JP4953294B2 - 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 invention is provided with a bubble generating part at the bow bottom for flowing a large number of bubbles along the bottom surface of the ship bottom during navigation, and the bubbles deviate sideways from the ship bottom when the hull rolls. It is an object of the present invention to provide an apparatus capable of sufficiently reducing the frictional resistance of the hull while sailing while rationalizing the supply of high-pressure gas for generating bubbles in consideration of prevention.

The hull frictional resistance reduction device of the present invention is provided with a bubble generating part for flowing a large number of bubbles along the bottom surface of the bottom of the ship at the time of navigation, and the deviation of the bubbles generated from the bubble generating part to the side of the hull is provided. A pair of left and right air bubble retaining plates are provided on both sides of the bottom of the ship and project from the bottom of the bottom of the ship toward the stern of the ship. In order to make the distribution of the bubbles flowing along the outer surface uniform, the bubble generating section moves toward the side where the draft becomes shallower when the hull is tilted based on the hull tilt angle detected by the hull roll sensor. it is characterized in that comprises a high pressure gas supply control system for causing reduced less than the bubble jet of bubbles ejected amount to the side deeper draft.

  Further, the hull frictional resistance reduction device of the present invention is provided such that the bubble generating portion is divided into a plurality of compartments in the bow portion across the width direction of the bottom of the vessel, and a plurality of bubble outlets are provided on the bottom wall of the same compartment. And a high-pressure gas supply pipe that leads from the high-pressure gas supply source to each of the plurality of compartments via a valve, and the high-pressure gas supply control system is detected by the roll sensor. The opening degree of the valve is controlled based on the lateral inclination angle.

  Further, in the hull frictional resistance reduction device of the present invention, the high-pressure gas supply control system is configured to stop the high-pressure gas supply to the branch chamber on the side where the draft is shallowest when the hull is tilted sideways. It is characterized by setting so that the said valve | bulb corresponding to may be closed.

  Further, the hull frictional resistance reduction device of the present invention is configured such that the high-pressure gas supply control system detects with a ship anemometer in order to control the amount of bubble ejection from the bubble ejection port according to the water speed of the hull during navigation. The high-pressure gas supply amount supplied to the compartment based on the ship speed is set so as to be adjusted by the opening of the valve.

  Furthermore, the hull frictional resistance reduction device of the present invention is based on the ship speed detected by the ship speedometer to control the amount of bubble ejection from the bubble ejection port according to the water velocity of the hull during navigation. A control system is provided for adjusting the amount of high-pressure gas supplied to the compartment by controlling a high-pressure gas generation source connected to the high-pressure gas supply pipe.

  Further, in the hull frictional resistance reduction device of the present invention, an intermediate bubble 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 bubble holding plates. It is a feature.

  In the hull frictional resistance reduction device of the present invention, a bubble generating part for flowing a large number of bubbles along the bottom surface of the ship bottom during navigation is provided at the bow bottom, and the bubbles generated from the bubble generating part deviate to the side of the hull. A pair of left and right air bubble retaining plates are provided along the sides of the bottom of the ship and project from the bottom of the bottom of the ship toward the stern of the ship. It comes to be appropriately covered with fine bubbles ejected from the bubble generating part.

Then, the bubble generating section determines the amount of bubble jetting toward the draft side when the hull is tilted based on the hull lateral tilt angle detected by the hull roll sensor. is provided with the high-pressure gas supply control system for causing reduced less than the ejection amount, even when the hull is rolling larger when sailing in waves, bubbles flowing along over the bottom outer surface ejected from the bubble generating portion The distribution of the distribution becomes uniform.

  In addition, the bubble generating section is divided into a plurality of compartments in the bow portion across the width of the bottom of the ship, and is provided with a plurality of bubble outlets on the bottom wall of the same compartment, and the plurality of compartments A high-pressure gas supply pipe that communicates with each of the high-pressure gas supply source from the high-pressure gas supply source, and the high-pressure gas supply control system is configured based on the hull lateral inclination angle detected by the roll sensor. By controlling the opening of the valve so as to reduce the amount of high-pressure gas supplied to the compartment on the side where the draft becomes shallower due to the lateral inclination than the amount of gas supplied to the compartment on the side where the draft becomes deep, Distribution of the bubbles for covering the bottom portion is appropriately performed without waste.

