JP2011088515A - Frictional resistance reducing ship - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frictional resistance reducing ship reducing the frictional resistance and enhancing the fuel economy. <P>SOLUTION: A wing 13 is configured by joining and connecting an inside plate 16 and an outside plate 17. In a state where the inside plate 16 and the outside plate 17 are joined to each other, a hollow portion 18 communicating with a passage is formed in the wing 13. When the navigation speed increases, an area with a negative pressure is formed near the outside surface of the inside plate 16 of the wing 13. Consequently, air in the hollow portion 18 of the wing 13 is jetted out from holes 19 by the negative pressure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a frictional resistance-reducing ship in which fine bubbles (microbubbles) are supplied to the outer surface of a hull to reduce the frictional resistance between the hull and water and a method for operating the same.

  Conventionally, it is known that the frictional resistance of a hull against water is reduced by supplying bubbles to the surface of the hull during navigation.

  In particular, Patent Document 1 discloses a technique in which a negative pressure is generated as a ship sails and air is drawn out by the negative pressure to form fine bubbles.

  This Patent Document 1 proposes a structure comprising a plate fitted into the opening and a negative pressure generating wing attached to the opening as a fine bubble generating member attached to the opening formed in the hull. Yes.

Japanese Patent No. 4212640

  In Patent Document 1, the wing attachment angle is oblique to the hull, specifically, the gap between the wing rear edge and the hull is larger than the gap between the wing front edge and the hull. By forming a negative pressure area on the side of the wing facing the hull as the ship navigates, air is drawn from the opening formed in the hull toward this negative pressure area, and the air at that time Fine bubbles are generated at the interface with seawater.

  In the structure disclosed in Patent Document 1, since the distance between the negative pressure region and the air supply port formed in the hull is large, even when the negative pressure region is formed, seawater around the negative pressure region immediately enters the negative pressure region. Therefore, the air cannot be sufficiently drawn out from the air supply port, and the generation of fine bubbles is insufficient.

  In order to solve the above problems, a frictional resistance reducing ship according to the present invention has a fine bubble generating member attached to an opening formed in a hull, the fine bubble generating member being attached to the opening, and a plate attached to the plate. It consists of a wing for generating negative pressure attached via a leg, and an air supply passage communicating with the atmosphere or a pressure air source is formed in the leg, and the wing forms a negative pressure when navigating the hull. The gap between the rear edge of the wing and the hull is made larger than the gap between the front edge of the wing and the hull so as to be a plane, and the wing has a hollow portion formed therein, A hole for communicating air in the hollow portion as fine bubbles by negative pressure is formed on the surface of the wing facing the hull and communicating with the air supply passage formed in the portion.

  The magnitude of the negative pressure generated according to the traveling speed of the ship is also affected. Therefore, it is preferable to provide a switching valve in the air supply pipe connected to the air supply passage formed in the leg portion so that either the atmospheric air or the pressurized air source can be selected as the air source. In addition, this invention includes the case where the piping for air supply is open | released only to air | atmosphere and the case where it connects only to a pressurized air source.

  Further, a convex portion may be provided on the surface of the hull behind the wing in order to cause the generated fine bubbles to stick to the side surface of the hull.

  According to the frictional resistance reduction ship according to the present invention, the bottom and side surfaces of the hull can be covered with microbubbles, so that the frictional resistance is further reduced and fuel efficiency is improved.

In particular, according to the present invention, the fine bubble generating member itself generates a negative pressure as the ship travels and effectively uses the negative pressure without waste, so that a sufficient amount of fine bubbles can be generated. it can.

Side view of a ship with reduced frictional resistance according to the present invention 1 is an enlarged view of the main part of FIG. A direction enlarged view of FIG. Front view of the microbubble generator Longitudinal sectional view of the microbubble generator attached to the side of the hull Cross sectional view of the microbubble generator (A) is an enlarged exploded view of the fine bubble generating member, (b) is an enlarged view of the fine bubble generating member. The same figure as FIG. 6 explaining the mechanism of generation of microbubbles The figure which shows another Example of a microbubble generation | occurrence | production member The same figure as FIG. 3 which shows another embodiment The same figure as FIG. 3 which shows another embodiment

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the frictional resistance reduction ship according to the present invention has a plurality of fine bubble generating members 10 attached along the ship bottom 2 from the outer surface 1 of the hull below the draft surface (LWL). ing. In the illustrated example, the plurality of fine bubble generating members 10 are arranged so as to form a straight line when viewed from the side, but they may be staggered or slanted.

In the present embodiment, the region below the draft surface (L.W.L.) is divided into an upper region (R1) near the draft surface and a lower region (R2) near the ship bottom, and the upper region (R1) and the lower region. The supply form of air to the fine bubble generating member 10 arranged in (R2) is different.

That is, the supply of air to the fine bubble generating member 10 disposed in the upper region (R1) is performed via the air supply pipe 3 whose tip is opened to the atmosphere, and the fine bubbles disposed in the lower region (R2). Air is supplied to the generating member 10 from the assist compressor 4 to the buffer tank 5 through the branch pipe 6 from the buffer tank 5.

That is, the supply of air to the fine bubble generating member 10 disposed in the lower region (R2) is performed not through the atmosphere but through a closed piping. In addition, in order to simplify the description, in the illustrated example, the number of fine bubble generating members 10 arranged in the upper region (R1) is one, but a plurality of fine bubble generating members 10 may be provided.

