JP4953296B2 - Hull frictional resistance reduction device - Google Patents

Description

  The present invention relates to a device for reducing the frictional resistance of water along the outer surface of the bottom of a hull during navigation.

In navigating vessels, the submerged surface of the bottom of the ship generally receives frictional resistance of water, and in the case of large ships in particular, most of the hull resistance is occupied by the frictional resistance generated by the relative flow of outside water at the bottom of the ship. It has been.
Therefore, a technique for reducing the hull frictional resistance by covering the bottom of the ship with a bubble flow during navigation has been proposed for a long time. And what provided the some diffusion suppression board extended in the ship length direction along the ship bottom so that the said bubble flow can suppress spreading | diffusion from the ship bottom to the side is also developed.
Japanese Patent No. 3692398 JP 2002-68073 A JP 2000-296797 A

In general, a ship is likely to be shaken by wind and waves during navigation, so it is difficult to always wrap the bottom of the ship uniformly with bubbles for reducing frictional resistance, especially on the bottom of the ship close to the ship side. There is a problem that the bubbles are separated from the hull when they are tilted and lifted along with the rolling motion.
In addition, providing the bubble ejection port over the entire surface of the ship bottom causes a significant cost increase.
Therefore, the present inventors provide a gas chamber without a bottom plate at the bottom of the bow of a large model ship (length: 50 meters) that runs at about 6 m / sec in a test water tank, and uses the gas chamber as a high-pressure gas supply source. Gas holding plates are provided on both sides of the bottom of the ship so that the gas can be prevented from deviating to the side of the bottom of the ship while being connected and released from the gas chamber downward and flowing relatively backward along the outer surface of the ship. As a result of the experiment, it was found that the gas ejected from the bottom of the gas chamber into a laminar flow automatically changed into a bubble flow and efficiently flowed rearward along the bottom of the ship bottom.
Based on the above-mentioned knowledge, the present invention provides a means for flowing the bubble flow backward along the bottom surface of the ship bottom during navigation, without providing a bubble generating part using a bottom plate or mesh having a number of small holes that has been conventionally used. The bubble flow for reducing the hull frictional resistance is generated by the synergistic action of the gas that flows into the water from the bottom opening without the bottom plate of the gas chamber at the bottom of the bow and flows into the water relatively and the gas holding plates along both sides of the bottom of the ship. It is an object of the present invention to provide a hull frictional resistance reduction device capable of efficiently flowing backward along the outer surface of the outer plate.

In order to solve the above-described problems, the hull frictional resistance reduction device of the present invention is configured to allow gas to flow downward at the bow bottom to form a bubble flow that flows relatively along the bottom bottom surface from the bow toward the rear during navigation. A gas chamber that can be discharged is provided in the width direction of the ship and includes a high-pressure gas supply source connected to the gas chamber via a valve, and the bubbles are formed from a layered flow along the bottom surface of the ship bottom that is press-fitted into the water from the gas chamber. A pair of left and right gas retaining plates that protrude from the bow to the stern along the sides of the bottom of the ship are projected on the bottom of the bottom of the ship along both sides of the bottom it has been open interior of the gas chamber in order to facilitate the release of the gas during sailing is into water through a free bottom opening of the bottom plate of the gas chamber Rutotomoni, the depending on to water speed of the boat during sailing Gas chamber In order to control the gas ejection amount from the above, the high-pressure gas supply amount connected to the high-pressure gas supply pipe is controlled by the high-pressure gas supply amount supplied to the gas chamber based on the ship speed detected by the ship speedometer, or A control system for adjusting according to the opening degree of the valve is provided, and when the ship speed detected by the ship speedometer is low, the control system is adjusted so as to suppress gas ejection .

  Further, the hull frictional resistance reducing device of the present invention is connected to the top wall of the gas chamber with a high-pressure gas supply pipe led from the high-pressure gas supply source, and connected to the top wall of the high-pressure gas supply pipe A baffle plate for receiving a high-pressure gas flow is provided inside the gas chamber at a position slightly spaced downward from the opening.

Furthermore, in the hull frictional resistance reduction device of the present invention, a plurality of the gas chambers are provided in a row in the ship width direction, and in order to make the bubble flow uniform in the ship width direction during navigation, The control system determines the supply amount of high-pressure gas to the gas chamber on the side where the draft becomes shallow due to the lateral inclination of the hull based on the hull lateral inclination angle detected by the hull roll sensor. than the supply amount of the high-pressure gas to the gas chamber is characterized and Turkey controls the valve to reduce.

  Further, the hull frictional resistance reduction device of the present invention is configured so that the high-pressure gas supply control system stops the high-pressure gas supply to the gas chamber on the side where the draft is shallowest when the hull is laterally inclined. The valve is set to close the valve corresponding to the gas chamber.

