JP5196961B2 - Wings for gyromill type windmills - Google Patents

Description

  The present invention relates to a wing for a gyromill type windmill and a windmill used therein, and more particularly to a wing for a gyromill type windmill that self-activates at a low wind speed and generates a high rotational torque, and the windmill used therein. .

  The history so far shows that various struggles over oil rights have been repeated since the energy source of developed countries was switched from coal to oil. With the growing concern about fossil fuel depletion, there is an increasing need to reduce dependence on petroleum energy and to shift to alternative energy sources.

  Recently, the use of “wind power” has been reviewed especially as an alternative to oil energy. Because “wind” is produced inexhaustably by heating the air on the earth by solar energy, and it can be used permanently by anyone without being monopolized by a specific person. It is.

  Regarding the “wind turbine” that converts the “wind” into energy, various methods and forms have been proposed since history, but broadly divided into “horizontal axis wind turbine” and “vertical axis wind turbine”. Can be classified.

  First, a “horizontal axis windmill” (particularly, “propeller type windmill”) has an advantage of high efficiency in converting wind into rotational energy (electric energy). However, the wind turbine of this method needs to secure a wide space around the wind turbine because of the structure that rotates the large-diameter rotor blade at high speed. In addition, a high wind speed is necessary for self-starting, and a very loud wind noise is generated during rotation.Therefore, a certain amount of air flow can be secured at the installation location, and the wind direction is stable. Installation in residential areas where the air volume and direction are limited and is limited to the vicinity of the coastline and the ridgeline of the mountains involved a large barrier.

  On the other hand, the “vertical axis windmill” converts wind from all directions into rotational energy without being limited by the wind direction, even though the efficiency of converting wind into rotational energy (electrical energy) is not as high as that of the horizontal axis windmill. In addition, since it does not require as high a wind speed as the horizontal axis wind turbine at the time of self-starting, it can be installed in a residential area where the air volume and direction are not stable.

  In this respect, in particular, in the “gyromill type windmill”, a plurality of blades (blades) are arranged so as to face each other in a substantially parallel state, so that the diameter of the rotating blades becomes small and can be installed even in a narrow space. In addition, there is an advantage that it is self-starting even at a relatively low wind speed and that noise during operation is extremely small. As described above, the “gyromill type windmill” is particularly advantageous when installed in a residential area or the like and used for power generation.

  Regarding this “gyromill type windmill”, the invention described in Patent Document 1 or Patent Document 2 has been proposed. The inventions described in each of these patent documents form a recess at the trailing edge of each blade that generates lift, and by receiving wind there, the drag is utilized like a Savonius type windmill, and the self at a low wind speed. It realizes start-up and can be said to be a very excellent invention.

However, since the blade described in Patent Document 1 bends a single metal plate into an “approximate character shape” when viewed from the end, and both ends thereof are open, the wind from the trailing edge side of the blade. In the case of receiving, there is a possibility that wind will escape from the open portions at both ends of the blade, and sufficient drag force may not be obtained. In this respect, in the invention described in Patent Document 2, since both sides of the dent of the trailing edge of the blade are shielded by the blade end plate, there is no problem of “escape from the open portion” as in the above Document 1, When the hollow receives a wind with a high wind speed, the inside of the hollow becomes a high pressure, and the wind does not enter the hollow and flows on the lower surface of the wing. Therefore, there is a possibility that a drag exceeding a certain value cannot be obtained.
JP 2005-307850 A JP 2006-46306 A

  The present invention has been made in view of the above-mentioned problems, and a problem to be solved is a blade for a gyromill type windmill that can self-start even in a low wind speed region and generates a high rotational torque in any wind speed region. And it is providing the windmill used here with a simple structure.

  Means taken by the present invention to solve the above problems are as follows.

  First, a blade 10 for a gyromill type windmill according to the first aspect of the present invention is a lower surface of the blade 10, and includes a recessed portion 11 formed of a space formed from a blade trailing edge toward a blade leading edge, and the recessed portion 11 and an opening 12 in which the upper surface of the blade 10 communicates with each other.

