JPH0521517Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a ship equipped with a stern flow field rectifier that is capable of rectifying the flow of water flowing into the screw propeller along the stern shell.

[Prior Art] When the stern of a ship becomes enlarged, as shown in FIG. There is a problem in that bilge vortices are generated and increase hull resistance.

Note that in FIG. 11, reference numeral 16 indicates a water line.

Therefore, in order to solve the above-mentioned problem, a concave part has been formed in the bilge part in order to prevent the generation of bilge vortices due to the separation of water flow along the outer skin of the hull. A ship equipped with a stern flow field rectifying device has been proposed, in which a rotating cylinder for accelerating the flow is installed in the recess.

In the above-mentioned ship equipped with the stern flow field rectifier, the rotation of the above-mentioned rotating cylinder accelerates the flow between the ship side and the bottom of the ship, prevents the generation of bilge vortices, and reduces the hull resistance. , course stability is also improved.

[Problem that the invention attempts to solve]

By the way, in ships equipped with such conventional stern flow field rectifiers, hull resistance is reduced, but
At the same time, the flow in the stern bilge section 5 is accelerated by the rotating cylinder, so the speed of the flow flowing into the screw propeller 21 increases.

Here, the propulsion efficiency η of a ship's screw propeller is generally defined as η _H = (1-t)/(1-w), where t in the above equation is the thrust reduction rate, w
is a wake coefficient, and this wake coefficient w becomes smaller as the speed of the flow flowing into the screw propeller increases.

Therefore, as the flow of water flowing into the screw propeller 21 is accelerated by the rotating cylinder, the wake coefficient w becomes smaller, and the propulsion efficiency η _H decreases. There is a problem in that the propulsion performance of conventional vessels equipped with a stern flow field rectifier is not necessarily improved.

Furthermore, in the above-mentioned ship equipped with a stern flow field rectifier, a recess is formed in the bilge part of the hull, and
Since the rotating cylinder is mounted in the recess, the structure is complicated, and there is also the problem that manufacturing and maintenance require a great deal of labor and expense.

The present invention aims to solve these problems by controlling the flow of outside water between the ship's side and the bottom of the ship at the stern of the ship in an asymmetrical manner to the port and starboard sides, thereby preventing the generation of bilge vortices. Equipped with a stern flow field rectifier that reduces hull resistance and gives a rotational component in the opposite direction to the rotational direction of the screw propeller to the flow flowing into the screw propeller, improving the propulsion efficiency of the ship. The purpose is to provide ships.

[Means for solving problems]

For this reason, the ship equipped with the stern flow field rectifier of the present invention has the bilge parts on the port and starboard sides of the stern exposed to the outside water in order to prevent the generation of bilge vortices due to separation of the water flow along the hull outer plate. An open water accelerator consisting of a pair of electrodes installed spaced apart from each other along the bilge on the port and starboard sides of the stern, and a superconducting magnet for driving open water that is energized between these electrodes. is provided, and the water accelerator is arranged asymmetrically on the port and starboard sides so that the flow flowing into the stern screw propeller through the electrodes generates a rotational component in the opposite direction to the rotational direction of the screw propeller. A control system is provided to operate the control system, and the control system includes a sensor that detects the flow velocity of the flow flowing from the outside water accelerator to the screw propeller, and a detection signal from the sensor and a preset setting value. The present invention is characterized in that it is comprised of a computing unit that calculates the operating state of the open water accelerator based on the above, and a controller that sends a control signal to the open water accelerator based on the calculation result from the computing unit.

[Effect]

In the above-mentioned ship equipped with the stern flow field rectifier of the present invention, the open water that is energized between the pair of electrodes is driven by the magnetic field generated by the superconducting magnet, so the open water is accelerated and rectified in the above-mentioned open water accelerator. Been,
The generation of bilge vortices is prevented.

In addition, the superconducting magnet is controlled by the control system, and the magnetic field generated by the superconducting magnet is adjusted asymmetrically between the port and starboard sides, so that the open water accelerator operates asymmetrically, so that the water flows into the ship's screw propeller. A rotational component in the direction opposite to the direction of rotation of the screw propeller is given to the flow.

〔Example〕

Hereinafter, embodiments of the present invention will be explained with reference to the drawings. Figures 1 to 7 show a ship equipped with a stern flow field rectifying device as a first embodiment of the present invention.
The figure is a perspective view schematically showing the stern section below the water surface, Figure 2 is a sectional view taken along the - arrow in Figure 1, Figure 3 is an illustration of its operation, and Figure 4 is a block diagram for explaining its control system. Figure 5 is a side view of the stern section, Figure 6 is a sectional view taken along the - arrow in Figure 5, and Figures 7 a and b.
is a flow velocity vector distribution diagram for explaining the state of inflow into the screw propeller when each of the open water accelerators is inactive and in operation.

