JP2000247288A - Water jet type ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water jet type ship eliminating uneven pressure distribu tion generated at an inlet part of an intake for sucking water. SOLUTION: A lip member 3 with lip shape formed at the outer peripheral surface is rotatably disposed at a ship bottom part 1 downstream of an intake 2 for taking in water for water jet, and a driving device 11 for rotating the lip member 3 to adjust its tip position is disposed in the ship bottom part 1. A first pressure sensor 16 is disposed to detect pressure in the intake 2 downstream of the lip member 3, and a second pressure sensor 17 is disposed to detect pressure outside of a hull downstream of the lip member 3. The driving device 11 for the lip member 3 is controlled on the basis of the detected pressure difference of both pressure sensors 16, 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water jet ship.

[0002]

2. Description of the Related Art Some high-speed boats use a water jet. As shown in FIG. 4, a water inlet 52 for taking in water for water jet is provided at a bottom 51 of such a high-speed boat. Is provided. By the way, the shape of the water intake 52 is determined by the IVR calculated from the ship speed and the suction speed at which the water jet pump operates most frequently.
(Expressed as pump suction speed / ship speed, also referred to as ship speed / velocity ratio) and the pressure distribution and cavitation generated at the lip, which is the inlet of the water intake, determined to maximize propulsion efficiency It had been.

[0003]

As described above, the intake 52
Is calculated in consideration of the IVR, pressure distribution, and cavitation. However, in actual operation, many transient states of acceleration and deceleration occur, and the design is affected by disturbances such as wind and waves. There is a problem that matching is difficult.

For example, when the intake port shape and the design IVR match, as shown in FIG. 5, a stagnation point S just occurs at the tip of the lip 53 of the intake 52, and near the lip 53, A uniform positive pressure distribution is provided over the upper and lower portions, so that water suction efficiency is improved and cavitation is prevented from occurring. However, as shown in FIG. 6, when the navigation IVR becomes smaller than the design IVR, the stagnation point S moves (occurs) to the upper surface side of the lip portion 53, so that the lower surface side of the lip portion 53 has a negative pressure. And the pressure distribution becomes non-uniform and cavitation occurs. Also, as shown in FIG. 7, when the IVR during navigation becomes larger than the design IVR, the stagnation point S moves (occurs) to the lower surface side of the lip portion 53, and the upper surface side of the lip portion 53 also becomes negative pressure. As a result, the pressure distribution becomes non-uniform.

As described above, when the stagnation point generated at the lip portion of the water intake, that is, at the inlet portion, is shifted to the upper surface side or the lower surface side, the pressure distribution at the inlet portion becomes uneven, the water suction efficiency is deteriorated, and the cavitation is reduced. Occurs,
Accordingly, there is a problem that the propulsion performance is reduced and the fatigue of the hull structure is adversely affected. Therefore,
SUMMARY OF THE INVENTION It is an object of the present invention to provide a water jet ship that can eliminate uneven pressure distribution generated at an inlet of a water intake port.

[0006]

In order to solve the above problems, a first means of the present invention is a ship having a water jet intake and being propelled by a water jet pump. A lip member having a lip shape formed on the outer peripheral surface is rotatably arranged on the bottom of the ship on the downstream side, and a drive device for rotating the lip member and adjusting the tip position thereof is arranged in the bottom of the ship. A first pressure sensor that detects a pressure in an intake port downstream of the lip member, and a second pressure sensor that detects a pressure outside the hull downstream of the lip member,
This is a water jet type marine vessel configured to control the driving device of the lip member based on the pressure difference detected by these two pressure sensors.

A second means of the present invention is a watercraft having a water jet intake and being propelled by a water jet pump, wherein a horizontal portion is provided on a bottom of the ship corresponding to a downstream lip portion of the intake. A flexible plate-like member in which long and narrow plate members are connected to each other in a bendable manner is arranged, and the outer periphery of the plate-like member is covered with a water-tight film-like material, and the position of the projecting tip of the plate-like member is adjusted. And a differential pressure detecting device for detecting a pressure difference between an inner surface and an outer pressure of the water intake in the vicinity of the plate-like member is provided, and the detected pressure from the differential pressure detecting device is detected. A water jet type vessel configured to control the tip position adjusting device on the basis of the above-mentioned tip position adjusting device; A moving member provided movably in the front-rear direction is, attached to the end of the moving body is obtained by construction of the roller body in contact with the inner surface of the plate-like member.