Furthermore the invention according to claim 1, the dimensions of the blade 10 for di Yairomiru windmill, the openings 12 and the upper surface of the concave portion 11 and wings 10 formed on the lower surface of the wing 10 are communicated with each other, the spanwise Is characterized in that 60% or less of the blade width is less than the blade width, and the dimension of the opening 12 in the direction of the blade chord is 1% of the chord length.

According to a second aspect of the present invention, in the blade 10 for a gyromill type wind turbine according to the first aspect, the concave portion is formed in order to prevent airflow from flowing out from the blade tip portion of the concave portion 11 formed on the lower surface of the blade 10. 11 is provided with a wing tip plate 13 for closing the wing tip portion.

Further, the invention according to claim 3 is the partition plate 14 for partitioning the concave portion 11 formed in the lower surface of the blade 10 in the blade width direction in the blade 10 for the gyromill type windmill according to claim 1 or 2. In the concave portion 11.

  The effects obtained by adopting the above solution are as follows.

  First, a blade 10 for a gyromill type wind turbine according to the first aspect of the present invention has a “recess 11” which is a lower surface of the blade 10 and includes a space formed from a blade trailing edge toward a blade leading edge. Therefore, when the concave portion 11 receives wind from the blade trailing edge direction, a drag force is obtained. And since the said recessed part 11 and the upper surface of the wing | blade 10 are mutually connected via the "opening part 12," when the wind of the wind speed high to such an extent that this recessed part 11 may become a high pressure is received, Since a part passes through the opening 12 and escapes to the upper surface of the blade 10, the phenomenon that the inside of the concave portion 11 flows on the lower surface of the blade due to the high pressure (hereinafter referred to as "the concave portion 11"). It is possible to eliminate the “upslip” and obtain further drag. Therefore, when the gyromill type windmill 100 is configured using the blade 10 of the invention according to the present invention and receives wind from the blade trailing edge direction, it can be self-started even in a low wind speed region, This makes it possible to improve the rotational torque of the windmill 100 in the region.

  Further, when the blade 10 receives wind from the blade leading edge direction, a part of the wind flowing on the lower surface side of the blade 10 passes through the opening 12 and escapes to the upper surface of the blade 10. Since it crosses (joins) with the wind flowing on the upper surface side, separation of the flow (airflow) on the upper surface is prevented, and the lift of the blade 10 is increased. Therefore, when the gyromill type windmill 100 is configured using the blade 10 of the invention according to the present invention and the wind from the blade leading edge direction is received, the lift is increased and the rotational torque of the windmill 100 is improved. It will be.

Furthermore, in the invention according to claim 1 , the sum of the dimensions in the blade width direction of the opening 12 where the concave portion 11 formed on the lower surface of the blade 10 and the upper surface of the blade 10 communicate with each other is 60 with respect to the blade width. %, And the dimension of the opening 12 in the direction of the chord is 1% with respect to the chord length, thereby preventing a reduction in rotational torque caused by excessive wind escape from the opening 12. Thus, the rotational torque of the windmill 100 can be reliably improved.

In the invention according to claim 2 , since the blade end plate 13 is provided at the blade tip of the concave portion 11 formed on the lower surface of the blade 10, the wind received by the concave portion 11 from the blade trailing edge direction is released from the blade tip. Therefore, it is possible to reliably obtain a drag force and to suppress variation in generated torque.

Further, in the invention according to claim 3 , since the partition plate 14 for partitioning the concave portion 11 formed on the lower surface of the blade 10 in the blade width direction is erected in the concave portion 11, the concave portion 11 is the trailing edge of the blade. Since the wind received from the direction can be received for each small section of the recess 11, a drag can be obtained with certainty. In addition, since the partition plate 14 rectifies the wind (airflow) in the recess 11, variations in generated torque are suppressed.

  The technical idea of the present invention will be described below with reference to FIGS. 1 to 7 showing a preferred embodiment (hereinafter referred to as “Example 1”).

  First, FIG.1 and FIG.2 shows the gyromill type windmill 100 comprised using the blade | wing 10 which concerns on Example 1. FIG. This windmill 100 is formed by connecting three blades 10 (blades) to the output shaft 30 via two arms 20 respectively. Note that the blade 10 according to the present embodiment shown in the above drawings is for experimentation (mini blade) for the purpose of collecting data, and therefore the blade width is further extended when put into practical use.

