WO2015190297A1 - Wave-activated power generation system - Google Patents

Abstract

Provided is a wave-activated power generation system that can improve power generation efficiency while preserving quiet. The wave-activated power generation system is used with a seawall, dissipates the energy of waves, and generates power from the energy of the waves, wherein provided are a rotating-body row and a generator. The seawall is disposed in the water and has an impermeable wall but does not have a permeable front-wall on the offshore side of the impermeable wall. The rotating-body row consists of a plurality of rotating bodies which are, on the offshore side of the impermeable wall, arranged along the direction of extension of the impermeable wall in plan view. The generator converts the rotation energy of the plurality of rotating bodies into electrical power.

Description

Wave power generation system

The present invention relates to a wave power generation system that dissipates wave energy and generates power from the wave energy.

In recent years, power generation using renewable energy (natural energy) has attracted attention as a countermeasure against environmental problems such as depletion of fossil fuels and global warming. Of these, wave power generation uses wave power generated in the sea covering 70% of the earth's surface, and has attracted attention as a powerful energy source.

However, from the viewpoints of ship navigation safety and securing of fishing grounds, the installation of structures in the ocean may be severely restricted, and the installation of a wave power generation system may be difficult. In view of such a problem, Patent Document 1 discloses a wave power generation system in which a water turbine is installed in a recreation water chamber of a breakwater that is installed in a relatively large amount in a harbor sea area. That is, the wave power generation system disclosed in Patent Document 1 can be easily installed because it uses the existing port infrastructure, and can further reduce the cost required for adding a power generation device and a power transmission facility.

By the way, in Patent Document 1, a breakwater having an impermeable wall on the shore side and a permeable front wall having a vertical slit on the offshore side is used. This type of breakwater ensures the calmness of the shore by reflecting the waves on the impervious wall and dissipates the energy of the waves by the vortices generated in the vicinity of the vertical slit on the front wall. Thereby, the reflectance of the wave in an impermeable wall can be reduced and not only the shore side but the calmness of the offshore side through which a ship etc. pass can be ensured.

JP 2013-2410 A

However, it seems necessary to dissipate wave energy by the permeable front wall from the viewpoint of wave dissipation, but it is inefficient from the viewpoint of power generation.

The present invention aims to provide a wave power generation system capable of improving power generation efficiency while maintaining quietness.

A wave power generation system according to a first aspect of the present invention is a wave power generation system that is used together with a breakwater to dissipate wave energy and generate electric power from the wave energy. With. The breakwater is a breakwater that is installed in water and has an impermeable wall, but does not have a permeable front wall on the offshore side of the impermeable wall. The rotating body row includes a plurality of rotating bodies arranged on the offshore side of the impermeable wall along a direction in which the impermeable wall extends in a plan view. The generator converts rotational energy of the plurality of rotating bodies into electric power.

Here, on the shore side of the impermeable wall on the breakwater, a transmissive front wall is not installed, but a rotating body row is installed instead. Thereby, conventionally, the energy of the wave that has been dissipated by generating a vortex in the vicinity of the water-permeable hole (slit) on the front wall is efficiently used for the rotation of the rotating body. That is, from the viewpoint of wave extinction, energy loss due to generation of excessive vortices can be prevented from the viewpoint of power generation while dissipating wave energy as rotational energy of the rotating body. Therefore, power generation efficiency can be improved by using wave energy that has been intentionally dissipated in the past as an energy source for power generation while maintaining quietness.

A wave power generation system according to a second aspect of the present invention is the wave power generation system according to the first aspect, wherein adjacent rotating bodies included in the rotating body row are configured to rotate in opposite directions. ing.

Here, the movement of the adjacent rotating body does not interfere, and the water flow can pass through the rotating body row smoothly. Therefore, the power generation efficiency can be further improved.

The wave power generation system according to the third aspect of the present invention is the wave power generation system according to the first aspect or the second aspect, and further includes at least one of a first rectification member and a second rectification member. Between the rotating shafts of adjacent rotating bodies included in the rotating body row, an inflow region where waves flowing from the offshore side to the impermeable wall side pass, or waves flowing out from the impermeable wall side to the offshore side pass. It becomes a spill area. At least one of the inflow region and the outflow region is formed. The first rectification member is disposed in the vicinity of the outflow region on the offshore side, and guides a wave flowing from the offshore side to the impermeable wall side to the inflow region. The second rectifying member is disposed in the vicinity of the impermeable wall side of the inflow region, and guides a wave flowing out from the impermeable wall side to the offshore side to the outflow region.

Here, between the rotating shafts of adjacent rotating bodies is a wave inflow region or an outflow region. In addition, when adjacent rotating bodies included in the rotating body row rotate in opposite directions, the inflow regions and the outflow regions are alternately formed. In addition, here, the first rectifying member guides the wave that flows into the impermeable wall side to the inflow region, and / or the second rectifying member causes the wave that tries to flow out from the impermeable wall side. Guided to the area. That is, the wave that the first rectifying member is to flow into can be guided to the inflow region without stagnation, and / or the wave that the second rectification member is to flow out can be guided to the outflow region without stagnation. Therefore, the power generation efficiency can be further improved.

The wave power generation system according to a fourth aspect of the present invention is the wave power generation system according to the third aspect, wherein the rotating body included in the row of rotating bodies includes a portion corresponding to the inflow region and the outflow region. They are arranged at different intervals from the corresponding locations.

A wave power generation system according to a fifth aspect of the present invention is the wave power generation system according to any of the first to fourth aspects, wherein the rotating bodies included in the rotating body row are arranged at unequal intervals. Has been.

A wave power generation system according to a sixth aspect of the present invention is the wave power generation system according to any one of the first to fifth aspects, wherein the wave power generation system extends in a horizontal direction from the impermeable wall and supports the rotating body. An upper wall is further provided.

Here, since the impervious wall and the rotating body can be unitized, installation work at the site can be facilitated.

The wave power generation system according to the seventh aspect of the present invention is the wave power generation system according to any one of the first to fifth aspects, and further includes a caisson. The caisson includes the impervious wall, and a bottom part and an upper wall part extending from the lower part and the upper part of the impervious wall to the offshore side, respectively.

A wave power generation system according to an eighth aspect of the present invention is the wave power generation system according to any one of the first to seventh aspects, wherein the rotating body row is installed, and It further includes a foundation whose water depth is shallower than the water depth at the offshore side.

Here, the installation location of the rotating body is raised by the base, and the rotating body is installed at a position where the water level is lower (shallow) than the location on the offshore side. Therefore, in this case, the traveling speed of the wave passing between the rotating bodies is increased, and the dissipation of the wave energy is increased. Therefore, the wave reflectance can be reduced.

The wave power generation system according to the ninth aspect of the present invention is the wave power generation system according to the eighth aspect, wherein the base has a vertical surface facing the offshore side.

Here, a step with a sudden change in water depth is formed near the offshore side of the water turbine, and the flow velocity of the incoming waves increases. Therefore, the wave reflectance is further reduced, and the power generation efficiency is further improved.

A wave power generation system according to a tenth aspect of the present invention is the wave power generation system according to any one of the first to ninth aspects, wherein the rotating body rotates in a constant direction regardless of a wave direction. It is a water wheel.

