KR20220099257A - Air lubrication system for ship - Google Patents

Abstract

The present invention is a ship including an air lubrication system, and more specifically to the ship including an air lubrication system comprising a ship body and an air supply part provided inside the ship body, wherein the ship body includes a step part formed concavely along the longitudinal direction of the ship body on the bottom surface of the ship body. The air supply part includes a driving part for providing a driving force capable of flowing air, and a jet orifice for injecting the air flowed from the driving part into water. The ship including an air lubrication system can more effectively reduce frictional resistance caused by viscous friction with seawater during ship operation.

Description

A ship including an air lubrication system {Air lubrication system for ship}

The present invention is a ship including an air lubrication system, and more specifically, by spraying air along the bottom surface of the ship's hull to form an air layer, thereby reducing frictional resistance generated due to viscous friction with seawater during the operation of the ship. It relates to a ship comprising an air lubrication system.

In ship operation, reducing frictional resistance, which accounts for 60% to 80% of the total resistance of the ship, is the most important part in improving operation speed and saving energy, which is the most efficient way to reduce ship operating costs and greenhouse gas emissions . For example, Korean Patent Registration No. 10-1750761 (June 20, 2017) discloses an air lubrication device and a ship including the same.

On the other hand, conventional technologies mainly utilize a method of reducing frictional resistance by installing an air injection hole at the bottom of an existing ship to cover air bubbles in the form of bubbles on the surface of the hull, but an air layer is formed on the bottom of the ship There was a problem in that the resistance reduction rate was lower than that of the In addition, in order to increase the resistance reduction rate, an air layer is sometimes formed on the bottom of the ship, but the step for forming the air layer is not formed on the bottom of the ship, and the air layer is properly formed due to the arrangement of the injection hole that does not consider the recirculation flow at the bottom There was a problem that could not be done.

Republic of Korea Patent Publication No. 10-1750761 (2017.06.20.)

The present invention has been devised to solve the problems of the prior art as described above, and a ship including an air lubrication system capable of more efficiently reducing frictional resistance caused by viscous friction with seawater during the operation of the ship Its purpose is to provide

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems to be solved by the present invention not mentioned here are to those of ordinary skill in the art to which the present invention belongs from the description below. can be clearly understood.

In a ship including an air lubrication system according to a preferred embodiment of the present invention, it includes a ship body and an air supply unit provided inside the ship body, wherein the ship body is disposed on a bottom surface of the ship body. It includes a step portion concavely formed along the longitudinal direction of the body, and the air supply unit comprises a driving unit for providing a driving force for flowing air and a jetting port for injecting the air flowed from the driving unit into the water. do.

In addition, the injection hole according to a preferred embodiment of the present invention, characterized in that a plurality of arranged along the width direction of the ship body.

In addition, the injection hole according to a preferred embodiment of the present invention, a virtual first row formed along the width direction of the ship body, and a virtual second row formed parallel to the first row and spaced apart by a predetermined interval It is characterized in that it is arranged along

In addition, the injection port according to a preferred embodiment of the present invention is characterized in that it is provided to be inclined with respect to the water surface.

In addition, at least a portion of the step portion according to a preferred embodiment of the present invention is characterized in that it is formed to be round.

By means of a solution to the above problem, the ship including the air lubrication system of the present invention sprays air along the bottom surface of the ship's hull to form an air layer, so that friction generated due to viscous friction with seawater during the operation of the ship It is effective to provide a ship including an air lubrication system for reducing resistance.

In addition, in the ship including the air lubrication system of the present invention, the first row is formed at a distance spaced apart by 9 times the height of the step from one end of the step, and the separation distance between the first and second row is in the longitudinal direction of the step. By making it to be formed at 1/3 of the length, there is an advantage in that the air layer can be prevented from collapsing by the recirculation flow. That is, in the ship including the air lubrication system of the present invention, the air injected from the plurality of injection holes arranged in the first row and the air injected from the plurality of injection holes arranged in the second row are combined to form a balanced and stable air layer as a whole. There is an advantage.

In addition, since the bending angle of the bent part 111 of the ship including the air lubrication system of the present invention is formed to be inclined at 130 degrees with respect to the water surface, there is an advantage that the frictional resistance of the ship body can be further reduced.

The effects of the present invention are not limited to the above-mentioned effects, and the effects of the present invention not mentioned herein will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. .