  Further, in the hull frictional resistance reduction device of the present invention, an intermediate gas holding plate extending from the bow portion toward the stern portion is projected on the bottom surface of the bottom between the pair of left and right gas holding plates. It is a feature.

In the above-described hull frictional resistance reduction device of the present invention, during navigation, the gas that is efficiently injected into the water through the bottom opening without the bottom plate of the gas chamber provided in the ship width direction at the bow bottom is accompanied by the progress of the hull. Since it changes from a laminar flow along the bottom surface of the ship to a large amount of bubble flow and covers the bottom surface of the ship bottom, coupled with the fact that the deviation of the bubble flow to the side of the hull is prevented by a pair of left and right gas holding plates, This will contribute to a significant reduction in frictional resistance due to the relative water flow of the hull.
In addition, when the water speed of the ship is low, the frictional resistance due to the outside water of the hull is also reduced, so that the above control is performed so that the amount of gas jetted from the gas chamber can be controlled according to the water speed of the hull during navigation. When the system is set so that the supply amount of the high-pressure gas supplied to the gas chamber can be adjusted by the opening of the valve based on the ship speed detected by the ship speed meter, if the ship speed is low, the gas is blown out. It is possible to reduce the amount of high-pressure gas supply.
Further, the high-pressure gas supply amount supplied to the gas chamber based on the ship speed detected by the ship speedometer so that the gas ejection amount from the gas chamber can be controlled according to the water speed of the hull during navigation. In the case where a control system for adjusting the pressure by controlling the high-pressure gas supply source connected to the high-pressure gas supply pipe is provided, the high-pressure gas supply amount is suppressed by suppressing gas ejection when the boat speed is low. Can be saved.

  And when the baffle plate for receiving the high pressure gas injected into the gas chamber from the high pressure gas supply pipe connected to the top wall of the gas chamber is provided, the gas chamber is filled by the action of the baffle plate. The high-pressure gas is injected into the water from the bottom opening without the bottom plate of the gas chamber into the water in a substantially uniform state. Is possible.

  In addition, a plurality of the gas chambers are provided in a row in the width direction of the ship, and based on the hull lateral inclination angle detected by the hull roll sensor, the side of the draft becomes shallower due to the horizontal inclination of the hull. A ship equipped with a high-pressure gas supply control system for controlling the opening of the valve so as to reduce the amount of high-pressure gas supplied to the gas chamber to be less than the amount of gas supplied to the gas chamber on the deeper side of the draft; Distribution of the bubbles for covering the bottom surface of the bottom portion is appropriately performed without waste.

  Further, the high-pressure gas supply control system closes the valve corresponding to the gas chamber so as to stop the high-pressure gas supply to the gas chamber on the side where the draft is shallowest when the hull is inclined sideways. When the vessel is set to, even when the hull is largely tilted when turning a marine vessel that is navigating, the gas supply amount is appropriately distributed to the outer surface of the bottom of the vessel without waste.

  Further, when an intermediate gas holding plate extending from the bow portion toward the stern portion is provided on the bottom surface of the ship bottom between the pair of left and right gas holding plates, the airflow and the bubble group are maintained along the bottom surface of the ship bottom. Is more appropriately performed, and can contribute to the reduction of the hull frictional resistance during navigation.

  FIG. 1 is a side view of a ship provided with a hull frictional resistance reducing device as one embodiment of the present invention, FIG. 2 is a hull bottom view taken along the line AA in FIG. 1, and FIG. 3 is a BB line in FIG. 4 is a sectional view taken along the line CC of FIG. 3, FIG. 5 is a system diagram showing a control system of the above apparatus, and FIG. 6 is a hull showing a modification of the present invention corresponding to FIG. It is a cross-sectional view.

  As shown in FIGS. 1 and 2, a gas chamber 2 formed in the ship width direction is provided in the bottom of the bow as shown in FIGS. Yes.

  The gas chamber 2 is divided into three gas chambers 2a by a partition wall 2b over the width direction of the ship bottom portion 1, and as shown in FIG. 4, the ship bottom outer plate portion corresponding to each gas chamber 2a is cut off, A bottom opening 1a without a gap is formed. Thus, each gas chamber 2a has a function as a gas discharge part.

  That is, as shown in FIGS. 3 to 5, a high-pressure gas supply pipe 3 leading to each gas chamber 2a is disposed in the ship, and each high-pressure gas supply pipe 3 has a gas flow rate control unit D as shown in FIG. A valve 5 and a flow meter 6 for constituting (see FIG. 3) are provided, and the main pipe 3A is an air compressor as a source of high-pressure gas of about 1.5 to 5 atm via a main plug 7. (Or air blower) 8 is connected. As shown in FIG. 3, a high-pressure air chamber 8 a may be interposed between the air compressor 8 and the main plug 7.