  In this invention, the wing | blade 10 has the recessed part 11 in a lower surface. The recess 11 is formed of a space formed by cutting away from the blade trailing edge toward the blade leading edge. Depending on the shape and size of the recess 11, the performance of the blade 10 changes. In this embodiment, an airfoil “NACA6521” which can obtain a large lift even at a low wind speed is adopted, and FRP molding is performed with dimensions of a chord length of 30 cm and a blade width of 40 cm, and as shown in FIG. The recess 11 is formed by cutting out 15% of the length from the rear edge.

As shown in FIG. 5, an opening 12 is formed on the blade leading edge side of the recess 11, and the recess 11 and the upper surface of the blade 10 communicate with each other. The opening 12 allows a part of the wind that has entered the recess 11 to escape to the upper surface side of the blade 10. That is, as shown in FIG. 6 (a), when the concave portion 11 receives wind from the blade trailing edge direction and receives wind with a high wind speed that causes the inside of the concave portion 11 to have a high pressure, When the portion passes through the opening 12 and escapes to the upper surface of the blade 10, “upslip on the concave portion 11” caused by high pressure in the concave portion 11 is eliminated, and further drag is obtained. Is possible. In addition, as shown in FIG. 6B, when the blade 10 receives wind from the blade leading edge direction, part of the wind flowing on the lower surface side of the blade 10 passes through the opening 12. Then, the air flows into the upper surface of the blade 10 and intersects (combines) with the wind flowing on the upper surface side, so that the separation of the flow (airflow) on the upper surface is prevented and the lift of the blade 10 is increased. . In the present invention, the shape of the opening 12 is not particularly limited, such as “hole shape”, “slit shape”, “open window shape”, etc., but according to the experimental results shown in Chart 1 (FIG. 8). The following numbers are derived: First, when the size in the chord direction is constant at 1% (3 mm) of the chord length, a dimension corresponding to 60 % or less of the blade width (40 cm) ( 240 mm or less) is preferable. A slit having a dimension (40 mm) corresponding to 10% of the blade width (40 cm) may be employed. As a reference example, when the size in the blade width direction is constant at 70% (40 mm × 7), the width dimension (4.5 mm or less) corresponding to 1.5% or less of the chord length (30 cm) Preferably, a slit having a width dimension (3 mm) corresponding to 1% of the chord length (30 cm) may be employed.

  Further, as shown in FIG. 3, the concave portion 11 may be provided with a partition plate 14 that partitions the inside in addition to the blade end plate 13 disposed at the blade tip of the concave portion 11. When the wing tip plate 13 is arranged at the wing tip, it is possible to prevent the wind that the concave portion 11 has received from the wing trailing edge direction from escaping from the wing tip. Thus, the variation in torque can be suppressed. On the other hand, when the partition plate 14 is erected in the recess 11, the wind received by the recess 11 from the direction of the trailing edge of the blade can be received for each small section of the recess 11. You can get it. In addition, since the partition plate 14 rectifies the wind in the recess 11, the generated torque variation is suppressed.

Next, the performance of the blade 10 according to the above embodiment will be described using measurement data.
The data shown in the following chart 2 (FIG. 9) to chart 5 (FIG. 13) is obtained by measuring the performance of the blade 10 according to this embodiment. Note that “attack angle α” (deg) in each chart means that the wind is applied from each direction shown in FIG.

Charts 2 to 5 compare the performance of four types of samples. The four types of samples are: (1) a wing 10a of the wing type “NACA6521”, (2) a wing 10b with a recess 11 added to the wing 10a, and (3) a wing tip plate 13 added to the wing tip of the wing 10b. Wings 10c, (4) Wings 10d with openings 12 added to the wings 10c. In addition, the rotational torque (CT: dimensionless amount) of the wind turbine can be expressed by the following equation using a lift coefficient (Cl), a drag force (Cd), and an angle of attack (α).
CT = Cl (α) sinα−Cd (α) cos (α)
From this equation, when increasing the rotational torque of the wind turbine, first, the “lift coefficient” (Cl) is large in the range of angles of attack of 0 ° (deg) to 180 ° (deg), and the angle of attack is 180 ° (deg). It is better to make it smaller in the range of ˜360 ° (deg). On the other hand, the “drag coefficient” (Cd) is large in the range of the angle of attack of 90 ° (deg) to 270 ° (deg), and the angle of attack of 0 ° (deg) to 90 ° (deg) and the angle of attack 270 ° (deg). ) To 360 ° (deg), it is better to make it smaller.

