JP2012193678A - Airflow generation device, and insulating film for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an airflow generation device that is superior in the barrier discharge performance and has an insulating film which is usable under the outdoor environment or plasma discharge for a long period.SOLUTION: The airflow generation device includes: a first electrode; the insulating film that is laminated on the first electrode such that an end of the first electrode exposes and contains silica-base inorganic polymer which has mainly siloxane bond; and a second electrode that is laminated on the insulating film.

Description

  Embodiments described herein relate generally to an airflow generation device and an insulating film for the airflow generation device.

  At present, various energy efficiency improvements are being studied for various fluid devices that use air as a working fluid, such as aircraft and wind turbines for power generation. Among them, the airflow generator that actively controls the airflow using the jet induced by the plasma generated by the principle of dielectric barrier discharge has no working part and can easily control the airflow by electrical control. It has been attracting attention as a new fluid control method.

  In particular, wind turbines for wind power generation have a relatively low energy cost and a relatively large number of locations among renewable energy power generation systems that are being introduced on a global scale from the viewpoint of preventing global warming. This is one of the power generation methods that are being actively promoted. In Japan, development subsidies are being promoted by the government, but the penetration rate is still low compared to Europe.

  The difficulty of spreading wind power generation in Japan is largely attributable to its geographical constraints. First, because of the mountainous weather, the wind power and the wind direction change rapidly and it is difficult to maintain a stable output. This reduces the power generation efficiency per wind turbine, and as a result, increases the introduction cost of the wind power generation system.

  Secondly, in Japan, where the land area is narrow, as wind power generation has become widespread, problems with the location environment have become apparent, especially when it is necessary to locate near private houses and villages. Trouble occurs. In order for Japan to achieve the goal of introducing Europe and the United States, it is essential to develop a wind turbine unique to Japan that overcomes these problems.

  For application to wind turbines for power generation, etc., development of airflow generators using plasma airflow control is underway. By arranging the airflow generator on the windmill blade surface, wind turbine blades and wind power generation systems that can be controlled in response to wind fluctuations and achieve high efficiency and low noise have been devised. A wind power generation system control method for controlling a wind power generation system based on measurement information of wind speed and direction has been devised.

  The basic configuration of the airflow generation device is a configuration in which an insulating layer (dielectric layer) is disposed between two electrodes. However, when the airflow generation device is used for a fluid device used outdoors such as a windmill or an aircraft, Since the airflow generator is exposed to severe outdoor environments such as rainfall, temperature / humidity, ultraviolet rays, and dust, the development of airflow generators that maintain excellent characteristics under these operating environments as well as material deterioration due to plasma discharge It is essential. However, until now, organic resin materials have been mainly used especially in the insulating layer part because of ease of use, etc., and material deterioration was rapid when used outdoors, and there was a problem in practical use.

JP 2008-25434 A

  The problem to be solved by the present invention is to provide an airflow generation device having an insulating layer that is excellent in barrier discharge performance and can be used for a long time even in an outdoor environment or under plasma discharge.

  In an embodiment of the present invention, a silica-based inorganic polymer mainly composed of a siloxane bond, which is laminated on a first electrode and the first electrode so as to expose an end portion of the first electrode, The present invention relates to an airflow generation device comprising: an insulating layer including: a second electrode stacked on the insulating layer.

  According to the present invention, it has excellent barrier discharge performance and can be used for a long time even in an outdoor environment or plasma discharge.

It is a figure which shows schematic structure of the airflow generator in 1st Embodiment. It is a figure which shows schematic structure of the airflow generator in 2nd Embodiment. It is a graph which shows the lifetime of the airflow generator in an Example.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating a schematic configuration of an airflow generation device of the present embodiment.
As shown in FIG. 1, the airflow generation device 10 according to the present embodiment includes a first electrode 11, an insulating layer (dielectric layer) 12 stacked on the first electrode 11, and the insulating layer 12. And the second electrode 13 stacked on each other. As shown in FIG. 1, the airflow generation device 10 generates a plasma airflow as described below, and performs its original function. The first electrode 11 is laminated so that the end portion 11A of the first electrode 11 is exposed.

  The 1st electrode 11 and the 2nd electrode 12 can be comprised from what is well-known as an electrode material. For example, metals such as stainless steel, Inconel (registered trademark), Hastelloy (registered trademark), titanium, platinum, tungsten, molybdenum, nickel, copper, gold, silver, tin, and chromium, and alloys mainly composed of these metal elements Also, it can be used according to the environment in which good inorganic conductors such as carbon nanotubes and conductive ceramics, and good organic conductors such as conductive plastics are used.