  In each gas chamber 2a, a baffle plate 16 for receiving a high-pressure gas flow is attached to the arm 16a at a position slightly spaced downward from the connection opening to the top wall of the high-pressure gas supply pipe 3 connected to the top wall. It is provided so that it may be supported.

  Then, as shown in FIG. 4, the distribution of the laminar air flow flowing from the bottom opening 1 a of each gas chamber 2 a along the outer surface of the ship bottom portion 1 during the navigation and the changed bubble flow of the air flow is made uniform. Therefore, as shown in FIG. 5, a hull roll sensor 9 and a high-pressure gas supply control system for controlling the amount of high-pressure gas supplied to each gas chamber 2a based on the hull lateral tilt angle detected by the roll sensor 9 And 10 are provided.

  In other words, the high-pressure gas supply control system 10 increases the draft of the high-pressure gas supply amount to the gas chamber 2a on the side where the draft becomes shallow, when the hull is inclined, based on the detection information from the roll sensor 9. The opening degree of the valve 5 can be controlled so as to reduce the amount of the high-pressure gas supplied to the gas chamber 2a on the side.

  The high-pressure gas supply control system 10 is configured to stop the high-pressure gas supply to the gas chamber 2a on the side where the draft is shallowest when the hull is inclined, based on the detection information from the roll sensor 9. The valve 5 corresponding to the gas chamber 2a is set to be closed.

  Further, the high-pressure gas supply control system 10 adjusts the ship speed detected by the ship anemometer 11 so that the gas ejection amount from the bottom opening 1a of each gas chamber 2a can be controlled according to the water speed of the hull during navigation. It is set so that the amount of high-pressure gas supplied to the gas chamber 2 a can be adjusted based on the opening of the valve 5.

  Further, a high-pressure gas supply that is supplied to the gas chamber 2a based on the ship speed detected by the ship speedometer 11 so that the gas ejection amount from the bottom opening 1a can be controlled according to the water speed of the hull during navigation. An air compressor control system 12 is also provided as a control system for adjusting the amount by controlling the air compressor 8 as a high-pressure gas generation source.

  In this embodiment, particularly during navigation, the laminar flow and bubble flow of gas that are press-fitted into the water from the bottom opening 1a of the gas chamber 2a at the bow bottom and flow backward along the bottom surface of the ship bottom deviate to the side of the hull. 1 to 3, a pair of left and right gas holding plates 15, 15 are provided on the bottom surface of the bottom of the ship from the bow to the stern along the sides of the bottom of the ship.

  In addition to the gas holding plate 15, the intermediate gas holding plate 15A is also provided from the bow portion to the stern at the position of the partition wall 2b of each gas chamber 2a as in the modification shown in FIG. 6 corresponding to FIG. You may project on the bottom of the bottom of the ship. In FIG. 6, the same reference numerals as those in FIG.

  In addition, as shown in FIG. 4, a slide-type opening / closing lid that can be operated remotely so as to prevent marine organisms such as barnacles from entering and adhering to the bottom opening of each gas chamber 2 a when the ship is anchored. 17 is desirable.

  In the hull frictional resistance reduction device of the above-described embodiment, during navigation, the gas efficiently injected into the water through the bottom opening 1a without the bottom plate of the gas chamber 2 arranged in the ship width direction at the bottom of the bow is hull. As the flow progresses, the laminar flow along the bottom surface of the ship changes to a large amount of bubble flow, covering the bottom surface of the ship bottom. Coupled with being prevented, the frictional resistance due to the relative water flow of the hull can be greatly reduced.

  And since the baffle plate 16 for receiving the high pressure gas injected into the gas chamber 2a from the high pressure gas supply pipe 3 connected to the top wall of each gas chamber 2a is provided, the action of the baffle plate 16 In this way, the high-pressure gas filled in the gas chamber 2a is pressed into the water in a substantially uniform state from the bottom opening 1a without the bottom plate of the gas chamber 2a in this manner, and in this way, the gas chamber 2a is efficiently aligned along the bottom of the ship. It is possible to generate a bubble flow that flows backward.

  A plurality of gas chambers 2a are provided in a row in the width direction of the ship, and on the side where the draft becomes shallow due to the horizontal inclination of the hull based on the horizontal inclination angle of the hull detected by the roll sensor 9 of the hull. Since the high-pressure gas supply control system 10 that controls the opening degree of the valve 5 is provided so that the high-pressure gas supply amount to the gas chamber 2a is reduced more than the gas supply amount to the gas chamber 2a on the deeper draft side. The air bubbles for covering the bottom surface of the ship bottom are appropriately distributed without waste.

  Further, the high-pressure gas supply control system 10 closes the valve 5 corresponding to the gas chamber 2a so as to stop the high-pressure gas supply to the gas chamber 2a on the side where the draft is shallowest when the hull is inclined. Therefore, even when the hull is largely inclined at the time of turning of the marine vessel that is being navigated, the distribution of the gas supply amount to the outer surface of the bottom of the vessel is appropriately performed without waste.

