U.S. patent application number 13/209748 was filed with the patent office on 2012-02-02 for rotor blade.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Gialdy Irizarry-Perez, Xiomara Irizarry-Rosado.
Application Number | 20120027615 13/209748 |
Document ID | / |
Family ID | 45526937 |
Filed Date | 2012-02-02 |
United States Patent
Application |
20120027615 |
Kind Code |
A1 |
Irizarry-Rosado; Xiomara ;
et al. |
February 2, 2012 |
ROTOR BLADE
Abstract
A rotor blade for a wind turbine is disclosed. The rotor blade
includes an outer shell having exterior surfaces and interior
surfaces, the exterior surfaces defining a pressure side and a
suction side each extending between a leading edge and a trailing
edge, the interior surfaces defining a rotor blade interior. The
rotor blade further includes a structural member extending through
at least a portion of the interior, and a generally elastic
material connecting the structural member to an interior surface.
The generally elastic material allows movement of the outer shell
with respect to the structural member.
Inventors: |
Irizarry-Rosado; Xiomara;
(Greer, SC) ; Irizarry-Perez; Gialdy; (Mayaguez,
PR) |
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
45526937 |
Appl. No.: |
13/209748 |
Filed: |
August 15, 2011 |
Current U.S.
Class: |
416/226 |
Current CPC
Class: |
F03D 1/0683 20130101;
Y02P 70/523 20151101; F05B 2240/30 20130101; Y02P 70/50 20151101;
Y02E 10/721 20130101; Y02E 10/72 20130101; F03D 1/0675 20130101;
F05B 2230/50 20130101 |
Class at
Publication: |
416/226 |
International
Class: |
F01D 5/14 20060101
F01D005/14 |
Claims
1. A rotor blade for a wind turbine, the rotor blade comprising: an
outer shell having exterior surfaces and interior surfaces, the
exterior surfaces defining a pressure side and a suction side each
extending between a leading edge and a trailing edge, the interior
surfaces defining a rotor blade interior; a structural member
extending through at least a portion of the interior; and, a
generally elastic material connecting the structural member to an
interior surface, the generally elastic material allowing movement
of the outer shell with respect to the structural member.
2. The rotor blade of claim 1, wherein the generally elastic
material is an elastomer.
3. The rotor blade of claim 1, wherein the generally elastic
material is a rubber.
4. The rotor blade of claim 1, wherein the structural member
extends in a generally span-wise direction through at least a
portion of the interior.
5. The rotor blade of claim 1, wherein the structural member is a
shear web.
6. The rotor blade of claim 1, wherein the structural member is
connected to interior surfaces adjacent to the pressure side and
the suction side.
7. The rotor blade of claim 1, wherein the generally elastic
material allows twist of the outer shell with respect to the
structural member.
8. The rotor blade of claim 7, wherein the generally elastic
material allows a maximum twist of the outer shell with respect to
the structural member of approximately 15 degrees.
9. The rotor blade of claim 1, further comprising a stop, the stop
positioned to prevent movement of the outer shell with respect to
the structural member beyond a maximum movement.
10. The rotor blade of claim 9, wherein the generally elastic
material allows twist of the outer shell with respect to the
structural member, and wherein the stop prevents movement of the
outer shell with respect to the structural member beyond a maximum
twist.
11. The rotor blade of claim 10, wherein the maximum twist is
approximately 15 degrees.
12. The rotor blade of claim 9, wherein the stop comprises a ball
portion and a socket portion.
13. The rotor blade of claim 9, wherein the stop comprises a
protrusion extending from the structural member.
14. A wind turbine comprising: a plurality of rotor blades, at
least one of the plurality of rotor blades comprising: an outer
shell having exterior surfaces and interior surfaces, the exterior
surfaces defining a pressure side and a suction side each extending
between a leading edge and a trailing edge, the interior surfaces
defining a rotor blade interior; a structural member extending
through at least a portion of the interior; and, a generally
elastic material connecting the structural member to an interior
surface, the generally elastic material allowing movement of the
outer shell with respect to the structural member.
15. The wind turbine of claim 14, wherein the generally elastic
material is an elastomer.
16. The wind turbine of claim 14, wherein the structural member
extends in a generally span-wise direction through at least a
portion of the interior.
