JP6491981B2 - Airflow generator and wind power generation system - Google Patents

Description

  The present invention relates to an airflow generation device and a wind power generation system.

  In the wind power generation system, power is generated using wind energy.

  The amount of power generated by the wind power generation system may be reduced due to the occurrence of a separation flow on the surface of the wind turbine blade. As a countermeasure, it has been proposed to suppress the generation of the separation flow by installing an airflow generation device on the surface of the wind turbine blade and generating a plasma airflow. Moreover, vibration and noise in a fluid equipment system such as a wind power generation system can be suppressed by using the airflow generation device.

  Usually, the airflow generation device includes a dielectric, a columnar electrode embedded in the dielectric, and a columnar electrode disposed on the surface of the dielectric (Patent Document 1). A metal material or the like is generally used as a constituent material of the columnar electrode of such an airflow generation device.

JP 2008-25434 A

  However, when a columnar electrode made of a metal material that has been conventionally used is used as the columnar electrode provided in the airflow generation device having the above structure, electric field concentration occurs in the vicinity of the apex M at both ends of the columnar electrode (see FIG. 1), the dielectric 2 and the columnar electrodes 3 and 4 are damaged, and there is a problem that the life of the airflow generator is shortened. In particular, the electrode 3 inside the dielectric is difficult to replace, and the replacement requires high cost and long working time.

  The present invention has been made to solve the above-described problems, and is intended to provide an airflow generation device capable of suppressing electric field concentration in the vicinity of the apexes at both ends of a columnar electrode inside a dielectric. is there.

  The airflow generation device according to the embodiment includes a dielectric, a first columnar electrode provided inside the dielectric, a first electrode on the surface of the dielectric or in the vicinity of the surface, and the first columnar electrode. And a second columnar electrode arranged so that the longitudinal directions are parallel to each other, and the columnar electrode of the first columnar electrode has an electric resistance value provided in the vicinity of the apexes at both ends thereof A relatively high electrical resistance portion, and a low electrical resistance portion having a relatively low electrical resistance value provided on the inner side in the longitudinal direction of the first columnar electrode from the high electrical resistance portion. Is.

  According to the present invention, electric field concentration in the vicinity of the apexes at both ends of the columnar electrode can be suppressed, and a long-life airflow generation device can be realized.

It is a figure which shows the result of the electric field analysis in an airflow generator. It is a schematic cross section which shows the airflow generator by embodiment. It is a schematic cross section which shows the airflow generator by other embodiment. It is a top view when the airflow generator by embodiment is seen from upper direction. It is a top view when the airflow generator by other embodiment is seen from upper direction. It is a figure which shows the change of the electrical resistance value in the longitudinal direction of the electrode of the dyne with which the airflow generator shown in FIG. 5A is equipped. It is a top view when the airflow generator by other embodiment is seen from upper direction. It is a top view when the airflow generator by other embodiment is seen from upper direction. It is a schematic cross section for demonstrating the manufacturing method of the airflow generation device by embodiment. It is a schematic cross section for demonstrating the manufacturing method of the airflow generation device by embodiment. It is a perspective view which shows the wind power generation system by embodiment. It is a schematic cross section which shows the windmill blade by embodiment. It is a perspective view which shows the windmill blade by embodiment.

[Airflow generator]
As shown in FIG. 2, in one embodiment, the airflow generator 1 is
Dielectric 2;
A first columnar electrode 3 provided inside the dielectric 2;
A second columnar electrode that is separated from the first electrode 3 on the surface of the dielectric 2 or in the vicinity of the surface, and is arranged so that the longitudinal direction of the first columnar electrode 3 is parallel to the longitudinal direction. 4 and.

As shown in FIG. 3, in another embodiment, the airflow generator 1 is
A first dielectric 2a;
A second dielectric member 2b laminated on the first dielectric member 2a;
A first columnar electrode 3 provided on or near the surface of the first dielectric member 2a on the second columnar electrode 4 side;
A second columnar electrode 4 provided on or near the upper surface of the second dielectric member 2b and arranged such that the longitudinal direction of the first columnar electrode 3 is parallel to the longitudinal direction. And comprising.

[Dielectric]
In the embodiment of the present invention, the airflow generation device includes a dielectric.