Each branch pipe 6 is provided with pressure reducing valves V1 to V4, and the supply pressure of air to the fine bubble generating member 10 arranged in the lower region (R2) is varied. In this embodiment, the throttle amount is increased as the pressure reducing valve is located at the upper side, and the high pressure air is supplied to the fine bubble generating member 10 at the lower side. Since the distance from the gas-liquid interface in the branch pipe 6 to the fine bubble generating member 10 becomes larger as the fine bubble generating member 10 below, a pressure reducing valve is provided so that air is supplied uniformly from the buffer tank 5.

The pressure reducing valve V4 may not be provided in the branch pipe to the fine bubble generating member 10 located at the lowest position. Furthermore, the air pressure supplied from the buffer tank 5 may be adjusted as a whole in accordance with the navigation speed.

Next, the structure of the fine bubble generating member 10 will be described with reference to FIGS. The fine bubble generating member 10 includes a plate 11 fitted in an opening 1a formed in the hull, and a wing 13 for generating negative pressure attached to the plate 11 via a leg 12.

The inner side of the opening 1a is closed by a backup plate 14 that supports the plate 11, a passage 15 communicating with the atmosphere or a pressure source is formed in the leg 12, and the wing 13 has a surface facing the hull. The gap g2 between the rear end edge of the wing 13 and the hull is made larger than the gap g1 between the front end edge of the wing 13 and the hull so as to form a negative pressure forming surface during navigation.

The wing 13 is configured by combining the inner plate 16 and the outer plate 17 together, and a hollow portion 18 communicating with the passage 15 is formed inside the wing 13 in a state where the inner plate 16 and the outer plate 17 are combined. .

The surface of the inner plate 16 becomes a negative pressure forming surface during navigation, and a number of fine holes 19 are formed in the inner plate 16.

In the above, since the speed is low immediately after the ship starts to sail, the negative pressure generated by the wing 13 is also small, and the inside of the air supply pipe 3 that supplies air to the fine bubble generating member 10 disposed in the upper region (R1). Since the effect of lowering the gas-liquid interface is not sufficient, fine bubbles are not generated from the fine bubble generating member 10 in the upper region (R1).

However, since the high-pressure air is supplied from the buffer tank 5 to the fine bubble generating member 10 disposed in the lower region (R2), the air supplied to the hollow portion 18 is ejected from the hole 19 formed in the inner plate 16. To do.

On the other hand, when the navigation speed increases, a negative pressure region is formed near the outer surface of the inner plate 16 of the wing 13. As a result, the air in the hollow portion 18 of the wing 13 is ejected from the hole 19 by the negative pressure.

Although the ejected fine bubbles move to the rear of the hull, the streamlined convex portion 20 is provided on the hull 1 or the plate 11 on the downstream side of the wing 13, so that the ejected fine bubbles are attached to the rear so that the fine bubbles stick to the hull. Moving. This state is shown in FIG.

FIG. 9 is a view showing another embodiment of the fine bubble generating member. In this embodiment, a slit-shaped opening 22 is provided on the surface of the plate 11 facing the wing 13, and the branch pipe 6 is formed in the slit-shaped opening 22. It is the structure where air is supplied through. In addition, the shape of the opening formed in the plate 11 is not limited to the slit shape.

FIGS. 10 and 11 are views similar to FIG. 3 showing another embodiment. In the other embodiment shown in FIG. 10, the air supply connected to the fine bubble generating member 10 provided in the upper region R1 close to the draft surface. Even if the branch pipe 6 from the buffer tank 5 is connected to the pipe 3 via the switching valve 21, and the switching valve 21 is operated even at an extremely low speed that does not reach the cruising speed, the air in the buffer tank 5 is supplied. I try to do it. In this case, the pressure reducing valve V0 provided in the branch pipe 6 is set to have a higher degree of throttle than the other pressure reducing valves V1 to V4.

In another embodiment shown in FIG. 11, an intermediate region R3 is provided between the upper region R1 and the lower region R2, and air from the atmosphere opening and buffer tank 5 is supplied to the fine bubble generating member 10 disposed in the intermediate region R3. To be.

DESCRIPTION OF SYMBOLS 1 ... Outer surface of a hull, 1a ... Opening of a hull, 2 ... Ship bottom, 4 ... Assist compressor, 5 ... Buffer tank, 6 ... Branch pipe, 10 ... Fine bubble generating member, 11 ... Plate, 12 ... Leg part, 13 ... Wing, 14 ... backup plate, 15 ... passage, 16 ... inner plate, 17 ... outer plate, 18 ... hollow portion, 19 ... fine hole, 20 ... convex portion, 21 ... switching valve, 22 ... slit-like opening, R1 ... Upper region, R2 ... lower region, R3 ... intermediate region, g1 ... interval between the front edge of the wing and the plate, g2 ... interval between the rear edge of the wing and the plate.

Claims (2)

A frictional resistance reduction ship having a fine bubble generating member attached to an opening formed in a hull, wherein the fine bubble generating member has a plate fitted into the opening, and a negative pressure attached to the plate via a leg. An air supply passage communicating with the atmosphere or a pressurized air source is formed in the leg portion, and the wing has a front edge of the wing so that a surface facing the hull becomes a negative pressure forming surface during navigation The gap between the rear edge of the wing and the hull is larger than the gap between the wing and the hull, and the wing has a hollow portion formed therein, and the hollow portion communicates with the air supply passage formed in the leg portion. Further, a ship for reducing frictional resistance, wherein a hole for ejecting air in the hollow portion as fine bubbles by negative pressure is formed on a surface of the wing facing the hull. 2. The frictional resistance reduction ship according to claim 1, wherein an air supply pipe is connected to an air supply passage formed in the leg portion, and a switching valve for selecting either air or a pressurized air source as the air source is connected to the pipe. A ship with reduced frictional resistance, characterized in that