17. The wind turbine of claim 14, wherein the structural member is
connected to interior surfaces adjacent to the pressure side and
the suction side.
18. The wind turbine of claim 14, wherein the generally elastic
material allows twist of the outer shell with respect to the
structural member.
19. The wind turbine of claim 14, further comprising a stop, the
stop positioned to prevent movement of the outer shell with respect
to the structural member beyond a maximum movement.
20. A rotor blade for a wind turbine, the rotor blade comprising:
an outer shell having exterior surfaces and interior surfaces, the
exterior surfaces defining a pressure side and a suction side each
extending between a leading edge and a trailing edge, the interior
surfaces defining a rotor blade interior; and, a structural member
extending through at least a portion of the interior, the
structural member movably connected to an interior surface such
that passive movement of the outer shell is allowed with respect to
the structural member.
Description
FIELD OF THE INVENTION
[0001] The present disclosure is directed in general to rotor
blades, and more particularly to apparatus for allowing movement,
such as twist, of the rotor blade with respect to inner structural
members of the rotor blade.
BACKGROUND OF THE INVENTION
[0002] Wind power is considered one of the cleanest, most
environmentally friendly energy sources presently available, and
wind turbines have gained increased attention in this regard. A
modern wind turbine typically includes a tower, generator, gearbox,
nacelle, and one or more rotor blades. The rotor blades capture
kinetic energy of wind using known airfoil principles. The rotor
blades transmit the kinetic energy in the form of rotational energy
so as to turn a shaft coupling the rotor blades to a gearbox, or if
a gearbox is not used, directly to the generator. The generator
then converts the mechanical energy to electrical energy that may
be deployed to a utility grid.
[0003] The construction of a modern rotor blade generally includes
shell components, spar caps, and one or more shear webs. The shell
components, typically manufactured from layers of fiber composite
and a lightweight core material, forms the exterior aerodynamic
foil shape of the rotor blade. The spar caps provide increased
rotor blade strength by integrating one or more structural elements
running along the span of the rotor blade on both interior sides of
the rotor blade. Shear webs are structural beam-like components
running essentially perpendicular between the top and bottom spar
caps and extending across the interior portion of the rotor blade
between the shell components.
[0004] The size, shape, and weight of rotor blades are factors that
contribute to energy efficiencies of wind turbines. An increase in
rotor blade size increases the energy production of a wind turbine,
while a decrease in weight furthers the efficiency of a wind
turbine. Furthermore, as rotor blade sizes grow, extra attention
needs to be given to the structural integrity of the rotor blades.
Presently, large commercial wind turbines in existence and in
development are capable of generating from about 1.5 to about 12.5
megawatts of power. These larger wind turbines may have rotor blade
assemblies larger than 90 meters in diameter. Additionally,
advances in rotor blade shape encourage the manufacture of a
forward swept-shaped rotor blade having a general arcuate contour
from the base to the tip of the blade, providing improved
aerodynamics. Accordingly, efforts to increase rotor blade size,
decrease rotor blade weight, and increase rotor blade strength,
while also improving rotor blade aerodynamics, aid in the
continuing growth of wind turbine technology and the adoption of
wind energy as an alternative energy source.
[0005] Rotor blades with such increases and improvements in size,
shape, and weight may, however, have various disadvantages. For
example, these rotor blades must be relatively flexible in order to
prevent damage when experiencing high loading. Thus, for example,
many such rotor blades may be formed from materials that allow
bending towards the tower when experiencing high loading from, for
example, high wind speeds. However, too much bending may cause a
rotor blade to strike the tower, potentially causing damage to both
the rotor blade and tower. Some blades are thus curved, as
discussed above, to allow twisting of the rotor blade. Twisting of
the rotor blade may allow for shedding of loads when high loads are
experienced, which may help prevent a rotor blade from striking the
tower. However, curving in many cases does not allow for sufficient
twisting.
[0006] Thus, a rotor blade that can twist sufficiently to allow
desirable levels of load shedding would be desired in the art.
BRIEF DESCRIPTION OF THE INVENTION
[0007] Aspects and advantages of the invention will be set forth in
part in the following description, or may be obvious from the
description, or may be learned through practice of the
invention.