Here, the rotating body rotates in the same direction both when the wave is applied to the impermeable wall and when the wave is drawn. Therefore, the power generation efficiency can be further improved.

A wave power generation system according to an eleventh aspect of the present invention is the wave power generation system according to the tenth aspect, wherein the rotating body is a Savonius turbine.

Here, a Savonius turbine is used as the rotating body. Therefore, it is possible to construct a power generation system that generates a large torque even at a low speed and is easy to operate even at a low flow rate.

A wave power generation system according to a twelfth aspect of the present invention is the wave power generation system according to any one of the first to eleventh aspects, wherein a rotation axis of the rotating body extends in a vertical direction. In the present specification, the term “vertical direction” includes the case of being completely parallel to the vertical direction and the case of being substantially parallel to the vertical direction, unless otherwise specified.

Here, the generator can be easily installed at an appropriate position on the water.

According to the present invention, energy loss can be prevented from the viewpoint of power generation while dissipating wave energy as rotational energy of the rotating body from the viewpoint of wave suppression. Therefore, power generation efficiency can be improved by using wave energy that has been intentionally dissipated in the past as an energy source for power generation while maintaining quietness.

1 is a longitudinal sectional view of a wave power generation system according to a first embodiment of the present invention. II-II sectional drawing of FIG. The longitudinal cross-sectional view of the wave power generation system which concerns on 2nd Embodiment of this invention. IV-IV sectional drawing of FIG. The transverse cross section of the wave power generation system concerning a 3rd embodiment of the present invention. The cross-sectional view of the wave power generation system which concerns on 4th Embodiment of this invention. The cross-sectional view of the wave power generation system which concerns on a modification. The longitudinal cross-sectional view of the wave power generation system which concerns on another modification. The longitudinal cross-sectional view of the wave power generation system concerning another modification. 1 is a side view of experimental equipment including a wave power generation system according to Embodiment 1. FIG. Plan view of a wave power generating system according to Example 1 (the case of D _s = 0.084m). Plan view of a wave power generating system according to Example 1 (the case of D _s = 0.140m). Plan view of a wave power generating system according to Example 1 (the case of D _s = 0.210m). 1 is a side view of a power measurement system included in an experimental facility in Example 1. FIG. The graph which shows the comparison result of the reflectance in Example 1 (point) and a comparative example (curve) (in the case of Ds / h ₌ 0.215). The graph which shows the comparison result of the reflectance in Example 1 (point) and a comparative example (curve) (in the case of Ds / h ₌ 0.350). The graph which shows the comparison result of the reflectance in Example 1 (point) and a comparative example (curve) (in the case of Ds / h ₌ 0.525). The graph which shows the relationship between the reflectance in Example 1, and load torque (in the case of Ds / h ₌ 0.215). The graph which shows the relationship between the reflectance in Example 1, and load torque (in the case of Ds / h ₌ 0.350). The graph which shows the relationship between the reflectance in Example 1, and load torque (in the case of Ds / h ₌ 0.525). The graph which shows the power acquisition efficiency in Example 1 (in the case of Ds / h ₌ 0.215). The graph which shows the power acquisition efficiency in Example 1 (in the case of Ds / h ₌ 0.350). The graph which shows the power acquisition efficiency in Example 1 (in the case of Ds / h ₌ 0.525). The graph which shows the rotational speed of the water turbine in Example 1 (in the case of Ds / h ₌ 0.215). The graph which shows the rotational speed of the water turbine in Example 1 (in the case of Ds / h ₌ 0.350). The graph which shows the rotational speed of the water turbine in Example 1 (in the case of Ds / h ₌ 0.525). The top view (upper figure) and side view (lower figure) of the experimental installation containing the wave power generation system which concern on Example 2. FIG. The front view of the wave power generation system which concerns on Example 2. FIG. The top view of the wave power generation system which concerns on Example 2. FIG. The graph which shows the comparison result of the reflectance in Example 2 and a comparative example (in the case of l '= 0.24m) The graph which shows the comparison result of the reflectance in Example 2 and a comparative example (in the case of l '= 0.34m). The graph which shows the comparison result of the reflectance in Example 2 and a comparative example (in the case of l '= 0.44m). The graph (case 2) which shows the relationship between the energy conversion efficiency in Example 2, and load torque. The graph which shows the relationship between the energy conversion efficiency and load torque in Example 2 (case 3). The graph which shows the reflectance in Example 2, and the maximum flow velocity which passes between waterwheels. The graph which shows the primary conversion efficiency in Example 2 (when 1 / l '= 0.91). The graph which shows the primary conversion efficiency in Example 2 (in the case of l / l '= 0.45).

Hereinafter, a wave power generation system according to some embodiments of the present invention will be described with reference to the drawings.

<1. First Embodiment>
<1-1. Configuration of wave power generation system>
1 and 2 show a wave power generation system 1 according to the first embodiment. FIG. 1 is a longitudinal sectional view of the wave power generation system 1, and FIG. 2 is a sectional view taken along the line II-II in FIG. The wave power generation system 1 is a structure that is installed in the sea and has a function as a breakwater and a function as a power generation system. As shown in FIGS. 1 and 2, the wave power generation system 1 includes an impermeable wall 10 and a water turbine row 2 (rotating body row) installed on the offshore side of the impermeable wall 10. The impermeable wall 10 extends so as to intersect the traveling direction of the waves, and is installed so as to separate the shore side and the offshore side. The water turbine row 2 is configured by arranging a plurality of water turbines 20 (rotating bodies) along a direction in which the impermeable wall 10 extends in a plan view. As shown in FIG. 2, the line connecting the rotation shafts 21 of the plurality of water turbines 20 constituting the water turbine row 2 and the impermeable wall 10 are substantially parallel in a plan view.

As shown in FIG. 1, the impermeable wall 10 is a rectangular flat plate that is installed on a base 11 formed on the seabed and stands upright from the base 11. From the upper part of the impervious wall 10, a rectangular roof portion 12 (upper wall part) protrudes to the offshore side so as to be orthogonal to the impervious wall 10. And the rectangular bottom 13 protrudes so as to be orthogonal to the impermeable wall 10. That is, the roof portion 12 and the bottom portion 13 spread in the horizontal direction. The bottom portion 13 is installed on the base 11 and firmly supports the impermeable wall 10 and the roof portion 12 formed integrally with the bottom portion 13. The water turbine 20 according to the present embodiment has a rotating shaft 21 extending in the vertical direction, and a lower portion of the rotating shaft 21 is rotatably fixed to the bottom portion 13. The generator 3 is installed in the lower part of the roof part 12, and the upper part of the rotating shaft 21 is received by the generator 3 so that rotation is possible. The impermeable wall 10, the roof portion 12, and the bottom portion 13 constitute a caisson, and are made of concrete, for example. The foundation 11 can also be made of concrete.

