JP4781521B2 - High speed ship sea chest - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sea chest provided in a ship, and more particularly to a sea chest suitable for a high-speed ship.
[0002]
[Prior art]
As shown in FIG. 4, the sea chest 1 provided in the ship in order to take in the seawater necessary for the ship during navigation is formed by a box-shaped depression formed in the bottom of the ship. The water is obtained by pumping the seawater in the sea chest 1 through a water intake pipe 2 connected to the sea chest 1.
[0003]
However, as the ship speed increases and the flow of seawater at the bottom of the ship increases, the amount of seawater entering the inside of the sea chest 1 from the ship bottom increases with respect to the flow rate pumped by the pump. A large vortex as indicated by an arrow in FIG. 4B is generated. And this vortex causes vibration and sometimes breaks the sea chest.
[0004]
On the other hand, for the purpose of preventing the inflow of dust into the sea chest, a grid 3 such as punching metal is often attached to the opening 1a of the sea chest 1 provided on the bottom of the ship, as shown in FIG. In this case, with the increase in the speed of the seawater flow outside the hull, the amount of seawater entering the inside of the sea chest 1 from the bottom of the ship due to the presence of the grid 3 is insufficient, and the internal pressure of the sea chest 1 decreases. When the internal pressure of the sea chest 1 becomes a negative pressure exceeding the performance of the pump, it is impossible to take in a necessary amount of cooling water, which hinders the operation of the high-speed ship itself.
[0005]
Therefore, in order to solve such a problem, as shown in FIG. 6, a baffle plate 4 is provided from the bottom of the stern side of the sea chest 1 in order to increase the dynamic pressure inside the sea chest 1. As shown in FIG. 7, the shape of the sea chest itself is changed from a box shape to a scoop shape often found in a water jet intake.
[0006]
[Problems to be solved by the invention]
However, when the baffle plate is provided, the ship speed decreases due to the dynamic pressure acting on the baffle plate, the joint portion of the baffle plate to the ship bottom is damaged by the dynamic pressure, and further, the rear of the baffle plate Cavitation tends to occur. These problems will seriously affect the propulsion performance of high-speed ships, and the severity of these effects will increase as the ship speed increases.
[0007]
In addition, adopting a scoop shape having a large curved surface structure for all the sea chests provided on a single ship necessitates a longer work period as the number of production steps increases.
[0008]
The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a sea chest capable of stably taking in seawater without adversely affecting propulsion performance particularly in a high-speed ship. .
[0009]
[Means for Solving the Problems]
In order to achieve the above-described object, a high-speed ship sea chest according to the present invention has an opening portion of a sea chest formed by a box-shaped depression provided at the bottom of the ship, and one radial surface is directed to the deck direction of the hull. An arrangement in which the other radial surface faces the bow direction and the outer circumferential arc surface faces downward in the stern direction, the other radial surface facing the bow direction has an angle of 5 to 20 degrees with respect to the height direction of the hull. A plurality of rods obtained by rotating the outer peripheral circular arc surface in the bow direction about the intersection of the one and the other radial surfaces so that the cylinder is divided into ¼ equal in the cross-sectional direction , the central axis There is parallel to the ship width direction, and the outer peripheral end face is and kites arranged palisade so that the vessel bottom and the same plane. By doing so, it becomes possible to take in stable seawater without adversely affecting the propulsion performance particularly in a high-speed ship.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
High speed ship sea chest Ru engaged to the invention, provided in the vessel bottom, the opening of the sea chest, which is formed by the recesses of the box-shaped, the deck direction of one of the radial surfaces hull, the bow direction the other radial surface And the other radial surface facing the bow direction has an angle of 5 to 20 degrees with respect to the height direction of the hull. The outer circular arc surface is rotated in the bow direction around the intersection of the two radial surfaces and the other, and the bar is divided into quarters in the cross-sectional direction, and the central axis is parallel to the ship width direction. And it arrange | positions in the shape of a fence so that an outer peripheral end surface may become the same surface as a ship bottom.
[0012]
According to engagement Ru high speed vessels sea chest to the present invention described above, by the flow along each arc such as to induce seawater within the sea chest is formed in the opening of the sea chest, boat speed of the ship Even at high speed, the flow of seawater from the bottom of the ship to the inside of the sea chest is stably supplied.
[0013]
Moreover, (the radius surface facing the bow direction at high speed ship sea chest Ru engages the present invention) arc portion located at the bow side take dynamic pressure of the vessel bottom stream so does not project from the ship's bottom, fast flow in the perpendicular direction There is no collision and the propulsion performance of the ship is not greatly reduced.