  In particular, when the first electrode 11 and the second electrode 12 are made of a heat-resistant or corrosion-resistant metal such as Inconel, Hastelloy, titanium, etc., they are used for a long time even in a highly corrosive atmosphere such as high temperature and high humidity and oxidation An electrode that can be realized can be realized.

  The insulating layer 12 is made of a silica-based inorganic polymer mainly composed of siloxane bonds. This silica-based inorganic polymer is a polymer whose main skeleton is composed of Si—O (oxygen) —Si inorganic bonds. Such a silica-based inorganic polymer has low hygroscopicity and has high weather resistance and durability equivalent to ceramics. Therefore, it does not deteriorate even under severe outdoor environments such as rainfall, temperature / humidity, ultraviolet rays, and dust, and severe conditions such as plasma discharge. As a result, the airflow generation device 10 of the present embodiment can be used over a long period of time even under severe conditions such as the outdoor environment and plasma discharge described above.

  The first electrode 11 can be formed by processing the electrode material described above into a predetermined shape such as a plate shape.

  The insulating layer 12 is made of, for example, a raw material mainly composed of a solventless type alkoxysilane compound (for example, “Permeate” manufactured by Day and Day Co., Ltd., “Liquid Glass Paint” manufactured by Moktec Kamemura). It can form by apply | coating on the main surface of the electrode 11 of this, and solidifying by reaction with the water | moisture content in air. Alternatively, a solution or dispersion medium obtained by dissolving or dispersing a silica-based inorganic polymer in a solvent such as alcohol is applied on the main surface of the first electrode 11 and then the solvent is evaporated. it can.

  Thus, since the insulating layer 12 is formed by a wet method, the insulating layer 12 can be formed so as to have a certain degree of high adhesion to the first electrode 11.

  The second electrode 13 is an electrode obtained by processing the electrode material described above into a predetermined shape such as a plate shape, similar to the first electrode 11, before the silica-based inorganic polymer is cured as described above. By disposing the member and then curing the silica-based inorganic polymer, the polymer can be used as an indirect adhesive and formed on the insulating layer 12. Even after the silica-based inorganic polymer is cured, it can be formed by sputtering, plating, printing, thermal spraying, or the like.

  In addition, the thickness of the 1st electrode 11 can be 0.05 mm-5 mm, for example. The thickness of the insulating layer 12 can be set to, for example, 50 μm to 1000 μm. The thickness of the 2nd electrode 13 can be 0.05 mm-5 mm, for example. As shown in the figure, in the first electrode and the exposed second electrode, the electrode 1 is wider and has a structure expanded in the direction in which the plasma flow is to be induced, or the first electrode is the second electrode. It is common to have a structure with the following width and shifted in the direction in which the plasma flow is to be induced. The width of the first electrode and the second electrode can be set to 1 mm to 50 mm, for example.

Further, of the silica-based inorganic polymer constituting the insulating layer 12 is preferably more than 80 wt% is silicon oxide (SiO _2). In this case, since the hygroscopicity reduction, weather resistance and durability of the silica-based inorganic polymer are further improved, the deterioration under the severe outdoor environment as described above and severe conditions such as plasma discharge is more effective. The airflow generation device 10 of the present embodiment can be used for a longer period even under severe conditions such as the outdoor environment and plasma discharge described above.

  The upper limit of the ratio of silicon oxide in the silica-based inorganic polymer is not particularly limited as long as the above-described effects are exhibited, but is currently about 70% by mass. This mainly depends on the silicon oxide formation method described below. Note that if bulk silicon oxide is used, the upper limit of the ratio of silicon oxide can be set to 100% by mass. In this case, sufficient adhesion between the first electrode 11 and the second electrode 13 is obtained. I can't.

  When silicon oxide is formed in the silica-based inorganic polymer as described above, the silica-based inorganic polymer is subjected to heat treatment at 300 ° C. or higher, preferably 600 ° C. or lower for several hours in an oxygen-containing atmosphere, for example. A silica-based inorganic polymer can be added to silicon oxide, and the content ratio of silicon oxide in the silica-based inorganic polymer can be 80% by mass or more as described above.

  In addition, the surface roughness Rmax of the main surface of the first electrode 11 on which the insulating layer 12 is formed is preferably 0.5 μm to 50 μm. Thus, as described above, when the insulating layer 12 is formed by a wet method, the solventless raw material or the like enters the concavo-convex portion of the main surface and solidifies as it is. The adhesion between the first electrode 11 and the insulating layer 12 is improved. The surface roughness as described above can be formed by, for example, performing groove processing or sand blast processing on the main surface of the first electrode 11.