The foundation 11 also plays a role of stably supporting the caisson and the water wheel train 2, but can also reduce the wave reflectance. It is also possible to increase power generation efficiency. That is, the installation position of the water turbine 20 is raised by the base 11 (and the bottom 13), so that the water turbine 20 is installed at a low (shallow) water level. In this case, the wave passing between the water turbines 20 This is because the traveling speed of the wave increases and the dissipation of wave energy increases. The base 11 of the present embodiment extends between the impermeable wall 10 and the water turbine row 2 and is inclined downward from the vicinity of the water turbine row 2 near the offshore side toward the offshore side.

The impervious wall 10 is a structure that forms a breakwater, reflects waves from the offshore side, and returns them to the offshore side. The impermeable wall 10 has a vertical surface on the offshore side. The water level of the sea surface varies depending on tides and weather conditions, but the impervious wall 10 according to the present embodiment has a height that exceeds the sea surface at an arbitrary time under general weather conditions. is there. In addition, the impervious wall 10 and the water wheel train 2 are arranged at a predetermined interval as if constituting a water reserving chamber.

The wave that has reached the water turbine train 2 from the offshore side passes through the water turbine train 2 and collides with the impervious wall 10 to be reflected. Then, the reflected wave passes through the water wheel train 2 again and returns to the offshore side. During this time, the water turbine 20 rotates by the action of the waves passing through the water turbine train 2, and the energy of the waves is converted into rotational energy of the water turbine 20. That is, the water wheel train 2 plays a role of a wave extinguishing work that dissipates wave energy together with the impermeable wall 10. Further, as described above, the water turbine row 2 is installed on the offshore side of the impermeable wall 10, but a conventional permeable front wall (see Patent Document 1) having a water-permeable hole is not installed. In this sense, it can be said that the water turbine train 2 is an alternative to the permeable front wall used in conventional breakwaters.

The water wheel 20 according to the present embodiment is a water wheel that rotates in a certain direction regardless of the wave direction. Therefore, each water wheel 20 rotates in the same direction at the time of a spilling wave and a drawing wave with respect to the impermeable wall 10 and contributes to power generation. As shown in FIG. 1, each turbine 20 according to the present embodiment includes a plurality of (in this embodiment, three stages) Savonius turbines 20A to 20C that are stacked in the vertical direction and have a common rotating shaft 21. Have. Therefore, the water turbine 20 has a general property of the Savonius turbine, such that it generates a large torque at a low rotation and is easy to operate at a low flow rate. In other embodiments, each turbine 20 can be configured in a single stage. The water turbine 20 according to the present embodiment is arranged so that at least a part of the Savonius turbines 20A to 20C arranged in the vertical direction exist below the sea surface at an arbitrary time under general weather conditions. Therefore, the wave power generation system 1 can always rotate all the water turbines 20 without being affected by the tidal wave.

As shown in FIG. 2, the Savonius turbines 20A to 20C according to the present embodiment each include two semicircular turbine blades 22 in a cross-sectional view. These two water turbine blades 22 are arranged in such a positional relationship that when one of them is rotated by 180 ° around the rotation shaft 21, it overlaps the other. Further, the turbine blades 22 of the Savonius turbine adjacent in the vertical direction are arranged at a position shifted by a predetermined angle around the rotation shaft 21, and thereby the rotation of the entire turbine 20 is made smooth. In the present embodiment, the angle of this deviation is set to 120 ° obtained by dividing 360 ° by 3 which is the number of stages of the Savonius turbine, and the smoothness of rotation is optimized.

Further, as shown in FIG. 2, two adjacent water turbines 20 included in the water turbine train 2 according to the present embodiment are configured to rotate in opposite directions. That is, in the water wheel train 2, the clockwise water wheels 20 and the counterclockwise water wheels 20 are alternately arranged. As a result, the movement of the water turbine 20 or the direction of the water flow accompanying this does not interfere between adjacent water turbines 20, and the waves can pass through the water turbine train 2 smoothly. The plurality of water turbines 20 included in the water turbine row 2 have the same structure except that the rotation directions of two adjacent water turbines are different.

The configuration in which two adjacent water turbines included in the water turbine row 2 rotate in opposite directions (hereinafter referred to as staggered rotation configuration) is not limited to the wave power generation system 1 according to the present embodiment, but various wave power generation systems. Can be employed. For example, the staggered rotation configuration can be applied to a water turbine row arranged in a water break chamber of a breakwater having a permeable front wall on the offshore side of an impermeable wall as described in Patent Document 1. .

As described above, when the water wheel 20 is rotated by the action of the wave, the generator 3 receives the rotational force via the rotating shaft 21 and generates power. In addition, since the structure of the generator which converts the rotational energy of a water turbine into electric power is known, detailed description is abbreviate | omitted here. The configuration of the generator 3 is not limited as long as the rotational energy of the rotating shaft 21 can be converted into electric power. The same applies to the arrangement of the generator 3, and the generator 3 can be installed not only above the rotating shaft 21 but at an arbitrary position.

And the electric power generated by the generator 3 is transmitted to a land-side substation or the like via a power transmission facility (not shown). Since the wave power generation system 1 is normally installed near the sea in order to fulfill the function of a breakwater, power loss due to power transmission is suppressed.

As described above, in the wave power generation system 1, the wave energy is efficiently converted into the rotational energy of the water turbine 20, and the rotational energy is converted into electric power by the generator 3. Thereby, the wave energy is dissipated, the wave is dissipated, and power can be generated efficiently from the wave energy.

<1-2. Features>

In the wave power generation system 1, a permeable front wall is omitted on the offshore side of the impermeable wall 10 on the breakwater, and a water turbine row 2 is installed instead. As a result, the energy of the wave is not dissipated by the vortex generated in the vicinity of the water-permeable hole in the front wall as in the conventional wave power generation system having the permeable front wall, and is efficient in the rotation of the water turbine row 2. Used. That is, from the viewpoint of wave dissipation, energy loss due to the generation of vortices is prevented from the viewpoint of power generation while dissipating wave energy as the rotational energy of the water turbine row 2. Therefore, in the wave power generation system 1, quietness is maintained and power generation efficiency is increased.

The wave power generation system 1 can be realized as a port facility such as a fishing port, a commercial port, or an evacuation port. The wave power generation system 1 can be introduced relatively smoothly if the existing breakwater needs to be replaced due to deterioration or the like.

<2. Second Embodiment>
Next, the wave power generation system 101 according to the second embodiment will be described. 3 is a longitudinal sectional view of the wave power generation system 101, and FIG. 4 is a sectional view taken along the line IV-IV in FIG. The wave power generation system 101 is a structure that is installed in the sea and has a function as a breakwater and a function as a power generation system, and is common in many respects to the wave power generation system 1 according to the first embodiment. In the following description, differences from the first embodiment will be mainly described, and the same components as those in the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted.

Similar to the first embodiment, the wave power generation system 101 includes an impermeable wall 10, a roof portion 12 (upper wall portion), a bottom portion 13, a base 11, a water wheel train 2, and a generator 3, and a first rectifying member. 150 and the second rectifying member 160. The main difference between the wave power generation system 101 according to the present embodiment and the wave power generation system 1 according to the first embodiment is whether or not the first rectifying member 50 and the second rectifying member 60 are present. .