  In one embodiment, the dielectric comprises a flexible material, and the flexible material is preferably a resin material because it can impart electrical insulation to the dielectric.

  Examples of the resin material include a thermosetting resin, a thermoplastic resin, and a crosslinked rubber. Among these, a crosslinked rubber is preferable in consideration of mechanical strength and stability of the airflow generator. Examples of thermosetting resins include epoxy resins, unsaturated polyesters, and phenol resins. Examples of the thermoplastic resin include polyethylene, polystyrene, polyethylene terephthalate, vinyl chloride, ABS resin, acrylic resin, and polycarbonate. Moreover, as crosslinked rubber, nitrile rubber, hydrogenated nitrile rubber, fluorine rubber, acrylic rubber (ACM), silicone rubber, urethane rubber, ethylene propylene rubber, chloroprene rubber, chlorosulfonated polyethylene, epichlorohydrin rubber, natural rubber, isoprene rubber, Examples thereof include styrene butadiene rubber, butadiene rubber, and norbornene rubber. The dielectric may contain one or more of the above resin materials.

  In one embodiment, the dielectric comprises inorganic fine particles such as layered silicate belonging to the smectite group, kaolin group, mica group or vermiculite group. Examples of the layered silicate belonging to the smectite group include montmorillonite, hectorite, saponite, sauconite, beidellite, stevensite, and nontronite. Examples of the layered silicate belonging to the kaolin group include kaolinite, nacrite, dickite and halosite. Examples of the layered silicate belonging to the mica group include mascobite, margarite, illite, clintonite, anandite, biotite, and lipidoid. Examples of the layered silicate belonging to the vermiculite group include trioctahedral vermiculite and dioctahedral vermiculite. Among these, it is desirable to use a layered silicate belonging to the smectite group from the viewpoint of dispersibility. The dielectric may contain one or more of the inorganic fine particles.

  The content of the inorganic fine particles in the dielectric is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the resin material. By setting the content of the inorganic fine particles within the above numerical range, the distance between the inorganic fine particles can be maintained at an appropriate value, and the mechanical strength of the airflow generating device is prevented from being lowered due to the formation of fine particle aggregates. And suitable electrical characteristics can be provided. More preferably, it is 1-10 mass parts, More preferably, it is 1-5 mass parts. Here, the electrical characteristics refer to, for example, dielectric breakdown strength and discharge erosion resistance, and the mechanical characteristics refer to, for example, fracture toughness.

  The average primary particle diameter of the inorganic fine particles is preferably 1000 nm or less and 1 nm or more, and more preferably 500 nm or less and 5 nm or more. By making the average primary particle diameter of the inorganic fine particles within the above numerical range, it is possible to prevent the aspect ratio of the inorganic fine particles from becoming too large, and the accompanying increase in the viscosity of the mixture with the resin material. Therefore, it is possible to prevent a reduction in work efficiency. In addition, this average particle diameter is a median diameter (particle diameter when the cumulative amount is 50% in the cumulative distribution curve) of the cumulative distribution (cumulative distribution). The size of the inorganic fine particles can be measured by a laser diffraction scattering method, a dynamic light scattering method, a method using a dielectrophoresis phenomenon and diffracted light, or the like.

  The surface of the dielectric is preferably subjected to surface activation treatment such as corona treatment or coupling treatment from the viewpoint of improving adhesiveness.

  In one embodiment, the dielectric may be a laminated body in which a plurality of dielectric members are laminated. Specifically, it can be a laminate composed of a first dielectric member and a second dielectric member. With such a configuration, in the manufacturing process of the airflow generation device, a structure in which the first columnar electrode is embedded in the dielectric can be easily obtained by sandwiching the first columnar electrode described later between the two dielectric members. It can be formed (see, for example, FIG. 3). The resin material of the first dielectric member and the resin material of the second dielectric member may be the same or different. However, from the viewpoint of the adhesion between the first dielectric member and the second dielectric member and the mechanical characteristics of the airflow generation device, the resin material constituting the first dielectric member and the second dielectric member are constituted. The resin to be used is preferably the same.

