U.S. patent application number 11/832717 was filed with the patent office on 2009-02-05 for wind turbine blade drainage.
This patent application is currently assigned to General Electric Company. Invention is credited to Nicholas K. Althoff, Brandon S. Gerber, Thomas B. Jenkins, Jamie T. Livingston, Amir Riahi.
Application Number | 20090035148 11/832717 |
Document ID | / |
Family ID | 40176040 |
Filed Date | 2009-02-05 |
United States Patent
Application |
20090035148 |
Kind Code |
A1 |
Livingston; Jamie T. ; et
al. |
February 5, 2009 |
Wind Turbine Blade Drainage
Abstract
A wind turbine includes a tower supporting a drive train with a
rotor, at least one hollow blade extending radially from the rotor;
a drain hole arranged in a tip portion of the blade; a baffle,
arranged inside the blade and inboard of the drain hole, for
impeding a flow of particulate matter to the drain hole; a flexible
drain conduit arranged inside the blade for connecting to the drain
hole; and a non-flexible drain conduit arranged inside the blade
for connecting to the flexible drain conduit, the non-flexible
conduit having a plurality of openings for receiving fluid from
inside the blade.
Inventors: |
Livingston; Jamie T.;
(Simpsonville, SC) ; Jenkins; Thomas B.;
(Cantonment, FL) ; Althoff; Nicholas K.; (Ware
Shoals, SC) ; Gerber; Brandon S.; (Ware Shoals,
SC) ; Riahi; Amir; (Langhorne, PA) |
Correspondence
Address: |
GE ENERGY GENERAL ELECTRIC;C/O ERNEST G. CUSICK
ONE RIVER ROAD, BLD. 43, ROOM 225
SCHENECTADY
NY
12345
US
|
Assignee: |
General Electric Company
|
Family ID: |
40176040 |
Appl. No.: |
11/832717 |
Filed: |
August 2, 2007 |
Current U.S.
Class: |
416/232 |
Current CPC
Class: |
F05B 2260/602 20130101;
Y02E 10/722 20130101; F03D 80/00 20160501; Y02E 10/72 20130101;
F03D 1/0675 20130101; Y02E 10/721 20130101 |
Class at
Publication: |
416/232 |
International
Class: |
F04D 11/00 20060101
F04D011/00 |
Claims
1. A hollow blade for a wind turbine comprising a flexible drain
conduit arranged inside the blade for connecting to a drain hole
through a surface of the blade.
2. The blade recited in claim 1, wherein the flexible drain conduit
includes a plurality of openings for receiving fluid from inside
the blade.
3. The blade recited in claim 2, wherein an internal dimension of
each of the openings is smaller than an internal dimension of the
conduit.
4. The blade recited in claim 3, wherein the conduit is
tubular.
5. The blade recited in claim 3, wherein a shape of the openings is
selected from the group consisting of round, quadrilateral, square,
slotted, and octagonal.
6. The blade recited in claim 3, wherein the conduit is secured to
an internal surface of the blade.
7. The blade recited in claim 6 wherein the flexible conduit is
laminated to an internal surface of the blade.
8. The blade recited in claim 6, wherein the flexible conduit is
adhesively bonded to an internal surface of the blade.
9. The blade recited in claim 1, further comprising a non-flexible
drain conduit arranged inside the blade for connecting to the
flexible drain conduit, the non-flexible conduit having a plurality
of openings for receiving fluid from inside the blade.
10. The blade recited in claim 9 wherein the non-flexible drain
conduit is laminated to an internal surface of the blade.
11. The blade recited in claim 9 wherein the non-flexible conduit
is adhered to an internal surface of the blade.
12. The blade recited in claim 9 wherein the non-flexible conduit
is integrally-formed with an internal surface of the blade.
13. A hollow blade for a wind turbine, comprising a drain hole
through a surface of the blade; and a baffle, arranged inside the
blade and inboard of the drain hole, for impeding a flow of
particulate matter to the drain hole.
14. The wind turbine blade recited in claim 13, wherein the baffle
comprises a first deflector extending from a leading edge of the
blade; and a second deflector extending from a trailing edge of the
blade.
