JPS6332987B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a wave power generation device that generates electricity using wave energy. (Prior technology) Conventionally, in this type of wave power generation device, a central pipe is attached to a floating body, passing through the center of the floating body and opening the bottom surface into still water where it is not affected by waves. It is known to drive an air turbine generator by means of an air flow generated within the generator. In this case, the wave period that can be used as energy for power generation is 2 to 10 seconds, and when this wave period and the natural vibration period of the floating body match (T ₁ in Figure 2), or the vertical vibration period of the water surface in the central pipe. When the wave periods match (T ₂ in Figure 2), a large power output can be obtained. (Problem to be solved by the invention) However, as is clear from Figure 2, in the conventional wave power generation device, if the wave period deviates even slightly from the natural vibration period of the floating body or the vertical vibration period of the water surface in the central pipe, The power generation efficiency was extremely low because the power generation output decreased rapidly. On the other hand, recently there has been a demand for light buoys that use wave power generation devices as a power source, and they have high optical power, great visibility, and multi-purpose ones that can be equipped with various equipment such as sonic beacons, and their average power consumption is as high as 200W. ing. An object of the present invention is to set the dimensions of the outer diameter of the floating body, the inner diameter of the central pipe, and the length of the central pipe below the water surface within a certain range, so that the natural vibration period of the floating body or the center To provide a wave power generation device that solves the above problems by suppressing a decrease in power generation output even if the horizontal vertical vibration period in a pipe is slightly shifted and obtaining high power generation output for a wide range of wave periods. There is a particular thing. (Means for Solving the Problems) As a means for solving the above problems, the present invention provides a wave power generation device that includes a horizontally floating hollow annular floating body and a central portion of the floating body. A central pipe extending in the axial direction and having an open end on the submerged side, and a central pipe disposed at the end of the central pipe on the floating body side to prevent air flow in the central pipe caused by vertical movement of the floating body due to waves. an air turbine generator driven by an air turbine generator, the ratio of the outer diameter of the floating body to the inner diameter of the central pipe is a value necessary to generate a buoyancy force greater than its own weight; The submerged edge from the water surface of the center pipe when the diameter is set to three times or less the inner diameter of the center pipe, and the water surface outside the floating body and the water surface inside the center pipe are at the same height. and the inner diameter of the central pipe is a value necessary for the portion of the central pipe protruding from the lower surface of the floating body to attenuate the rolling motion of the floating body, and The length from the water surface of the central pipe to the submerged edge is set to 3.5 times or less the inner diameter of the central pipe when the water surface of the central pipe and the water surface inside the central pipe are at the same height. . (Function) With the above configuration, the present invention has an effective wave period of 2 to 10.
The output ratio (air pressure head/wave height) to seconds is the third
As shown in the figure, it is always "1" or more, suppressing a decrease in the output ratio and achieving high power generation output. (Example) Hereinafter, an example of the present invention will be illustrated and explained. As shown in FIGS. 1 and 4, the floating body 1 of the wave power generation device is formed into an annular body with a substantially rectangular cross section, and one end side of the inner diameter part forming the wall surface of the central hole of the floating body 1 is The central pipe 2 is integrally formed with the floating body 1 by protruding further and extending in the axial direction of the floating body 1 in a cylindrical shape. The end of the central pipe 2 protruding from the floating body 1 is opened and immersed in water. At the end of the central pipe 2 opposite to the submerged end, that is, at the upper end of the floating body 1, a power generation device section including an air turbine generator 3 is arranged via a truncated cone-shaped air flow path 4. . The air flow path 4 has a shape in which the diameter on the floating body 1 side is large and the diameter on the air turbine generator 3 side is small.A cylinder 5 is attached to the end on the small diameter side, and the air turbine generator 3 is connected to the upper end of the cylinder 5. Turbine blades 6 and air guide vanes 7 are arranged, and an inlet valve 9 that opens inward is provided in an opening 8 on the circumferential surface of the cylindrical body 5. A truncated conical generator cover 10 is disposed above the cylinder 5, an opening/closing lid 11 is provided at the center of the top of the generator cover 10, and a controller storage chamber 12 is formed inside the center of the top. opening 8
A filter 13 is disposed outside the suction valve 9, and a filter 14 is disposed between the cylinder body 5 and the generator cover 10.