1 is a side view showing the configuration of a ship including an air lubrication system according to an embodiment of the present invention.
2 is an enlarged view showing the configuration of a step portion of a ship including an air lubrication system according to an embodiment of the present invention.
3 is a bottom view showing the configuration of a step portion of a ship including an air lubrication system according to another embodiment of the present invention.
Figure 4 (a) is a conceptual diagram showing a state in which the air injected through the injection unit of the ship including the air lubrication system according to an embodiment of the present invention forms an air layer.
Figure 4 (b) is a conceptual diagram showing a state in which the jetted air flows in the prior art.
5 is a view showing the analysis result of the frictional resistance reduction rate of the ship body according to the inclination angle of the injection port of the ship including the air lubrication system according to an embodiment of the present invention.

Terms used in this specification will be briefly described, and the present invention will be described in detail.

The terms used in the present invention have been selected as currently widely used general terms as possible while considering the functions in the present invention, but these may vary depending on the intention or precedent of a person skilled in the art, the emergence of new technology, and the like. Therefore, the term used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than the name of a simple term.

In the entire specification, when a part “includes” a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

Hereinafter, with reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the embodiments of the present invention. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein.

Specific details including the problem to be solved for the present invention, the means for solving the problem, and the effect of the invention are included in the embodiments and drawings to be described below. Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 , in a ship including an air lubrication system according to a preferred embodiment of the present invention, a ship body 100 and an air supply unit 200 provided in the ship body 100 are included. .

First, the ship body 100 is provided. The ship body 100 is a structure that can float on water, load people, livestock, and materials, and move on water, and may be a boat, a ferry, a steamer, a warship, a cargo ship, a passenger ship, an oil tanker, etc., but is not limited thereto.

At this time, the ship body 100 includes a step portion 110 formed by being concavely recessed along the longitudinal direction of the ship body 100 on the bottom surface of the ship body 100 . In addition, at least a portion of the step portion 110 may be formed to be rounded. In more detail, one end of the step portion 110 is bent from the ship body 100 to provide a bent portion 111 formed in a stepwise manner, and the other end of the step portion 110 has a gentle slope. A round portion 112 formed to be round is provided. At this time, the bent portion 111 is provided with a spray hole 220 to be described later. Accordingly, an air layer is formed while the air injected from the injection hole 220 to be described later flows along the step portion 110 . In other words, the air injected from the injection port 220, which will be described later, forms an air layer while flowing in the direction from the bent portion 111 to the round portion 112, thereby reducing the frictional resistance of the ship body 100. will be.

Next, the air supply unit 200 is provided. The air supply unit 200 is provided in the interior of the ship body 100 and adjacent to the bottom surface. At this time, the air supply unit 200 serves to supply air to the stepped portion 110 to form an air layer in the stepped portion 110 .

In more detail, the air supply unit 200 includes a driving unit 210 that provides a driving force to allow air to flow, and an injection hole 220 that injects the air flowed from the driving unit 210 into the water. In this case, the driving unit 210 and the injection port 220 may be connected through a pipe, and a supply unit (not shown) for supplying air to the driving unit 210 may be provided.

Here, the injection hole 220 may be provided in the bent portion 111 . That is, the air injected from the injection hole 220 flows in a direction from the bent portion 111 toward the round portion 112 to form an air layer in the step portion 110 . At this time, by preventing the direct interference between the air injected from the injection port 220 and the fluid in the water by the bent portion 111, the air layer can be more uniformly formed in the step portion 110. For example, when the ship body 100 is operated in the left direction, the bent part 111 is provided at the left end of the ship body 100, and the air injected from the injection port 220 is in the water. It is to minimize the interference with the fluid. In addition, the speed of the air injected from the injection port 220 by the round part 112 toward the other end of the step part 110 may be maintained. For example, when the ship body 100 is operated in the left direction, the round part 112 is provided at the right end of the ship body 100 , and the air injected from the injection port 220 is the round It is to minimize the decrease in the flow velocity toward the part 112 .

And, referring to FIG. 2 , a plurality of the injection holes 220 may be arranged along the width direction of the ship body 100 . In more detail, the injection hole 220 is formed in a virtual first row 221 formed along the width direction of the ship body 100, parallel to the first row 211 and spaced apart by a predetermined interval. may be arranged along the virtual second column 222 . That is, the air flowing by the driving unit 210 is divided into the plurality of injection holes 220 and uniformly sprayed as a whole. In other words, the plurality of injection holes 220 are arranged along the width direction of the step portion 110 so that air flows in the step portion 110 in the direction toward the round portion 112 uniformly as a whole. .