Further, in the water turbine train 2 according to the second embodiment, the impermeable wall 10 extends in plan view while leaving a plurality of water turbines 120 (rotating bodies) at a certain distance from the impermeable wall 10 as in the first embodiment. It is configured by arranging along the direction. However, unlike the first embodiment, each turbine 120 is not a multi-stage configuration in which Savonius turbines are stacked in the vertical direction, but is a single-stage configuration. However, the Savonius turbine 120 according to the second embodiment may be configured in a multistage configuration.

The water wheel 120 has a shaft upper part 131, a wing part 132, and a shaft lower part 133 in order from the top in the vertical direction. The wing portion 132 includes an upper flange 134, a lower flange 135, and a pair of water turbine blades 136.

Each turbine blade 136 has a semi-cylindrical shape, and the turbine 120 is a Savonius type in which two turbine blades 136 are arranged 180 degrees rotationally symmetrical with respect to the rotating shaft 121 of the turbine 120. For this reason, like the first embodiment, the water wheel 120 can also rotate in only one direction. Each turbine blade 136 has an upper flange 134 connected to the upper end and a lower flange 135 connected to the lower end, and reaches the outer periphery of both flanges 134 and 135, but does not protrude outward from the outer periphery. Further, the upper part of the water turbine blade 136 is always exposed above the water surface 114 under general weather conditions. The shaft upper portion 131 and the shaft lower portion 133 are parallel to the impermeable wall 10 and are arranged at a certain distance from the impermeable wall 10.

The lower end portion of the shaft upper portion 131 is connected to the center of the upper surface of the upper flange 134, and the shaft upper portion 131 and the upper flange 134 are coaxial. The shaft upper portion 131 extends in the vertical direction, and an upper end portion thereof is inserted into a through hole 115 provided in the roof portion 12, and is rotatably supported. Similarly, the upper end portion of the shaft lower portion 133 is connected to the center of the lower surface of the lower flange 135, and the shaft lower portion 133 and the lower flange 135 are coaxial. The lower shaft portion 133 extends in the vertical direction, and a lower end portion thereof is inserted into a bearing hole 116 provided on the upper surface of the bottom portion 13 and is rotatably supported.

Moreover, as shown in FIG. 4, the two adjacent water turbines 120 according to the present embodiment are also configured to rotate in opposite directions. That is, there are a water wheel 120 that rotates counterclockwise in plan view (hereinafter also referred to as the first water wheel 120A) and a water wheel that rotates clockwise in plan view (hereinafter also referred to as the second water wheel 120B). The water turbines 120 are alternately arranged along the arrangement direction. In the cross-sectional view, the adjacent first and second water turbines 120A and 120B have a line-symmetric shape with respect to a straight line that is equidistant from the rotating shaft 121 of both the water turbines 120A and 120B. When the wave passes between the water turbine trains 2, the two water turbine blades 136 of the first water wheel 120A are both pushed by the wave so that the first water wheel 120A rotates counterclockwise in plan view. Similarly, the two water turbine blades 136 of the second water turbine 120B are both pushed by the waves so that the second water turbine 120B rotates clockwise in plan view.

As described above, the water turbines 120A and 120B adjacent to each other have the rotation directions opposite to each other. For this reason, between the rotating shaft 121 of the adjacent first water wheel 120A and the rotating shaft 121 of the second water wheel 120B, an inflow region 118 through which the wave F1 that flows from the offshore side to the impermeable wall 10 side passes, Or it becomes the outflow area | region 119 through which the wave F2 which is going to flow out from the impermeable wall side to the offing side passes. The inflow areas 118 and the outflow areas 119 are alternately formed along the arrangement direction of the water turbines 120.

In the present embodiment, a plurality of first rectifying members 150 are present to form a row, and a plurality of second rectifying members 160 are also present to form a row. The first rectifying member 150 and the second rectifying member 160 each extend in the vertical direction, each upper end portion is fixed to the lower surface of the roof portion 12, and each lower end portion is fixed to the upper surface of the bottom portion 13. . The first rectifying member 150 and the second rectifying member 160 have a rectangular parallelepiped shape, and as shown in FIG. 4, the cross section (horizontal cross section) has a square shape. The dimensions of the diagonal lines of the square cross section of the first rectifying member 150 and the second rectifying member 160 are substantially the same as the diameters of the upper flange 134 and the lower flange 135 of the water turbine 120.

The first rectifying member 150 is disposed in the vicinity of the outflow region 119 on the offshore side, and one of the four vertices of the cross section (hereinafter referred to as the first vertex 151) is directed to the outflow region 119 side. More specifically, in the first rectifying member 150, an imaginary line 142 passing through the first vertex 151 of the first rectifying member 150 and the diagonally second vertex 152 in the cross-sectional view is adjacent to the first water wheel 120 </ b> A and the first It arrange | positions so that it may pass along the midpoint of the virtual line segment 141 which passes along the point respectively corresponding to the rotating shaft 121 of 2 water turbine 120B, or its vicinity. The virtual line 142 and the virtual line segment 141 are orthogonal. The first vertex 151 is located on the offshore side of the imaginary line segment 141, but the first rectifying member 150 enters a gap formed between the adjacent first and second water turbines 120A and 120B.

The second rectifying member 160 is disposed in the vicinity of the impermeable wall 10 side of the inflow region 118, and one of the four vertices (hereinafter referred to as the first vertex 161) of the cross section thereof is directed toward the inflow region 118. ing. More specifically, the second straightening member 160 has a virtual line 144 passing through the first vertex 161 of the second straightening member 160 and the diagonally second vertex 162 in the cross-sectional view. It arrange | positions so that it may pass along the midpoint of the virtual line segment 143 which passes along the point respectively corresponding to the rotating shaft 121 of 2 water turbine 120B, or its vicinity. The virtual line 144 and the virtual line segment 143 are orthogonal to each other. The first vertex 161 is on the impermeable wall 10 side with respect to the imaginary line segment 143, but the second rectifying member 160 enters a gap formed between the adjacent water turbines 120.

Next, a description will be given of a mechanism in which the wave power generation system 101 generates power while quenching waves. As shown in FIG. 4, the wave F <b> 1 about to flow into the impermeable wall 10 side is an angle corresponding to the second vertex 152 located on the offshore side of the first rectifying member 150 disposed on the downstream side of the outflow region 119. It is divided into left and right (up and down direction in FIG. Thereafter, the wave F1 pushes the inner peripheral surfaces of the water turbine blades 136 of the first water wheel 120A and the second water wheel 120B to rotate both water wheels 120A and 120B. At this time, the first water wheel 120A rotates counterclockwise and the second water wheel 120B rotates clockwise in plan view. After the first water wheel 120A and the second water wheel 120B are rotated, the wave F1 is at the corner corresponding to the first vertex 161 located on the offshore side of the second rectifying member 160 disposed on the downstream side of the inflow region 118. It collides and flows into the outflow area 119 without stagnation.

