The present invention relates to a corrugated panel for a wind power generator blade. More particularly, the present invention relates to a corrugated panel that is coupled to a wind power generator blade in order to improve an aerodynamic performance of the wind power generator blade.
Wind force power generation is a clean energy source that hardly causes environment contamination as a promising replacement energy source that can replace fossil fuel. It is known that in replacement energy sources by present technology, wind force power generation has highest economic efficiency. Therefore, research and development for a wind power generator has been actively performed, and an example of installing wind power generators in a region having an abundant wind amount increases.
In general, the wind power generator includes a rotor in which a plurality of blades are coupled to a hub to rotate by a wind force and a generator that receives a torque from a main shaft that is connected to the rotor and that converts the torque to electrical energy.
Referring to
The rotor includes the hub 130 and a plurality of blades 140 that are coupled to the hub 130. The hub 130 is connected to a generator (not shown) that is installed within the neosel 120 by a main shaft (not shown).
The pillar-shaped tower 110 is installed at a ground 1, and the neosel 120 is supported by the tower 110. In this case, the neosel 120 is generally rotatably coupled to an upper end portion of the tower 110 about a length direction of the tower 110 to rotate a rotor in a windward direction.
Therefore, at a region in which the wind power generator 100 is installed, when a wind blows, if the hub 130 rotates the neosel 120 in a windward direction, a force by a wind is applied to the blade 140 and thus the hub 130 rotates, and a torque of the hub 130 is transferred to a generator (not shown) through a main shaft (not shown) to be converted to electrical energy.
In this case, in order to improve power generation efficiency of the wind power generator 100, it is necessary to increase efficiency in which the blade 140 converts a force that is applied by a wind to a torque. Therefore, in order to enable the blade 140 to have a shape that can obtain highest efficiency from an aerodynamic viewpoint, research and development for a shape of the blade 140 has been continuously performed.
Referring to
Here, a shape of the suction side 141 and the pressure side 142 is formed so that a section of the blade 140 may have a shape of an airfoil such as a blade of an aircraft and as described above, this is to increase efficiency in which the blade 140 converts a force of a wind to a torque.
At a section of the blade 140 having a shape of an airfoil, a leading edge, 143, a trailing edge 144, a chord 145, a mean camber line 146, and a chord length LC are represented, and this is well known to a person of an ordinary skill in the art and therefore a detailed description thereof will be omitted.
Referring again to
where P is power, ρ is an air density, V is a wind velocity, CP is a coefficient of power, and A is a swept area of the blade 140.
The air density ρ and the wind velocity V are different according to an installed location of the wind power generator 100, but cannot be arbitrarily adjusted. Therefore, in order to increase power P that is generated by the wind power generator 100, a method of increasing a swept area of blade A or a method of increasing a coefficient of power Cp is considered.
In order to increase the swept area of blade A, a length of the blade 140 should be extended, but as a length of the blade 140 is extended, a cost and a time that are consumed for production of the blade 140 increase, and due to increase of a linear velocity of a tip portion of the blade 140, a problem that noise and a vibration increase occurs. Therefore, a limitation exists in extending a length of the blade 140.
Therefore, when designing the blade 140, by increasing a coefficient of power Cp to the maximum, power P that is generated by the wind power generator 100 may be increased.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
The present invention has been made in an effort to provide a corrugated panel for a wind power generator blade having advantages of improving power generation efficiency of a wind power generator by improving aerodynamic characteristics of the wind power generator blade.
An exemplary embodiment of the present invention provides a corrugated panel for a wind power generator blade including: a plurality of wrinkles that are coupled to one surface or the other surface of the wind power generator blade having an airfoil transverse section and that are formed in a length direction of the blade, wherein a gap and a height at a predetermined position of the plurality of wrinkles each have a value of a predetermined ratio to a chord length of the airfoil transverse section of the blade at the predetermined position, when the plurality of wrinkles are coupled to the blade.
The corrugated panel for a wind power generator blade may cover an entire width of one surface of the blade from one end portion to the other end portion of the blade and may be coupled to the entire width of one surface of the blade.
The corrugated panel may be made of a material including one of a titanium alloy, an aluminum alloy, and a synthetic resin.
Another embodiment of the present invention provides a corrugated panel for a wind power generator blade, the corrugated panel including: a panel body having one surface that is coupled to one surface or the other surface of the wind power generator blade having an airfoil transverse section; a wrinkle portion that has a plurality of wrinkles in a length direction of the blade at the other surface of the panel body, wherein a gap and a height at a predetermined position of the plurality of wrinkles each have a value of a predetermined ratio to a chord length of an airfoil transverse section of the blade at the predetermined position, when the panel body is coupled to the blade.