  Further, the high-pressure gas supply control system is set to close the valve corresponding to the same compartment in order to stop the supply of the high-pressure gas to the compartment on the side where the draft is shallowest when the hull is laterally inclined. In this case, even when the hull is largely tilted when turning a marine vessel that is being navigated, the bubbles are appropriately distributed to the outer surface of the bottom of the vessel without waste.

  Also, when the water velocity of the ship is small, the frictional resistance due to the outside water of the hull is also reduced, so that the amount of bubble ejection from the bubble outlet can be controlled according to the water velocity of the hull during navigation. If the high-pressure gas supply control system is set so that the amount of high-pressure gas supplied to the compartment can be adjusted by the opening of the valve based on the ship speed detected by the ship speedometer, It is possible to reduce the amount of high-pressure gas supply by suppressing the ejection of bubbles.

  Further, the amount of high-pressure gas supplied to the compartment based on the ship speed detected by the ship speedometer so that the amount of bubble jet from the bubble outlet can be controlled according to the water velocity of the hull during navigation. Even when a compressor control system for adjusting the pressure by controlling the compressor connected to the high-pressure gas supply pipe is provided, it is possible to suppress the ejection of bubbles when the ship speed is low, thereby reducing the amount of high-pressure gas supply. Can be planned.

  Further, when an intermediate bubble holding plate extending from the bow portion toward the stern portion is projected on the bottom surface of the ship bottom between the pair of right and left bubble holding plates, the bubble group along the bottom surface of the ship bottom is further retained. It will be carried out appropriately and will 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 an explanatory view of a part of FIG. 3, and FIG. 5 is a system diagram showing a control system of the apparatus.

  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 compartments 2a by a partition wall 2b over the width direction of the ship bottom portion 1, and as shown in FIG. 4, a large number of bubble outlets are provided in the ship bottom skin portion 1a corresponding to each compartment 2a. 1b is formed, and thus the gas chamber 2 has a function as a bubble generating part. In addition, you may make it employ | adopt the porous board which covers the recessed part formed in this ship bottom outer plate so that it may communicate with the compartment 2a for this ship bottom outer plate part 1a. In particular, when a stainless sintered wire mesh as a porous plate obtained by laminating and sintering a large number of stainless steel wire meshes is mounted on the ship bottom outer plate portion 1a, sufficient strength and durability can be ensured.

  Moreover, as shown in FIGS. 3-5, the high-pressure gas supply pipe | tube 3 which leads to each compartment 2a is arrange | positioned in a ship, and as shown in FIG. A valve 5 and a flow meter 6 for constructing the air compressor (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). 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.

  Then, as shown in FIG. 4, in order to uniformize the distribution of the bubbles b that flow from the bubble outlets 1b of the respective compartments 2a and travel along the outer surface of the ship bottom 1 during navigation, as shown in FIG. And a high-pressure gas supply control system 10 that controls the amount of high-pressure gas supplied to the compartment 2 a based on the hull lateral inclination angle detected by the roll sensor 9.

  That is, the high-pressure gas supply control system 10 determines the amount of high-pressure gas supplied to the compartment 2a on the side where the draft becomes shallower when the hull is tilted based on the detection information from the roll sensor 9 on the side where the draft becomes deeper. The opening degree of the valve 5 can be controlled so as to reduce the amount of the high-pressure gas supplied to the compartment 2a.

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

  Further, the high-pressure gas supply control system 10 moves to the compartment 2a based on the ship speed detected by the ship speedometer 11 so that the amount of bubble injection from the bubble outlet 1b can be controlled according to the water velocity of the hull during navigation. The high-pressure gas supply amount to be supplied is set so as to be adjusted by the opening degree of the valve 5.

  In addition, the high-pressure gas supply supplied to the compartment 2a based on the ship speed detected by the ship speedometer 11 so that the amount of air bubbles ejected from the air bubble outlet 1b 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, in order to prevent the bubbles flowing backward from the gas chamber 2 as the bubble generating part of the bow bottom at the time of sailing along the bottom surface of the ship bottom from deviating to the side of the hull, FIGS. As shown, a pair of left and right bubble holding plates 15, 15 are provided on the bottom surface of the bottom of the ship from the bow part toward the stern part along both sides of the ship bottom.
The bubble holding plate 15 projects from the bottom of the ship bottom toward the stern part from the bow part to the stern part even at the positions of the mutual partition walls 2b of the respective compartments 2a as in the modification shown in FIG. 6 corresponding to FIG. can do.