Further, the wave F <b> 2 about to flow out from the impermeable wall 10 side is at a corner corresponding to the second vertex 162 located on the impermeable wall 10 side of the second rectifying member 160 disposed on the downstream side of the inflow region 118. The collision is divided into left and right and led to the outflow area 119. Thereafter, the wave F2 pushes the inner peripheral surfaces of the water turbine blades 136 of the first water wheel 120A and the second water wheel 120B to rotate both water wheels 120A and 120B. At this time, the first water wheel 120A rotates counterclockwise and the second water wheel 120B rotates clockwise in plan view. The wave F2 corresponds to the first vertex 151 located on the impermeable wall 10 side of the first rectifying member 150 disposed on the downstream side of the outflow region 119 after rotating the first water wheel 120A and the second water wheel 120B. It collides with the corner and flows out offshore without itchiness.

In this way, the entire waves F1 and F2 that are about to flow in and out are guided to the inflow region 118 and the outflow region 119 by the first rectifying member 150 and the second rectifying member 160, and the first water turbine 120A and the second water wheel 120B are made to flow. Can be rotated in one direction. In other words, this breakwater can convert most of the wave energy into the rotational energy of the water wheel 120 and can be wave-dissipated. The waves F1 and F2 guide the water flow to the inner peripheral surface of the water turbine blade 136 of the water turbine 120 by the first rectifying member 150 and the second rectifying member 160, but do not guide the water flow to the outer peripheral surface of the water turbine blade 136. The rotation resistance of the water wheel 120 does not become resistance.

When the water turbine 120 rotates as described above, the generator 3 receives the rotational force via the shaft upper portion 131 and generates power. In addition, as shown in FIG. 3, in this embodiment, the generator 3 is arrange | positioned on the roof part 12, but you may arrange | position below the roof part 12 similarly to 1st Embodiment. Also in the present embodiment, as in the first embodiment, the arrangement and configuration of the generator 3 can be appropriately selected. The electric power generated by the generator 3 is transmitted to a land-side substation or the like via a power transmission facility (not shown). In addition, as shown in FIG. 3, the impervious wall 10 can also be installed so that the coast 125 may be touched or substantially contacted.

<3. Third Embodiment>
Next, a wave power generation system 201 according to the third embodiment will be described. FIG. 5 is a cross-sectional view of the wave power generation system 201. The wave power generation system 201 is common in many respects to the wave power generation systems 1 and 101 according to the first and second embodiments. In the following description, differences from the first and second embodiments will be mainly described. The same reference numerals are given to the same components as those in the first and second embodiments, and detailed description thereof will be omitted.

Similar to the first and second embodiments, the wave power generation system 201 includes an impermeable wall 10, a roof portion 12 (upper wall portion), a bottom portion 13, a base 11, a water wheel train 2, and a generator 3. The first straightening member 250 and the second straightening member 260 are provided. The main difference between the wave power generation system 201 according to the present embodiment and the wave power generation system 101 according to the second embodiment is the distance between the water turbines 120 included in the water turbine train 2.

More specifically, in the present embodiment, the adjacent first water wheel 120A and the second water wheel 120B are arranged substantially without a gap. By doing so, it is possible to reduce the amount of waves that pass through the gap between the first water wheel 120A and the second water wheel 120B without substantially contributing to the rotation of the water wheels 120A and 120B. That is, power generation efficiency can be improved.

In the present embodiment, a plurality of first rectifying members 250 exist to form a row, and a plurality of second rectifying members 260 also exist to form a row. The first and second rectifying members 250 and 260 are different from the first and second rectifying members 150 and 160 according to the second embodiment only in the cross-sectional shape, and have the same configuration in other points. .

As shown in FIG. 5, the cross-sectional shape of the first rectifying member 250 is a shape having four vertices surrounded by a pair of adjacent curves 253 and a pair of adjacent line segments 254. The first rectifying member 250 is disposed in the vicinity of the outflow region 119 on the offshore side, and is one of the four vertices of the cross section, and an intersection of a pair of curves 253 (hereinafter referred to as a first vertex 251). It faces the outflow area 119 side. The second vertex 252 is an intersection of a pair of line segments 254. More specifically, in the first rectifying member 250, a virtual line 242 passing through the first vertex 251 of the first rectifying member 250 and the diagonally second vertex 252 in the cross-sectional view is adjacent to the first turbine 120 </ b> A and the first It arrange | positions so that it may pass along the midpoint of the virtual line segment 241 which passes along the point respectively corresponding to the rotating shaft 121 of 2 water turbine 120B, or its vicinity. Further, the virtual line 242 and the virtual line segment 241 are orthogonal to each other. The first vertex 251 is located on the offshore side of the virtual line segment 241, but the first rectifying member 250 enters a gap formed between the adjacent water turbines 120. Of the four vertices of the cross section of the first rectifying member 250, the dimension between the remaining vertices that are not the first vertex 251 and the second vertex 252 is substantially the same as the diameters of the upper flange 134 and the lower flange 135 of the water turbine 120. is there. In the cross section of the first rectifying member 250, a curved line 253 extending from the corner corresponding to the first vertex 251 in the left-right direction (the vertical direction in FIG. 5, the same applies hereinafter) includes the upper flange 134 and the lower flange 135 of the water turbine 120. It is concentric and has a slightly larger arc shape.

The cross-sectional shape of the second rectifying member 260 is a shape having four vertices surrounded by a pair of adjacent curves 263 and a pair of adjacent line segments 264. The second rectifying member 260 is disposed in the vicinity of the impermeable wall 10 side of the inflow region 118, and is one of the four vertices of the cross section thereof, and is an intersection of a pair of curves 263 (hereinafter referred to as the first vertex 261). Is directed to the inflow region 118 side. The second vertex 262 is an intersection of a pair of line segments 264. More specifically, the second straightening member 260 has a virtual line 244 passing through the first vertex 261 of the second straightening member 260 and the diagonally second vertex 262 in the cross-sectional view, and the adjacent first turbine 120A and the second It arrange | positions so that it may pass along the midpoint of the virtual line segment 243 which passes along the point respectively corresponding to the rotating shaft 121 of 2 water turbine 120B, or its vicinity. The virtual line 244 and the virtual line segment 243 are orthogonal to each other. Although the first vertex 261 is located on the side of the impermeable wall 10 with respect to the imaginary line segment 243, the second rectifying member 260 enters a gap formed between the adjacent water turbines 120. Among the four vertices of the cross section of the second rectifying member 260, the dimension between the remaining vertices that are not the first vertex 261 and the second vertex 262 is substantially the same as the diameters of the upper flange 134 and the lower flange 135 of the water turbine 120. is there. In the cross section of the second rectifying member 260, a curved line 263 extending from the corner corresponding to the first vertex 261 in the left-right direction (the vertical direction in FIG. 5, the same applies hereinafter) includes the upper flange 134 and the lower flange 135 of the turbine 120. It is concentric and has a slightly larger arc shape.

With the above configuration, the wave power generation system 201 according to the third embodiment can improve the power generation efficiency compared with the wave power generation systems 1 and 101 already described.

<4. Fourth Embodiment>
Next, a wave power generation system 301 according to the fourth embodiment will be described. FIG. 6 is a cross-sectional view of the wave power generation system 301. The wave power generation system 301 is common in many respects to the wave power generation systems 1, 101, 201 according to the first to third embodiments. In the following description, differences from the first to third embodiments will be mainly described. The same components as those in the first to third embodiments will be denoted by the same reference numerals, and detailed description thereof will be omitted.

