JPH10246171A - Wave-activated generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure preventing infiltration of seawater in a generating room without using a particular complicated mechanism without increasing a height of a building of air chamber or the like, in a wave-activated generating set transmitting wave energy to a turbine generator with air serving as the medium. SOLUTION: An air chamber 3 supported on the sea surface to have an opening part 3a in the sea and a seawater de-energizing chamber 22 in the upward thereof are connected by a ventilating pipe 23, in an upper position from the seawater de-energizing chamber 22, a generator 14 by a turbine 13 is provided, a sectional area of the ventilating pipe 23 is formed sufficiently smaller than a sectional area of the air chamber 3 and the seawater de- energizing chamber 22. When the sea surface rises in the case of large wave height, air escaping upward from the air chamber is sufficiently small throttled by the ventilating pipe 23, to be expanded in the seawater de-energizing chamber 22, so as to delay therein a rising speed of the sea surface, a height of a water level in the seawater de-energizing chamber 22 can be suppressed lower than in the past.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Wave energy generators, which are known in the art, capture the wave energy in the ocean as the vertical movement of the water surface, rotate the turbine using air as a medium, and operate the generator to convert the energy into electric energy. Some of them are used. The present invention relates to a wave power generation device that prevents seawater from interfering with a machine in such a structure.

[0002]

2. Description of the Related Art As an example of a wave power generator, as shown in FIG. 4, a breakwater 2 is constructed on a large area mound 1 provided on the seabed such as a harbor, and a caisson is assembled on the breakwater 2 in a vertical direction. An air chamber (caisson) 3 having an opening 3a communicating with water is fixed to the breakwater 2 at a position on the sea surface, and an air damper chamber (caisson) 4 and a power generation chamber (caisson) 5 are provided above the air chamber 3. The wave power generator 6 is configured (see Japanese Patent Application Laid-Open No. 8-134882). In addition, the ventilation hole 7 which connects the air chamber 3 and the air damper chamber 4,
An input port 8 for communicating the power generation chamber 5 with the power generation chamber 5 and an intake / exhaust port 9 for communicating the power generation chamber 5 with the outside are provided on the partition walls of each chamber.

A ventilation screen 7 has a screen 1 for dust removal.
An input pipe 11 is attached to the input port 8 toward the inside of the air damper chamber 4, a float valve 12 is provided at the tip thereof, and a turbine 13 and a generator 14 are provided at the input port 8 of the power generation chamber 5. It is arranged. In addition, a shielding plate 15 is provided inside and outside the intake / exhaust port 9 of the power generation chamber 5 at a distance from the wall surface.

Further, a U-shaped water valve water tank 16 is provided in the air damper chamber 4 through the side wall. In addition, a drain pipe 17 is provided from the power generation chamber 5 to the water valve water tank 16.

[0005] The wave power generator 6 configured as described above operates the turbine 13 and the generator 14 by operating the turbine 13 and the generator 14 by raising and lowering the water surface of the air chamber 3 and oscillating the air inside the air chamber 3. Get.

By the way, when the seawater filled in the air chamber 3 invades the air damper chamber 4 when the seawater abnormally rises and further interferes with the turbine 13 and the generator 14 through the input pipe 11,
There is a possibility that the turbine 13 and the generator 14 may be deteriorated. Therefore, the above-mentioned water valve water tank 16 allows seawater pressure to escape to the outside so that seawater does not enter the turbine 13 and the generator 14. Alternatively, it is considered that the height of the air chamber 3 and the air damper chamber 4 is set to a height that allows a sufficient working height in abnormal waves.

As shown in FIG. 5, a communication pipe 19 having a motor-driven valve 18 is connected between the air hole 7 and the input port 8, and a sensor 20 is mounted below the valve 18. There is a structure provided with a control device 21 for operating the valve 18 based on the output of the sensor 20. In this configuration, when seawater abnormally rises, the sensor 20 detects when seawater has entered the communication pipe 19. The signal of the sensor 20 is sent to the control device 21 which operates to close the valve 18.

[0008]

However, as a countermeasure against abnormal waves of the wave power generator 6, when the water valve water tank 16 is used, air is prevented from flowing in and out of the water valve water tank 16 in normal times. It is necessary to always keep it in a watered state. For this reason, it is necessary to install a replenishing device (not shown) and a monitoring device (not shown) for supplying water to the water tank, which increases costs. Further, the rising speed of the seawater is the same in the air chamber 3 and the air damper chamber 4, and in consideration of the case where the water valve
And the height of the air damper room 4 must be increased, and the strength of the building against wind and rain must be increased.
An increase in the height of the building may impair the aesthetics.

Further, as shown in FIG. 5, when a sensor 20 and a valve 18 driven by a motor are added, there arises a problem that the mechanism becomes complicated and the production cost becomes high.
There is a problem that a failure easily occurs due to the presence of the mechanically movable portion.

For this reason, a structure that prevents seawater from entering the power generation room 5 by using a property of fluid without using a special complicated mechanism, increasing the height of a building such as an air chamber, and utilizing a property of fluid is desired. Was rare. An object of the present invention is to provide a wave power generation device in which the shape of an air flow path is changed so that seawater does not reach a power generation chamber containing a turbine and a generator.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an air chamber which is stably supported on a sea surface and has an opening in the sea, A seawater attenuating chamber is installed above the chamber, a generator by a turbine is provided above the seawater attenuating chamber, and the air chamber and the seawater attenuating chamber are connected to each other by a ventilation pipe. A chamber and the turbine input section are connected by an input pipe, and a cross-sectional area of the ventilation pipe is sufficiently smaller than a cross-sectional area of the air chamber and the seawater abatement chamber.

The cross-sectional area of the air chamber and the seawater abatement chamber mentioned herein means a horizontal cross-section, and the cross-sectional area of the ventilation pipe means a passage cross-section.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that members described in the related art are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 1, a seawater attenuating chamber 22 is provided between the air chamber 3 and the power generating chamber 5 containing the turbine 13 and the generator 14, and the air chamber 3 and the seawater attenuating chamber 22 communicate with each other through a ventilation pipe 23. Thus, the seawater abatement chamber 22 and the turbine 13 of the power generation chamber 5 communicate with each other through the input pipe 24.

In order to explain the wave power generator 6, the structure shown in FIG. 1 is schematically shown in FIG. 2, and the rise and fall of seawater are shown by patterns in FIG. At this time, h is the average sea level height, dc (the length of the submerged portion), and ho (the height of the air chamber 3) are the same amount of sea surface displacement, and a regular wave height: Z _i = a
・ Assuming that sinωt has occurred, the time t ₁
and lifting height is between up to t _4, between t = t ₁ ~t _2, seawater enters from the air chamber 3 to the vent pipe 23 as seawater energy dissipation chamber 22 a. Further, between t = t ₃ ~t _4, water surface shrinkage is sea water is below the air chamber 3 submerged portion. In addition, A _{1 is the} cross-sectional area of the air chamber, A _{2 is the} cross-sectional area of the first ventilation pipe, and A _{3 is} the cross-sectional area of the seawater abatement chamber.

As shown in FIG. 1, seawater enters the air chamber 3 from the wave inlet 3a opened into the seawater, and when the seawater abnormally rises, the seawater rises the surface of the air chamber 3 to fill the room. After that, it enters the seawater abatement chamber 22 through the ventilation pipe 23. At this time, since the cross-sectional area of the passage of the ventilation pipe 23 is smaller than the horizontal cross-sectional area of the air chamber, an input loss based on hydrodynamics occurs, and when seawater enters the seawater attenuating chamber 22 from the ventilation pipe 23, Since the horizontal cross-sectional area of the seawater attenuating chamber 22 is larger than the cross-sectional area of the passage of the trachea 23, the seawater attenuating chamber 22 causes a spreading loss. Therefore, in the seawater attenuating chamber 22, the rising speed decreases in inverse proportion to the ratio of the cross-sectional areas, and the rising speed of the seawater decreases due to the water pressure based on the rising water level. Therefore,
By setting the cross-sectional area of the ventilation pipe 23 and the cross-sectional area and the height of the seawater abatement chamber 22, even a wave having a high wave height can be prevented from entering the power generation chamber 5.

[0016] First, when seawater invasion, Nami圧P ₁ in the air chamber 3 (submerged director -dc), due small amplitude wave theory, the seawater density [rho, if the gravitational acceleration and g, P ₁ / (Ρ · g) = dc + a · cosh · k (h−d
c) · sin ωt / cosh (kh), and when the wave is rising to a height higher than the ceiling of the air chamber, P ₁ ′: pressure at the ceiling of the air chamber: P ₁ ′ = P ₁ −ρ · g (dc + ho).

The Z-axis is taken above the lower end of the seawater abatement chamber, and the Bernoulli equation is applied to each of the ceiling of the air chamber 3, the ventilation pipe 23, and the water surface of the seawater abatement chamber 22. The seawater rising speed in the air chamber 3 is V ₁ , the flow velocity in the ventilation pipe 23 is V ₂ , the pressure is P ₂ , the flow velocity in the seawater deceleration chamber 22 is V ₃ , and the water surface pressure is P.
₃ (= 0), ^{_{when, V 1 2 / 2g + P}} 1 '/ (ρ · g) = V 2 2 / 2g + P 2 /
A _{(ρ · g) + h 12} V 2 2 / 2g + P 2 / (ρ · g) = V 3 2 / 2g + Z + h 23. However, the pressure at the ceiling of the air chamber and the pressure at Z = 0 were approximately equal. Here, h ₁₂ is the loss in the case where the cross-sectional area sharply contracts, a ^{_{h 12 = V 2 2 / 2g}} (1 / c 1 -1) 2. c ₁ is the contraction coefficient in the case of A ₂ <A _1/10, 0.61. Also, h ₂₃ is the loss in the case where the cross-sectional area rapidly _{expanding, h 23 = 1 / 2g (} V 2 -V 3) 2 = V 2 2 / 2g (1-A
₂ / A ₃ ) ² .

The above equations are arranged as equation (1) below. _{P 1 '/ (ρ · g} ) = Z + V 3 2 /2g{1+0.409(A 3 / A 2) 2 + (1-A 2 / A 3) 2 (A 3 / A 2) 2 - (A 3 / A ₁ ) ²・ ・ ・ (1) As an example, if the diameter of the ventilation pipe 23 is 0.2 m and the diameter of the seawater abatement chamber 22 is 1 m, A ₃ / A ₂ = 25, and
(A ₃ / A ₂ ) ² = 625. Therefore, in equation (1), the value inside ｛｝ is 800 or more, which is 800 times or more the value when the loss is not considered.

Next, when sea water drainage, seawater intrusion upon as well as on the water surface of sea water energy dissipation chamber 22, in the vent tube 23, applying the equation of Bernoulli each cross section of the air chamber 3 ceilings, V ₃ ² / ^{_{2g + Z = V 2 2 /}} 2g + P 2 / (ρ · g) + h 32 V 2 2 / 2g + P 2 / (ρ · g) = V 1 2 / 2g + P 1 '/
(Ρ · g) + h ₂₁ Here, h ₃₂ is the loss in the case where the cross-sectional area sharply contracts, a ^{_{h 32 = V 2 2 / 2g}} (1 / c 2 -1) 2. Incidentally, c ₂ is the contraction coefficient, A ₂ <A _3/1
In the case of 0, it is 0.61. Also, h ₂₁ is the loss coefficient in the case where the cross-sectional area rapidly _{expanding, h 21 = 1 / 2g (} V 2 -V 1) 2 = V 2 2 / 2g (1-A
₂ / A ₁ ) ² .