  Further, as in the modification shown in FIG. 7 (bottom bottom view), the second gas for forming the second-stage bubble generating part on the bottom of the ship behind the gas chamber 2 as the bubble generating part in the bow. The chamber 2A may be provided.

  In this case as well, a pair of left and right bubble holding plates 15 and 15 are provided on both sides of the bottom of the ship in order to prevent deviation of the air bubbles generated so as to follow from the gas chambers 2 and 2A to the bottom of the bottom of the ship during navigation. And projecting on the bottom bottom of the ship from the bow to the stern.

  Further, as in the modification shown in FIG. 8 (bottom bottom view), a pair of bubble generating gas chambers 2 and 2 are provided at the bow bottom so as to incline backward to form a pair on the left and right sides. A central bubble holding plate 15a may be provided between the pair of left and right bubble holding plates 15 and 15 along the line.

  Further, in the modified example shown in FIG. 9 (bottom bottom view), the bubble generating side gas chambers 2B and 2B are provided on the bow bottom at the back of the bow slightly behind the leading bubble generating gas chamber 2 on the left and right sides. A pair of intermediate bubble holding plates 15b, 15b are provided between the bubble holding plates 15, 15 in the section.

  Further, the modification shown in FIG. 10 shows a case where the inside of the bubble generating gas chamber 2 is not divided into compartments as compared with that shown in FIG. By providing an appropriate number of intermediate bubble holding plates 15c between the bubble holding plates 15 and 15 in the ship length direction, a sufficient bubble holding effect can be obtained.

  Further, in the modification shown in FIG. 11 corresponding to FIG. 3, the bubble generating gas chamber 2 at the bow bottom is divided into a number of compartments 2a, and an air flow rate control unit D is provided for each compartment 2a. The bubble generation from the respective compartments 2a to the bottom surface of the ship bottom is precisely controlled.

  Further, in the modification shown in FIG. 12, the gas chamber 2 for generating bubbles protrudes below the bottom surface 1 of the ship bottom so that bubbles can be efficiently generated from the lower surface or the rear side of the gas chamber 2. In this case as well, bubble holding plates 15 are provided on both sides of the ship bottom.

  In the hull frictional resistance reduction device of the above-described embodiment and each modified example, the bubble generating part for flowing a large number of bubbles b along the bottom surface of the ship bottom during navigation is provided on the bow bottom and the bubbles generated from the bubble generating part A pair of left and right air bubble retaining plates 15 for preventing the deviation of the ship to the side of the hull are projected on the bottom of the bottom of the ship from the bow to the stern along the sides of the bottom of the ship. The outer surface of the ship bottom is appropriately covered with the fine bubbles b ejected from the bubble generating part at the bow.

  Then, the bubble generating section performs the bubble ejection to 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 9 from the bubble ejection to the side where the draft becomes deeper. Is equipped with a high-pressure gas supply control system 10 for reducing the amount of jets, so that the bubbles that flow along the outer surface of the jet bottom from the above-mentioned bubble generating part even when the hull largely rolls during navigation in waves The distribution of b is made uniform.

  In addition, the bubble generating part is divided into a plurality of compartments 2a across the width of the bottom of the ship at the bow and is provided with a plurality of bubble outlets 1b in the ship bottom skin portion 1a as the bottom wall of the compartment 2a. The high-pressure gas supply control system 10 is detected by the rolling sensor 9. The high-pressure gas supply control system 10 is connected to the plurality of compartments 2 a through a valve 5. Based on the hull lateral inclination angle, the high-pressure gas supply amount to the compartment 2a on the side where the draft becomes shallow due to the horizontal inclination of the hull is made smaller than the gas supply amount to the compartment 2a on the side where the draft becomes deep, By controlling the opening of the valve 5, the distribution of the bubbles b for covering the bottom of the ship is appropriately performed without waste.

  Further, the high pressure gas supply control system 10 is set to close the valve 5 corresponding to the branch chamber 2a in order to stop the supply of the high pressure gas to the branch chamber 2a on the side where the draft becomes the shallowest when the hull is inclined sideways. As a result, even when the hull is largely inclined during turning of the marine vessel that is being navigated, air bubbles are appropriately distributed to the outer surface of the bottom of the vessel 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 amount of bubble ejection from the bubble outlet 1b can be controlled according to the water speed of the hull during navigation. If the gas supply control system 10 is set so that the amount of high-pressure gas supplied to the compartment 2a can be adjusted by the opening of the valve 5 based on the ship speed detected by the ship speedometer 11, the ship speed is low. Can reduce the amount of high-pressure gas supply by suppressing the ejection of bubbles.

