intake
section is typically followed by a compression section where the
incoming air is compressed by a rotating compressor and
accelerated. The compressed air is then passed into a combustion
section, where heat is added through the burning of fuel to produce
a high-velocity gas stream that is passed to a turbine section. In
the turbine section, the high-velocity gas stream rotates a
turbine, which is connected to and rotates at least the
compressor.
[0003] In a turboprop engine, the turbine portion of the gas
turbine engine is connected by a shaft to the compressor and to a
propeller that (typically) resides forward of and outside of the
turbine engine housing. Rotation of the turbine thus causes a
corresponding rotation of the propeller, which displaces the
surrounding air and produces thrust. In a turbojet engine, the
turbine is still connected to the compressor, but all of the thrust
is typically generated by passing the high-velocity gas stream
through a propelling nozzle at it exits the engine. The nozzle
constricts the flow of the exiting gas stream, thereby maximizing
the velocity thereof.
[0004] Of particular interest in the present application is the
turbofan engine. Like the turboprop and turbojet engine, a turbofan
engine also includes a forward air intake, followed by a compressor
section, a combustion section, a turbine section and an exhaust
section. In a turbofan engine, however, a rotating fan of typically
large diameter resides upstream of the compressor section and
within the engine housing, which may also be referred to as a
nacelle, case, or duct (hence the "ducted fan" nomenclature often
associated with turbofan engines). The fan is driven by the turbine
along with the compressor. The fan is used to increase the amount
of air that is passed through the engine, thereby increasing the
thrust produced by the engine.
[0005] Turbofan engines normally come in two variations--low bypass
engines and high bypass engines. These designations refer to the
ratio of the amount of air that passes through the combustion
portion of the engine to the amount of air that passes around the
combustion section (i.e., through only the fan). In either case,
the fan is typically designed to move as much air as possible
through the engine, so the tips of the fan blades normally rotate
in very close proximity to the inside of the fan housing. The
resultant minimized gap between the fan blades and the interior of
the fan housing can be problematic, as gravity, dynamic forces of
rotation or flight movement, and/or different rates of thermal
expansion, may result in contact between the tips of the rotating
fan blades and the interior of the fan housing. This contact
typically occurs, but is not restricted to, approximately the 5:00
and 7:00 positions within the fan housing (i.e., along a bottom
portion of fan rotation). At a minimum, such contact may damage or
cause a wearing of the fan blade tips. If blade-tip-to-housing
contact is sufficiently severe, however, engine damage or engine
failure may result.
[0006] Turbofan engine designers are aware of and usually
anticipate the possibility of contact between the fan blade tips
and the interior of the engine housing. To this end, the housing
interior surrounding the fan is commonly covered with an abradable
material, such as in the form of a circumferential contact strip.
The abradable material is sacrificial in nature, meaning that it is
designed to wear away upon contact with the tips of the fan blades.
A number of useable abradable materials would be familiar to one of
skill in the art.
[0007] When contact between the fan blade tips and the abradable
material of the fan housing is detected, it may be desirable to
slightly increase the blade tip-to-abradable material minimized gap
in the area of contact. The amount of material removed is normally
very small--on the order of thousandths of an inch, for example.
This makes it very difficult, if not impossible, to acceptably
effectuate the removal of abradable material with a power tool. It
is also desirable that the abradable material be removed in a
manner that follows the contour/curvature of the fan housing and
associated abradable material layer. Consequently, it is also very
difficult, if not impossible, to consistently effectuate the
removal of abradable material by hand--such as by means of a
hand-held sandpaper sheet or the like.
[0008] It can be understood from the foregoing comments that there
is a need for a device and method of efficiently, accurately and
consistently removing small amounts of abradable material from the
interior of a gas turbine engine housing. Devices and methods of
the invention satisfy this need.
SUMMARY
[0009] The invention is directed to devices and methods by which
small amounts of gas turbine engine housing abradable material may
be removed along the path of a rotatable engine fan. A device of
the invention is generally comprised of an abradable material
removal tool having an abradable material contacting base with a
handle or other gripping portion extending therefrom. The base is
preferably formed from a substantially rigid material with a curved
profile that matches the curvature (i.e., circumference) of the
abradable material contact surface. A rigid or semi-rigid rib may
extend from a top surface or other portion of the base. The rib
preferably extends substantially perpendicularly upward therefrom
to facilitate handling and use of the tool (i.e., to act as a
handle), and may also help to maintain the desired curvature of the
base.