In each of the above constructions, the lip member is rotated upward or downward in accordance with the pressure difference between the inner surface and the outer surface of the water intake, or the tip of the flexible plate member is moved upward or downward. By moving, the pressure distribution in the lip portion can be made uniform, and therefore, a reduction in the suction efficiency into the water intake and the occurrence of cavitation can be prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A water jet type marine vessel according to a first embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1 and FIG. 2, a water intake 2 for taking in water for water jet is formed in a bottom 1 of a high-speed boat (an example of a ship), and a water intake 2 downstream of an inlet of the water intake 2. A cutout 1a is formed in the side portion.

A lip member 3 having an oval cross section (not limited to an oval shape) having a predetermined lip shape formed on the front outer peripheral surface is provided in the ship bottom 1. Is rotatably provided by a bearing 4 via a horizontal support shaft 3a provided in the hull width direction so as to protrude from the notch 1a. Of course, although not shown, the mounting portion of the lip member 3 to the ship bottom 1 has a watertight structure, and is provided with, for example, a packing material and a partition wall.

The lip member 3 is provided in the bottom 1 of the ship.
Is provided around the horizontal axis to adjust the position of the protruding tip, that is, the position of the lip tip substantially vertically. This driving device 11
A drive gear 13 meshing with a gear portion 12 comprising teeth provided on a rear outer peripheral surface of the lip member 3;
A rotation drive unit (for example, a hydraulic motor, an electric motor, or the like is used) 14 for rotating the motor, and a control unit 15 therefor.

Further, a first pressure sensor 16 for detecting the water pressure in the intake port 2 is provided at the bottom of the ship (inside of the intake port) 1 downstream of the lip member 3 and downstream of the lip member 3. A second pressure sensor 17 for detecting the water pressure outside the intake port 2 is provided on the outer surface of the hull (outside surface of the intake port), and the detected pressures from these two pressure sensors 16, 17 are sent to the control unit 15. The rotational drive unit 14 is input and controlled based on the pressure difference.

That is, when the IVR during navigation is smaller than the design IVR, the stagnation point moves to the upper surface side of the lip member 3 (inside of the water intake), and the lower surface side of the lip member 3 (the water intake). Negative pressure occurs on the outer side). In this case, the detection pressure of the first pressure sensor 16 is higher than that of the second pressure sensor 17, and the control unit 15 rotates the lip member 3 in the direction of arrow a in FIG. Then, the lip tip position is moved upward.

Then, the flow of seawater near the intake 2 is
Guided to the outer surface of the lip member 3, the pressure at the deep position of the water intake 2 is reduced, and the pressure at the outer surface of the lip member 3 is increased. [It is also called a C ^P distribution, and P / (ρU ² /
(Represented by 2)) (the stagnation point returns to an appropriate position), thereby preventing a reduction in the suction efficiency into the water intake port 2 and the occurrence of cavitation.

[0015] On the contrary, the IV
When R is larger than the design IVR, the stagnation point moves to the lower surface side of the lip member 3, and a negative pressure is generated on the upper surface side of the lip member 3. When this is detected by the control unit 15, the lip member 3 is rotated in the direction of the arrow b in FIG. 1, and the lip tip position is moved downward. Then, the flow of seawater near the water intake 2 is guided to the upper surface side of the lip member 3, so that the pressure on the outer surface side of the ship bottom 1 is reduced, and the pressure increases on the upper surface side of the lip member 3, Therefore, the pressure distribution on the upper and lower surfaces of the lip member 3 is made uniform, and the reduction of the suction efficiency into the water intake port 2 and the occurrence of cavitation are prevented.