The panel body may cover an entire width of one surface of the blade from one end portion to the other end portion of the blade and may be coupled to the entire width of the one surface of the blade.
The panel body and the wrinkle portion may be made of a material including one of a titanium alloy, an aluminum alloy, and a synthetic resin.
The transverse section of the wrinkle may have one shape of a polygon, a semicircle, and an oval, and particularly, the transverse section of the wrinkle may have a transverse section of a triangle shape.
The predetermined ratio may be 0.1 to 5%.
The panel body may include a foldable connection portion that is positioned between the wrinkles.
According to an exemplary embodiment of the present invention, by improving aerodynamic characteristics of a newly produced wind power generator blade and a blade that has already been installed in the wind power generator and that uses for the wind power generator, power generation efficiency of the wind power generator can be improved.
As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. It is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Further, detailed descriptions of well-known functions and structures incorporated herein may be omitted to avoid obscuring the subject matter of the present invention.
Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.
Referring to
As described above, a section of the blade 140 of the wind power generator (see 100 of
First,
The NACA 0012 type airfoil is a symmetrical airfoil and has a not-shown chord, i.e., a symmetrical shape about a portion between 0 and 1 in a horizontal axis of a graph. The NACA 4412 type airfoil is an asymmetrical airfoil and has an asymmetrical shape about a portion between 0 and 1 in a horizontal axis of a graph.
That is, although not shown, in the NACA 0012 type airfoil, the mean camber line (see 146 of
As shown in the drawing, it can be seen that a lift coefficient of the NACA 4412 type airfoil is always larger than that of the NACA 0012 type airfoil regardless of a change of an angle of attack within a predetermined range. Therefore, it is determined that a lift that is generated by the NACA 4412 type airfoil in which a camber is formed largely than a lift that is generated by the NACA 0012 type airfoil within a predetermined angle range.
For reference, a lift operating in the airfoil is represented by Equation 2.
where L is a lift, ρ is an air density, V is a wind velocity, CL is a coefficient of lift, and A is a swept area of the blade (140 of
In order to increase efficiency that converts a force operating by a wind to a torque, a section of the blade (140 of
Actually, the blade (140 of
Here, as a lift operating in the blade (140 of
Therefore, as an airfoil section shape of the blade (140 of
As described above, when the corrugated panel 20 is positioned at an air current, vortexes Va, Vb, Vc, Vd, Ve, Vf, Vg, Vh, Vi, and Vj (hereinafter, ‘Va to Vj’) are each formed in a relatively depressed portion by the plurality of wrinkles Ra to Rl.
Here, as shown in the drawing, as vortexes Va to Vj are continuously formed in space between a plurality of wrinkles Ra to Rl, a stable laminar flow LS is formed at the outside of the plurality of wrinkles Ra to Rl.
Therefore, as shown in the drawing, a section shape of the corrugated panel 20 is different from that of an airfoil, but performs the same operation as that of the airfoil, and it is determined that the same effect as that of forming of a camber is obtained according to a protrusion level of the plurality of wrinkles Ra to Rl.
For reference, an experimental result of operation of the corrugated panel 20 may be determined in “flow visualization study of the aerodynamics of modeled dragonfly wings (AIAA-2007-0483)” that is disclosed at No. 47 (Dec. 12, 2009) of an AIAA journal that is published by American Institute for Aeronautics and Astronautics (AIAA) and “an experimental investigation on bio-inspired corrugated airfoil (AIAA-2009-1087)” that is announced at the 47th AIAA aerospace sciences meeting including the new horizons forum and aerospace exposition that was held at Jan. 5 to 8, 2009 at Orlando, Fla., USA and therefore a detailed description thereof will be omitted.
Nowadays, in an aviation field and a shipbuilding field, a method of delaying separation of a fluid by forming a micro groove or protrusion, i.e., a dimple or a riblet at a surface in which a friction with a fluid occurs has continuously been researched, developed, and applied.
However, the above-described wrinkles Ra to Rl have a considerable size, compared with an entire size of the corrugated panel 20, unlike such a micro groove or protrusion. Further, the above-described wrinkles Ra to RI are not for delay of separation and are different from such a micro groove or protrusion in that the corrugated panel 20 having a section different from that of an airfoil performs the same operation as that of an airfoil.
Therefore, as shown in
Referring to
When the corrugated panel 200 for the wind power generator blade is coupled to one surface of the blade 140, the corrugated panel 200 for the wind power generator blade covers from one end portion to the other end portion, i.e., from a root portion to a tip portion of the blade 140 in a length direction of the blade 140 and is coupled thereto. However, the corrugated panel 200 may cover only a portion in a length direction of the blade 140 and may be coupled thereto, as needed.