[0010] An abrasive material, such as a sheet of sand paper, may be
affixed to the contacting surface 85 of the base--with the abrasive
material facing outward therefrom. The fixed curvature of the base
allows the curvature of the abradable material to be substantially
maintained when the tool is used in an abradable material removal
operation.
[0011] The base 55 is also dimensioned and provided with a shape
that permits its insertion between adjacent leading and trailing
fan blades 20 of the turbofan engine 5. Consequently, a
hand-generated back-and-forth rotation of the fan 15 while the
abradable material removal tool is positioned therebetween and
depressed against the surface of the abradable material, will
result in a controlled removal of abradable material along a path
traced by the tips of the fan blades.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In addition to the features mentioned above, other aspects
of the present invention will be readily apparent from the
following descriptions of the drawings and exemplary embodiments,
wherein like reference numerals across the several views refer to
identical or equivalent features, and wherein:
[0013] FIG. 1 depicts a portion of an exemplary turbofan jet
engine, wherein the blades of a fan portion thereof are shown to be
rotatably mounted within a fan housing having an abradable material
lining;
[0014] FIG. 2 is a perspective view of one exemplary embodiment of
an abradable material removal tool of the invention;
[0015] FIGS. 3A-3C are front, side and top views, respectively, of
the exemplary abradable material removal tool of FIG. 2;
[0016] FIG. 4 shows the exemplary abradable material removal tool
of FIG. 2 with a trimmed sheet of sand paper removably affixed to
an abradable material contacting surface of a base portion thereof;
and
[0017] FIG. 5 shows the exemplary abradable material removal tool
of FIG. 2 properly positioned for use within a housing and between
the fan blades of an exemplary turbofan jet engine fan.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S)
[0018] An intake portion of one exemplary embodiment of a turbofan
jet engine 5 is depicted in FIG. 1. As shown, the engine 5 includes
a housing 10 within which rotates a fan 15. As described
previously, the fan 15 is rotated by a turbine-driven shaft (not
visible) to push air through the engine 5. The fan 15, can be seen
to have a plurality of circumferentially spaced fan blades 20 that
are designed and oriented to produce an airstream that will travel
rearward through the engine when the fan is rotated. Each of the
fan blades 20 terminates in a flared blade tip 25 at its free
end.
[0019] An abradable material lining 30 is visible along the inside
of the fan housing 10, along the rotational travel path of the
blade tips 25. During fan rotation, a minimized gap 35 separates
the blade tips 25 from an adjacent (contact) surface 40 of the
abradable material lining 30. In this particular example, an area
of contact 45 between the blade tips 25 and the abradable material
lining 30 is visible. It may be desirable to remove an amount of
the abradable material lining 30 in this area 45 so as to minimize
or eliminate further contact thereof by the blade tips 25 of the
fan 15.
[0020] One exemplary embodiment of an abradable material removal
tool 50 according to the invention is depicted in FIGS. 2-4. For
purposes of illustration, the abradable material removal tool 50 is
described below with reference to its use on the turbofan jet
engine 5 of FIG. 1. However, the abradable material removal tool
may also be used with other jet engines.
[0021] As shown, the abradable material removal tool 50 includes an
abradable material contacting base 55 having a leading end 55a, a
trailing end 55b, and a curved profile C that corresponds to the
curvature (i.e., circumference) of the abradable material contact
surface 40 when the abradable material removal tool is in a proper
working orientation (see FIG. 5). The base 55 is preferably formed
from a rigid or substantially rigid material that will retain the
desired curvature.
[0022] For reasons described in more detail below, the abradable
material contacting base 55 is also of a size and shape that allows
it to fit accurately between adjacent blades 20 of the jet engine
fan 15 and to trace the path followed by the blade tips 25. More
particularly, the abradable material contacting base 55 preferably
includes a long edge 60, and a shorter opposite edge 65 having a
leading bevel or taper 70.
[0023] A rigid or semi-rigid rib 75 may extend from a top surface
80 or other portion of the base 55. The rib 75 preferably, but not
necessarily, extends substantially perpendicularly upward therefrom
to facilitate handling and use of the tool 5 (i.e., to act as a
handle). The rib 75 may also help to maintain the desired curvature
C of the base 55 or, in embodiments where the base itself is not
sufficiently rigid to do so, may actually establish and maintain
the curvature of the base.