15. The wind turbine blade recited in claim 14, wherein the baffle
further comprises a third deflector spaced apart from the leading
and trailing edges of the blade.
16. The wind turbine blade recited in claim 15, wherein at least a
portion of at least one of the deflectors curves toward a root of
the blade.
17. The wind turbine blade recited in claim 13, further comprising:
a flexible drain conduit arranged inside the blade for connecting
to the drain hole; and a non-flexible drain conduit arranged inside
the blade for connecting to the flexible drain conduit, the
non-flexible conduit having a plurality of openings for receiving
fluid from inside the blade.
18. A wind turbine, comprising: a tower supporting a drive train
with a rotor; at least one hollow blade extending radially from the
rotor; a drain hole arranged in a tip portion of the blade; and a
baffle, arranged inside the blade and inboard of the drain hole,
for impeding a flow of particulate matter to the drain hole.
19. The wind turbine recited in claim 18, wherein the baffle
comprises a first deflector extending from a leading edge of the
blade; a second deflector extending from a trailing edge of the
blade; and a third deflector spaced apart from the leading and
trailing edges of the blade.
20. The wind turbine recited in claim 18, further comprising a
flexible drain conduit arranged inside the blade for connecting to
the drain hole; and a non-flexible drain conduit arranged inside
the blade for connecting to the flexible drain conduit, the
non-flexible conduit having a plurality of openings for receiving
fluid from inside the blade.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The subject matter described here generally relates to fluid
reaction surfaces with specific blade structures that are apertured
or permeable, and, more particularly, to clog-resistant drains for
wind turbines blades.
[0003] 2. Related Art
[0004] A wind turbine is a machine for converting the kinetic
energy in wind into mechanical energy. If that mechanical energy is
used directly by machinery, such as to pump water or to grind
wheat, then the wind turbine may be referred to as a windmill.
Similarly, if the mechanical energy is further transformed into
electrical energy, then the turbine may be referred to as a wind
generator or wind power plant.
[0005] All wind turbines use one or more airfoils in the form of a
"blade" to generate lift and capture momentum from moving air that
is them imparted to a rotor. Each blade is typically secured at its
"root" end, and then "spans" radially "outboard" to a free, "tip"
end. The front, or "leading edge," of the blade connects the
forward-most points of the blade that first contact the air. The
rear, or "trailing edge," of the blade is where airflow that has
been separated by the leading edge rejoins after passing over the
suction and pressure surfaces of the blade. A "chord line" connects
the leading and trailing edges of the blade in the direction of the
typical airflow across the blade. The length of a chord line is
simply referred to as the "chord."
[0006] Wind turbines are typically categorized according to the
vertical or horizontal axis about which the blades rotate. One
so-called horizontal-axis wind generator is schematically
illustrated in FIG. 1. This particular configuration for a wind
turbine 1 includes a tower 2 supporting a drive train 4 with a
rotor 6 that is covered by a protective enclosure referred to as a
"nacelle." The blades 8 are arranged at one end of the rotor 6
outside the nacelle for driving a gearbox 10 and electrical
generator 12 at the other end of the drive train 4 inside the
nacelle.
[0007] Wind turbine blades are typically hollow in order to reduce
their weight. Consequently, water vapor will sometimes condense
inside the blade where it can wreak havoc on the balance of the
rotor, freeze and crack the blade structure, cause steam explosions
when rapidly heated by lightning strikes, or simply flow down the
blade and into the nacelle. Wind turbine blades are therefore
typically provided with a drain hole at their tip. However, since
the relatively high tip speeds of modern turbines can cause air
moving over the tip opening to vibrate or whistle, these blade tip
drain openings are typically limited to about six millimeters in
diameter. At that small size, any extraneous material left inside
the blade after manufacturing, or that comes loose during normal
operation, can easily clog the drain hole, especially when
propelled by centrifugal force along the length of the span.
[0008] Various approaches have been suggested for draining liquids
from turbine blades. For example, an English-language abstract of
European Patent Publication No. 1,607,623 describes a rotor blade
for a wind turbine with one or more drainage apertures having a
diameter of five millimeters and a net, gauze, or felt in the
hollow space adjacent to each aperture. U.S. Patent Publication No.