[0008] In one embodiment, a rotor blade for a wind turbine is
disclosed. The rotor blade includes an outer shell having exterior
surfaces and interior surfaces, the exterior surfaces defining a
pressure side and a suction side each extending between a leading
edge and a trailing edge, the interior surfaces defining a rotor
blade interior. The rotor blade further includes a structural
member extending through at least a portion of the interior, and a
generally elastic material connecting the structural member to an
interior surface. The generally elastic material allows movement of
the outer shell with respect to the structural member.
[0009] In another embodiment, a rotor blade for a wind turbine is
disclosed. The rotor blade includes an outer shell having exterior
surfaces and interior surfaces, the exterior surfaces defining a
pressure side and a suction side each extending between a leading
edge and a trailing edge, the interior surfaces defining a rotor
blade interior. The rotor blade further includes a structural
member extending through at least a portion of the interior, the
structural member movably connected to an interior surface such
that passive movement of the outer shell is allowed with respect to
the structural member.
[0010] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A full and enabling disclosure of the present invention,
including the best mode thereof, directed to one of ordinary skill
in the art, is set forth in the specification, which makes
reference to the appended figures, in which:
[0012] FIG. 1 is a side view of a wind turbine according to one
embodiment of the present disclosure;
[0013] FIG. 2 is a perspective view of a rotor blade according to
one embodiment of the present disclosure;
[0014] FIG. 3 is a cross-sectional view of a rotor blade according
to one embodiment of the present disclosure;
[0015] FIG. 4 is a cross-sectional view of a rotor blade according
to another embodiment of the present disclosure; and,
[0016] FIG. 5 is a perspective view of a stop according to one
embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Reference now will be made in detail to embodiments of the
invention, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope or spirit of the invention. For instance, features
illustrated or described as part of one embodiment can be used with
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0018] FIG. 1 illustrates a wind turbine 10 of conventional
construction. The wind turbine 10 includes a tower 12 with a
nacelle 14 mounted thereon. A plurality of rotor blades 16 are
mounted to a rotor hub 18, which is in turn connected to a main
flange that turns a main rotor shaft. The wind turbine power
generation and control components are housed within the nacelle 14.
The view of FIG. 1 is provided for illustrative purposes only to
place the present invention in an exemplary field of use. It should
be appreciated that the invention is not limited to any particular
type of wind turbine configuration.
[0019] Referring to FIG. 2, a rotor blade 16 according to the
present disclosure may include a shell 20. The shell 20 may have
exterior surfaces defining a pressure side 22 and a suction side 24
extending between a leading edge 26 and a trailing edge 28, and may
extend from a blade tip 32 to a blade root 34. The exterior
surfaces may be generally aerodynamic surfaces having generally
aerodynamic contours, as is generally known in the art.
[0020] The shell 20 may further have interior surfaces. The
interior surfaces may define an interior 40 of the rotor blade 16.
Further, the interior surfaces may include a pressure side interior
surface 42, suction side interior surface 44, leading edge interior
surface 46, and trailing edge interior surface 48.
[0021] The rotor blade 16 according to the present disclosure may
include a plurality of individual rotor blade sections aligned in a
generally span-wise, end-to-end, order between the blade tip 32 and
the blade root 34. Each of the individual rotor blade sections may
be uniquely configured so that the plurality of rotor blade
sections define a complete rotor blade 16 having a designed
aerodynamic profile, length, and other desired characteristics. For
example, each of the rotor blade sections may have an aerodynamic
profile that corresponds to the aerodynamic profile of adjacent
rotor blade sections. Thus, the aerodynamic profiles of the rotor
blade sections may form a continuous aerodynamic profile of the
rotor blade 16.
[0022] The rotor blade 16 may, in exemplary embodiments, be curved.
Curving of the rotor blade 16 may entail bending the rotor blade 16
in a generally flapwise direction and/or in a generally edgewise
direction. The flapwise direction may generally be construed as the
direction (or the opposite direction) in which the aerodynamic lift
acts on the rotor blade 16. The edgewise direction is generally
perpendicular to the flapwise direction. Flapwise curvature of the
rotor blade 16 is also known as pre-bend, while edgewise curvature
is also known as sweep. Thus, a curved rotor blade 16 may be
pre-bent and/or swept. Curving may enable the rotor blade 16 to
better withstand flapwise and edgewise loads during operation of
the wind turbine 10, and may further provide clearance for the
rotor blade 16 from the tower 12 during operation of the wind
turbine 10.