[First columnar electrode]
In one embodiment, the first columnar electrode 3 provided in the airflow generation device 1 is disposed in the dielectric 2 so as to be separated from the second columnar electrode 4 (see FIG. 2). In addition, when the dielectric 2 is formed of a laminated body including the first dielectric member 2a and the second dielectric member 2b, the first columnar electrode 3 is the second dielectric member 2a. 2 is preferably disposed on or near the surface of the columnar electrode 4 (see FIG. 3). In any case, the first columnar electrode 3 is arranged so that the longitudinal direction thereof is parallel to the longitudinal direction of the second columnar electrode 4. This is because if the distance between the first and second electrodes is not constant, electric field concentration may occur in a portion where the electrode distance is narrow. The second columnar electrode preferably has a longer length in the longitudinal direction than the first columnar electrode.

  The airflow generation device according to the embodiment is intended to be applied to a wind turbine blade or the like. For this reason, since it is preferable to generate an airflow over the longitudinal direction of the wind turbine blade, the electrode preferably has a columnar shape having a certain length. In addition, the cross-sectional shape of the columnar electrode is not particularly limited, and examples thereof include a quadrangle, a semicircle, a semi-ellipse, a circle, and an ellipse. Specifically, the columnar electrode in the embodiment can have a shape such as a columnar shape, a prismatic shape, or a plate shape. The end portion of the columnar electrode generally has a vertex, but the end portion may be rounded so as not to have a vertex. The first columnar electrode used in the embodiment may have an appropriate shape depending on the purpose.

  In one embodiment, the first columnar electrode includes a high electrical resistance portion having a relatively high electrical resistance value provided in the vicinity of the apexes at both ends thereof, and a length of the first columnar electrode from the high electrical resistance portion. And a low electric resistance portion having a relatively low electric resistance value provided on the inner side in the direction. In the embodiment, “near the apex” refers to an area close to the apex of the columnar electrode, and “near the apex” refers to a wider area, for example, the entire length of the columnar electrode from both ends. Each region is about 30% long. Since the first columnar electrode has such a configuration, electric field concentration in the vicinity of the apex at the end of the first columnar electrode can be suppressed, and the dielectric breakdown time of the first columnar electrode can be suppressed. Can be extended.

  In one embodiment, the portion 3a having a relatively low electrical resistance value of the first columnar electrode 3 and the second columnar electrode 4 when viewed from vertically above the dielectric surface on which the second columnar electrode is provided. Are preferably not duplicated (see, for example, FIG. 4).

  A specific example of the configuration of the first columnar electrode will be described below with reference to FIGS. 4 to 7, the second columnar electrode is longer in the longitudinal direction than the first columnar electrode, but is not limited thereto.

  In the first embodiment, as shown in FIG. 4, the first columnar electrode 3 is provided at a central portion 3a (low electrical resistance portion) having a relatively low electrical resistance value and at both ends of the central portion 3a. And an end portion 3b (high electric resistance portion) having a relatively high electric resistance value. Adhesion between the central portion 3a and the end portion 3b can be performed through a conductive adhesive or the like as necessary. With such a configuration, it is possible to disperse a plurality of portions where electric field concentration can occur, and as a result, it is possible to suppress electric field concentration.

  In the second embodiment, as shown in FIGS. 5A and 5B, the first columnar electrode 3 may be configured such that the electric resistance value continuously increases from the center in the longitudinal direction toward the end. As a method of continuously changing the electric resistance value, for example, a method of gradually increasing the content of a material having a relatively high electric resistance value from the center to the end of the first columnar electrode 3, And a method of gradually reducing the cross-sectional area of the columnar electrode 3. The first columnar electrode 3 formed by these methods is preferable because there is no interface in the electrode and the mechanical strength is high.

  In the third embodiment, as shown in FIG. 6, the first columnar electrode 3 includes a central portion 3c formed of a material having a relatively low electrical resistance value, and an electrical resistance value covering the central portion. And a covering portion 3d made of a relatively high material. In FIG. 6, the entire central portion 3 c is covered, but the present invention is not limited to this, and only a portion (particularly, near the apexes at both ends of the central portion) may be covered. The coating can be formed by using a coating method such as a screen printing method or a doctor blade method. It can also be formed by a resin molding method such as a casting method.