  First, Chart 2 shows the numerical value of the lift coefficient obtained by applying the same wind speed to the samples (1) to (4) from the angle of attack of 0 ° (deg) to 360 ° (deg). It is a comparison. As shown in FIG. 2, improvement in lift of the samples (2), (3), and (4) provided with the recesses 11 is observed near the angle of attack of 30 ° (deg) to 90 ° (deg). This is because the inside of the concave portion 11 receiving the wind becomes high pressure and the lift is increased.

  Further, as shown in FIG. 2 above, the sample (4) having the opening 12 has air from the opening 12 to the bottom surface at the angle of attack of 180 ° (deg) to 230 ° (deg). Flows, the pressure on the lower surface increases and the lift decreases. Further, as shown in Chart 3 (FIG. 10) in which the range of the angle of attack of 100 ° (deg) to 190 ° (deg) in Chart 2 is enlarged, the angle of attack is around 160 ° (deg) to 180 ° (deg). A dramatic improvement in lift is recognized. This is because in this angle-of-attack range, the airflow passes from the lower surface to the upper surface through the opening 12, and the air pressure on the upper surface increases, so that the reduction in lift is suppressed.

  Chart 4 (FIG. 11) compares the drag coefficient values of the samples (1) to (4). As shown in FIG. 4, when the concave portion 11 receives wind, the drag is increased in a range of angles of attack of 90 ° (deg) to 150 ° (deg). Furthermore, as shown in Chart 5 in which the range of angles of attack of 160 ° (deg) to 180 ° (deg) in Chart 4 is enlarged, in the range of angles of attack of 160 ° (deg) to 175 ° (deg), samples ( 2) and sample (3) will fall to below the numerical value of sample (1), but according to sample (4) according to the present invention, the reduction in the numerical value can be improved and high drag can be obtained. It can be done.

  Subsequently, FIG. 6 (FIG. 13) shows a one-blade wind turbine 100 configured by connecting the blades 10a to 10d according to the samples (1) to (4) to the output shaft 30 through the two arms 20. On the other hand, the numerical values (calculated values) of the rotational torque obtained by applying the wind of the same wind speed from the direction of the angle of attack of 0 ° (deg) to 360 ° (deg) are compared. As FIG. 6 shows, the rotational torque of the sample (4) provided with the opening 12 traces the peak values of the sample (2) and the sample (3) over almost the entire angle of attack. This is because lift is improved in the range of 30 ° (deg) to 90 ° (deg) of angle of attack (see Chart 2) and 115 ° (deg) to 150 of angle of attack due to wind entering the recess 11. In addition to improving drag in the range of ° (deg) (see Chart 4), in the range of angle of attack 230 ° (deg) to 270 ° (deg), the provision of the opening 12 can provide high rotational torque. This is because it can be done (see Chart 6).

  Further, for a three-blade wind turbine 100 having a diameter of 80 cm configured by connecting the blades 10a to 10d according to the samples (1) to (4) to the output shaft 30 via the two arms 20, the wind speed is 8 m per second. The average value obtained by measuring the number of rotations (rpm) obtained by applying the wind of 20 times is 218.7 rpm for sample (1), 212.2 rpm for sample (2), 3) was 218.3 rpm and sample (4) was 219.6 rpm. That is, the rotation speed of the wind turbine of the sample (4) is improved by about 1% as compared with the conventional wind turbine. The improvement in the number of revolutions is also expected to improve the amount of electric power obtained when the wind turbine is connected to the generator. It is self-evident that there will be a big difference in long-term operation. Further, the wing 10d according to the above embodiment is an experimental wing (mini wing) for the purpose of data collection. However, when put into practical use, the wing width is extended to about 4 to 5 times. . That is, since the above embodiment is a “mini wing”, the “effect by providing the opening 12” is caused by the air resistance received by the two arms 20 connecting the wing 10 (blade) and the output shaft 30. Will be killed. However, when a large wingspan such as a practical model is provided, the “effect due to the provision of the opening 12” becomes large, and the air resistance received by the arm 20 becomes relatively small. Under such conditions, in the case where the blade widths of the blades 10a to 10d according to the samples (1) to (4) are configured to be large and the rotational speed is measured, the sample (4) according to the present invention is measured. The superiority becomes clearer.