[0024] The rib (handle) 75 may be of virtually any height and
shape. However, the bottom edge thereof is preferably shaped to
conform to the curvature C of the base 55. The rib 75 may be
secured to the base 55 by any technique known in the art, such
techniques being at least somewhat dependent on the materials used
to construct the base and rib. When the base 55 and rib 75 are
comprised of plastic materials, attachment of the rib to the base
may be accomplished by, for example, adhesive bonding, vibratory
welding, etc. Alternatively, the base 55 and rib 75 may be a
unitary structure formed by molding, casting, etc. The rib 75 may
also include cutouts/holes and/or protrusions of various shape and
size for purposes of improving the handling and use of the
abradable material removal tool 5.
[0025] Use of the abradable material removal tool 5 to remove an
amount of abradable material from within a turbofan housing also
requires an abrasive material. To that end, this particular
exemplary abradable material removal tool 5 is shown in FIG. 4 with
a sheet of sandpaper 90 removably affixed to the abradable material
contacting (bottom) surface 85 of the base 55. The abrasive
material side of the sandpaper sheet faces away from the base 55,
such that the abrasive material is exposed and will be in contact
with the abradable material lining 30 of the engine housing 10 when
the abradable material removal tool 5 is properly used. When an
abrasive material sheet or other abrasive material carrier is
affixed to the abradable material contacting surface 85 of the base
55, it is preferably trimmed or otherwise provided with
substantially the same planform shape as the base. This helps to
ensure that abradable material removal will occur only under the
footprint cast by the base 55 of the abradable material removal
tool 5.
[0026] An abradable material removal tool of the invention is not
limited to use with an abrasive material sheet, such as the sheet
of sandpaper 95 shown in FIG. 4. For example, the base of an
abradable material removal tool of the invention may instead be
provided with an abradable material contacting surface that is
inherently abrasive, such as through molding, casting, etc. The
base of an abradable material removal tool of the invention may
also instead have an abrasive material (without or without a
carrier element) permanently adhered to the abradable material
contacting surface of its base, or may have a base with an
abradable material contacting surface into which an abrasive
material has been embedded. The base of an abradable material
removal tool of the invention may also be partially or fully
impregnated with an abrasive material so that use of the tool may
continue as the base wears.
[0027] As mentioned above, the base 55 of the abradable material
removal tool 5 is dimensioned so as to fit between adjacent leading
and trailing fan blades 20 of the fan 15. It is preferred that the
base 55 be dimensioned such that the abradable material removal
tool 5 may be easily inserted between adjacent fan blades 20, while
also being properly oriented by the blades. The abradable material
removal tool 5 is shown in such an orientation in FIG. 5, with the
abrasive material side of the sandpaper sheet 90 residing against
the surface 40 of the abradable material lining 30.
[0028] Referring still to FIG. 5, it can be observed that the
planform shape of the base 55 of the abradable material removal
tool 5 preferably results in the base tracing the path of the fan
blade tips 25 when the fan 15 is rotated while the tool resides
between fan blades 20 thereof. More specifically, the tapered
portion 70 along the leading end 55a of the base 55 is designed to
substantially follow an imaginary line between leading tips 25 of
adjacent fan blades 20 when the abradable material removal tool 5
is properly located between said fan blades.
[0029] With the abradable material removal tool 5 positioned
substantially as shown in FIG. 5, an amount of the abradable
material 30 may be slowly and deliberately removed by manually
rotating the fan 15 back-and-forth through a desired arc while the
abradable material removal tool is pressed toward the engine
housing to maintain contact between the abrasive material (e.g.,
sandpaper sheet 90) and the surface 40 of the abradable material.
The abradable material removal tool 5 may be depressed against the
surface 40 of the abradable material lining 30 during fan rotation
by, for example, a finger(s) of the user of the tool.
Alternatively, it may be possible to produce an abradable material
removal tool 5 where the rib 75 thereof may be clamped to one of
the fan blades 20 in a manner that maintains a desired amount of
pressure between the base 55 of the tool and the surface 40 of the
abradable material 30. In any case, use of the abradable material
tool 5 as described will result in a controlled removal of
abradable material 30 along a path traced by the tips 25 of the fan
blades 20.
[0030] While certain embodiments of the present invention are
described in detail above, the scope of the invention is not to be
considered limited by such disclosure, and modifications are
possible without departing from the spirit of the invention as
evidenced by the following claims:
* * * * *