[0014]
In particular, in a high speed ship sea chest engaging Ru in the present invention, the flow induced sea chest side by 1/4 arc-shaped outer peripheral surface of the equally divided bar the cylinder located on the bow side in the cross section direction, the cylinder By colliding with a radial surface facing the bow direction of the rod divided into 1/4 equal to the cross section direction, the cylinder located in the wake of the bar divided into 1/4 equal to the cross section direction in the sea chest Since the flow direction of the flowing seawater is changed upward, it becomes easier for the seawater to flow into the sea chest.
[0015]
At that time, the radius surface facing the ship neck direction, becomes what the flow impinging on the corner of the outer circumferential arc surface is further decelerated than boat speed, scale of potential delamination caused by this corner is suppressed Therefore, cavitation caused by this is less likely to occur.
[0016]
According to the simulation of the present inventor, when the angle is less than 5 degrees, separation that causes cavitation is hardly suppressed. Conversely, when the angle exceeds 20 degrees, the cylinder located in the wake is 1 / The effect that seawater easily flows into the sea chest due to the collision of the equally divided rods with the radial surface facing the bow direction was weakened, and good results were obtained at 5 to 20 degrees.
[0017]
【Example】
Hereinafter, the high-speed ship sea chest according to the present invention will be described based on the embodiment shown in FIG . 2 (c) and FIG.
FIG. 1 is a schematic explanatory diagram of a high-speed ship sea chest in which a plurality of cylinders are arranged in a fence shape so that the central axis is parallel to the ship width direction at the opening of the sea chest provided on the ship bottom . Overall view, (b) shows a column arranged in a fence shape and the flow around the column, and FIG. 2 shows a bar in which the column is divided into quarters in the cross-sectional direction instead of the column in FIG. It is schematic explanatory drawing of a high-speed ship sea chest, (a) is a general view, (b) shows the bar material which divided the column arranged in the shape of a fence into 1/4 equal to the cross section direction, and the flow around this bar material. Fig. 3 (c) is a view similar to Fig. 3 (b) of the high-speed ship sea chest according to the present invention in which a bar material obtained by dividing the cylinder into 1/4 in the cross-sectional direction is rotated. it is a schematic perspective view of the engagement Ru high speed vessels sea chest to the present invention which is rotated as shown in FIG. 2 (c) 1/4 equally divided bars in.
[0018]
In Figure 1, 1 1 of the high-speed ship sea chest, the opening 11aa seawater intake box 11a provided to the ship's bottom, the central axis is parallel to the ship width direction, and so that the outer peripheral lower end surface is a ship bottom and the same plane The plurality of cylinders 12 are arranged in a fence shape.
[0019]
According to high-speed vessels sea chest 11 described above, and FIG. 1 (b) in as indicated by arrows, flows along the arc of the cylinder 12 so as to induce seawater inside the opening of the sea chest 11 Since it is formed in 11aa, the flow of seawater from the ship bottom to the inside of the sea chest 11 is stably supplied even when the ship speed increases.
[0020]
In addition, according to the high speed ship sea chest 11 as described above, since the arcuate portion of the cylinder 12 positioned on the bow side take dynamic pressure of the vessel bottom stream does not project from the ship's bottom, fast flow impinges perpendicularly And the propulsion performance of the ship is not greatly reduced.
[0021]
Further, in FIG. 2, 2 1 high speed craft Shichesu bets, instead of the cylindrical 12 at high speed ship sea chest 11 shown in FIG. 1 described above, 1/4 equally divided bars in the cross sectional direction of the cylindrical ( (Hereinafter referred to as “¼ cylinder”) 22 is formed in the opening 21aa of the seawater suction box 21a provided on the bottom of the ship, the central axis is parallel to the width direction of the ship, and the outer peripheral lower end surface is flush with the bottom of the ship, for example. It is the structure which has arrange | positioned so that it may become two or more fences.
[0022]
Then, in this high-speed vessels sea chest 21, the quarter cylinder 22, as shown in FIG. 2 (b), the one radial surface 22a faces the deck direction of the hull, the other radial surface 22b bow The outer circumferential arc surface 22c is disposed so as to face downward in the stern direction.
[0023]
According to high-speed vessels sea chest 21 as described above, and FIG. 2 (b) in as indicated by arrows, the arc-shaped outer peripheral surface 22c flow sea chest 21 along that induce seawater inside the sea chest 21 As the first high-speed ship sea chest 11 is formed, the flow of seawater from the ship bottom to the inside of the sea chest 21 is stably supplied even when the ship speed increases. Will be.
[0024]
Then, the high-speed ship sea chest 21 was placed 1/4 cylinder 22, since the flow along each arc-shaped outer peripheral surface 22c described above collides with the radius surface 22b facing the bow direction of the downstream side, ship propulsion although reduced rates of performance first slightly larger than the high-speed boat sea chest 11 of disposing the cylindrical 12, flow of seawater from the ship bottom to the inside of the sea chest 21 is even better than the high speed ship sea chest 11.