Interpose. The ratio D/d of the outer diameter D of the floating body 1 and the inner diameter d of the central pipe 2 is a value that provides the necessary dimension for the floating body to generate a buoyancy force that is at least greater than its own weight, and the outer diameter of the floating body 1. The diameter D is set to be three times or less the inner diameter d of the central pipe 2. The lower limit of this D/d can be close to 1.0 in theory, but in actual buoys, it has to be kept afloat for about 2 years so that it does not sink even if it gets a variety of deposits, so empirically it has to be about half of the total buoyancy. is determined to be its own weight. The upper limit determines the effective range based on theoretical calculations and experimental values.
The above D/d=3.0 is within a range where high output can be obtained over a wide range of wave periods, as will be described later. The length of the central pipe 2 below the water surface and the water surface when the floating body 1 is at rest, that is, the length of the central pipe 2 when the water surface outside the floating body 1 and the water surface S inside the central pipe 2 are at the same height. The length of the central pipe 2 from the internal water surface S to the submerged end (hereinafter referred to as the effective length of the central pipe 2) l,
The ratio l/d to the inner diameter d of the central pipe is a value necessary for the part of the central pipe 2 protruding from the lower surface of the floating body to attenuate the rolling motion of the floating body, and the effective length of the central pipe 2. The diameter l is set to be 3.5 times or less the inner diameter d of the central pipe 2. This l/
The lower limit value of d can theoretically be close to 1.0, but in actual buoys, the water surface S often does not extend downward from the bottom surface of the floating body 1, and it is necessary to reduce the balance weight added instead of the balance weight. In addition, the effective length l that effectively acts as a roll prevention fin is equal to the inner diameter d.
It is set to a value nearly twice that of . Similar to D/d, theoretical calculations and experimental values show that l/d=3.5 is an effective range in which high output can be obtained over a wide range of wave periods. The dimensions of the truncated conical air flow path 4 are as follows: If the inner diameter d of the central pipe 2 is 640 millimeters (mm), the narrow diameter (smaller diameter) dt on the air turbine generator side is
200 millimeters (mm), height h of truncated cone shape
135 millimeters (mm). With this configuration, when the wave surface moves upward, the central pipe 2
Due to the increase in the space area above the water surface S inside, the intake valve 9 is opened and outside air is sucked in. At this time, very little outside air flows in between the turbine blades 7. When the wave surface moves downward, due to the decrease in the space area above the water surface S in the central pipe 2, the air in the pipe closes the intake valve 9, passes between the turbine blades 6 and the air guide blades 7, and passes through the filter 14. It flows out of the pipe. At this time, the airflow is guided by the air guide vanes 7 and acts on the turbine blades 6, driving the air turbine generator 3 to generate electricity. When power is generated in this way, as shown in Figure 3, the output ratio (air pressure head/wave height) for an effective wave period of 2 to 10 seconds is always 1 or more, and the
The output ratio is approximately three times that of the conventional example shown in the figure. In addition, when the wave period and the natural vibration period of the floating body 1 match, the output ratio _T1 is the air output La when the wave period T = 4.0 seconds and the wave height H = 30 centimeters (cm) is the outer diameter of the floating body 1. FIG. 5 shows a graph based on the ratio D/d between D and the inner diameter d of the central pipe 2, and a graph based on the ratio l/d between the effective length l of the central pipe 2 and the inner diameter d of the central pipe 2. FIG. 6 shows a graph expressed as . As a result, D/d3.0
It has been shown that at l/d3.5, the air output La is high and fluctuations are gradual, and a relatively stable output can be obtained. In Figures 7 and 8, l/d is 2.0, respectively.
and 3.5, and is a graph showing the relationship between the wave period T and the output La using D/d as a parameter. By the way, this type of wave power generation device is generally used in inner bays, and the average wave period in inner bays is 2.7 to 4.5.
