JP2012241705A - Axial flow turbine windmill of flat plate blade with curved plate or cylinder as front edge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop an axial flow turbine windmill which can be made lightweight and manufactured easily, is rotated in the same direction at all the time even in an outgoing/incoming flow, and is operable in a wide low and middle rotation speed area and in which a startup time is short, by solving a disadvantage in a wells turbine conventionally used for wave farm, e.g., the length of a startup time or torque maintenance in a low rotation area and proposing a high-efficiency and low-priced turbine utilizing wave power for middle-type and small-type distributed power sources, namely, by combining a blade plate having uniform thickness with a structure (cylinder or curved plate or the like) having a curvature.SOLUTION: A blade plate body has uniform thickness and has no torsion. Therefore, in comparison with a conventional wing-type axial flow turbine, a turbine can be made lightweight and manufactured easily, and thereby reducing costs for manufacturing facilities. At the same time, in the axial flow turbine windmill, roundness such as a cylinder is added to a front edge of the blade plate, and thereby remarkably shortening a startup time from stop to normal rotation. Therefore, since an axial load torque during stop can be enlarged, a performance to maintain rotations even in low and middle rotation speed area is provided and an operating range is widened.

Description

  The present invention relates to a flat-blade axial turbine turbine having a novel shape.

  Effective use of natural energy such as waves and winds is one of the important issues to be solved for Japan with limited resources, and it must be developed and disseminated in order to measure the synergistic effects of diversifying energy resources. This is a technical problem that must be avoided.

  One of the devices that convert the energy generated by the up-and-down motion of the waves into air pressure and reciprocating flow is a Wells turbine having symmetrical airfoil blades. This Wells turbine always rotates in the same direction with respect to the reciprocating flow, but on the other hand, the start-up time is long from the start to the steady rotation, and jumping in which the number of rotations rapidly increases during the start-up time. However, it has been pointed out that the load resistance decreases suddenly at a medium speed or less, leading to a sudden stop. A long start-up time is disadvantageous when a long-period wave is used, and a jumping phenomenon in the number of rotations may increase vibration and noise of connected devices. However, this Wells turbine uses the vertical motion of the wave by converting it into pressure energy and velocity energy of the air, so that the turbine is housed in a cylinder standing perpendicular to the sea surface. Since it always rotates in a certain direction, a direction switching valve for switching the direction of flow is not required, which simplifies the apparatus.

  For example, Japanese Patent Publication No. 6-89645 is an improved patent for Wells turbine, but the present technology has improved the disadvantages of conventional Wells turbines, such as long start-up time and stopping at low torque. Not only is there a huge production cost due to the shape of the two-leaf turbine. Japanese Patent Publication No. 6-89645 proposes an improvement of the Wells turbine. However, the present technology improves the disadvantages of the conventional Wells turbine, such as a long start time and a stop at a low torque. Not only has it been done, but the production costs are huge due to the shape of the two-leaf turbine. Japanese Patent Application Laid-Open No. 10-176649 shows a generator using an air flow generated by wave power. However, since it rotates only in one direction of air flow, a valve for controlling the air flow is required. Too much equipment.

Japanese Patent Publication No. 6-89645 JP-A-10-176649

  As described above, the power generation turbine using the wave power of the ocean typified by the Wells turbine has disadvantages such as a long start-up time, a low torque and a high facility cost.

  An object of the present invention is to improve the drawbacks of the Wells turbine and to develop a turbine that reaches a predetermined rotational speed in a short start-up time or a low-cost turbine that can be easily manufactured in a wide operating rotational speed range. If this turbine is put to practical use, it can be used greatly as a driving source for wave power generation, wind power generation, pumping equipment and transportation, and can contribute greatly to society.

  In order to achieve the above object, the present inventor has completed the present invention as a result of intensive studies. That is, the first aspect of the present invention is an axial flow turbine in which a plurality of blades of uniform thickness are arranged on the outer periphery of the hub, and a symmetric curvature structure is formed on the leading edge in the rotation direction of each blade. It is a windmill.

  The second aspect of the present invention is an axial turbine turbine having 2 to 8 blades.

  A third aspect of the present invention is an axial turbine turbine having a blade thickness of 2 to 10 mm.

  A fourth aspect of the present invention is an axial-flow turbine wind turbine in which the blades are made of at least one material selected from aluminum, iron, fiber reinforced plastic, and wood. In particular, a hollow honeycomb structure or the like is preferable in order to reduce weight and increase rigidity.