[0025]
In the high speed ship sea chest 21 as described above, as the radius surface 22b facing the bow direction of 1/4 cylinder 22 has an angle of 5-20 degrees with respect to the height direction of the hull, and FIG. 2 (c) As shown in FIG. 2, when the outer peripheral circular arc surface 22c is rotated in the bow direction around the intersection of the radius surfaces 22a and 22b of the quarter cylinder 21, the radius of the quarter cylinder 22 in the bow direction is Since the flow that collides with the angle between the surface 22b and the outer peripheral circular arc surface 22c is further decelerated from the ship speed, the scale of separation that may occur due to this angle is suppressed, resulting in this. Cavitation is less likely to occur.
[0026]
Figure 3 is a schematic perspective view of the engagement Ru high speed vessels sea chest 21 in the present invention which is rotated as shown in FIG. 2 (c) 1/4 cylinder 22, 1/4 as cylinder 22 above It is arranged in advance in the seawater suction grid 23 in the shape of a simple fence, and the seawater suction grid 23 is attached to the opening 21aa of the seawater suction box 21a via, for example, an attachment piece 24 welded to the hull. Yes. In addition, 25 in FIG. 3 is a reinforcing material.
[0027]
The diameter of the above-described cylinder 12 and the radius of the quarter cylinder 22 are not particularly limited, but according to the experiments of the present inventors, 5 to 20 in the length direction of the first high-speed ship sea chest 11 is used. %, And the interval between the adjacent cylinders 12 and the quarter cylinder 22 is 30 to 200% of the diameter of the cylinder 12 or the radius of the quarter cylinder 22, more preferable results are obtained.
[0028]
In addition, although explanation is omitted in the present embodiment, it is from the viewpoint of suppressing cavitation that the corners of the radial surface 22b facing the bow direction and the outer circumferential arc surface 22c in the quarter cylinder 22 are curved. Needless to say, it is desirable.
[0029]
【The invention's effect】
As described above, according to the present invention, there is no protrusion from the bottom of the ship, that is, without lowering the ship speed, and without reducing the pressure inside the sea chest, that is, the lack of pump capacity. In this way, the flow of seawater can be effectively induced in the sea chest using the speed of the high-speed ship.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory diagram of a high-speed ship sea chest in which a plurality of cylinders are arranged in a fence shape so that the central axis is parallel to the ship width direction at the opening of the sea chest provided at the bottom of the ship. Is a general view, (b) is a diagram showing a cylinder arranged in a fence shape and the flow around the cylinder.
2 is a schematic explanatory view of a high-speed ship sea chest in which rods obtained by dividing the cylinder into quarters in the cross-sectional direction instead of the cylinder of FIG . 1 are arranged , (a) is an overall view, and (b) is a fence. The figure which showed the 1/4 cylinder arranged in the shape and the flow around this cylinder, (c) is the same figure as (b) of the high-speed ship sea chest based on this invention which rotated the 1/4 cylinder. .
Figure 3 is a schematic perspective view of the engagement Ru high speed vessels sea chest to the present invention which is rotated as shown in a quarter cylinder Fig 2 (c).
4A and 4B are schematic explanatory views of a conventional sea chest, in which FIG. 4A is a perspective view, and FIG. 4B is a cross-sectional view.
5A and 5B are schematic explanatory views when a grid is installed in an opening of a sea chest, where FIG. 5A is a perspective view and FIG. 5B is a cross-sectional view.
6A and 6B are schematic explanatory views when a baffle plate is installed from the bottom of the stern side of the sea chest, where FIG. 6A is a perspective view and FIG. 6B is a cross-sectional view.
FIG. 7 is a schematic explanatory diagram of a sea chest changed to a scoop shape.
[Explanation of symbols]
11 high-speed ship sea chest 11aa opening 12 cylinder 21 high-speed ship sea chest 21aa opening 22 1/4 cylinder 22a radially faces 22b radially face 22c arc-shaped outer peripheral surface

Claims (1)

At the opening of the sea chest formed by a box-shaped depression provided on the bottom of the ship, one radial surface faces the hull deck direction, the other radial surface faces the bow direction, and the outer circumferential arc surface faces downward in the stern direction. The outer circumference is centered on the intersection of the one and the other radial surfaces so that the other radial surface facing the bow direction has an angle of 5 to 20 degrees with respect to the height direction of the hull. A plurality of rods obtained by rotating the circular arc surface in the bow direction and dividing the cylinder into 1/4 equal to the transverse section direction , the central axis is parallel to the ship width direction, and the outer peripheral end surface is flush with the ship bottom. A high-speed ship sea chest characterized by being arranged like a fence.

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