  In the fourth embodiment, as shown in FIG. 7, the electric resistance value of the first columnar electrode 3 when viewed from vertically above the surface of the dielectric 2 provided with the second columnar electrode 4. A relatively large portion 3d and the second columnar electrode 4 overlap, and a portion 3c having a relatively small electrical resistance value of the first columnar electrode 3 and the second columnar electrode 4 It is preferable not to overlap. As a result, the electrolysis in the portion where the airflow is generated can be made uniform, and the stability of the generated discharge can be improved. In addition, mechanical breakage of the first columnar electrode 3 can be suppressed.

  In one embodiment, the high electrical resistance portion included in the first columnar electrode comprises a conductive resin composition. In the present invention, the “conductive resin composition” may be made of a resin material having conductivity itself (hereinafter, referred to as “conductive resin material” in some cases). In addition, the “conductive resin composition” may include a resin material having no conductivity (hereinafter, sometimes referred to as “non-conductive resin material”) and conductive fine particles. . Furthermore, the “conductive resin composition” may include a conductive resin material, a non-conductive resin material, and / or conductive fine particles.

  Examples of the conductive resin material include polyacetylene, polypyrrole, polythiophene, and polyaniline. The conductive resin composition may contain one or more of the conductive resin materials.

  Examples of the non-conductive resin material include a thermosetting resin, a thermoplastic resin, and a crosslinked rubber. Among these, a crosslinked rubber is preferable in consideration of mechanical strength and stability of the airflow generator. Examples of thermosetting resins include epoxy resins, unsaturated polyesters, and phenol resins. Examples of the thermoplastic resin include polyethylene, polystyrene, polyethylene terephthalate, vinyl chloride, ABS resin, acrylic resin, and polycarbonate. Moreover, as crosslinked rubber, nitrile rubber, hydrogenated nitrile rubber, fluorine rubber, acrylic rubber (ACM), silicone rubber, urethane rubber, ethylene propylene rubber, chloroprene rubber, chlorosulfonated polyethylene, epichlorohydrin rubber, natural rubber, isoprene rubber, Examples thereof include styrene butadiene rubber, butadiene rubber, and norbornene rubber. The conductive resin composition may contain one or more of the above non-conductive resin materials.

  Specific examples of the conductive fine particles include carbon-based fine particles, metal-based fine particles, and metal oxide-based fine particles, which may include one or more of these.

  Examples of the carbon-based fine particles include carbon powder such as carbon black, nanocarbon such as carbon nanofiber, and carbon fiber.

  Further, examples of the metal-based fine particles include metal powders such as aluminum, copper, gold, silver, nickel, chromium, iron, molybdenum, titanium, and tungsten, and metal fibers such as iron, copper, and stainless steel.

Examples of the metal oxide fine particles include tin oxide, indium oxide, and zinc oxide.
The average primary particle diameter of the conductive fine particles is preferably 0.1 μm to 500 μm, and more preferably 1 μm to 100 μm.

  The conductive fine particles in the conductive resin material are preferably added in an amount of 1 to 200 parts by weight, more preferably 5 to 100 parts by weight, with respect to 100 parts by weight of the conductive resin material. Moreover, it is preferable to add 1-500 mass parts with respect to 100 mass parts of nonelectroconductive resin materials, and it is preferable to add 5-200 mass parts.

  In one embodiment, the low electrical resistance portion included in the first columnar electrode comprises a metal material such as nickel, stainless steel, titanium, molybdenum, tungsten, or an alloy thereof.

[Second columnar electrode]
The second columnar electrode 4 provided in the airflow generation device is provided on the surface of the dielectric 2 or in the vicinity of the surface (see FIG. 2). On the surface of the dielectric, discharge plasma is generated when a voltage is applied to the first columnar electrode and the second columnar electrode via the cable wiring. Therefore, it is preferable that the second columnar electrode includes a conductive material having discharge resistance and oxidation resistance. Examples of the conductive material included in the second columnar electrode include metal materials such as nickel, stainless steel, titanium, molybdenum, tungsten, and alloys thereof. Among these, tungsten and titanium are preferable because they are particularly excellent in oxidation resistance and discharge resistance.