  The fifth aspect of the present invention is an axial-flow turbine wind turbine having a turbine outer shape of at most 5 m.

  A sixth aspect of the present invention is an axial turbine turbine having a width ratio of a structure having a curvature with respect to a blade chord length of 0.05 to 0.3.

  A seventh aspect of the present invention is an axial turbine turbine having a blade and a hub made of a single material.

  The eighth aspect of the present invention is an axial-flow turbine wind turbine in which blades and a hub are separately manufactured, assembled and combined.

  A ninth aspect of the present invention is an axial turbine turbine having a curvature that is a circle, an ellipse, or a parabola.

  The tenth aspect of the present invention is an axial-flow turbine wind turbine having a structure in which an outer end of a structure having a curvature is opened or closed.

  An eleventh aspect of the present invention is an axial-flow turbine wind turbine in which the start-up time from a stationary state to a steady rotational speed when no load is applied is 1/5 or less compared to a Wells turbine of the same size.

  A twelfth aspect of the present invention is an axial-flow turbine wind turbine in which the ratio of the torque coefficient at the peripheral speed ratio 0 and the peripheral speed ratio 4 is 1 or more.

  The axial-flow turbine wind turbine of the present invention is a turbine-type wind turbine that always rotates in the same direction following the reciprocating flow of the fluid in the axial direction, like the Wells turbine, but is characterized by improving the drawbacks of the conventional Wells turbine. It is. For example, the start-up time from no rotation to a predetermined number of revolutions is greatly shortened, and it is possible to continue the rotation while generating a high torque even in a low revolution number region. In addition, although the equipment cost is high in Wells turbine, there is a problem in the cost performance of power generation, but since the present invention is a structure in which a curved root or a cylinder is assembled to a plurality of rectangular or fan-shaped flat blades arranged on the circumference, It is relatively easy to manufacture and can be manufactured at low cost, and is also highly practical as a relatively small scale generator for distributed power.

  Therefore, the windmill is preferable when the reciprocating flow of air accompanying ocean waves and the energy of normal wind are converted into mechanical energy for use. In particular, since it can be operated by generating a high torque in the middle and low speed range, it can be used as a driving force source for a generator via a mechanical device operating at a low speed or a transmission. It can be installed especially in sea areas and coasts with appropriate wave heights, or in areas or remote islands with appropriate wind power areas, and it is effective in creating manufacturing facilities and related businesses for that purpose. Distributed power sources and power sources in those areas and remote islands Can be used as

Outline of axial turbine turbine Curved plate or cylinder assembled to the blade leading edge 3A shows a turbine having a four-blade leading edge cylinder, and FIG. 3B shows a turbine having a six-blade leading edge cylinder. Relationship between flow velocity and fluid force acting on blades Relationship between Torque Coefficient CT and Peripheral Speed Ratio λ In the symbol CMF4Ta, CMFT indicates an axial-flow turbine wind turbine with a leading edge cylinder, numeral 4 indicates a blade, and subscript a indicates a case where a slit is provided at the outer end of the cylinder. The same applies hereinafter. Relationship between output coefficient CL and peripheral speed ratio λ Comparison of startup time

  As shown in FIG. 1, the present invention has a very simple structure comprising a flat hub and a plurality of blades. In order to change the reciprocating flow by the fluid into a rotational force in a certain direction, it is characterized by having a structure with a symmetrical curvature at the leading edge of the blade. Because of this simple structure and material, the design of the shape can be made very free, and the manufacturing cost is greatly reduced compared with the conventional Wells turbine. The structure having a curvature for generating a propulsive force may be a cylinder or a half cylinder. Alternatively, it may have a parabola, an ellipse, or any other curvature, but the optimal curvature for the fluid can be calculated. In addition, the manufacturing cost and the ease of maintenance should be taken into consideration. Further, the number of blades of the turbine of the present invention may be an even number or an odd number as long as it is two or more, but it may be set in a balance of cost and performance. Preferably, it is about 2-8 sheets. When the number is 8 or more, the production is not only troublesome but also the weight and cost increase. The blade material is preferably lighter and more rigid because it can be made larger and lighter, but it is preferably made of one or a combination of materials such as aluminum, iron, fiber reinforced plastic, and wood. The hub and blades are combined to form a turbine, but if this outer shape becomes too large, the facilities of the power generation system become a problem and the utility is lost. Therefore, it is about 5 m at most. Preferably, it is used as a small-medium-standard distributed power source of about 1-3 m. The blade and hub may be made separately and fixed by rivets, screwing or welding, or the hub and blade portions may be cut out from a single piece of material. This is also possible with a relatively small turbine of about 3 m, which reduces costs and facilitates maintenance.