Since the wave period is in seconds, the design is such that the maximum output can be obtained within this wave period range. When the figure is viewed from this perspective, it can be seen that this design purpose has been fully achieved. Next is the wave height in the inner bay, which is usually 10~
Within 50 cm, the average is 25-30 cm. The wave power generation device according to the present invention is designed so that a large output La can be obtained when the wave height H is within the range of 10 to 50 cm. Of course, during a rainstorm, the wave height H is 100.
In some cases, the waves can exceed 1 cm, and the structure is designed to withstand such waves. However, from the perspective of output efficiency, it is important to
It is designed with a target of 10 to 50 cm and a wave period of 2.7 to 4.5 seconds. A comparison of these experimental results with theoretical analysis reveals the following. (For details on the basic theory, see, for example, the Defense Agency Technical Research Headquarters Technical Report, Vol. 5, No. 39, May 1966, or the Research Report of the Faculty of Engineering, Hoiba University, Vol. 18, No. 34.
(Refer to December 1967, etc.) First, the symbols related to the coordinates when the device operates are defined as shown in Figure 7, and the equilibrium value when there is no wave is given a subscript 0, and the change from this equilibrium value is defined. Let's express it by adding Δ to the minute. Assuming that air is a perfect gas and ignoring changes in temperature, Assume that λ is a constant, and σ≒M ₀ /ζ ₀ S ₁ =P ₀ /R′T′ ……(2). The temporal change rate of the mass balance in the air chamber above the pipe is dΔM/dt=S ₁ /R′T′(ζ ₀ dΔP/dt+P ₀ dΔζ/dt)…
…(3) The amount of air passing through the nozzle is The equation for the movement of the entire device up and down is W/g・d ² ΔZ/dt ² = {W ^v /g・d ² (εΔh−ΔZ)/dt
² +Kd(εΔh−ΔZ)/dt}+{W ^v / _i /g・d ² (ΔH
−ΔZ)/dt ² +Kid(ΔH−ΔZ)/dt}+C(Δh−ΔZ)+S ₁ ΔP ……(5) The equation of motion of seawater in the central pipe is S ₁ l ₀ ρd ² ΔH/dt ² =-{W ^v / _i / g・d ² (ΔH − ΔZ) / d
t ² +Kid(ΔH−ΔZ)/dt}+S ₁ gρ(Δh−ΔH) −S ₁ ΔP ……(6) The air output of the central pipe is P=｜1/σ・dM/dtΔP｜……(7 ) The average horsepower when the airflow is full-wave rectified is = 1/T'∫ ^T ₅ λ [ΔP(t)] ² dt ...(8) When these equations are integrated over time by a computer, Figure 10 is obtained. As shown in FIG. 11, results are obtained using each wave frequency T as a parameter, confirming that the initial setting conditions are satisfied. Here, each symbol above is as follows: P: Pressure (Kg/m ² ) V: Volume (m ³ ) S ₁ : Internal cross-sectional area of the central pipe T': Absolute temperature (〓) M: Mass of air (KgS ² /m ) R′: Constant (m ² /S ² deg) σ: Density of air (KgS ² /m ⁴ ) S ² : Cross-sectional area of nozzle (m ² ) W: Weight of entire device (Kg) W ^v , W ^v _i : Virtual weight of outer and inner seawater (Kg) K, K _i : Resistance coefficient between outer and inner seawater and equipment wall (KgS/m) C: Buoyancy coefficient (Kg/m): Wave resistance due to seawater depth Average value of the coefficient representing the attenuation of the amplitude in the vertical direction l ₀ : Submerged length of pipe (m) ΔP : Pressure difference Further, the case where the air flow path 4 is provided between the floating body 1 and the cylindrical body 5 and the case where it is provided Table 1 shows a comparison with the case without. In the comparison of the theoretical air output in the table, an improvement of about 20% is recognized by providing the air flow path 4.