2007/0086897 discloses a wind turbine blade with an eight to
fifteen millimeter wide bore located in the root area and within
five centimeters of an enclosure member for strengthening the root
and enclosing the blade. U.S. Pat. No. 6,979,179 discloses a wind
turbine blade in which a drain passage is formed of a longitudinal
bore in a lightening receptor, where the longitudinal bore
communicates with the inner cavity of the blade through openings in
the lightening receptor.
[0009] However, these and other related wind turbine blade drainage
techniques can suffer from various drawbacks. For example, the net
or gauze can become clogged with fine sediment, grease, or resin
particles that are flushed from inside the blade. Any relatively
large bores in the blade, especially near the root, require
additional strengthening with corresponding additional material and
weight. Similarly, the metallic materials that are required for
lightening receptors can be relatively heavy and sometimes
difficult to properly align and fit with the drain hole through the
surface of the blade.
BRIEF DESCRIPTION OF THE INVENTION
[0010] These and other drawbacks of such conventional approaches
are addressed here by providing, in various configurations, a
hollow blade for a wind turbine including a flexible drain conduit
arranged inside the blade for connecting to a drain hole through a
surface of the blade. Also provided is a hollow blade for a wind
turbine, including a a drain hole through a surface of the blade;
and a baffle, arranged inside the blade and inboard of the drain
hole, for impeding a flow of particulate matter to the drain hole.
In another configuration, the subject matter disclosed here relates
to a wind turbine, including a tower supporting a drive train with
a rotor; at least one hollow blade extending radially from the
rotor; a drain hole arranged in a tip portion of the blade; and a
baffle, arranged inside the blade and inboard of the drain hole,
for impeding a flow of particulate matter to the drain hole. The
wind turbine may also include a flexible drain conduit arranged
inside the blade for connecting to the drain hole; and a
non-flexible drain conduit arranged inside the blade for connecting
to the flexible drain conduit where the non-flexible conduit has a
plurality of openings for receiving fluid from inside the
blade.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Various aspects of this technology will now be described
with reference to the following figures ("FIGS.") which are not
necessarily drawn to scale, but use the same reference numerals to
designate corresponding parts throughout each of the several
views.
[0012] FIG. 1 is a schematic illustration of a conventional wind
turbine.
[0013] FIG. 2 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0014] FIG. 3 is a schematic cross-sectional view taken along
section line III-IV in FIG. 2.
[0015] FIG. 4 is an alternate schematic cross-sectional view taken
along section line III-IV in FIG. 2.
[0016] FIG. 5 is a schematic cross-sectional illustration of a tip
of a Wind turbine blade for use with the wind turbine shown in FIG.
1.
[0017] FIG. 6 is a schematic cross-sectional view taken along
section line VI-VI in FIG. 5.
[0018] FIG. 7 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0019] FIG. 8 is a schematic cross-sectional view taken along
section line VIII-VIII in FIG. 7.
[0020] FIG. 9 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0021] FIG. 10 is a schematic cross-sectional view taken along
section line X-X in FIG. 9.
[0022] FIG. 11 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0023] FIG. 12 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0024] FIG. 13 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0025] FIG. 14 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0026] FIG. 15 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0027] FIG. 16 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0028] FIG. 17 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0029] FIG. 18 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
[0030] FIG. 19 is a schematic cross-sectional illustration of a tip
of a wind turbine blade for use with the wind turbine shown in FIG.
1.
DETAILED DESCRIPTION OF THE INVENTION
[0031] FIGS. 2-19 are schematic cross-sectional illustrations of
various configurations for a tip portion of a wind turbine blade 20
for use with the wind turbine 1 shown in FIG. 1. For example, the
blade 8 shown in FIG. 1 may be modified to include any of the
features of the various configurations of the blades 20 illustrated
in FIGS. 2-19, and/or combinations of those features.