Industrial application fields

  In the above embodiment, “NACA6521” which can obtain a large lift even at a low wind speed is adopted, but the technical idea of the present invention is not particularly limited to this airfoil. That is, in view of the fact that the above action of the present invention is caused by the pressure distribution acting on the blade, the same effect as described above can be obtained even when applied to any airfoil including “NACA2412”, “NACA23012”, etc. Expected to be obtained.

It is the figure which showed the gyromill type | mold windmill 100 comprised using the wing | blade 10 (mini wing | blade) which concerns on Example 1 from diagonally upward. It is a top view of the gyromill type windmill 100 shown in FIG. It is the figure which showed the wing | blade 10 which concerns on another Example from diagonally upward. FIG. 3 is a diagram schematically showing a blade cross section of a blade 10 according to the first embodiment, and shows the position of a recess 11. FIG. 3 is a diagram schematically showing a blade cross section of a blade 10 according to the first embodiment, and shows a position of an opening 12. (A) It is the figure which represented the flow of the wind which the wing | blade 10 typically shown in FIG. 4 received from the wing | tip trailing edge direction. (B) It is the figure which represented the flow of the wind which the wing | blade 10 typically shown in FIG. 4 received from the wing leading edge direction. This indicates from which direction the wind is applied when measuring the performance of the blade 10 alone. 4 is a chart 1 showing measurement data of a preferred dimensional ratio of the opening 12. It is the chart 2 which compared the numerical value of the lift coefficient obtained by having applied the wind of the same wind speed from the direction of angle of attack 0 degree (deg)-360 degrees (deg) with respect to samples (1) thru | or (4). . FIG. 3 is an enlarged diagram 3 showing a range of angles of attack of 100 ° (deg) to 190 ° (deg) in FIG. FIG. 5 is a chart 4 comparing drag values obtained by applying winds of the same wind speed from the direction of angles of attack of 90 ° (deg) to 180 ° (deg) to samples (1) to (4). 6 is an enlarged diagram 5 showing a range of angles of attack of 160 ° (deg) to 180 ° (deg) in the diagram 4; Chart 6 of samples (1) to (4), using the lift coefficient (Cl) and drag (Cd) measured for each angle of attack (α), and calculating and comparing the rotational torque (CT: dimensionless amount) using the following equation It is. CT = Cl (α) sinα−Cd (α) cos (α)

Explanation of symbols

10 Wings 11 Recesses 12 Openings 13 Wing End Plates 14 Partition Plates 20 Arms 30 Output Shafts 100 Gyromill Wind Turbine

Claims (3)

A lower surface of the wing, a concave portion formed of a space formed from the trailing edge of the wing toward the leading edge of the wing;
An opening through which the recess and the upper surface of the wing communicate with each other;
Equipped with a,
The sum of the dimensions of the openings in the wing span direction is 60% or less of the wing span,
A blade for a gyromill type windmill, characterized in that the dimension of the opening in the direction of the chord is 1% of the chord length . In the wing for the gyromill type windmill according to claim 1 ,
A blade for a gyromill type windmill, wherein a blade end plate for closing the blade end portion of the concave portion is provided to prevent outflow of airflow from the blade tip portion of the concave portion formed on the lower surface of the blade. In the blade for a gyromill type windmill according to claim 1 or claim 2 ,
A blade for a gyromill type windmill, characterized in that a partition plate for partitioning a recess formed on the lower surface of the blade in the blade width direction is provided upright in the recess.

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