[0023] The rotor blade 16 may further define a chord 52 and a span
54 extending in chord-wise and span-wise directions, respectively.
As shown, the chord 52 may vary throughout the span 54 of the rotor
blade 16.
[0024] In some embodiments, the outer shell 20 may additionally
include a spar cap or spar caps (not shown). The spar caps may
extend through at least a portion of the rotor blade 16, such as in
the generally span-wise direction along at least a portion of the
span 54. For example, in some embodiments, the outer shell 20 may
include a pressure side spar cap and a suction side spar cap.
[0025] As shown in FIGS. 3 and 4, the rotor blade 16 may further
include a structural member 60 or a plurality of structural members
60. Each structural member 60 may extend though at least a portion
of the interior 40. A structural member 60 may have any suitable
cross-sectional shape. For example, a structural member may be
generally rectangular, or may be generally I-shaped, or may have
any other suitable cross-sectional shape. As discussed below, the
structural member 60 may be connected to the outer shell 20. Thus,
the structural member 60 may provide structural integrity to the
rotor blade 16. In some embodiments, for example, the structural
member 60 may be a shear web, as shown. However, it should be
understood that the structural member 60 is not limited to shear
webs, and rather that any suitable structural member 60 is within
the scope and spirit of the present disclosure.
[0026] In some embodiments, the structural member 60 may extend in
a generally span-wise direction through at least a portion of the
interior 40, and thus through at least a portion of the span 54. In
other embodiments, however, the structural member 60 may extend in
a generally chord-wise direction through at least a portion of the
interior 40, or may extend in at any suitable angle or in any
suitable direction through at least a portion of the interior.
[0027] A structural member 60 may be connected to the outer shell
20, such as to one or more interior surfaces of the outer shell 20.
For example, a structural member 60 may be connected to any one or
more interior surfaces adjacent to the pressure side 22, suction
side 24, leading edge 26, and/or trailing edge 28, such as to any
one or more of the pressure side interior surface 42, suction side
interior surface 44, leading edge interior surface 46, and/or
trailing edge interior surface 48. In some embodiments as shown,
for example, a structural member 60 is connected to the interior
surfaces adjacent to the pressure side 22 and the suction side 24,
such as connected to the pressure side interior surface 42 and
suction side interior surface 44. Further, the shear web may in
some embodiments be connected to the spar caps of the outer shell
20.
[0028] The structural members 60 according to the present
disclosure may allow passive movement of the outer shell 20 with
respect to the structural members 60. Passive movement according to
the present disclosure means movement due to external forces, such
as high speed winds, rather than active movement, such as
mechanical movement, of a structural member 60 to move the outer
shell 20. Thus, the outer shell 20 may passively move linearly or
rotate with respect to the structural member 60. This movement may
generally occur due to loading of the rotor blade 16, such as from
high speed winds or other forces. Further, after such loading has
decreased or discontinued, the outer shell 20 to return to its
approximate original position with respect to the structural member
60.
[0029] In some embodiments, for example, passive twisting of the
outer shell 20 with respect to the structural member may occur.
Twist is generally defined as rotation in twist direction 72, such
as about an axis generally defined as extending in the direction of
the span 54. However, it should be understood that the present
disclosure is not limited to twist, and rather that any suitable
movement, linearly and/or rotationally, is within the scope and
spirit of the present disclosure.
[0030] For example, the rotor blade 16 according to the present
disclosure may further include a generally elastic material 70. The
material 70 connects a structural member 60 to an interior surface
of the outer shell 20, as discussed above. The material 70 thus
adheres the structural member 60 to the outer shell 20, allowing
the structural member 60 to provide structural rigidity to the
rotor blade 16.
[0031] The generally elastic material 70 may be, for example, an
elastomer, such as a rubber. For example, the material 70 may be a
saturated rubber, an unsaturated rubber, a thermoplastic elastomer,
a resilin, an elastin, a polysulfide rubber, or any other suitable
elastomer. Alternatively, the generally elastic material 70 may be
any suitable material that allows movement of the outer shell 20
with respect to the structural member 60, as discussed below.