[0032] In FIG. 2, the wind turbine blade 20 is provided with a
drain hole 22 for draining fluids that may accumulate inside the
blade. A flexible drain conduit (or drain line) 24 is arranged
inside the turbine blade 20 and connected to the drain hole 22 at
one end. The flexibility of the drain conduit 24 allows it to be
easily positioned and/or attached inside the blade 20. For example,
the flexible drain conduit may be loosely coiled near the tip of
the blade 20 and/or secured to an internal surface of the blade 20
by various techniques including fastening, laminating and/or
adhesive bonding. The drain hole 24 may also be provided with a
coupling, spigot, nozzle, or other feature (not shown) for
receiving an end of the flexible drain conduit 24. Alternatively,
the (butt) end of the flexible drain conduit 24 may be welded,
glued, or otherwise adhered to the perimeter of the drain hole 22
inside the blade 20.
[0033] In the configuration shown in FIG. 2, the flexible drain
conduit 24 includes one or more openings 26 for receiving fluid
from inside the blade 20. These openings help to prevent
particulate material from accumulating inside the flexible drain
conduit 24 and/or otherwise clogging the fluid flow path through
the drain hole 22. Therefore, and internal dimension at each of the
openings 26 is typically smaller than an internal dimension of the
conduit. However, the openings 26 in the drain conduit 24 may be
formed in a variety of sizes, configurations, and shapes including
round, square, diamond-shaped, quadrilateral, slot-shaped,
elliptical, octagonal, and/or a variety of other shapes. If one of
the openings 26 becomes clogged by particulate matter, then the
remaining openings 26 will continue to allow fluid flow through the
drain hole 24.
[0034] The shape of the flexible drain conduit 24 may also be
arranged in various configurations. For example, FIGS. 3 and 4 are
alternate schematic cross-sectional views taken along section line
III-IV in FIG. 2 showing rectangular and tubular cross-sections of
the flexible drain conduit 24, respectively. However, the flexible
drain conduit 24 may also be provided in a variety of other shapes
and the size of the conduit 24 may change along its length. For
example, the flexible conduit 24 may be larger at its free end. The
free end of the flexible drain conduit 24 may also be closed, as
illustrated in FIG. 3, open, or partially open as illustrated in
FIG. 4. In the tubular flexible drain conduit configuration of FIG.
4, the free end of the tubular (or any other shape) flexible drain
conduit 24 is provided with one or more openings 26 which may have
other shapes, sizes, or configurations. As in FIG. 2, the round
openings 26 in the end of the tubular flexible drain conduit 24
shown in FIG. 4 are also smaller than the outer diameter of the
tubular flexible drain conduit 24 shown in FIG. 4.
[0035] Turning to FIG. 5, the turbine blade 20 may also be further
provided with a non-flexible conduit 28 for connecting to the
flexible drain conduit 24. For example, the non-flexible conduit 28
may be formed from fiberglass, polyvinyl chloride, wood, metal, or
other relatively rigid material. In FIG. 5, the non-flexible
conduit 28 includes one or more openings 26 for receiving fluid
from inside the blade 20. The flexible drain conduit 24 may also be
provided with openings (not shown in FIG. 5). These openings also
help to prevent particulate material from accumulating inside the
non-flexible drain conduit 28, flexible drain conduit 24, and/or
otherwise obstructing the fluid flow path through the drain hole
22. In this configuration, and the flexible drain conduit 24 is
particularly useful for connecting the end of the non-flexible
conduit 28 with the drain hole 22. The flexibility of the drain
conduit 24 thus accommodates for any errors in the position or
alignment of the non-flexible drain conduit 28 and improves the
manufacturability of the blade 20.
[0036] FIGS. 6-8 illustrate various techniques for securing the
non-flexible conduit 28 to an internal surface of the blade 20.
However, similar techniques may also be used for securing the
flexible drain conduit 24 inside the blade 20.
[0037] FIG. 6 is a schematic cross-sectional view taken along
section line VI-VI in FIG. 5 while FIG. 8 is a schematic
cross-sectional view taken along section line VI-VII in FIG. 7. In
FIG. 6, the rectangular non-flexible conduit 28 is adhered to an
internal surface of the blade 20 by an adhesive 30. For example, in
the adhesive 30 may include a resin which is used to impregnate the
fiberglass, carbon fiber, or other material of the body of the
blade 20. In FIG. 8, the non-flexible conduit 28 is secured to the
internal surface of the blade 20 by straps 32. The straps 32 may be
fastened, adhered, bonded, or otherwise secured to the internal
surface all of the played 20 by a variety of techniques. For
example, be straps 32 may be strips of fiberglass, carbon fiber, or
other material which are resin-impregnated and bonded to the
internal surface of the blade 20.