Similar to the first to third embodiments, the wave power generation system 301 includes an impermeable wall 10, a roof portion 12 (upper wall portion), a bottom portion 13, a base 11, a water wheel train 2, and a generator 3. The first straightening member 350 and the second straightening member 360 are provided. The main difference between the wave power generation system 301 according to the present embodiment and the wave power generation systems 101 and 202 according to the second and third embodiments is in the distance between the water turbines 120 included in the water turbine train 2.

More specifically, in the wave power generation system 301, the water turbines 120 included in the water turbine row 2 are arranged at unequal intervals. In particular, in the present embodiment, the water turbines 120 included in the water turbine row 2 are arranged at different positions at locations corresponding to the inflow region 118 and locations corresponding to the outflow region 119. The interval between adjacent water turbines 120 at a position corresponding to the outflow region 119 is wider than the interval between adjacent water turbines 120 at a position corresponding to the inflow region 118, but may be reversed as shown in FIG. Is possible.

In the present embodiment, since the breakwater does not have a permeable front wall on the offshore side of the impermeable wall 10, the degree of freedom of the installation position of the water turbine 120 is high. Therefore, the amount of wave inflow and outflow to the breakwater that improves the power generation efficiency is determined for each installation location, and at the same time, each interval between adjacent water turbines 120 included in the water turbine row 2 is set separately. be able to. In particular, it is significant that the interval at the position corresponding to the inflow region 118 and the interval at the position corresponding to the outflow region 119 can be set separately.

<5. Modification>
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning. For example, the following changes can be made. Moreover, the gist of the following modifications can be combined as appropriate.

<5-1>
In the above embodiment, a Savonius turbine is used as the rotating body, but the present invention is not limited to this, and other types of turbines can also be used. However, from the viewpoint of power generation efficiency, it is preferable to use a water turbine that rotates in a certain direction regardless of the direction of the waves so that power generation can be easily performed at the time of spilling and at the time of wave drawing. As an example of such a water wheel, there is a cross flow water wheel in addition to the Savonius water wheel. Further, in the water wheel of the above embodiment, a water wheel deformed so as to have a different number of water wheel blades such as three or four can be used.

<5-2>
In the said embodiment, although the water turbine row | line 2 was set as the staggered rotation structure, it is not limited to this, For example, you may comprise so that all the water turbines 20 may rotate in the same direction.

<5-3>
In the above-described embodiment, the upper and lower sides of the rotating shaft of the water turbine are pivotally supported.

<5-4>
In the said embodiment, although the rotating shaft of the water turbine was directly connected with the generator, you may make it connect with a generator indirectly through other apparatuses, such as a hydraulic pump, for example.

<5-5>
In the second to fourth embodiments, the rotation shaft is arranged separately above and below the central wing, but may pass through the wing 132.

<5-6>
In the second to fourth embodiments, the upper part of the wing part 132 is exposed above the water surface, but may be always submerged.

<5-7>
In the above embodiment, the wave power generation system is installed in the sea, but it can also be installed in a river or a lake.

<5-8>
In the second to fourth embodiments, one of the first rectifying member and the second rectifying member may be omitted.

<5-9>
In the said embodiment, the offshore side of the base 11 was comprised so that a slope might be formed with respect to a perpendicular direction. However, as shown in FIG. 8, instead of the base 11, a base 11A having a vertical surface 111A on the offshore side may be provided. In addition, as shown in FIG. 9, a base 11 </ b> B may be further formed on the bottom portion 13 provided on the base 11. The base 11B in FIG. 9 is formed substantially only below the water wheel 20 and is a rectangular parallelepiped base that does not reach the impervious wall 10 in a longitudinal sectional view, but reaches the impervious wall 10 through the base 11B. It can also be a foundation. When the base is not a trapezoidal shape as shown in FIG. 1 in the longitudinal sectional view as in this modification, the water depth changes abruptly near the offshore side and immediately below the water turbine 20. A step is formed, the wavelength of the incoming wave changes, and the flow velocity increases. Therefore, in this case, the effect of reducing the wave reflectance and the effect of improving the power generation efficiency are expected.

Hereinafter, Example 1 of the present invention will be described. However, the present invention is not limited to the following Example 1.

<1. Experimental conditions>
Here, as Example 1, a wave power generation system as shown in FIG. Specifically, the size of the wave-making water tank is 20.00 m in length, 0.50 m in width, 0.50 m in height, and constant at a water depth h = 0.40 m. Install a wave plate on one end side (offshore side) in the length direction of the wave tank, so that the rotating shaft of the turbine is located 13.68 m away from the wave plate on the other side (shore side) A watermill was installed. Each turbine included in the turbine train is a Savonius turbine having a three-stage configuration similar to that described in the first embodiment. Three types of water turbine trains were prepared, and the diameter D _s [m] of the Savonius turbine in each turbine train was set to D _s = 0.084, 0.140, 0.210. The number of turbines included in the turbine wheel row is 5 (see FIG. 11A) when D _s = 0.084, and 3 when D _s = 0.140 (see FIG. 11) in relation to the width of the wave tank. 11B), and when D _s = 0.210, two (see FIG. 11C). All the water turbine trains have a staggered rotation configuration. The distance between the turbines D = D _s + 2a (2a is the distance between the blade tips of adjacent turbine wheels) is set to 2a / D = 0.11 (constant), and the turbine height H _w is H _w / h was set to be approximately constant at 0.8. Further, an impermeable wall was further installed on the shore side of l [m] = 0.38 from the water wheel train.

Moreover, in the wave power generation system which concerns on Example 1, the power measurement system shown in FIG. 12 was installed instead of the generator. The rotating shaft of the water turbine (water turbine shaft) was supported at its lower end by using a ball bearing bearing so that friction was minimized. The upper end of the water wheel axis is connected to the magnetic brake, the water axle gave load torque T _q [N · m] by the magnetic brake. As the magnetic brake, Perma-Tork HC01-1 manufactured by Nippon Sohatsu Co., Ltd. was used. In addition, an accelerometer was fixed to the turbine shaft, and the rotation speed (angular velocity) R _E [rps] of the turbine was measured for 30 to 80 seconds after the start of wave formation at a sampling frequency of 100 Hz. In addition, two capacitive wave height meters were installed approximately 3.5 m offshore from the water wheel shaft, and the water level fluctuation was measured. In addition, one capacitive wave height meter was installed 0.18 m offshore from the water wheel shaft, and the water level fluctuation near the water wheel train was measured. The sampling frequency of the wave height meter was 100 Hz. The working wave was a regular wave with a period T [s] = 0.81 to 1.67 and a waveform gradient H / L = 0.01. Note that H is the wave height and L is the wavelength.

<2. Experimental results and evaluation>
<2-1. Reflectivity>
T _q = 1.1 reflectance K _r in the case of × 10 ^-3 N · m has resulted represented by "dots" in FIGS. 13A ~ FIG 13C. 13A to 13C show data when D _s /h=0.215, 0.350, and 0.525, respectively. The reflectivity K _r is calculated based on the measurement results of two capacitive wave height meters approximately 3.5 m offshore from the turbine wheel train. This was calculated using the separation / estimation method of incoming and reflected waves, Port Technology Institute data, No. 248). Further, assuming a model (comparative example) of a vertical slit upright wave breaker when a columnar column is used instead of a turbine row (other conditions are the same as those of the first embodiment described above), When the reflectance K _r was calculated as a theoretical solution based on previous studies, the results shown by “curves” in FIGS. 13A to 13C were obtained. Note that the column column in the comparison column is a column in which columns having the same diameter as the above-described turbine column are arranged at the same interval.