Further, when the corrugated panel 200 for the wind power generator blade is coupled to one surface of the blade 140, the corrugated panel 200 for the wind power generator blade covers from the leading edge 143 to the trailing edge 144 in a width direction of the blade 140 and is coupled thereto. However, the corrugated panel 200 may cover only a portion in a width direction of the blade 140 and may be coupled thereto, as needed.
When the corrugated panel 200 for the wind power generator blade is coupled to the blade 140, a gap p and a height hr of a plurality of wrinkles 202 that are formed in the corrugated panel 200 for the wind power generator blade may be each formed to have a predetermined ratio of value to a chord length LC of a transverse section of the airfoil of the blade 140 at a predetermined position.
Here, the chord length LC of a transverse section of the airfoil of the blade 140 may be continuously changed from one end portion to the other end portion in a length direction of the blade 140. Therefore, because a gap p and a height hr of a plurality of wrinkles 202 may have a predetermined ratio of value to the chord length LC, a gap p and a height hr of the wrinkles 202 may be each changed proportional to a chord length LC at a corresponding position according to a predetermined position according to a length direction of the blade 140.
An entire shape of the corrugated panel 200 for the wind power generator blade may be formed to have the same shape as that of a surface to which the corrugated panel 200 for the wind power generator blade is to be attached.
For example, as shown in the drawing, in the corrugated panel 200 for the wind power generator blade, a lower boundary line LL in which a protruded end portion of a plurality of wrinkles 202 that are protruded in a direction to be coupled to the suction side 141 of the blade 140 is virtually connected may be formed to have a shape of the suction side 141 of the blade 140.
Further, although not shown, when the corrugated panel 200 for the wind power generator blade according to an exemplary embodiment of the present invention is coupled to the pressure side 142 of the blade 140, the lower boundary line LL may be formed to have a shape of the pressure side 142 of the blade 140.
Referring to
In this case, the corrugated panel 200 for the wind power generator blade may be coupled by an adhesive to the blade 140 and may be coupled using a separate fastening member (not shown) such as a volt and a nut.
For reference, when a separate fastening member (not shown) is used, a through-hole for coupling a fastening member (not shown) to the blade 140 and the corrugated panel 200 for the wind power generator blade may be formed, and as a stress is concentrated at such a through-hole, rigidity of the blade 140 and the corrugated panel 200 for the wind power generator blade may be deteriorated.
Further, when the fastening member (not shown) is protruded from a surface of the blade 140 and the corrugated panel 200 for the wind power generator blade, noise may occur by resistance with air.
Therefore, it is advantageous to use an adhesive for coupling of the corrugated panel 200 for the wind power generator blade and the blade 140. In this case, because the blade 140 is installed and used outdoors, as an adhesive to be used outdoors, an adhesive that can maintain enough strength while having high weather resistance and water resistance is selected and used.
In the corrugated panel 200 for the wind power generator blade, an upper boundary line UL in which a protruded end portion of a plurality of wrinkles 202 that are protruded in an opposite direction of a direction that is coupled to the suction side 141 of the blade 140 is virtually connected may have a shape similar to that of the suction side 141 of the blade 140.
When the blade 140 to which the corrugated panel 200 for the wind power generator blade according to an exemplary embodiment of the present invention is attached is positioned at an air current, an vortex may be formed between the plurality of wrinkles 202, as in the corrugated panel (20 of
In the blade 140 of the wind power generator 100, as described above, research and development for a shape of the blade 140 for enabling to have a shape that can minimize generation of noise and a vibration while increasing efficiency that changes a wind to a torque to the maximum has been continuously performed.
Therefore, in the already installed and using wind power generator 100, it may be necessary to compensate a shape of the blade 140. That is, even when a camber of the blade 140 may be further increased, a shape thereof may not be applied.
In such a case, by coupling the corrugated panel 200 for the wind power generator blade according to an exemplary embodiment of the present invention to the blade 140, a performance of the blade 140 can be compensated.
Until a state before a state in which efficiency is rapidly deteriorated, as a stall phenomenon occurs when increasing a camber of the blade 140, as a camber increases, a lift of the blade 140 may increase.
A level in which a camber increases by the corrugated panel 200 for the wind power generator blade according to an exemplary embodiment of the present invention may be determined by a gap p and a height hr of the plurality of wrinkles 202 that are formed in the corrugated panel 200 for the wind power generator blade.