  In addition, when the water speed of the ship is low, the frictional resistance due to the outside water of the hull is also reduced, so that the high-pressure gas can be controlled so that the gas ejection amount from the gas chamber 2a can be controlled according to the water speed of the hull during navigation. When the ship speed is low because the supply control system 10 is set so that the amount of high-pressure gas supplied to the gas chamber 2a can be adjusted by the opening of the valve 5 based on the ship speed detected by the ship speedometer 11. Can reduce the amount of high-pressure gas supply by suppressing gas ejection.

  Further, based on the ship speed detected by the ship speedometer 11, the gas is supplied to the gas chamber 2a so that the amount of gas jetted from the gas jet bottom opening 1a can be controlled according to the water speed of the hull during navigation. Control systems 10 and 12 for adjusting the high-pressure gas supply amount by controlling the high-pressure gas supply source connected to the high-pressure gas supply pipe 3 are provided. Further, it is possible to reduce the amount of high-pressure gas supply.

  Further, when an intermediate gas holding plate 15A extending from the bow portion toward the stern portion is projected on the bottom surface of the ship bottom between the pair of left and right gas holding plates 15, layered airflow and bubbles along the bottom surface of the ship bottom The group can be held more appropriately and can contribute to the reduction of the hull frictional resistance during navigation.

It is a side view of the ship provided with the hull frictional resistance reduction apparatus as one Example of this invention. It is a ship bottom view in the AA arrow line of FIG. It is an expanded sectional view which follows the BB arrow line of FIG. It is an expanded sectional view which follows the CC arrow line of FIG. It is a systematic diagram which shows the control system of the said apparatus. FIG. 4 is a transverse cross-sectional view of a hull showing a modification of the device of the present invention corresponding to FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ship bottom 1a Bottom opening 2, 2a Gas chamber 2b Bulkhead 3 High pressure gas supply pipe 3A Main pipe 5 Valve 6 Flow meter 7 Main plug 8 Air compressor 8a High pressure air chamber 9 Roll sensor
10 High-pressure gas supply control system
11 Ship speedometer
12 Air compressor control system
15 Gas retaining plate
15A Intermediate gas holding plate
16 Baffle plate
16a arm
17 Open / close lid D Gas flow control unit

Claims (5)

In order to form a bubble flow that flows relatively along the bottom bottom of the ship bottom from the bow to the rear during navigation, a gas chamber capable of releasing gas downward is provided at the bow bottom in the ship width direction. A high-pressure gas supply source connected via a valve is provided, and the gas to be changed from the laminar flow along the bottom surface of the ship bottom into the water by being pressed into the water from the gas chamber and the deviation of the bubble flow to the side of the hull A pair of left and right gas retaining plates for prevention are provided on the bottom of the bottom of the ship from the bow to the stern along the sides of the bottom of the ship. internal is opened into water through a bottom without bottom opening of plate of the gas chamber Rutotomoni, to control the gas ejection amount from the gas chamber in accordance with to water speed of the boat during sailing, is detected by the boat speed meter Based on ship speed A control system for adjusting the amount of high-pressure gas supplied to the gas chamber by controlling the high-pressure gas supply source connected to the high-pressure gas supply pipe or the opening of the valve is provided. A hull frictional resistance reduction device, wherein when the detected ship speed is low, the control system is adjusted to suppress gas ejection .   A high-pressure gas supply pipe led from the high-pressure gas supply source is connected to the top wall of the gas chamber, and the gas is located at a position slightly spaced downward from the connection opening to the top wall of the high-pressure gas supply pipe. The hull frictional resistance reduction device according to claim 1, wherein a baffle plate for receiving a high-pressure gas flow is provided inside the chamber. A plurality of the gas chambers are provided in a row in the ship width direction, and the control system detects with the roll sensor of the hull to make the bubble flow uniform in the ship width direction during navigation. The amount of high-pressure gas supplied to the gas chamber on the side where the draft becomes shallower than the amount of high-pressure gas supplied to the gas chamber on the side where the draft becomes deeper due to the horizontal inclination of the hull characterized the Turkey controls the valve so as to, ship-body frictional resistance reducing device according to claim 1 or 2.   The high-pressure gas supply control system is set to close the valve corresponding to the gas chamber in order to stop the high-pressure gas supply to the gas chamber on the side where the draft becomes the shallowest when the hull is inclined horizontally. The hull frictional resistance reduction device according to claim 3, wherein the hull frictional resistance reduction device is provided. The ship bottom underside between each other the pair of gas holding plate, wherein the intermediate gas holding plate extending toward the bow to the stern portion is protruded, claim 1-4 The hull frictional resistance reduction device as described in one.

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