Note that the reference numerals already mentioned in the drawings indicate almost the same parts.

As shown in FIGS. 1 and 2, in a ship in which the screw propeller 21 rotates in the direction 21n (see FIG. 5), that is, in the clockwise direction when viewed from the rear of the stern, the bottom 2 of the stern 1 and the ship's side 3, a pair of electrodes 8a, 8b and 8 are provided on the port and starboard sides, respectively.
a' and 8b' are provided along the bilge portion 5 at intervals in the front and back so that they are exposed to the outside water.

These electrodes 8a, 8b and 8a', 8b' are
It is electrically insulated from the hull outer panel 9 and is formed to follow the surface shape of the hull outer panel 9 of the bilge portion 5 .

Further, as shown in FIG. 5, the above electrodes 8a,
8b and between the electrodes 8a', 8b' and flowing into the rotating surface 23 of the screw propeller 21. The positions of electrodes 8a, 8b and 8a', 8b' are determined.

Further, each electrode 8a, 8b and 8a', 8
b' is connected to a power source (not shown) provided inside the hull, and positive voltage is applied to electrodes 8a and 8a'.
A negative voltage is applied to the electrodes 8b, 8b'.

On the other hand, between the electrodes 8a and 8b and the electrode 8
A superconducting magnet 11 is disposed in the hull interior 10 of the bilge portion 5 between a' and 8b' in close proximity to the hull outer plate 9, and each superconducting magnet 1
1 is connected to a power source (not shown) provided inside the hull.

The pair of electrodes 8a, 8b and the superconducting magnet 11 constitute a port-side open water accelerator 30, and the electrodes 8a', 8b' and the superconducting magnet 11 constitute a starboard-side open water accelerator 30'. Ru.

In addition, the above-mentioned external water accelerators 30, 30' have a fourth
As shown in the figure, it is connected to a control system 40 consisting of a setting device 35, a sensor 36, an arithmetic unit 37, and a controller 38.

As shown in FIG.
The outer water accelerators 30, 3 are provided further forward.
0' to the screw propeller 21 can be detected.

Furthermore, the control system 40 separately adjusts the currents flowing through the superconducting magnets 11 and 11 of the open water accelerators 30 and 30' based on the set value in the setting device 35, thereby controlling the current generated in these superconducting magnets 11. The magnetic field can be adjusted asymmetrically to port and starboard.

Since the ship equipped with a stern flow field rectifying device as the first embodiment of the present invention is configured as described above,
In the open water between the electrodes 8a and 8b on the port side, a current flows in the direction indicated by reference numeral 12 in FIG.

Furthermore, when the superconducting magnet 11 is energized near the electrodes 8a and 8b, a magnetic field is generated in the direction of reference numeral 13 shown in FIG. 2.

Therefore, the external water energized between the electrodes 8a and 8b has a reference numeral 14 shown in FIG.
A force is applied in the direction of , and as a result, the water flow that goes around from the bottom 2 to the ship side 3 is driven and accelerated by the external water accelerator 30 on the port side, and as shown in Fig. 3, there is no bilge vortex. It becomes flow 24.

Also, due to the open water accelerator 30' on the starboard side,
In the same manner as on the port side, the flow of water going around from the bottom 2 to the side 3 of the ship is driven and accelerated.

By the way, the flow 24' flowing from the starboard side open water accelerator 30' to the screw propeller 21 flows from the port side open water accelerator 30 to the screw propeller 21.
1, the operation of the external water accelerators 30, 30' is adjusted asymmetrically on the port and starboard sides by the control system 40 in the following manner.

That is, first, the sensor 36 detects the flow velocity of the flows 24, 24' flowing into the screw propeller 21 from the port and starboard open water accelerators 30, 30', and the detection signal is sent to the computing unit 37.

Next, based on this detection signal and the set value set in the setter 35, the calculator 37 calculates the appropriate operating state of the outside water accelerators 30, 30'.

Furthermore, based on this calculation result, in order to accelerate the flow faster in the outer water accelerator 30' on the starboard side than the outer water accelerator 30 on the port side, a control signal from the controller 38 is used to magnet 11
The current flowing through the superconducting magnet 11 on the starboard side is adjusted as appropriate so that it becomes larger than the superconducting magnet 11 on the starboard side.

As described above, as shown in FIG.
The flow 24' flowing into the outer water accelerator 3 on the port side
Flow 2 accelerated by 0 and flowing into the rotating surface 23
4, a flow from starboard to port occurs above the propeller shaft 20 on the rotating surface 23, as shown in FIG.