  If the surface roughness Rmax of the first electrode 11 is less than 0.5 μm, the unevenness of the main surface of the first electrode 11 is not sufficiently large, so that the anchor effect becomes insufficient, and the first When the surface roughness Rmax of the electrode 11 exceeds 50 μm, the irregularities formed on the main surface of the first electrode 11 become excessively large, and solvent-free raw materials and the like can sufficiently penetrate into these irregularities. Therefore, the anchor effect is insufficient. Therefore, the adhesion between the first electrode 11 and the insulating layer 12 may not be improved.

  Furthermore, the first electrode 11 can be formed to have a porosity of 5% to 30%. Also in this case, as described above, when the insulating layer 12 is formed by the wet method, the solventless raw material or the like enters the pores opened in the main surface of the first electrode 11 and solidifies as it is. Therefore, the adhesion between the first electrode 11 and the insulating layer 12 is improved by a so-called anchor effect.

  Note that the porosity can be controlled by adjusting the compression ratio, the sintered density, and the like during pressing when the first electrode 11 is made of the above-described metal material. Further, in the thermal spraying method, it can also be performed by adjusting the discharge amount and discharge speed of the metal material constituting the first electrode 11.

  When the porosity of the first electrode 11 is less than 5%, the anchor effect becomes insufficient, and when the porosity of the first electrode 11 exceeds 30%, the pores opened in the main surface of the first electrode 11 Since the ratio of pores remaining without the raw material or the like entering therein increases, the anchor effect becomes insufficient as a result. Therefore, the adhesion between the first electrode 11 and the insulating layer 12 may not be improved.

  Next, a mechanism for generating plasma airflow by the airflow generation device 10 shown in FIG. 1 will be briefly described.

  When a voltage is applied between the first electrode 11 and the second electrode 12 from a discharge power source (not shown) and a potential difference equals or exceeds a certain threshold value, a discharge is induced between the first electrode 11 and the second electrode 12. The Since this discharge is generated through the insulating layer (dielectric layer) 12 existing between these electrodes, it is called a barrier discharge. As a result, a low temperature plasma P is generated. In these discharges, energy can be given only to electrons in the gas, so that the gas can be ionized to generate electrons and ions with little heating of the gas.

  As shown in FIG. 1, since the end 11A of the first electrode 11 is exposed from the insulating layer 12 and the second electrode 13, the generated electrons are particularly the end 11A of the first electrode 11. The momentum shifts to gas molecules when they are driven by the electric field generated in and collide with the gas molecules. As a result, the plasma airflow S can be generated behind the generated low temperature plasma P. The magnitude and direction of the plasma airflow S can be controlled by changing the current-voltage characteristics such as the voltage, frequency, current waveform, and duty ratio applied between the first electrode 11 and the second electrode 13.

(Second Embodiment)
FIG. 2 is a diagram illustrating a schematic configuration of the airflow generation device of the present embodiment. It should be noted that the same reference numerals are used for components that are similar or identical to the components shown in FIG.

  As shown in FIG. 2, the airflow generation device 20 according to the present embodiment includes a first electrode 11, an insulating porous base layer 21 laminated on the first electrode 11, and the base layer 21. And an insulating layer (dielectric layer) 12 stacked on the insulating layer 12 and a second electrode 13 stacked on the insulating layer 12. As shown in FIG. 2, the airflow generator 20 generates a plasma airflow as described in the first embodiment, as shown in FIG. The second electrode 13 is laminated so that the end portion 11A of the first electrode 11 is exposed.

  Since the underlayer 21 is insulative and porous, for example, aluminum oxide, zirconium oxide, hafnium oxide, neodymium oxide, lanthanum oxide, yttrium oxide, magnesium oxide, phosphate compound, calcium oxide And oxides such as silicon oxide. However, aluminum oxide is preferable from the viewpoints of high insulation performance, ease of forming operation, economy, and the like.

  When forming the base layer 21 from the above-described material, particularly aluminum oxide, the base layer 21 is porous. Therefore, the first electrode 11 is placed in a predetermined mold, and the first layer 11 is formed in the mold. The electrode 11 can be filled with aluminum oxide powder and formed using a powder sintering process such as pressing and sintering. However, oxides such as aluminum oxide have a high sintering temperature and are sintered. There is a concern that the first electrode 11 is dissolved in the process and the form as an electrode is not left.

  Therefore, in this embodiment, it is preferable to use a thermal spraying method when forming the foundation layer 21. In this case, the porosity in the foundation layer 21 can be controlled by adjusting the discharge amount and discharge speed when discharging the dispersion medium in which aluminum oxide or the like is dispersed in a predetermined solvent.