  Further, a high-pressure gas supply supplied to the compartment 2a based on the ship speed detected by the ship speedometer 11 so that the amount of bubble injection from the bubble outlet 1b can be controlled according to the water velocity of the hull during navigation. Even when the compressor control system 12 for adjusting the amount by controlling the air compressor 8 connected to the high-pressure gas supply pipe 3 is provided, the high-pressure gas is suppressed by suppressing the ejection of bubbles when the ship speed is low. The amount of supply can be saved.

  Further, when intermediate bubble holding plates 15, 15a, 15b, 15c extending from the bow portion toward the stern portion are provided on the bottom surface of the ship bottom between the pair of left and right bubble holding plates 15, It is possible to more appropriately hold the air bubble group along, and 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. Is an enlarged sectional view taken along taken along line B-B line of sight of FIG. It is explanatory drawing about a part 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. It is a hull bottom view which shows the other modification of the apparatus of this invention corresponding to FIG. It is a hull bottom view which shows the other modification of the apparatus of this invention corresponding to FIG. It is a hull bottom view which shows the other modification of the apparatus of this invention corresponding to FIG. It is a hull cross-sectional view showing another modification of the device of the present invention corresponding to FIG. It is a hull cross-sectional view showing another modification of the device of the present invention corresponding to FIG. It is a longitudinal cross-sectional view of the main part of the hull which shows the modification of the apparatus of this invention corresponding to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ship bottom part 1a Ship bottom skin part 1b Bubble jet 2 Gas chamber 2a Branch 2A 2nd gas chamber 2B Bubble side gas chamber 2b Partition 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 Bubble holding plate
15a Central bubble holding plate
15b, 15c Intermediate bubble holding plate b Bubble D Air flow control unit

Claims (6)

A pair of left and right air bubbles to prevent the air bubbles generated from the air bubble generating part from escaping to the side of the hull are provided along with the air bubble generating part on the bow bottom for flowing many air bubbles along the bottom surface of the ship bottom during navigation. A plate is projected on the bottom of the bottom of the ship along the sides of the bottom of the ship from the bow to the stern, and the distribution of the bubbles flowing along the outer surface of the bottom of the ship is ejected from the bubble generation section during navigation. In order to reduce the draft, the bubble generating portion is configured to reduce the amount of bubble jetting to the side where the draft becomes shallow when the hull is tilted based on the hull lateral tilt angle detected by the hull roll sensor. characterized in that it comprises a high pressure gas supply control system for causing reduced less than the bubble ejection amount to, ship-body frictional resistance reducing device.   The bubble generating section is divided into a plurality of compartments across the width of the bottom of the ship at the bow and is provided with a plurality of bubble outlets on the bottom wall of the same compartment, and a high pressure to the plurality of compartments A high-pressure gas supply pipe that communicates from the gas supply source through the valve, and the high-pressure gas supply control system controls the opening of the valve based on the hull lateral inclination angle detected by the roll sensor. The hull frictional resistance reduction device according to claim 1, wherein the device is configured to control.   The high-pressure gas supply control system is set to close the valve corresponding to the same compartment in order to stop the high-pressure gas supply to the compartment on the side where the draft is shallowest when the hull is inclined sideways. The hull frictional resistance reduction device according to claim 2, wherein   The high-pressure gas supply control system is supplied to the compartment based on the ship speed detected by the ship speedometer in order to control the amount of bubble injection from the bubble outlet according to the water speed of the hull during navigation. The hull frictional resistance reduction device according to claim 2 or 3, wherein a high-pressure gas supply amount is set so as to be adjusted by an opening degree of the valve.   In order to control the amount of bubble ejection from the bubble ejection port according to the water velocity of the hull during navigation, the amount of high-pressure gas supplied to the compartment is determined based on the ship speed detected by a ship speedometer. The hull frictional resistance reduction device according to any one of claims 2 to 4, further comprising a control system for adjusting by controlling a high-pressure gas generation source connected to the gas supply pipe.   6. The intermediate bubble holding plate extending from the bow portion toward the stern portion is projected on the bottom surface of the ship bottom between the pair of right and left bubble holding plates. 6. The hull frictional resistance reduction device as described in one.

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