As a result, in the ship equipped with the stern flow field rectifier as the first embodiment of the present invention described above, the open water accelerator 3
0 and 30' are not operated, as shown in FIG. As shown in FIG. 7b, the screw propeller 21 has a rotational component in a direction opposite to the rotational direction 21n of the screw propeller 21.

Therefore, the rotational energy dissipated in the wake of the screw propeller 21 is recovered, and the propulsion efficiency of the ship can be increased.

Furthermore, since the open water accelerators 30 and 30' prevent flow separation occurring in the bilge portion 5, hull resistance is reduced and the course stability of the ship is also improved.

Since the superconducting magnet 11 is used as the electromagnet required for the open water accelerators 30, 30', a strong magnetic field can be obtained efficiently and power consumption can be reduced.

In the figure, reference numeral 22 indicates a rudder, 25 indicates a rotation locus of the tip of the screw propeller 21, and 27 indicates a hull centerline.

Next, Figures 8 to 10 show a ship equipped with a stern flow field rectifying device as a second embodiment of the present invention, and Figure 8 is a perspective view schematically showing the stern section of the ship under water. The figure is a side view of the stern part, and FIG. 10 is a flow velocity vector distribution diagram for explaining the state of flow into the screw propeller when the open water accelerator is in operation.

In the second embodiment of the present invention, as shown in FIGS. 8 and 9, the bilge part 5 that forms the boundary between the bottom 2 and the ship's side 3 of the stern part 1 has a space between the front and back on the port side. A pair of electrodes 8a, 8b spaced apart
An open water accelerator 31 consisting of a superconducting magnet 11 (see Fig. 2) is provided, and on its starboard side,
An open water accelerator 31' is provided in the bilge portion 5, and includes a pair of electrodes 8a' and 8b' spaced apart from each other and a superconducting magnet 11.

In addition, electrodes 8c, 8d and 8 are arranged in the bilge part 5 further back of the open water accelerators 31, 31' on both the port and starboard sides, respectively, at intervals in the front and back.
There are provided external water accelerators 32 and 32' consisting of c' and 8d' and superconducting magnets 11 and 11.

The flows 24a, 24a' accelerated by the above-mentioned external water accelerators 31, 31' and flowing into the rotating surface 23 of the screw propeller 21 flow into the upper part of the rotating surface 23, and flow into the external water accelerators 32, 32'. The flows 24b and 24b' accelerated by
The external water accelerator 31,
The positions of 31', 32, and 32' are determined.

Furthermore, each external water accelerator 31, 31', 32,
32' is a control system 40 similar to the first embodiment.
(see FIG. 4), and its operating state is adjusted asymmetrically by the control system 40.

Note that the rotation direction 21 of the screw propeller 21
n is the same direction as in the case of the ship in the first embodiment.

A ship equipped with a stern flow field rectifying device as a second embodiment of the present invention is constructed as described above.
The outer water accelerator 32 on the port side and the outer water accelerator 31' on the starboard side are controlled by the control system 40 and are operated in the direction of accelerating the flow from the bottom 2 to the side 3 of the ship.

At the same time, the outer water accelerator 31 on the port side
The outer water accelerator 32′ on the starboard side is controlled by the control system 40.
The external water accelerators 31' and 32 are controlled by
It is operated in the opposite direction, that is, in the direction of decelerating the flow flowing from the bottom 2 to the side 3 of the ship.

As a result, the flows 24b and 24a' accelerated by the external water accelerator 32 on the port side and the external water accelerator 31' on the starboard side flow into the lower port side and the upper side of the starboard side of the rotating surface 23, respectively, and flow to the outer side of the port side. Flows 24a and 24b' decelerated by the water accelerator 31 and the starboard side external water accelerator 32' flow into the upper port side and the lower starboard side of the rotating surface 23, respectively.

In this way, as shown in FIG. 10, the flow flowing into the screw propeller 21 is caused to flow in the opposite direction to the rotational direction 21n of the screw propeller 21 due to the operation of the external water accelerators 31, 31', 32, and 32'. It has a rotational component in the direction.

Therefore, also in the second embodiment of the present invention,
As in the first embodiment, the rotational energy dissipated in the wake of the screw propeller 21 is recovered, which increases the propulsion efficiency of the ship. Since separation is prevented, hull resistance is reduced and course stability is improved.

In addition, in the ship equipped with the stern flow field rectifier as the second embodiment of the present invention described above, the open water accelerator 31 on the port side and the open water accelerator 32' on the starboard side are larger than the above-mentioned open water accelerators 31' and 32. The water accelerators 31', 32 may be operated in the same direction as the water accelerators 31', 32 to accelerate the flow to lower velocities, resulting in substantially the same effect.