[0038] FIGS. 9 and 10 illustrate another embodiment of a hollow
blade 20 for a wind turbine 1 in which the non-flexible conduit 28
is integrally-formed into an internal surface of the blade 20. FIG.
10 is a cross-section taken along section line X-X in FIG. 9, and
illustrates a pocket space 34 formed by the non-flexible conduit 28
over the internal surface all of the blade 20. For example, where
the blade 20 is formed through a resin impregnated fiberglass
transfer molding process, the non-flexible conduit 28 may be formed
from a resin-impregnated fiberglass layer which is spaced from the
internal surface of the blade. Once the top surface of the
non-flexible conduit is formed and hardened, then openings 26 may
be drilled or otherwise machined in the exterior surface of the
non-flexible conduit 28. The flexible conduit 24 then aids in
aligning and connecting the non-flexible conduit 28 with the drain
hole 22. The flexible conduit 24 may also be replaced and/or
supplemented with an extension of the non-flexible conduit 26 or a
separate non-flexible conduit leading to the drain hole 22.
[0039] In addition to the flexible and non-flexible drain conduits
24 and 28 discussed above, the blade 28 may also be provided with a
baffle, arranged inside the blade and inboard of the drain hole 22,
for in restricting the flow of particular matter to the drain hole.
For example, various wind turbine blade baffle configurations are
illustrated in FIGS. 11-18. However, other baffle configurations
may also be implemented.
[0040] For example, as illustrated in FIG. 11, the baffle 36 may
include one or more first flow deflectors 38 extending from a
leading edge of the blade 20 and/or one or more second flow
deflectors 40 extending from the opposite, trailing edge of the
blade 20. In FIG. 11, each of the flow deflectors 38 and 40 extends
from one edge substantially across the entire chord, except for a
flow space at one end. In FIG. 12, some of the first and second
flow deflectors are shorter than those illustrated in FIG. 11, and
there are third flow deflectors 42 spaced from the leading and the
trailing edge of the blade 20. In FIG. 13, the first and second
flow deflectors 38 and 40 are angled inboard from their respective
leading and trailing edges, while the third float deflector 42
extends substantially along a chord which is substantially
perpendicular to the leading and trailing edges of the blade 20.
However, others of the flow deflectors 38-42 may also be aligned
with the chord or angled in the inboard and/or outboard
directions.
[0041] In FIG. 14, the end portions of the first flow deflector 38
and the second flow deflector 40 are curved inboard toward a third
flow deflector 42 which also extends substantially along a chord
that is perpendicular to the leading and trailing edges. In FIGS.
15 and 16, the ends of these third flow deflector 42 have been
curved toward a tip of the blade so that a convex portion of the
third flow deflector 42 is oriented toward the inboard direction on
blade 20. In FIG. 16, the first and second flow deflector 38 and 40
have been curved toward a root of the blade 20, so that a convex
portion of the flow deflectors 38 and 40 is oriented toward a tip
portion of the blade. In FIG. 17, the radius of curvature for each
of the first, second, and third flow deflectors 38, 40, and 42 has
been increased and the third flow deflector 42 has been oriented
with a convex portion facing the inboard direction of the blade 20.
In FIG. 18, each of the flow deflectors 42 is provided with a
generally cylindrical shape. However, a variety of other shapes may
also be used including triangular, rectangular, pentagonal, et
cetera.
[0042] FIG. 19 illustrates another embodiment of a wind turbine
blade 20 which includes the baffle 36 configuration illustrated in
FIG. 11 and the flexible conduit 24 and nonflexible drain conduit
28 configuration illustrated in FIG. 7. Combinations of other
baffle and/or conduit configurations, including ones not explicitly
shown in these Figures, are also within the scope of this
disclosure.
[0043] It should be emphasized that the embodiments described
above, and particularly any "preferred" embodiments, are merely
examples of various implementations that have been set forth here
to provide a clear understanding of various aspects of this
technology. These embodiments may be modified without substantially
departing from scope of protection defined solely by the proper
construction of the following claims.
* * * * *