  “The ratio of the width of the structure with curvature to the chord length of the blade is preferably 0.05-0.3 in the present invention in the context of the leading edge cylinder. If it becomes smaller, there will be a problem that sufficient thrust cannot be obtained, and if it becomes larger than 0.3, the separation area of the rear flow of the structure becomes excessive, it is easy to decelerate, and there is a possibility that sufficient rotation speed cannot be obtained. This ratio, that is, the blade maximum thickness ratio is about 0.12-0.3, and the lower limit is greatly different from the present invention. The entire structure, the rear surface, or the upper and lower end surfaces of the structure may be closed, or may be opened somewhere to control the flow of fluid. The shape and size of the open part depends on the operating condition, etc. It can be optimized Ri.

  The present invention is also characterized in that it is lightweight because it has a simple structure as described above. Accordingly, rotation starts even with a minute fluid flow. This is a significant feature compared to conventional Wells turbines. For example, the start-up time from the stationary state of the turbine to the steady rotational speed having a predetermined rotation under no load under the same conditions is 1/5 or less compared to a normal Wells turbine. That is, it shows that the operating time is greatly increased. Further, in the conventional Wells turbine, the torque becomes zero when the rotation is low, but the turbine of the present invention maintains a predetermined torque almost to a low speed region and is advantageous for power generation at a low rotation. For example, the ratio of the torque coefficient between the peripheral speed ratio 0 and the peripheral speed ratio 4 is 1 or more.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated in detail, this invention is not restrict | limited at all by an Example.

Example 1
The turbine of the present invention has a typical shape as shown in FIG. Here, in order to verify the performance, an experiment was carried out by producing a model in which the blade leading edge (2) in FIG. 1 has a cylinder with a diameter of 16 mm. Each aluminum plate having a thickness of 2 mm was used to make cuts. The outer diameter of the impeller is 360 mm, the inner and outer diameters of the blades = 260/360 = 0.722, the chord length is 110 mm, the blade width is 50 mm, and a cylinder with a diameter of 16 mm at the front edge is cut in a vertical direction with a width of 2 mm (slit ) And assembled. The thickness of the wheel plate was 2 mm, and the thickness of the axle fixed to the bearing with a bearing was 16 mm.

FIG. 2 shows the shape of the structure (cylinder) having the curvature of the front edge. Aluminum was used for this material. Both cylinders are sharply cut and sharpened on the inside, and the outer end is covered with a lid. The difference between the two cylinders is whether or not an appropriately sized opening is provided near the outer end on the downstream side in the rotational direction. [FIG. 2] (1) is a case where no opening is provided, and [FIG. 2] (2) is a case where an opening is provided. The experiment was carried out by installing in a blow-out small wind tunnel (test section diameter 370 mm, length 1300 mm), sucking air with a blower (rated flow rate 200 m ³ , 5.5 kW), and driving the wind turbine under test. The measurement was performed by changing the rotation speed and the torque simultaneously.

  [FIG. 3] (Photo A) and [FIG. 3] (Photo B) are turbine impellers having four blades (CMF4T) and six blades (CMF6T), respectively, which were similarly prepared. The vehicle plate was made of an aluminum plate having a thickness of 2 mm, and the cylinder at the blade leading edge was made of an aluminum cylinder having a thickness of 1 mm and an outer diameter of 16 mm.

  [FIG. 4] (a) and [FIG. 4] (b) show the principle of rotation of the turbine of the present invention. The relation between the speed triangle and force when the blade moves forward at the speed u due to the generation of the drag D and lift L based on the pressure distribution around the blade due to the flow of the velocity V hitting the flat plate blade of the leading edge cylinder. Show. α is the angle of attack of the blade with respect to the relative speed W.