  The shape of the second columnar electrode can be selected from those described in the section of the first columnar electrode. Note that the shape of the second columnar electrode need not be the same as the shape of the first columnar electrode.

  However, as described above, electric field concentration can also occur in the vicinity of the apexes at both ends of the second columnar electrode. Therefore, like the first columnar electrode, the second columnar electrode has a relatively high electrical resistance value provided in the vicinity of the apexes at both ends thereof, and the second electrical resistance portion has a higher electrical resistance value than the second electrical field. And a low electric resistance portion having a relatively low electric resistance value provided on the inner side in the longitudinal direction of the columnar electrode. Specifically, the structure shown in the first to fourth aspects of the first columnar electrode can be employed. In the second columnar electrode, in consideration of erosion due to discharge plasma, the high electrical resistance portion is preferably formed of conductive ceramics such as conductive zirconia, alumina-titanium carbide, or silicon carbide.

[Production Method of Airflow Generator]
The manufacturing method of the airflow generation device in one embodiment will be described as follows.
First, as shown in FIG. 8, the first dielectric member 2 a is disposed in the lower mold 5. Next, the first columnar electrode 3 is disposed on the first dielectric member 2a. Further, the second dielectric member 2b is stacked on the first dielectric member 2a so as to sandwich the first columnar electrode 3 therebetween.

  Subsequently, the first dielectric member 2 a, the first columnar electrode 3, and the second dielectric member 2 b are integrated by heating and pressing with the upper mold 6 and the lower mold 5.

  Subsequently, the integrated dielectric is taken out from the mold, and the second columnar electrode 4 is joined to the upper surface of the second dielectric member 2b, whereby the airflow generator 1 can be obtained (not shown). ) As a bonding method, for example, the surface of the second dielectric member 2b to be bonded to the second columnar electrode 4 is modified with an alkoxysilane compound or the like, and then the second columnar electrode 4 is contacted and heated. Is mentioned. Examples of the alkoxysilane compound include tetramethoxysilane, tetraethoxysilane, and methyltrimethoxysilane.

The manufacturing method of the airflow generation device in another embodiment will be described as follows.
First, as shown in FIG. 9, the first dielectric member 2 a is disposed in the lower mold 5. Next, the first columnar electrode 3 is disposed on the first dielectric member 2a. Further, the second dielectric member 2b is stacked on the first dielectric member 2a so as to sandwich the first columnar electrode 3 therebetween. Then, the second columnar electrode 4 is disposed on the second dielectric member 2b.

  Subsequently, by heating and pressurizing the first dielectric member 2a, the first columnar electrode 3, the second dielectric member 2b and the second columnar electrode 4 with the upper mold 6 and the lower mold 5. By integrating, the airflow generator 1 can be obtained. In addition, the heating temperature and the pressurizing pressure are preferably in the same range as described above.

  8 and 9, the first columnar electrode 4 is arranged near the surface of the first dielectric member 2a on the second columnar electrode 4 side, that is, embedded in the first dielectric member 2a. However, the material may be embedded in the second dielectric member 2b by appropriately selecting the materials constituting the first dielectric member 2a and the second dielectric member 2b. .

[Wind power generation system]
FIG. 10 is a perspective view showing the wind power generation system 7 in one embodiment. As shown in FIG. 10, in the wind power generation system 7, a nacelle 10 accommodating a generator (not shown) and the like is attached to the top of a tower 9 installed on the ground 8. A wind turbine blade 11 is attached to the rotating shaft of the generator protruding from the nacelle 10. Further, an anemometer 12 for measuring the wind direction and the wind speed of the cold is provided on the upper surface of the nacelle 10. In one embodiment, as shown in FIG. 11, a voltage is applied between the first columnar electrode 3 and the second columnar electrode 4 of the airflow generation device via the cable wiring 13. A discharge power supply 14 is installed. When a voltage is applied from the discharge power supply 14 between the first columnar electrode 3 and the second columnar electrode 4 and a potential difference equals or exceeds a certain threshold value, the first columnar electrode 3 and the second columnar electrode 4 During this period, a dielectric barrier discharge occurs, and a discharge plasma is generated along with the dielectric barrier discharge. As shown in FIG. 11, the dielectric barrier discharge causes an air flow along the surface of the first dielectric member 2a in one direction perpendicular to the longitudinal direction of the first columnar electrode 3 and the second columnar electrode 4. AF occurs. In FIG. 11, the airflow AF is generated in the direction from the second columnar electrode 4 to the first columnar electrode 3 when viewed from vertically above the dielectric surface. However, the present invention is not limited to this. Instead, it can be controlled by changing the current-voltage characteristics such as the voltage applied to the electrode, frequency, current waveform, duty ratio, etc., or changing the electrode installation method. Further, the size of the airflow can be similarly controlled.