Here, the first row 221 is provided in the bent part 111 . In addition, the separation distance between the first row 221 and the second row 222 may be 1/3 of the length of the step part 110 in the longitudinal direction. Accordingly, the air injected from the injection hole 220 provided in the first row 221 is combined with the air injected from the injection hole 220 provided in the second row 222 to recirculate flow (reverse flow). This does not occur and an air layer is formed up to the round part 112 .

That is, the air injected from the injection hole 220 provided in the first row 221 forms an air layer, and the recirculation flow occurs at a point that is 1/3 of the length in the longitudinal direction of the step portion 110 . do. As such, when the air injected from the injection hole 220 provided in the first row 221 is recirculated, the boundary of the air layer is collapsed, and the frictional resistance of the ship body 100 is increased. In order to solve this problem, the separation distance between the first row 221 and the second row 222 is 1/3 of the length of the step part 110 in the longitudinal direction.

Next, the first row 221 may be formed at a distance from the bent portion 111 that is 9 times the step height H of the stepped portion 110 . That is, the first row 221 may be formed at a distance spaced apart from one end of the step portion 110 by 9 times the step height H. Therefore, since the reattachment distance of the recirculation flow can be determined in proportion to the step height H of the step part 110 , the first row 221 is the step height from one end of the step part 110 . (H) is formed at a distance separated by 9 times, and the distance between the first row 221 and the second row 222 is 1/3 of the length of the step 110 in the longitudinal direction. As much as possible, there is an advantage in that it is possible to prevent the collapse of the air layer by the recirculation flow.

Next, the separation distance between the injection hole 220 arranged in the first row 221 and the adjacent injection hole 220 may be formed to be 0.05 to 0.2 times the distance in the width direction of the ship body 100 . At this time, when the separation distance between the injection hole 220 arranged in the first row 221 and the adjacent injection hole 220 is less than 0.05 times the distance in the width direction of the ship body 100, the injection hole ( 220) increases the time and cost required for manufacturing abruptly increases, and the distance between the injection hole 220 and the adjacent injection hole 220 is reduced, so that the injection hole 220 and the adjacent injection hole 220 There is a problem in that the air layer is not formed in parallel with the step portion 110 due to interference between the sprayed air. In addition, when the separation distance between the injection hole 220 arranged in the first row 221 and the adjacent injection hole 220 exceeds 0.2 times the distance in the width direction of the ship body 100, the injection hole 220 ) and the adjacent injection hole 220 increases, there is a problem that the air injected from the injection hole 220 and the adjacent injection hole 220 does not form a balanced air layer as a whole. Accordingly, the separation distance between the injection hole 220 arranged in the first row 221 and the adjacent injection hole 220 is 0.05 to 0.2 times the distance in the width direction of the ship body 100 .

And, the separation distance between the injection hole 220 arranged in the second row 222 and the adjacent injection hole 220 may be formed to be 0.2 to 0.3 times the distance in the width direction of the ship body 100 . That is, the plurality of injection holes 220 arranged in the second row 222 have a larger separation distance between the adjacent injection holes 220 than the plurality of injection holes 220 arranged in the first row 221 . will become Therefore, there is an advantage that can reduce the time and cost required for manufacturing the injection hole 220 . In addition, the separation distance between the injection holes 220 arranged in the second row 222 and the adjacent injection holes 220 is 0.05 times the distance in the width direction of the ship body 100 in the same manner as in the first row 221 . to 0.2 times.

Also, referring to FIG. 3 , the plurality of injection holes 220 arranged in the first column 221 and the plurality of injection holes 220 arranged in the second column 222 may be alternately arranged with each other. have. Accordingly, the air injected from the plurality of injection holes 220 arranged in the first row 221 and the air injected from the plurality of injection holes 220 arranged in the second row 222 are combined to create a balanced overall balance. There is an advantage that a stable air layer can be formed.

Next, referring to FIG. 4A , the injection hole 220 may be inclined with respect to the water surface. That is, the injection hole 220 is provided inclined with respect to the longitudinal direction of the ship body 100, so that the air layer is uniformly formed as a whole by the air injected from the injection hole 220, and the boundary layer is clearly formed. . In addition, while the air injected from the injection holes 220 arranged in the first row 221 flows, the air injected from the injection holes 220 arranged in the second row 222 is minimized from interfering with each other. There is an advantage in that the air layer can be stably formed.