  As is clear from the configuration shown in FIG. 2, the insulating layer 12 is formed on the base layer 21. As described above, the insulating layer 12 is mainly composed of a solventless alkoxysilane compound. After applying a raw material (for example, “Permeate” manufactured by Day and Day Co., Ltd., “Liquid Glass Paint” manufactured by Mocktec Kamemura Co., Ltd.) on the main surface of the base layer 21, it reacts with moisture in the air. It can be formed by solidifying. Alternatively, it can be formed by applying a solution or dispersion medium obtained by dissolving or dispersing a silica-based inorganic polymer in a good solvent such as alcohol on the main surface of the base layer 21 and then evaporating the solvent. .

  Since the underlayer 21 is porous, there are open pores in its main surface. Therefore, since the solventless raw material or the like constituting the insulating layer 12 enters into the pores opened in the main surface of the base layer 21 at the time of formation, the base layer 21, the insulating layer 12, Improved adhesion.

  The porosity of the underlayer 21 is preferably 5% to 30%. When the porosity of the underlayer 21 is less than 5%, the anchor effect becomes insufficient, and when the porosity of the underlayer 21 exceeds 30%, the above-mentioned raw materials are contained in the pores opened in the main surface of the underlayer 21. Since the proportion of pores remaining without intrusion increases, the anchor effect is insufficient as a result. Therefore, the adhesion between the base layer 21 and the insulating layer 12 may not be improved.

  The conditions and manufacturing method required for the first electrode 11, the insulating layer 12, and the second electrode 13 are the same as those in the first embodiment, and a description thereof will be omitted.

Example 1
The first electrode 11 was formed by processing to a thickness of 0.5 mm, and the second electrode 13 was formed by processing to a thickness of 0.2 mm. Further, the insulating layer 12 is formed to a thickness of 100 μm using “Permeate” manufactured by Day and Day Co., Ltd. and “Liquid Glass Paint” manufactured by Mocktec Kamemura Co., Ltd. An airflow generation device 10 as shown in FIG.

  Next, a lifetime evaluation was performed on the airflow generation device 10 thus obtained by applying an AC voltage of 10 kHz outdoors to generate a plasma airflow. As a result, it was found that a plasma stream can be generated even after 300 hours have passed. The results are shown in FIG.

(Comparative Examples 1-3)
Instead of the liquid glass paint in Example 1, a 300 μm thick polyimide film (Comparative Example 1), a 250 μm thick alumina film (Comparative Example 2) formed by thermal spraying, and an alumina film by thermal spraying An airflow generator as shown in FIG. 1 was produced using a film (Comparative Example 3) subjected to a sealing treatment using a sealing material composed of a solvent and a solid.

  For each airflow generation device thus obtained, as in Example 1, a 10 kHz alternating voltage was applied outdoors to evaluate the life when a plasma airflow was generated. As a result, in the case of the comparative example 1, the plasma air stream can no longer be generated after about 120 hours, in the case of the comparative example 2, the plasma air stream cannot be generated after about 30 hours, and in the case of the comparative example 3, about 180 hours. It was later found that a plasma stream could not be generated. The results are shown in FIG.

  Therefore, as is clear from the above-described examples and comparative examples, according to the present invention, the insulating layer 12 constituting the airflow generation device 10 is composed of a silica-based inorganic polymer mainly composed of siloxane bonds, thereby enabling outdoor environments. It has been found that it is possible to provide an airflow generation device having an insulating layer that can be used for a long time even under a plasma discharge.

  The present invention has been described in detail based on the above specific examples. However, the present invention is not limited to the above specific examples, and various modifications and changes can be made without departing from the scope of the present invention.

10, 20 Airflow generator 11 First electrode 12 Insulating layer (dielectric layer)
13 Second electrode P Low temperature plasma S Plasma stream 21 Underlayer

Claims (8)

A first electrode;
An insulating layer containing a silica-based inorganic polymer mainly composed of a siloxane bond, which is laminated on the first electrode so as to expose an end portion of the first electrode;
A second electrode laminated on the insulating layer;
An airflow generating device comprising: _2. The airflow generation device according to claim 1, wherein the insulating layer contains silicon oxide (SiO ₂ ) at a ratio of 80 mass% or more as the silica-based inorganic polymer.   3. The airflow generation device according to claim 1, wherein a surface roughness Rmax of a main surface of the first electrode on which the insulating layer is laminated is in a range of 0.5 μm to 50 μm.   The airflow generation device according to any one of claims 1 to 3, wherein the first electrode has a porosity of 5% to 30%.   The airflow generation device according to any one of claims 1 to 4, further comprising a porous underlayer exhibiting insulating properties between the first electrode and the insulating layer.   The airflow generation device according to claim 5, wherein the porosity of the underlayer is 5% to 30%.   An insulating film for an airflow generator, comprising a silica-based inorganic polymer mainly composed of siloxane bonds. The insulating film for airflow generation according to claim 7, wherein the silica-based inorganic polymer contains silicon oxide (SiO ₂ ) at a ratio of 80% by mass or more.

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