From FIG. 13A to FIG. 13C, it can be seen that the reflectance K _r tends to be lower in Example 1 than in the comparative example. This tendency was particularly remarkable on the short cycle side. This is presumably because a larger shear flow is generated by passing through the upper surface of the water wheel existing below the water surface and energy is lost. In addition, it is considered that the larger the diameter D _{s of} the turbine wheel, the larger the area of the upper surface of the turbine wheel, so that more wave energy is dissipated and the reflectance K _r is reduced. In other words, it was found that the water turbine train can be sufficiently extinguished without installing a permeable front wall. Moreover, in order to maintain the calmness of the sea area, it was found that the diameter of the water wheel should be determined according to the water depth and the wave period. Further, when the diameter of the water wheel is set to about 20% to 50% of the water depth, it is possible to realize a reflectance of about 30% to 80%. In particular, the diameter of the water wheel is set to about 50% of the water depth. In some cases, a reflectivity of about 30% to 50% can be achieved.

Further, in the wave power generation system according to the above embodiment, since the generator is attached to the water wheel shaft, it is expected that a load (brake) is applied to the water wheel shaft by this power generator, and the rotation speed of the water wheel shaft is reduced. . Therefore, in order to evaluate this influence, the rotational speed R _E and the reflectance K _r with respect to various load torques T _q were measured, and the results shown in FIGS. 14A to 14C were obtained. 14A to 14C show data when D _s /h=0.215, 0.350, and 0.525, respectively.

From FIG. 14A to FIG. 14C, it can be seen that as the load torque T _q increases, the rotational speed _RE decreases, but no significant change is observed in the reflectance K _r . That is, it has been found that the reflectivity is not affected by the load of the generator and is determined according to the structural conditions (wave conditions such as water depth, water wheel diameter, period, wavelength, etc.). In addition, since the reflectance is constant regardless of the load on the generator, energy consisting of the amount of energy dissipated by the generation of vortices formed around the turbine and the amount of energy used to rotate the turbine It was found that the total dissipated amount was constant regardless of the generator load.

<2-2. Acquisition power>
Acquisition power efficiency K _e to the diameter D _s of different waterwheel, was calculated according to the following equation, the results shown in FIGS. 15A ~ FIG 15C is obtained. 15A to 15C show data when D _s /h=0.215, 0.350, and 0.525, respectively. P _p below is the acquired power per unit width obtained by the rotation of the water turbine, and P _w is the wave energy per unit width. Note that ρ is the density of water and g is the acceleration of gravity. Further, R _E in the following formula is an average rotation speed.

According to previous studies, the power generation efficiency (acquired power efficiency) for wave energy generated by Savonius turbines is about 5%. Meanwhile, in the wave activated power generation system according to the first embodiment, as shown in FIGS. 15A ~ FIG 15C, even for the diameter D _s of any hydraulic turbine, the maximum value of the acquired power efficiency K _e becomes 10% or more, high power It turns out that efficiency is expected.

In addition, from the viewpoint of power generation stability, it is required that fluctuations in the rotational speed of the water turbine be small. Therefore, the transition varies η at 0.18m offshore water axle, was examined the relationship between the rotational speed R _E of the water wheel, the results shown in FIGS. 16A ~ FIG 16C is obtained. 16A to 16C show data when D _s /h=0.215, 0.350, and 0.525, respectively.

As shown in FIG. 16A, in the case of D _s /h=0.215, two rotation speed peaks appeared for one wave. Such a tendency is considered to be due to the fact that the rotational speed increases when the incident wave passes through the water wheel train and increases again when the reflected wave reflected by the non-transparent wall propagates offshore. Further, as shown in FIGS. 16B and 16C, as D _s / h is increased and 0.350,0.525, variation of the rotational speed R _E was smaller. That is, if the diameter of the water wheel is large, it is considered that after the water wheel starts to rotate once, the moment of inertia acts to make it difficult to receive the frequency characteristic of the wave, and the water wheel rotates at a stable speed. Therefore, it can be said that the larger diameter of the water turbine is more advantageous from the viewpoint of the stability of power generation, and the diameter of the water turbine is preferably 30% or more of the water depth, particularly 50% or more. It turned out to be preferable.

Hereinafter, Example 2 of the present invention will be described. However, the present invention is not limited to the following Example 2.

<1. Experimental conditions>
Here, as Example 2, a wave power generation system as shown in FIGS. 17, 18 </ b> A, and 18 </ b> B was created using a wave-making water tank. Specifically, the size of the wave water tank is 20.00 m in length, 0.50 m in width, 0.60 m in height, and constant at a maximum water depth h = 0.40 m. A wave-making plate was installed on one end side (offshore side) of the wave-making water tank in the length direction, and a rotating shaft of the water wheel train was installed at a position about 14 m away from the wave-making plate on the other end side (shore side). In addition, an impermeable wall was installed on the l [m] shore side further from the rotation axis of the water wheel train. The diameter D _s [m] of the Savonius turbine was set to 0.072. The number of water turbines included in the water turbine train is six, and the water turbine train has a staggered rotation configuration in which adjacent water turbines rotate in reverse. In addition, a water wheel distance D [m] = 1.1D _s. Each turbine included in the turbine row is configured by changing the three-stage Savonius turbine described in the first embodiment to a two-stage configuration. In addition, a rectangular parallelepiped step 11A that spreads l '[m] from the impervious wall to the offshore side and widened by the width of the wave-making water tank in the width direction was prepared, and a water turbine row was arranged on the step 11A.

In the wave power generation system according to Example 2, a power measurement system similar to that shown in FIG. 12 was installed instead of the generator, and a load torque T _q [N · m] was applied to the water wheel shaft. In addition, an electromagnetic current meter made by Alec Electronics Co., Ltd. was installed at a position between the turbines (offshore) and 0.08 m below the static water surface, and the flow velocity between the turbines was measured. Further, the rotational speed ω of the water turbine was measured at a sampling frequency of 100 Hz using an accelerometer (sensor controller) manufactured by ATR Promotions Inc. attached to the upper end of the water wheel shaft. In addition, two capacitive wave height meters were installed approximately 3.5 m offshore from the rotating shaft of the turbine, and separate input / reflected wave estimation method (Goda et al., 1976, separate estimation of incoming / reflected wave in irregular waves). Law, Port Technology Research Institute, No. 248), the wave height H [m] and the reflectance K _r of the incident wave were obtained. Also, determine the primary conversion efficiency E obtained as the ratio of the acquired power P hydraulic turbine for wave energy D · Pω acting on one water turbine ^{(Pω = ρgH 2/8)} , which was converted to per unit length of the waterwheel The energy conversion efficiency E ′ = E / H _s was determined. H _s [m] is the height of the water wheel. The working wave was a regular wave having a period T [s] = 0.73 to 1.71 and a waveform gradient H / L = 0.020. Note that H is the wave height and L is the wavelength.