[Windmill Wings]
FIG. 13 is a perspective view showing the wind turbine blade 11 in one embodiment. As shown in FIG. 12, the windmill blade 11 includes a windmill blade body 15 and an airflow generation device 1 disposed on the windmill blade body 15.

  In one embodiment, the wind turbine blade body includes a dielectric material such as GFRP (glass fiber reinforced resin) obtained by solidifying glass fiber with a synthetic resin. Note that the wind turbine blade is not limited to the whole made of a dielectric material, and only a portion where the airflow generating device is arranged may be made of a dielectric material.

  Moreover, the airflow generation device by embodiment is applicable to various uses besides a windmill blade. For example, in order to reduce the air resistance generated during operation of a train, an automobile, or an aircraft, it can also be used for rectification of airflow generated on the surface of the airframe.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Airflow generator 2 Dielectric 2a 1st dielectric member 2b 2nd dielectric member 3 1st columnar electrode 4 2nd columnar electrode 4a Central part 4b End part 4c Central part 4d Covering part 5 Lower mold 6 Upper mold 7 Wind power generation system 8 Ground 9 Tower 10 Nacelle 11 Windmill blade 12 Wind direction anemometer 13 Cable wiring 14 Power supply for discharge 15 Windmill blade body AF Airflow

Claims (9)

A dielectric,
A first columnar electrode provided inside the dielectric;
A second columnar electrode that is spaced apart from the first electrode on or near the surface of the dielectric, and arranged so that the longitudinal direction thereof is parallel to the longitudinal direction of the first columnar electrode; Prepared,
The columnar electrode of the first columnar electrode includes a high electrical resistance portion having a relatively high electrical resistance value provided in the vicinity of the apexes at both ends thereof, and a longitudinal direction of the first columnar electrode from the high electrical resistance portion. An airflow generation device comprising: a low electrical resistance portion having a relatively low electrical resistance value provided inside.   The first columnar electrode includes a central portion having a relatively small electrical resistance value and end portions having a relatively large electrical resistance value provided at both ends in the longitudinal direction of the central portion. Item 2. The airflow generation device according to Item 1.   The airflow generation device according to claim 1, wherein the first columnar electrode is configured so that an electric resistance value continuously increases from a center in a longitudinal direction toward a terminal.   The first columnar electrode includes a central portion made of a material having a relatively small electric resistance value and a covering portion made of a material having a relatively large electric resistance value covering the central portion. The airflow generation device according to claim 1.   When viewed from vertically above the dielectric surface on which the second columnar electrode is provided, a portion having a relatively small electric resistance value of the first columnar electrode overlaps with the second columnar electrode. The airflow generation device according to any one of claims 1 to 4.   When viewed from vertically above the dielectric surface on which the second columnar electrode is provided, the relatively large portion of the electrical resistance value of the first columnar electrode overlaps the second columnar electrode, The airflow generation device according to claim 4, wherein a portion having a relatively small electric resistance value of the first columnar electrode does not overlap with the second columnar electrode.   The air current is generated from the second columnar electrode in the direction of the first columnar electrode when viewed from vertically above the dielectric surface provided with the second columnar electrode. The airflow generation device according to item 1.   The airflow generation device according to any one of claims 1 to 7, wherein the dielectric is a laminated body including a first dielectric member and a second dielectric member.   The columnar electrode of the second columnar electrode has a high electrical resistance portion having a relatively high electrical resistance value provided in the vicinity of the apexes at both ends thereof, and the longitudinal direction of the second columnar electrode from the high electrical resistance portion The airflow generation device according to any one of claims 1 to 8, further comprising a low electrical resistance portion having a relatively low electrical resistance value provided inside.