The relationship between the pressure difference on the upper surface side and the lower surface side of the lip member 3 and the position of the tip of the lip for eliminating the pressure difference (in a broad sense, for obtaining an appropriate value). Are obtained in advance through experiments or the like, and the data is input to the control unit 15. in this way,
When a pressure difference is generated between the inner and outer surfaces of the water intake port 2, that is, when the stagnation point is shifted from the lip tip position to either side, the lip member 3 is rotated in a direction in which the pressure difference disappears,
Since the pressure distribution on the upper and lower surfaces of the lip member 3 is made uniform, the reduction of the suction efficiency into the water intake port 2 and the occurrence of cavitation are prevented.

Next, a water jet ship according to a second embodiment of the present invention will be described with reference to FIG. In the first embodiment, the position of the lip tip is adjusted by rotating the lip member. On the other hand, in the second embodiment, the lip portion is made flexible. And the position of the protruding tip can be adjusted from the inside.

That is, the notch (opening) 2 is formed in the bottom 21 corresponding to the downstream portion which is the lip portion of the water intake 22.
1a, and a flexible plate-like member (having the same structure as a wind-up shutter) formed by connecting a plurality of horizontally elongated plate members 31 to the notch portion 21a so as to be bendable with each other. ) 32 is attached, the outer surface of the plate-like member 32 is covered with a water-tight film-like material 33, and a tip position adjusting device 34 capable of adjusting the position of the projecting tip of the plate-like member 32 is provided in the ship bottom 21. Are located in

The tip position adjusting device 34 is mounted on the bottom 21 of the ship.
Elevating body 4 provided on a vertical guide rod 41 so as to be able to move up and down
2 and a horizontal guide rod 4 attached to the lift 42
3, a movable body 44 provided movably in the front-rear direction, a roller body 45 attached to the tip of the movable body 44 and in contact with the inner surface of the plate-shaped member 32, and the elevating body 42 and the elevating body 44 And a control unit 46 for controlling the amount and the amount of movement. It should be noted that various driving methods such as a rack and pinion method or a linear driving method can be considered as the driving method of the elevating body 42 and the moving body 44.

A plate-like member 32 is provided in the bottom 21 of the ship.
A differential pressure detecting device 47 for detecting a pressure difference between the inner surface side and the outer surface side of the nearby water intake port 22 is provided.
The detection pressure difference detected at 7 is input to the control unit 46. Further, the differential pressure detecting device 47
Is disposed between, for example, the upper and lower edges of the notch 21a of the ship bottom 21 so as to detect a force acting on a rod-shaped detection member 48 disposed between both edges. Of course, in this case, the upper and lower edges of the notch 21a are deformed according to the water pressure.

As in the first embodiment, the pressure difference between the upper surface and the lower surface of the plate-like member 32 and the pressure difference between the plate member 32 and the plate member 32 are set so as to eliminate the pressure difference (to obtain an appropriate value). The relationship with the lip tip position is determined in advance by experiments or the like, and the data is input to the control unit 46.
In the above configuration, when the stagnation point moves to the upper surface side (the back side of the water intake) of the plate-shaped member 32 which is the lip portion, the pressure difference from the differential pressure detecting device 47 is input to the control unit 46, and The position control signal corresponding to this pressure difference is transmitted to the lifting body 4
2 and the moving body 44, and the roller body 45 at the tip is output.
Is moved upward, and the lip tip position is moved to a predetermined upper position.

Then, the flow of the seawater near the water intake 22 is guided to the outer surface side of the plate-like member 32, and the pressure at the deep position of the water intake 22 is reduced. Pressure on the upper and lower surfaces at the lip portion [also called C _P distribution, P / (ρ
U ^2/2 uniformly is attained (stagnation point represented] in) is returned to a proper position), the occurrence of reduction and cavitation of the suction efficiency of the intake port 2 is prevented.

Contrary to the above, the IV during navigation is
When R is larger than the design IVR, the control unit 46 drives the elevating body 42 and the moving body 44 based on the pressure difference from the differential pressure detecting device 47, so that the roller body 45 at the front end is moved. By moving downward, the lip tip position is moved to a predetermined lower position. Then, the flow of the seawater near the intake port 22 is guided to the upper surface side of the plate-shaped member 32, so that the pressure on the outer surface side of the ship bottom 21 is reduced,
The pressure increases on the upper surface side of the plate-like member 32, and therefore, the pressure distribution on the upper and lower surfaces of the lip portion is made uniform,
A reduction in suction efficiency into the water intake 2 and the occurrence of cavitation are prevented.