[0032] As mentioned, the generally elastic material 70
advantageously allows movement of the outer shell 20, such as any
portion thereof, with respect to the structural member 60. Thus,
the outer shell 20 may move linearly or may rotate with respect to
the structural member 60 due to the generally elastic material 70.
This movement may generally occur due to loading of the rotor blade
16, such as from high speed winds or other forces. Further, after
such loading has decreased or discontinued, the generally elastic
material 70 may allow the outer shell 20 to return to its
approximate original position with respect to the structural member
60.
[0033] In some embodiments, for example, the material 70 may allow
twist of the outer shell 20 with respect to the structural member.
Twist is generally defined as rotation in twist direction 72, such
as about an axis generally defined as extending in the direction of
the span 54. However, it should be understood that the present
disclosure is not limited to twist, and rather that any suitable
movement, linearly and/or rotationally, is within the scope and
spirit of the present disclosure.
[0034] In some embodiments, the material 70 may only allow the
outer shell 20 to move within a certain specified range, and up to
a certain maximum movement. For example, in some embodiments, the
material 70 may only allow a specified twist of the outer shell 20
with respect to the structural member 60. For example, the material
70 may allow a maximum twist 74 of approximately 30 degrees,
approximately 20 degrees, approximately 15 degrees, approximately
10 degrees, or any other suitable maximum twist range. It should be
understood that the specified range, such as maximum twist, is a
range in any direction from an original position. Thus, for
example, with a maximum twist of approximately 30 degrees, for
example, the outer shell 20 may be allowed to twist approximately
30 degrees in one twist direction as well as 30 degrees in the
opposite twist direction.
[0035] As shown in FIGS. 3 through 5, a rotor blade 16 according to
the present disclosure may further comprise a stop 80 or a
plurality of stops 80. Each stop 80 may be positioned to prevent
movement of the outer shell 20 with respect to the structural
member 60 beyond a maximum movement, such as a maximum twist. For
example, the stop 80 may be mounted to an interior surface and/or
to a structural member 60, and may limit the movement of the outer
shell 20 with respect to the structural member 60 to within the
maximum allowed movement, such as the maximum twist.
[0036] In some embodiments, as shown in FIGS. 3 and 5, for example,
a stop 80 may include a ball portion 82 and a socket portion 84.
The socket portion 84 may have one or more stop surfaces 85. The
ball portion 82 may be mounted to one of the interior surface or
the structural member 60, and the socket portion 84 may be mounted
to the other of the interior surface or the structural member 60.
The ball portion 82 may be movably mounted within the socket
portion 84, such that the ball portion 82 may move with respect to
the socket portion 84 when the outer shell 20 moves with respect to
the structural member 60. However, stop surfaces 85 may contact the
ball portion 82 to prevent movement of the ball portion 82 past a
certain point, which may define the maximum movement of the outer
shell 20 with respect to the structural member 60.
[0037] In other embodiments, as shown in FIG. 4, for example, a
stop 80 may comprise a protrusion 86. The protrusion 86 may extend
from an inner surface or from a structural member 60, and may be
integral with or a separate component from the inner surface or
structural member 60. The protrusion 86 may have one or more stop
surfaces 87. The protrusion 86 may be sized such that, when
movement of the outer shell 20 with respect to the structural
member 60 reaches a maximum movement, a stop surface 87 contacts
the other of the inner surface or structural member 60, thus
preventing movement past this maximum movement.
[0038] A stop 80 according to the present disclosure may extend
throughout at least a portion of the structural member 60 in the
direction that the structural member 60 extends with respect to the
rotor blade 16. For example, in embodiments wherein the structural
member 60 extends in a generally span-wise direction, the stop 80
may extend throughout at least a portion of the structural member
in the span-wise direction.
[0039] It should be understood that the present disclosure is not
limited to stops 80 as disclosed above, and rather that any
suitable stop device that may prevent movement of the outer shell
20 with respect to the structural member 60 past a maximum movement
is within the scope and spirit of the present disclosure.
[0040] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they include structural elements that do not
differ from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *