JPH09144642A - Underwater reverse oscillating wing axial-flow turbine for wave activated generation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a structure having a contraction flow part under the sea level, convert a vertically moving wave force energy into a reciprocating water flow passing the contraction flow part, and reversely oscillate a wing synchronously with the period of this reciprocating water flow, thereby rotating a spindle in one direction to drive a generator. SOLUTION: In this underwater reverse oscillating wing axial-flow turbine for wave activated generation, a funnel-shaped structure 2 having a contraction flow part under the sea level is set on the sea level by a float body 3 to convert a vertically moving wave force energy into a reciprocating water flow 4 passing the contraction flow part. A rotating spindle 7 is rotated in one direction by an axial-flow turbine 6 having a moving blade 5 reversely oscillating synchronously with the period of the reciprocating water flow 4 to generate power by a generator 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention converts a ocean wave into a reciprocating water flow (primary conversion), and is equipped with a moving blade that reciprocally swings in synchronization with the cycle of the reciprocating water flow. The present invention relates to an underwater reversing oscillating blade axial flow turbine for wave power generation that drives a generator by rotating in one direction regardless of the flow direction of water flow (secondary conversion).

[0002]

2. Description of the Related Art Many methods for converting ocean wave energy into mechanical energy have been proposed. However, most of them convert the wave energy into a reciprocating water flow and then generate a reciprocating air flow before the air turbine. Is a method of driving. As an example, there is a method of converting a reciprocating air flow into a one-way air flow by a switching valve to drive a fixed pitch air turbine. With this method, the efficiency of the air turbine main body is quite good, but it is necessary to provide a switching valve and a complicated air chamber in order to convert the reciprocating air flow into a one-way air flow. In addition, there are impulse turbines and wales turbines that rotate in one direction in the reciprocating airflow, and are attracting attention. On the other hand, there is also a method of converting ocean wave energy into a reciprocating water flow and directly driving an underwater turbine. As an example, a cross-flow turbine that rotates in one direction in a reciprocating water flow has been devised, but the rotational speed changes and the output also changes in synchronization with the reciprocating water flow.

[0003]

When converting ocean wave energy into mechanical energy, since the density of water is about 800 times the density of air, it is preferable to convert wave energy into air flow. Larger output can be obtained by directly converting energy from the reciprocating water flow with an underwater turbine. However, since water is an incompressible fluid, the resistance acting on the turbine rotor blade is much larger than that of the air turbine, and a method like the Wales turbine cannot be adopted. Further, in the method of driving a fixed-blade underwater turbine in a reciprocating water flow, sufficient turbine efficiency cannot be obtained because the rotational speed and rotational direction of the turbine repeat acceleration, deceleration, and reversal. Accordingly, the present invention provides a submerged reversing oscillating blade axial flow turbine for wave power generation, which includes turbine blades that reversely oscillate in synchronism with the cycle of reciprocating water flow and rotates in one direction regardless of the flow direction of the reciprocating water flow. It is intended to be provided.

[0004]

DISCLOSURE OF THE INVENTION The present invention is intended to develop an underwater reversing oscillating blade axial flow turbine for converting a vertically moving wave into a reciprocating water flow and rotating in a constant direction in the reciprocating water flow for wave power generation. , The following measures have been taken. In order to keep the inflow angle of the relative velocity flowing into the turbine rotor blade, that is, the angle of attack α, always at an appropriate value, the rotor blade was equipped with a rotor blade in which the mounting angle of the blade was reversed and oscillated in synchronization with the cycle of the reciprocating water flow. The submerged reversing oscillating blade axial flow turbine for wave power generation according to claim 1, wherein the moving blade is rotated in one direction to drive the generator regardless of the direction of the reciprocating water flow. .

Since the waves fluctuate periodically, the velocity of the reciprocating water flow also fluctuates periodically. Therefore, the input to the turbine also fluctuates periodically, and the output of the rotating shaft also fluctuates periodically, so that the fluctuating electric power can be obtained by the DC generator. Further, it is possible to drive an induction AC generator whose rotation is controlled at a constant rotation speed. In this case, a one-way clutch is provided between the turbine output shaft and the generator shaft. The one-way clutch is installed so that the two shafts are disengaged when the turbine speed becomes lower than the synchronous speed of the generator. When the turbine transmits a large torque to the induction AC generator during a period when the speed of the reciprocating water flow is high, the one-way clutch becomes engaged and the turbine rotates at the synchronous speed controlled by the induction AC generator. Generates power at a constant frequency. On the other hand, in the period when the speed of the reciprocating water flow is slow,
If the turbine rotates at a lower speed than the induction AC generator, the one-way clutch cuts off the power transmission to the generator, and the turbine applies torque to the induction AC generator. Instead, the induction AC generator acts as an induction motor by receiving a small amount of power from the power line and maintains rotation at a constant rotation speed. The underwater for wave power generation according to claim 2, wherein a means for directly transmitting power to a power line is provided by means of these means for constantly maintaining the rotation speed of the generator at a constant rotation speed and performing AC power generation at a constant frequency. Inverted oscillating blade axial flow turbine.

Since the moving blades of this turbine reversely oscillate, the direction of the force acting on the blades also reverses. Therefore, it is necessary to use symmetric blades without twists for the moving blades. It becomes the same at the position of. When the axial flow velocity v _f distribution is constant in the radial direction, the circumferential velocity v _u is small at the hub-side radial position of the moving blade, so the angle of attack α increases and the stall condition occurs. Since the circumferential velocity v _u is large at the tip-side radius position, the angle of attack α becomes small and a negative state occurs. The following measures were taken in order to avoid such a state and improve the attack angle α acting on the blade element at each radius.
As a method of increasing the boss ratio to reduce the circumferential velocity difference of the blade in the radial direction and making the axial velocity distribution in the radial direction approximately proportional to the radius, a cylindrical guide device is provided in front of and behind the moving blade to set the hub side. The submerged reversing oscillating blade axial flow turbine for wave power generation according to claim 3, wherein means are provided so that the moving blade operates at an optimum angle of attack over the entire radius from the radius to the tip side radius.

As a method of improving the performance of the moving blade at each radius, guide vanes held by a one-way clutch that freely rotates in the rotating direction of the moving blade are provided before and after the moving blade, and the hub side radius is set at the moving blade inlet. The absolute inlet velocity is given a pre-swirl in the direction of rotation of the blade so that the blade acts at the optimum angle of attack over the entire radius from the tip to the tip side radius. On the other hand, at the outlet of the moving blade, the outflow absolute velocity collides with the back surface of the inlet of the guide blade, and the force in the rotating direction of the moving blade acts on the guide blade, so that the one-way clutch can freely rotate in the rotating direction of the moving blade. The submerged reversing oscillating blade axial flow turbine for wave power generation according to claim 4, wherein measures are taken.

As a method for improving the performance of the moving blade at each radius, the moving blade is divided into an inner diameter side and an outer diameter side in the vicinity of the average radius,
Turbine performance is improved by making the swinging angle of the outer diameter side smaller than the swinging angle of the inner diameter side to create a twisted rotor blade where each part acts at the optimum angle of attack. The submerged reversing oscillating blade axial flow turbine for wave power generation according to claim 5, wherein a means for improving the above is taken.

Since this turbine swings in the reverse direction, since the blades are symmetrical blades without camber, the blade performance is inferior to that with blades with camber. Therefore, in order to improve blade performance, the first half and the second half of the chord of a turbine blade that reverses and oscillates in synchronism with the cycle of the reciprocating water flow are divided, and the swing angle of the first half of the chord is compared. 7. The submerged reversing oscillating blade axial flow turbine for wave power generation according to claim 6, wherein a means for improving blade performance is provided by forming a bent blade having a structure in which the swing angle of the latter half of the chord is reduced.

[0010]

Various methods are conceivable as a method for converting ocean wave energy into a reciprocating water flow. FIG.
(A) is an example in which a funnel-shaped structure 2 provided with a constricted portion 1 below the sea surface is installed in a semi-submerged state above the sea surface by a floating body 3. The sea surface moves up and down by waves and the water surface inside the structure. The head difference causes the reciprocating water flow 4 to be generated in the contracting section 1 in synchronization with the wave cycle. The turbine output shaft 7 is rotated in a certain direction by the axial flow turbine 6 having the moving blades 5 which are inverted and oscillated in synchronization with the cycle of the reciprocating water flow 4, and the generator 8 generates electric power. The oscillating mechanism of the moving blade 5 is configured to oscillate the oscillating control shaft 10 in the hollow turbine output shaft 7 relative to the turbine output shaft 7 by the wing oscillating control mechanism 9 provided on the upper part of the generator. Is configured. In the case of directly performing AC power generation using an induction AC power generator controlled to a constant rotation speed, the one-way clutch 11 connects the turbine output shaft 7 and the power generator 8 shaft. FIG. 1B shows an example of installation on the breakwater 12 or the like, in which the reciprocating water flow 4 is applied to the contraction part provided in the breakwater 12.
Is generated and electric power is generated by this turbine.

The operating principle of the axial turbine that rotates in one direction by the reciprocating water flow will be described. FIG. 2 shows the force acting on the blade element at the average radius γ _m of the axial flow turbine rotor blade 5. When the blade element 5 is rotating at the circumferential velocity u, the flow velocity v _f is changed from the lower direction. When the water flow is flowing, the relative velocity w acts on the blade element, and the blade mounting angle must be + θ in order to give the blade element an optimum attack angle α. At this time, a lift force L acts on the blade element in a direction perpendicular to w and a drag force D acts in a w direction, and a resultant force R of the lift force L and the drag force D can be decomposed into a circumferential rotational force F _u and an axial thrust F _{f. u} becomes the force to rotate the turbine in one direction. Where the reciprocating water flow v _f
Since the magnitude of fluctuates periodically (almost sinusoidally), the angle between the relative velocity w of the moving blade 5 and the chord, that is, the angle of attack α
In order to adjust the angle to an appropriate angle, the blade mounting angle θ must be inverted and oscillated in synchronization with the reciprocating water flow. FIG. 3 shows a state in which the moving blade 5 reversely swings during one cycle of reciprocating water flow. The turbine can be rotated in one direction by reversing and swinging the swing angle θ of the moving blade 5 in synchronization with the cycle of the reciprocating water flow.

FIG. 4 is a sectional view of the turbine body. A blade swing shaft 15 is fixed to the moving blade 5 so that the blade 5 can swing and rotate with respect to the rotary hub 13, and is further fixed to a bevel gear 16 in the rotary hub 13. The rotating hub 13 is supported by bearings on the shaft support boss 14, and the rotating hub 1
The rotation of the rotary hub 13 is transmitted to the generator 8 by the hollow turbine output shaft 7 fixed to the shaft 3. On the other hand, the rotor blade rocking control shaft 10 transmits the rocking motion of the rocking control motor 17 to the rotor blade 5 through the bevel gear 16 ′, which penetrates the turbine output shaft 7 and is attached to the lower end. The swing control motor 17 rotates together with the turbine output shaft 7, and swings and rotates the moving blade swing control shaft 10 relative to the turpin output shaft 7. With these mechanisms, it is possible to reversely swing the moving blade 5 in synchronization with the cycle of the reciprocating water flow 4.
5A is a perspective view showing a swinging mechanism of a moving blade using a link mechanism, and FIG. 5B is a sectional view. The moving blade rocking control shaft 10 is vertically movable relative to the turbine output shaft 7, and the moving blade rocking control shaft 10 is moved vertically by a rocking control piston (hydraulic piston, etc.) 21. As a result, it is possible to reversely swing the moving blade 5 via the crosshead 20 and the link 19.

FIG. 6 shows velocity triangles acting on the blade element at the hub-side radius γ _h , the average radius γ _m , and the tip-side radius γ _t of the rotor blade 5. Since the rotor blades 5 of the turbine 6 reversely oscillate, it is unavoidable to use a twist-free symmetrical blade for the rotor blades 5. Therefore, when the axial flow velocity v _f is constant in the radial direction, even if the swing angle θ is set so that the optimum attack angle α ₀ is obtained at the average radius γ _m , the circumferential velocity at the hub side radius γ _h is set. since u _h is slow, becomes stall state angle of attack alpha _h increases, whereas the chip-side radius gamma _t is the rotational direction is circumferential velocity u _t is large attack angle alpha _t is small, or negative A state in which the rotational force acts in the opposite direction may occur. In order to avoid such a state and improve the attack angle α acting on the blade element at each radius, the following method can be considered.

FIG. 7A shows the case where the radial distribution of the axial flow velocity v _f is made proportional to the radius, and the optimum elevation angle α is obtained at all radial positions from the hub side radius γ _h to the tip side radius γ _t. It becomes ₀ . In order to realize such an axial flow velocity distribution proportional to the radius, there is a method of providing several cylindrical guide devices 22 before and after the moving blade 5 as shown in FIG. The velocity distribution is formed as shown in the perspective view of FIG. The diameter ratio at both ends of the guide device 22 and the diameter ratio between the guide devices 22 are determined by the axial velocity v
The radial distribution of _f is chosen to be approximately proportional to the radius. As still another example, as shown in FIG. 7C, a method of extending the support boss 14 to the outside of the contraction portion, or as shown in FIG. A possible method is to reduce.

As another method of improving the performance of the rotor blade 5 at each radius, as shown in FIG. 8A, the absolute velocity v ₁ flowing into the rotor blade 5 with a constant axial flow velocity v _f is calculated as follows. By giving an appropriate pre-rotation in the rotation direction of, the optimum attack angle α ₀ can be obtained at all radial positions of the rotor blade 5 from the hub side radius γ _h to the tip side radius γ _t . Therefore, guide vanes held by a one-way clutch that can rotate only in the rotating direction of the moving blade 5 are provided before and after the moving blade 5, and the inflow angle of the guide blade is set to the axial direction (direction of v _f ),
As shown in the velocity diagram in FIG. 8 (b) hub side radius γ _h , (c) average radius γ _m , and (d) tip side radius γ _{t, the} outflow angle is as shown in FIG. The exit angles of (b) α _1h , (c) α _1m , and (d) α _1t should be set. However, the absolute outflow angle from the rotor blade 5 is (b) α _2h , (c) α _2m , (d) α _2t , and even if (c) α _2m ≈ α _{1m at} the average radius γ _m , the hub Since (b) α _2h <α _{1h on} the side and (d) α _2t > α _1t on the tip side, the collision component is generated because the angle does not follow the guide vane angle. In particular, the collision component on the tip side (d) becomes large (Δv _ut >> 0), and a rotational force in the rotating direction of the moving blade is generated in the guide blade, so that the one-way clutch can freely rotate in the rotating direction of the moving blade. It is designed to avoid energy loss due to collision.

As another method for improving the performance of the moving blade 5 at each radius, FIG. 9 (a) shows that the moving blade has an inner diameter 2 near the average radius.
4 and the outer diameter side 24 ', and the twist type moving blades 24, 24' are adopted in which the swing angle of the outer diameter side portion 24 'is smaller than the swing angle of the inner diameter side portion 24. Thus, both portions of the moving blade have the optimum angle of attack α ₀ as shown in FIG. 9B.
An example of the mechanism of the twisted rotor blade is shown in FIG. 9 (c). Inner diameter rotor blade 2
4 and the outer diameter side rotor blade 24 'are coaxial swing shafts 26, 2 respectively.
It swings by two sets of bevel gears 25 and 25 'through 6'. By appropriately combining the gear ratios of the two sets of bevel gears 25 and 25 ′, it is possible to make the swing angle of the outer diameter side moving blade 24 ′ smaller than the swing angle of the inner diameter side moving blade 24. Become. Similar swing can be achieved by the link mechanism of FIG.

Since this turbine swings in the reverse direction, since the blades are symmetrical blades without camber, the blade performance is inferior to that of blades with camber. Therefore, as shown in FIG. 10A, the first half 27 and the second half 2 of the chord of the turbine blade that reversely oscillates in synchronization with the cycle of the reciprocating water flow.
7 ′ is divided into bending blades 27, 27 ′ having a structure in which the swing angle of the latter half portion 27 ′ of the chord is smaller than the swing angle of the front half portion 27 of the chord. Can be improved. The first half 27 of the wing is the bevel gear 25, the second half 2
7'is a swing shaft 2 connected to a bevel gear 25 '.
6,26 'bends and deforms like a hinge.

【Example】

Of the present invention

1. An embodiment of the underwater reversing oscillating blade axial flow turbine for wave power generation according to claim 1 is shown below. FIG. 11 is an overall view of the experimental apparatus. Using the bellows 28, a reciprocating water flow is generated in the contracting section 1 in which the turbine 6 is installed. The swing control mechanism 9 was provided above the upper tank 29 whose liquid surface was opened to the atmospheric pressure, and the reverse swing control of the moving blade 5 and the turbine-generated power were measured. The vertical displacement of the water surface of the tank was detected by a liquid surface displacement gauge and used as a reference for the reverse swing control of the moving blade. FIG. 12 is a detailed view of the turbine body. The reversing swing mechanism of the moving blade 5 adopts the method of using the bevel gear illustrated in FIG.
Is fixedly supported by a casing made of transparent resin using several stays 31. The turbine output shaft 7 and the rotor blade swing control shaft 10 are the swing control mechanism 9 above the tank 29.
Is joined to.

FIG. 13 (a) is a schematic view of the experimental apparatus of the swing control mechanism 9 during a constant torque load operation. A swing control motor 17 installed on a rotating disk fixed to the turbine output shaft 7 swings and rotates the swing control shaft 10 relative to the turbine output shaft 7, and reversely swings the moving blade 5. It is a mechanism to let. The operation of the swing control motor 17 was performed by the radio control device, and the turbine rotation speed was measured by the slit disk 35 and the photocoupler 36. Due to the sliding friction of the wire wound around the friction cylinder 33 fixed to the turbine output shaft 7, the turbine 6 is loaded with a substantially constant torque.
The weight is applied to the wire by the weight 32, and the rotational reaction force is measured by the load cell 34 to calculate the turbine output. Further, the input to the turbine is calculated from the pressure difference ΔP before and after the moving blade and the flow rate. FIG. 13B shows an example of the experimental result. The abscissa represents a value obtained by making the time t dimensionless by the cycle T _c of the reciprocating water flow, and the ordinate represents the rotation speed N, the turbine torque T, the pressure difference ΔP before and after the moving blade, and the turbine output L _t , respectively. The solid line in the figure is the maximum swing angle of the rotor blade θ ₀ = 30 °, and the broken line is θ ₀ =
This is the case of 45 °. In the first half of t / T _{c, the} water flow is from bottom to top, and in the second half, the water flow is from top to bottom. In this turbine, the rotating blade N rotates in one direction regardless of the direction and size of the reciprocating water flow, and it has been proved that the turbine output L _t always obtains positive energy from the reciprocating water flow.

Of the present invention

2. An embodiment in which the turbine output shaft speed described in claim 2 is maintained constant is shown below. FIG. 14 is a schematic diagram of a swing control mechanism and a power measuring unit installed on the upper part of the tank. The turbine output shaft 7 is connected to one end of the one-way clutch 11 via a transmission gear 37, and the other end of the one-way clutch 11 is connected to a rotating shaft of a speed control motor 38. The speed control motor 38 is controlled so as to rotate at a constant rotation speed in synchronization with the commercial frequency. During a period in which the rotation speed of the turbine output shaft 7 becomes lower than the synchronous rotation speed of the speed control motor 38, the one-way clutch 11 is in a free state, and the power transmission between the turbine output shaft 7 and the motor shaft is cut off. The speed control motor 38 consumes a small amount of electric power and rotates as a motor at a synchronous rotation speed. The turbine output is calculated by measuring the reaction torque acting on the speed control motor 38 with the load cell 34. During the period when this torque is positive, the motor is operating as a generator.

[0021]

According to the present invention, ocean wave energy converted into a reciprocating water flow is converted into mechanical energy that rotates in one direction by a turbine equipped with a blade that reciprocally swings in synchronization with the cycle of the reciprocating water flow. Provided is an underwater reversing oscillating blade axial flow turbine for wave power generation, which converts and drives a generator to generate electric power. The DC generator can be driven by this turbine.In addition, a one-way clutch is installed between the turbine output shaft and the generator shaft to drive the induction AC generator controlled at a constant number of revolutions, so that it is always constant. It is possible to generate alternating-current power with a frequency, and to directly transmit power to the power line. This is confirmed by the experimental apparatus shown in the experimental example. Also,

3.

According to the structure of claim 6, the performance of the turbine body can be improved. The power generated by each turbine fluctuates in synchronization with the cycle of the reciprocating water flow, but the power generated by several turbines in parallel is leveled, and the total output of the wave power plant is almost constant. It is expected to obtain AC power output.

[Brief description of the drawings]

FIG. 1 is an overall view of the present submersible turbine showing a first embodiment and a second embodiment of the present invention.

FIG. 2 is a diagram showing a velocity and a fluid force acting on a blade element of a moving blade.

FIG. 3 is a diagram showing a relationship between an axial flow velocity and a blade swing angle.

FIG. 4 is a sectional view of a turbine blade oscillating mechanism using a bevel gear.

5A and 5B are a perspective view and a sectional view showing a swinging method using a link mechanism.

FIG. 6 is a diagram showing a velocity triangle acting on a rotor blade.

FIG. 7 is a sectional view and a perspective view of an axial flow velocity distribution control guide device showing a third embodiment of the present invention.

FIG. 8 is a view showing the operation of the guide vanes showing the fourth embodiment of the present invention.

FIG. 9 is an operational view and a cross-sectional view of a twisted moving blade showing a fifth embodiment of the present invention.

FIG. 10 is an operation view and a cross-sectional view of a bent blade showing a sixth embodiment of the present invention.

FIG. 11 is an overall view of a turbine experimental device.

FIG. 12 is a sectional view of a turbine body and a casing.

13A and 13B are a perspective view of a swing control mechanism and a power measuring device, and a diagram showing experimental results.

FIG. 14 is a cross-sectional view showing the installation of a one-way clutch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Contraction part 2 Funnel structure 4 Reciprocating water flow 5 Blade 6 Axial flow turbine 7 Turbine output shaft 8 Generator 9 Swing control mechanism 10 Blade swing control shaft 11 One-way clutch 22 Guide for axial flow velocity distribution control 23 Pre Guide blade for swirling 24 Twisting blade 27 Bending blade

Claims (6)

[Claims] 1. A structure provided with a contraction section below the sea surface is installed to generate a reciprocating water flow passing through the contraction section in synchronism with the waves of the ocean. A submerged reversing oscillating blade axial flow turbine for wave power generation, which has a moving rotor blade and drives the generator by rotating the turbine rotating shaft in one direction regardless of the direction of reciprocating water flow. 2. When driving an induction AC generator that rotates at a constant rotation speed controlled at a commercial frequency, a one-way clutch is provided between the turbine rotating main shaft (output shaft) and the generator shaft, and the turbine torque is set. Is a positive period during which the generator is driven to generate electricity and the turbine torque is negative,
That is, in the period in which the rotation speed of the turbine becomes slower than the rotation speed of the generator, the transmission of torque is interrupted by the one-way clutch to provide a power transmission device that always keeps the rotation speed of the induction AC generator at a constant rotation speed. The underwater reversing oscillating blade axial flow turbine for wave power generation according to claim 1, wherein 3. The boss ratio is increased so that the turbine blade, which is the target blade and which swings in the reverse direction without torsion in the radial direction, operates at the optimum angle of attack over the entire radius from the hub side to the outer diameter. A cylindrical guide for reducing the peripheral speed difference of the blades and for providing an axial speed distribution proportional to the radius in the casing throttle portions before and after the turbine rotor blade. The submerged reversing oscillating blade axial flow turbine for wave power generation described. 4. A guide vane held by a one-way clutch is provided in front of and behind the turbine rotor blade, and at the inlet of the turbine rotor blade, a pre-swirl is performed in the rotation direction so that the absolute velocity acts at the optimum attack angle over the entire radius of the rotor blade. The guide vane held by the one-way clutch is allowed to idle in the rotational direction of the turbine because the absolute flow velocity collides with the back face of the guide vane at the outlet of the turbine blade.
An underwater reversing oscillating blade axial flow turbine for wave power generation according to any one of 1 to 3 above. 5. A structure in which a moving blade is divided into an inner diameter side and an outer diameter side in the vicinity of an average radius, and the swing angle of the outer diameter side portion is smaller than the swing angle of the inner diameter side portion. 5. The submerged reversing oscillating blade axial flow turbine for wave power generation according to claim 1, wherein the turbine performance is improved by forming a twisted rotor blade such that each portion acts at an optimum angle of attack. 6. A first half and a second half of a chord of a turbine blade that reverse-oscillates in synchronism with the cycle of a reciprocating water flow are divided, and the latter half of the chord is relative to the swing angle of the first half of the chord. The submerged reversing oscillating blade axial flow turbine for wave power generation according to any one of claims 1 to 4, wherein the blade performance is improved by using a bent blade having a structure in which a swing angle of a portion is reduced.