By the way, in the first embodiment, the rotation drive unit is used to rotate the lip member. However, the lip member can be rotated by, for example, a hydraulic cylinder. Further, in the second embodiment, the differential pressure detecting device is provided. However, similarly to the first embodiment, the pressure sensors are arranged at the upper and lower positions of the notch, respectively, and the detected pressures of the two pressure sensors are detected. May be obtained by calculation.

Further, in the second embodiment, as the flexible plate member disposed at the lip portion, a plurality of elongated plate members connected in a bendable manner have been described.
For example, a thin stainless steel plate can be used.

[0026]

As described above, according to the configuration of each water jet type ship of the present invention, a lip member having a lip shape formed on the outer peripheral surface is provided on the downstream side of the intake port and on the inner surface side of the intake port and on the downstream side of the intake port. Rotation according to the pressure difference on the outer surface side, or adjustment of the projecting position of the plate-shaped member corresponding to the lip tip position of the lip portion, so that the lip tip The pressure distribution in the vicinity can be made uniform, so that the suction efficiency to the intake port and the occurrence of cavitation can be prevented. That is, it is possible to prevent a decrease in propulsion performance and to prevent a bad influence on fatigue of the hull structure.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a water jet type watercraft according to a first embodiment of the present invention, illustrating a vicinity of an intake port.

FIG. 2 is a view as viewed in the direction of arrows AA in FIG. 1;

FIG. 3 is a cross-sectional view near a water intake of a water jet type boat according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a hull bottom showing a water intake port of a ship in a conventional example.

FIG. 5 is a cross-sectional view of a main part showing an operation of a water intake in a conventional example.

FIG. 6 is a cross-sectional view of a main part showing an operation of a water intake in a conventional example.

FIG. 7 is a cross-sectional view of a main part showing an operation of a water intake in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ship bottom part 1a Notch part 2 Intake port 3 Lip member 11 Drive device 14 Rotation drive part 15 Control part 16 First pressure sensor 17 Second pressure sensor 21 Ship bottom part 21a Notch part 22 Water intake 31 Plate body 32 Flexible plate shape Member 33 Film-like body 34 Tip position adjusting device 42 Elevating body 44 Moving body 45 Roller body 46 Control unit 47 Differential pressure detecting device

Claims (3)

[Claims] 1. A marine vessel having a water jet intake port and propelled by a water jet pump, wherein a lip member having a lip shape formed on an outer peripheral surface is rotated at a bottom portion of a ship downstream of the intake port. A first pressure sensor for detecting the pressure in the water intake downstream of the lip member, wherein a drive device for rotating the lip member and adjusting the position of the tip thereof is disposed in the bottom of the ship. And a second pressure sensor for detecting a pressure outside the hull downstream of the lip member, and controlling a driving device of the lip member based on a difference between the detected pressures from the two pressure sensors. A water jet ship characterized by the following. 2. A watercraft having a water jet intake and propelled by a water jet pump, wherein a horizontally elongated plate is bent at a bottom portion corresponding to a downstream lip portion of the intake. A flexible plate-shaped member connected to the plate-shaped member is arranged, and the outer periphery of the plate-shaped member is covered with a water-tight film-like material. And a differential pressure detecting device for detecting a pressure difference between an inner surface and an outer pressure of the water intake in the vicinity of the plate-shaped member, and controlling the tip position adjusting device based on the detected pressure from the differential pressure detecting device. A water jet ship characterized by having a configuration as described above. 3. A tip position adjusting device comprising: an elevating body provided so as to be able to ascend and descend within a bottom of a ship; a moving body provided in the elevating body and provided so as to be movable in the front-rear direction; 3. A water jet type marine vessel according to claim 2, wherein said water jet type marine vessel is provided with a roller body which is attached and comes into contact with an inner surface of said plate-shaped member.