In addition, in the ship equipped with the stern flow field rectifier of the present invention, three or more open water accelerators are arranged in series in the bilge sections 5 on both the port and starboard sides, and these open water accelerators are connected to the control system 40 (see Fig. 4). (see) may be controlled asymmetrically.

[Effect of idea]

As described in detail above, in the ship equipped with the stern flow field rectifier of the present invention, in order to prevent the generation of bilge vortices due to separation of the water flow along the hull outer plating, the external a pair of electrodes installed along the bilge portions of the port and starboard sides of the stern at intervals, respectively, so as to be exposed to water;
An open water accelerator consisting of a superconducting magnet for driving open water that is energized between these electrodes is provided, and the flow flowing into the screw propeller at the stern through the above electrodes is driven by the same screw propeller. A control system is provided that operates the external water accelerator asymmetrically on the port and starboard sides so as to generate a rotational component in the opposite direction to the rotational direction of the U propeller, and the control system operates the external water accelerator from the external water accelerator to the screw propeller. A sensor that detects the flow velocity of the inflowing flow, a calculation unit that calculates the operating state of the external water accelerator based on the detection signal from the sensor and a preset setting value, and a calculation result from the calculation unit. It has a simple configuration consisting of a controller that sends control signals to the external water accelerator based on , the propulsion efficiency of ships can be greatly increased.

Furthermore, by using a superconducting magnet as an electromagnet in an open water accelerator, a strong magnetic field can be efficiently obtained, which has the advantage of reducing power consumption.

In addition, it is now possible to prevent the generation of bilge vortices due to separation of water flow in the stern bilge of the ship, which reduces hull resistance and improves the ship's course stability, improving the ship's propulsion performance. There are also benefits that can be improved.

Furthermore, since the above-mentioned ship equipped with a stern flow field rectifying device has an extremely simple structure, the labor and costs involved in its manufacture and maintenance can be significantly reduced.

[Brief explanation of the drawing]

Figures 1 to 7 show a ship equipped with a stern flow field straightening device as a first embodiment of the present invention, in which Figure 1 is a perspective view showing the underwater stern section, Figure 2 is a cross-sectional view of Figure 1 taken along the arrow, Figure 3 is an explanatory diagram of the operation, Figure 4 is a block diagram for explaining the control system, Figure 5 is a side view of the stern section, Figure 6 is a cross-sectional view of Figure 5 taken along the arrow, Figures 7a and 7b are flow velocity vector distribution diagrams for explaining the inflow state into the screw propeller when the external water accelerator is not in operation and when it is in operation, respectively, and Figures 8 to 10 show a ship equipped with a stern flow field straightening device as a second embodiment of the present invention, in which Figure 8 is a perspective view showing the underwater stern section of the ship, Figure 9 is a side view of the stern, and Figure 10 is a flow velocity vector distribution diagram for explaining the inflow state into the screw propeller when the external water accelerator is in operation.
FIG. 11 is a perspective view showing a typical underwater stern of a conventional ship. 1: stern; 2: ship bottom; 3: ship side; 4:
...flow, 5...bilge section, 8a, 8b, 8c, 8
d, 8a', 8b', 8c', 8d'...electrodes, 9...hull shell, 10...hull interior, 11...superconducting magnet, 16...waterline, 20...propeller shaft, 21
...Screw propeller, 21n...Rotation direction of screw propeller, 22...Rudder, 23...Rotation plane of screw propeller, 24, 24', 24a,
24b, 24a', 24b'...flow, 25...rotation path of the screw propeller tip, 27...hull centerline, 30, 30', 31, 31', 32, 32'
. . . External water accelerator, 35 . . . setting device, 36 . . . sensor, 37 . . . computing device, 38 . . . controller, 40 . . .
Control system.

Claims (1)

[Scope of utility model registration request] In order to prevent the generation of bilge vortices due to the separation of the water flow along the outer skin of the hull, the bilge parts on the port and starboard sides of the stern are spaced in front and behind each other so as to be exposed to the outside water. An open water accelerator is provided, which consists of a pair of electrodes installed with a gap between them, and a superconducting magnet for driving open water that is energized between these electrodes. A control system is provided to operate the external water accelerator asymmetrically on the port and starboard sides so that the flow flowing into the screw propeller generates a rotational component in the opposite direction to the rotation direction of the screw propeller. , a sensor that detects the flow velocity of the flow flowing from the outside water accelerator to the screw propeller, and a state in which the outside water accelerator should be operated is calculated based on a detection signal from the sensor and a preset setting value. A ship equipped with a stern flow field rectifier, characterized in that it is comprised of a computing unit and a controller that sends a control signal to the open water accelerator based on the calculation result from the computing unit.