Then, the condition of only step 11A (case 1: comparative example), the condition of only water turbine train (case 2: embodiment), and the condition of preparing both step 11A and water turbine train shown in FIG. 17 (case 3: implementation) In Example), the experiment was conducted while changing l ′ = l + 0.04 and changing l = 0.20 m, 0.30 m, and 0.40 m. Further, the experiment was conducted by changing l / l ′ with l ′ = 0.44 (constant). The wave power generation system of case 1 is obtained by removing the water wheel train from the wave power generation system of FIG. The wave power generation system of case 2 is obtained by removing step 11A from the wave power generation system of FIG. 17 and changing the two-stage water turbine train to a three-stage structure. Experimental conditions regarding h _s / h and the height H _s of the water wheel in case1 ~ case3 are shown in the table below. Note that h _s [m] is the water depth at the installation position of the water turbine.

<2. Experimental results and evaluation>
Step length - in the case of 'a l' (shore offshore length in the direction of the step 11A) l was varied with = 0.24,0.34,0.44m, maximum flow rate through the inter-reflectance K _r and waterwheel Vmax (measured value at the installation position of the water turbine in the case of only step 11A) was as shown in FIGS. 19A to 19C. Umax in the figure represents the maximum velocity amplitude obtained from the micro-amplitude wave theory at a water depth h = 0.40 m. From the figure, it was found that the reflectance K _r generally tends to be as high as 0.6 or more in case 1 including only step 11A. It was found that the case 2 with only the water wheel train has a lower reflectance than the case 1 under any l ′ conditions. Furthermore, in the case3 provided waterwheel column on step 11A, although almost the same K _r and case2 in short-period zone, decline significant K _r is observed in long period range, the step 11A It turned out that this tendency is so remarkable that it is long. On the other hand, Vmax / umax of case 3 is larger than that of case 2. Therefore, by installing a water wheel on step 11A, the energy dissipation becomes faster flow rate through the inter-turbine is increased, the reflectance K _r is considered to have reduced.

From the above, it was confirmed that the reflectivity Kr tends to be the lowest in case 3, the next lowest in case 2, and the maximum in case 1. Accordingly, it has been confirmed that the wave-dissipating performance is improved by the water wheel train, and further, when the water wheel train is installed on the step 11A, the wave-dissipating performance is further improved.

20A and 20B show the energy conversion efficiencies E ′ of case 2 and case 3, respectively, when the load torque T _q is given with the step length l ′ = 0.44 (constant). From the figure, the maximum value of E 'in case 3 is about 0.6, and in case 2 it is about 0.4. In case 3, the energy conversion efficiency E' is generally higher than in case 2. I understood. Therefore, it has been found that the power generation efficiency is improved by installing the water wheel train on the step 11A. More specifically, when the water turbine train is installed after the step 11A is provided, the energy conversion efficiency E ′ is substantially improved, and the load torque (T _q = 0. It was found that the maximum energy conversion efficiency was obtained at about 003 N · m). This means that the optimum load torque for efficiently acquiring energy is constant regardless of the wave period of interest, and the design of the secondary conversion mechanism (the mechanism for operating the generator, etc.) It can be said that useful knowledge has been obtained.

FIG. 21 shows the reflectance K _r and the distance between the water wheels when the length is changed to 1 / l ′ = 0.45, 0.68, 0.91 under the condition of the step length l ′ = 0.44 (constant). The maximum flow velocity Vmax passing through is shown. From the figure, the larger the l / l ', i.e., that there is a tendency that the minimum value of about K _r installation position of the water wheel column is offshore step 11A decreases were confirmed. Therefore, it was found that the water turbine train is preferably arranged in the vicinity of the offshore end of Step 11A from the viewpoint of wave extinction.

22A and 22B show the primary conversion efficiency E when l / l ′ = 0.91 and 0.45, respectively. From the figure, it was confirmed that the maximum value of the primary conversion efficiency E tends to increase as l / l ′ increases, that is, as the installation position of the water turbine row is on the offshore side of Step 11A. Therefore, it was found that the turbine train is preferably arranged in the vicinity of the offshore end of Step 11A also from the viewpoint of power generation efficiency.

1, 101, 201, 301 Wave power generation system 2 Water wheel train (rotating body train)
3 Generator 10 Impervious Wall 11, 11A, 11B Base (Step)
12 Roof part (upper wall part) 20,120 Water wheel (rotary body)
120A 1st water wheel 120B 2nd water wheel 21, 121 Rotating shaft 118 Inflow area 119 Outflow area 150, 250, 350 First rectifying member 160, 260, 360 Second rectifying member

Claims (12)

It is installed in water and has an impermeable wall, but is used with a breakwater that does not have a permeable front wall on the offshore side of the impermeable wall, dissipates wave energy, and generates electricity from the wave energy. A wave power generation system,
On the offshore side of the impermeable wall, a rotating body row composed of a plurality of rotating bodies arranged along a direction in which the impermeable wall extends in a plan view;
A wave power generation system comprising: a generator that converts rotational energy of the plurality of rotating bodies into electric power. The adjacent rotating bodies included in the rotating body row are configured to rotate in opposite directions.
The wave power generation system according to claim 1. Between the rotating shafts of adjacent rotating bodies included in the rotating body row, an inflow region where waves flowing from the offshore side to the impermeable wall side pass, or waves flowing out from the impermeable wall side to the offshore side pass. The outflow area
At least one of the inflow region and the outflow region is formed,
A first rectifying member that is disposed near the outflow region on the offshore side and guides waves flowing from the offshore side to the impermeable wall side to the inflow region, and disposed near the impermeable wall side of the inflow region And further comprising at least one second rectifying member for guiding the wave flowing out from the impermeable wall side to the offshore side to the outflow region,
The wave power generation system according to claim 1 or 2. The rotating bodies included in the rotating body row are arranged at different intervals at a position corresponding to the inflow area and a position corresponding to the outflow area,
The wave power generation system according to claim 3. The rotating bodies included in the rotating body row are arranged at unequal intervals.
The wave power generation system according to any one of claims 1 to 4. Further comprising an upper wall portion extending in a horizontal direction from the impermeable wall and supporting the rotating body;
The wave power generation system according to any one of claims 1 to 5. A caisson having the impervious wall, and a bottom part and an upper wall part extending from the lower and upper parts of the impervious wall to the offshore side, respectively.
The wave power generation system according to any one of claims 1 to 5. The foundation in which the rotating body row is installed, and the water depth at the installation location of the rotating body row is shallower than the water depth at the offshore side,
Further comprising
The wave power generation system according to any one of claims 1 to 7. The foundation has a vertical surface facing the offshore side,
The wave power generation system according to claim 8. The rotating body is a water wheel that rotates in a constant direction regardless of the direction of the waves.
The wave power generation system according to any one of claims 1 to 9. The rotating body is a Savonius turbine.
The wave power generation system according to claim 10. The rotating shaft of the rotating body extends in the vertical direction.
The wave power generation system according to any one of claims 1 to 11.

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