[Table] In this way, in this embodiment, the outer diameter of the floating body 1, the inner diameter of the central pipe 2, and the effective length of the central pipe 2 are determined so as to have a size ratio that allows the wave period to be used over a wide range. The cycle can be used effectively for power generation without causing a sudden drop in the output ratio, improving power generation efficiency. Furthermore, since the air flow path 4 is provided to allow the air flow generated in the central pipe to effectively act on the turbine blades, the power generation efficiency is further improved in conjunction with the above configuration. (Effects of the Invention) As described above, in the present invention, the ratio between the outer diameter of the floating body of the wave power generation device and the inner diameter of the central pipe extending in the axial direction from the center part of the floating body is set to 1.8 to 3.0. , and by setting the ratio of the effective length of the central pipe to the inner diameter of the central pipe to 1.8 to 3.5, the decrease in the output ratio in the effective wave period of 2 to 10 seconds can be suppressed and high power generation output can be maintained. As a result, a wide range of wave cycles can be effectively used for power generation, improving power generation efficiency.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view of the floating body of the wave power generation device of the present invention, Fig. 2 is a characteristic diagram of the wave period versus power generation output of the conventional wave power generation device, and Fig. 3 is the wave power generation device of the present invention. A characteristic diagram of the wave period versus power generation output of the power generation device. Fig. 4 is a partially cutaway front view of the generator section of the wave power generation device of the present invention. Fig. 5 shows the relationship between the outer diameter D of the floating body and the air output on the vertical axis. A graph showing the output curve with the horizontal axis representing the ratio D/d to the inner diameter d of the central pipe. Figure 6 shows the ratio l/d of the effective length l of the central pipe to the inner diameter d of the central pipe, with the vertical axis representing the air output. It is a graph showing an output curve with d as the horizontal axis. Figures 7 and 8 are graphs showing the relationship between wave period and output using D/d as a parameter, Figure 9 is an explanatory diagram of the symbols of each part forming the basis of theoretical analysis of wave power generation equipment, and Figure 10. is a graph showing the theoretical analysis results corresponding to FIG. 5, and FIG. 11 is a graph showing the theoretical analysis results corresponding to FIG. 1 is a floating body, 2 is a central pipe, 3 is an air turbine generator, 4 is an air flow path, 5 is a cylindrical body, 6 is a turbine blade, 7 is an air guide vane, 8 is an opening, 9 is an intake valve, D is a floating body , d is the inner diameter of the central pipe, l
is the effective length of the central pipe.

Claims (1)

[Claims] 1. A hollow annular floating body floating horizontally, a central pipe extending in the axial direction from the center of the floating body and having an open end on the submerged side, and a wave-shaped floating body disposed at the end of the central pipe on the floating body side. an air turbine generator driven by the air flow in the central pipe generated by the vertical movement of the floating body, and when the wave period is 2.7 to 4.5 seconds and the wave height is 10 to 50 cm, the floating body The ratio of the outer diameter to the inner diameter of the central pipe is a value necessary to generate buoyancy greater than its own weight, and the outer diameter of the floating body is set to 1.8 to 3 times the inner diameter of the central pipe, and When the water surface outside the floating body and the water surface inside the central pipe are at the same height, the ratio between the length of the central pipe from the water surface to the submerged edge and the inner diameter of the central pipe is the central pipe. This value is necessary for the portion of the floating body protruding from the lower surface of the floating body to attenuate the rolling motion of the floating body, and that the water surface outside the floating body and the water surface inside the central pipe are at the same height. In this case, the length from the water surface of the central pipe to the submerged edge is 1.8 to 3.5 of the inner diameter of the central pipe.
A wave power generation device characterized by being set to less than double the power.