On the other hand, as shown in (b) of FIG. 4 , when the injection hole 220 is provided perpendicular to the water surface, it is not easy for the air injected from the injection hole 220 to form an air layer, and from the injection hole 220 There is a problem in that the air is injected in a direction perpendicular to the flow direction of the injected air and interferes with each other. Therefore, the injection hole 220 is provided to be inclined with respect to the water surface.

Next, the bent part 111 may be inclined at an angle of 130 degrees with respect to the water surface. That is, the bending angle (R) of the bent portion 111 is formed to be 130 degrees based on the longitudinal direction of the ship body (100). Accordingly, the recirculation area of the air injected from the injection holes 220 arranged in the first row 221 is reduced, and the injection holes ( 220), a stable air layer is formed as the air injected from the coalesce is combined, and there is an advantage in that the frictional resistance reduction rate of the ship body 100 can be improved. That is, the air injected from the injection holes 220 arranged in the first row 221 is recirculated to form a thin air layer, and as it flows to the wake, the frictional resistance reduction rate of the ship body 100 is improved. will be.

More specifically, referring to FIG. 5 , numerical analysis was performed by setting the bending angle R of the bending part 111 to 45 degrees, 90 degrees, and 130 degrees with respect to the water surface, and the bending part 111 When the bending angle (R) of is provided to be inclined at an angle of 130 degrees relative to the water surface, the frictional resistance of the ship body 100 is reduced by 20.2% compared to the conventional ship, showing the highest reduction rate. That is, by forming the bending angle (R) of the bent portion 111 inclined at 130 degrees with respect to the water surface, the frictional resistance of the ship body 100 can be further reduced. At this time, the bottom part of the ship body 100 has a length of 7.59 m, a width of 1.70 m, and a height of 0.035 m at the bottom of the flat plate having a length of 8.19 m, a width of 1.71 m, and a height of 0.06 m so that the step part 110 is formed. The experiment was conducted under the conditions of Fr = 0.173 and Re = 1.1*10^7. In addition, in the analysis test, the value of the flow coefficient Cq was 0.149, and the injection speed was 1.551 m/s. At this time, the calculation of the flow coefficient is a value obtained by dividing the flow rate (Q) by the product of the inflow velocity (V), the width of the ship bottom plate part (B), and the step height (H). In addition, the step height of the step portion 110 was 0.035 m, and the length of the step portion 110 in the longitudinal direction was fixed to 7.59 m. In addition, the injection holes 220 were formed to have a circular cross-section, and a total of 16 nozzles were arranged in each row, each having a diameter of 0.0445 m and arranged to have an interval of 0.89 m.

As a result, in Case 1 where the bending angle (R) of the bent part 111 is 45 degrees, the frictional resistance of the ship body 100 was reduced by 18.4%, and the bending angle (R) of the bent part 111 was In case 3 where is 90 degrees, the frictional resistance of the ship body 100 was reduced by 19.3%, and in case 2 where the bending angle R of the bent part 111 was 130 degrees, the It was found that the frictional resistance decreased by 20.2%. Therefore, by forming the bending angle (R) of the bent portion 111 inclined to 130 degrees, there is an advantage that can further reduce the frictional resistance of the ship body (100).

As such, those skilled in the art to which the present invention pertains will understand that the above-described technical configuration of the present invention may be implemented in other specific forms without changing the technical spirit or essential characteristics of the present invention.

Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the following claims rather than the above detailed description, and the meaning and scope of the claims and their All changes or modifications derived from the concept of equivalents should be construed as being included in the scope of the present invention.

100: ship body
110: step part
111: bent part
112: round part
200: air supply
210: drive unit
220: nozzle
221: first row
222: second row
H: step height
R : bending angle of the bending part

Claims (5)

ship body; and
Including; an air supply unit provided in the interior of the ship body;
The ship body is
Including; and a step portion concavely formed along the longitudinal direction of the ship body on the bottom surface of the ship body,
The air supply unit,
a driving unit providing a driving force capable of flowing air; and
A ship including an air lubrication system comprising a; injection hole for jetting the air flowed from the driving unit into the water. According to claim 1,
The injection port, a ship including a plurality of air lubrication system, characterized in that arranged along the width direction of the ship body. 3. The method of claim 2,
The nozzle is
A vessel including an air lubrication system, characterized in that the imaginary first row formed along the width direction of the ship body and the imaginary second row formed parallel to the first row and spaced apart by a predetermined interval . According to claim 1,
The injection port is a vessel including an air lubrication system, characterized in that provided inclined with respect to the water surface. According to claim 1,
At least a portion of the step portion, a ship including an air lubrication system, characterized in that formed to be round.

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