That is, the above equations are rearranged into the following equation (2). _{P 1 '/ (ρ · g} ) = Z + V 3 2 /2g{1-0.409(A 3 / A 2) 2 - (1-A 2 / A 3) 2 (A 3 / A 2) 2 + ( A ₃ / A ₁ ) ²・ ・ ・ (2)

Next, C = 1 / g ｛1 + 0.409 (A ₃ / A ₂ ) ² + (1-
Assuming that A ₂ / A ₃ ) ² (A ₃ / A ₂ ) ² − (A ₃ / A ₁ ) ² Ｖ and V = V ₃ , the equation (1) is expressed as P ₁ ′ / (ρ · g) = Z + the (C / ²⁾ V 2. By differentiating both sides with t, dv /
Since dt = V, 1 / (ρ · g) dP ₁ ′ / dt = V + C · V · dv / dt = (1 + Cdv / dt) V (3)

By the way, P ₁ ′ = P ₁ −ρ · g (dc + ho) P ₁ / (ρ · g) = dc + a · cosh · k (h
−dc) · sinωt / cosh (kh), so that 1 / (ρ · g) dP ₁ ′ / dt = 1 · dP ₁ ′ / (ρ · gdt) = aω · cosh · k (h-dc) · cosωt / cosh (kh). Here, if D = aω · cosh · k (h−dc) / cosh (kh), then 1 / (ρ · g) dP ₁ ′ / dt = Dcosωt. ), (1 + C · dv / dt) V = D · cosωt.

The above differential equation is solved by a numerical solution, and t =
seek Zmax in t ₁ ~t _2. Next, t = t ₃
Even if Z is 0 to negative or Z is positive, the time until the next wave hits the ceiling of the air chamber 3 (t = T
At + t ₁ ), it is sufficient to confirm that seawater falls naturally.
Further, the height of the seawater abatement chamber 22 may be set to be equal to or higher than Zmax. Here, T is a wave cycle (unit: time).
Although the wave power generator 6 is manufactured on the breakwater 2, the wave power generator 6 may be provided on a floating body fixed with an anchor.

[0024]

The present invention is constructed as described above, and the wave pressure in the air chamber raises and lowers the upper air to operate the turbine connected through the ventilation pipe and the seawater abatement chamber to generate electric power. Although it is a wave power generator that moves the machine, when the sea level rises when an abnormal wave height acts, the air flowing upward from the air chamber is narrowed sufficiently by the ventilation pipe and expanded in the seawater depletion chamber, In the seawater dissipating room, the rising speed of the sea surface becomes slow, and the height in the seawater dissipating room can be suppressed lower than before. This makes it possible to prevent the influence of an abnormal rise in seawater without increasing the heights of the air chamber and the seawater abatement chamber and without providing a special mechanism.

[Brief description of the drawings]

FIG. 1 is a sectional view of a wave power generator according to the present invention.

FIG. 2 is a schematic diagram of the structure shown in FIG.

FIG. 3 is a graph showing a wave height at a place where the wave power generation device of FIG. 1 is installed.

FIG. 4 is a cross-sectional view of a conventional wave power generation device.

FIG. 5 is a cross-sectional view of another conventional wave power generation device.

[Explanation of symbols]

3 the cross-sectional area of the air chamber 3a openings 13 turbine 14 generator 22 seawater energy dissipation chamber 23 cross-sectional area A ₃ seawater energy dissipation chamber cross-sectional area A ₂ vent of the vent pipe 24 input pipe A ₁ air chamber

Claims (1)

[Claims] 1. An air chamber stably supported on the sea surface and having an opening in the sea, a seawater attenuating chamber installed above the air chamber, and a turbine located above the seawater attenuating chamber. The air chamber and the seawater abatement chamber are connected by a vent pipe, the seawater abatement chamber and the turbine input section are connected by an input pipe, and a cross-sectional area of the vent pipe is the air chamber. And a wave power generation device that is sufficiently smaller than a cross-sectional area of the seawater abatement chamber.