FIG. 5 shows the experimental results of the torque coefficient _CT and the peripheral speed ratio λ (= the peripheral speed / wind speed of the impeller) for the turbine blades created above. WT6 in the figure indicates a six-blade wells turbine (comparative example), and all others are flat-blade axial turbine turbines (CMF4Tb, CMF6Ta, etc .: examples of the present invention) in which curved plates or cylinders are assembled at the leading edge. Show. The subscript “a” indicates the case where no opening is provided at the tip of the structure (cylinder) having a curvature (corresponding to [FIG. 2] (1)), and the case where “b” is provided ([FIG. 2] ( Corresponds to 2). From this figure, the WT 6 has a peripheral speed ratio of up to about 15 and a large load torque, but cannot be measured at a medium speed ratio (about 7) or less and is suddenly stopped. In other words, it clearly represents the shortcomings of Wells turbine. Meanwhile, six-blade of the present invention (CMF6Ta and CMF6Tb) is the maximum peripheral speed ratio is approximately half of WT6 almost 7 about, _{C T} are comparable. The presence or absence of the opening slightly affects the peripheral speed. Further, four-blade, and the other impeller is smaller slightly C _T or the peripheral speed ratio lambda.

[FIG. 6] is an experimental result showing the relationship between the output coefficient C _P {= (torque × angular velocity) / (wind kinetic energy)} and the peripheral speed ratio λ. The symbols in the figure correspond to those in FIG. From this figure, WT 6 (Comparative Example) is C _P has reached 0.3 at lambda = 7, which following the tip speed ratio range is not output can be obtained by the rotation stop. On the other hand, in the six-blade CMF6Ta and CMF6Tb of the present invention, the maximum C _P is about 0.1 when the peripheral speed ratio is about 4, but the rotation continues even if the peripheral speed ratio further decreases due to an increase in load torque. You can see that Similarly four-blade, and for the other impeller, C _P indicates that low is susceptible operated at low peripheral speed ratio lambda.

  Next, FIG. 7 shows the relationship between the rotational speed n (rpm) and the elapsed time t (s, seconds) from the start to the steady rotation for each impeller. From this figure, the start-up time of WT6 (comparative example) is considerably long as 45 seconds, while the start-up time of the turbine of the present invention (CMF4Tb, CMF6Ta, etc.) is considerably short as about 5 seconds, which is almost 1/9 of WT6. It can be said.

  The windmill can be operated with high torque generated especially in the medium and low speed range when the reciprocating flow of air accompanying ocean waves and the energy of normal wind are converted into mechanical energy. Therefore, it can be used as a driving force source for a generator that operates at a low rotational speed or through a transmission. In particular, it can be installed in sea areas and coasts with appropriate wave heights, or in areas or remote islands that are in an appropriate wind area, which is effective in creating manufacturing facilities and related businesses, and is a power source and power source for those areas and remote islands. obtain.

(1) Hub (hub, root)
▲ 2 ▼ Leading edge cylinder or leading edge curved plate ▲ 3 ▼ Feather flat ▲ 4 ▼ Shaft hole ▲ 5 ▼ Fastening screw hole ▲ 6 ▼ Cylindrical fastening screw

Claims (12)

  An axial-flow turbine wind turbine in which a plurality of blades having a uniform thickness are arranged on the outer periphery of a hub, and a structure having a symmetrical curvature is provided on the leading edge in the rotation direction of each blade.   The axial-flow turbine windmill according to claim 1, wherein the number of blades is 2-8.   The axial-flow turbine wind turbine according to claim 1, wherein the blade has a thickness of 2 to 10 mm.   The axial-flow turbine windmill according to claims 1 to 3, wherein the blade is made of at least one material selected from aluminum, iron, fiber reinforced plastic, and wood.   The axial-flow turbine wind turbine according to claim 1, wherein an outer shape of the turbine is at most 5 m.   The axial flow turbine wind turbine according to claim 1, wherein a ratio of a width of a structure having a curvature to a chord length of a blade is 0.05 to 0.3.   The axial turbine turbine according to claim 1, wherein the blade and the hub are made of a single material.   The axial turbine turbine according to claim 1, wherein the blades and the hub are separately manufactured, assembled and combined.   The axial turbine turbine according to claim 1, wherein the curvature is a circle, an ellipse, or a parabola.   The axial-flow turbine wind turbine according to claim 1, wherein the outer end of the structure having a curvature is an open structure or a closed structure.   The axial-flow turbine wind turbine according to claim 1, wherein the startup time from a stationary state to a steady rotational speed when no load is applied is 1/5 or less compared to a Wells turbine of the same size.   The axial-flow turbine wind turbine according to claim 1, wherein the ratio of the torque coefficient between the peripheral speed ratio 0 and the peripheral speed ratio 4 is 1 or more.