Therefore, in order to improve a performance of the blade 140, after measuring a shape of the blade 140, by calculating a difference from a shape of an optimally designed blade (not shown), a gap p and a height hr of the plurality of wrinkles 202 to be formed in the corrugated panel 200 for the wind power generator blade may be determined according to a calculation result.
For reference, as an experimental result, a gap p of the plurality of wrinkles 202 may be selected within a range of 0.1% to 5% of a chord length LC of a transverse section of the airfoil of the blade 140 at a predetermined position. A height hr of the plurality of wrinkles 202 may be selected within a range of 0.1% to 5% of a chord length LC of a transverse section of the airfoil of the blade 140.
Although not shown, a plurality of wrinkles 202 that are formed in the corrugated panel 200 for the wind power generator blade may be each formed to have a transverse section of a triangle, and although not shown, a transverse section thereof may be formed to have one shape of a polygon, a semicircle, and an oval. A shape of a transverse section of the wrinkles 202 may be changed, as needed.
Further, the corrugated panel 200 for the wind power generator blade according to an exemplary embodiment of the present invention may be formed to have a light weight and enough strength.
That is, the corrugated panel 200 for the wind power generator blade may be made of various materials such as a titanium alloy, an aluminum alloy, and a synthetic resin. For reference, because a titanium alloy has excellent corrosion resistance to seawater, when the titanium alloy is applied to a blade of a wind power generator (not shown) that is installed on the sea, the titanium alloy is advantageous, and the aluminum alloy and the synthetic resin can have a light weight and high structural strength.
In this way, when the corrugated panel 200 for the wind power generator blade according to an exemplary embodiment of the present invention is coupled to the blade 140, an efficiency of the blade 140 is increased.
Further, the blade 140 increases stiffness to a bending moment that is generated by a wind by a plurality of wrinkles 202 that are formed in the corrugated panel 200 for the wind power generator blade, and thus an accident such as collision of a tip portion of the blade 140 with the tower 110 can be decreased.
Referring to
Here, one surface of the panel body 310 is a surface that may be coupled to the suction side (see 141 of
Therefore, when one surface of the panel body 310 is coupled to the suction side (see 141 of
A plurality of wrinkles that are formed in the wrinkle portion 320 may be formed at the other surface of the panel body 310 in a length direction of the blade (see 140 of
A plurality of wrinkles that are formed in the wrinkle portion 320 may have a value of a predetermined ratio, compared with a chord length (see LC of
Further, a height and a gap of a plurality of wrinkles that are formed in the wrinkle portion 320 may be the same as those that are described above, and as an experimental result, a gap of a plurality of wrinkles may be selected within a range of 0.1% to 5% of a chord length (see LC of
A transverse section of the plurality of wrinkles that are formed in the wrinkle portion 320 may have a triangle, as shown in the drawing and may have one shape of a polygon, a semicircle, and an oval that are not shown.
A coupling surface SSL that is indicated by a dotted line at the drawing may have a shape of a surface in which one surface of the panel body 310 is to be coupled, i.e., the suction side (see 141 of
In this case, when the connection portion 311 that connects a plurality of wrinkles that are formed in the wrinkle portion 320 is smoothly foldably produced, the panel body 310 may be easily coupled to coupling surfaces SSL of various shapes.
The panel body 310 may be made of various materials of a titanium alloy, an aluminum alloy, and a synthetic resin, and when the panel body 310 is made of a material no having flexibility, by installing a hinge (not shown) in a connection portion 311, the panel body 310 may have flexibility.
As in the corrugated panel (see 200 of
As described above, in exemplary embodiments of the present invention, by improving aerodynamic characteristics of a blade (not shown) that is already installed and using in the wind power generator (not shown) as well as a producing blade (not shown) of a wind power generator, power generation efficiency of the wind power generator (not shown) can be improved.
In the foregoing description, a corrugated panel for a wind power generator blade according to an exemplary embodiment of the present invention has been described, but the present invention is not limited to an exemplary embodiment that is suggested at this specification, and a person of an ordinary skill in the art understanding the spirit or scope of the present invention may easily suggest another exemplary embodiment by addition, change, deletion, and addition of an constituent element within of the same spirit or scope of the present invention, and this comes also within the spirit or scope of the present invention.
According to an exemplary embodiment of the present invention, by improving aerodynamic characteristics of a newly produced wind power generator blade and a blade that has already been installed in the wind power generator and that uses for the wind power generator, power generation efficiency of the wind power generator can be improved.
Number | Date | Country | Kind |
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10-2011-0029521 | Mar 2011 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/KR2012/000164 | 1/6/2012 | WO | 00 | 9/24/2013 |