KR102524912B1 - Air lubrication system for ship - Google Patents

Abstract

The present invention relates to a ship including an air lubrication system, and more particularly, includes a ship body and an air supply unit provided inside the ship body, wherein the ship body has a longitudinal direction of the ship body on the bottom surface of the ship body. and a stepped portion concavely formed along the air supply unit, characterized in that it includes a driving unit providing a driving force capable of flowing air and a jetting hole for injecting the air flowed from the driving unit into water.

Description

Ships including air lubrication system {Air lubrication system for ship}

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

In ship operation, reducing frictional resistance, which accounts for 60% to 80% of the ship's total resistance, is the most important part in improving sailing speed and saving energy, which is the most efficient way to reduce ship operating costs and greenhouse gas emissions. . For example, Republic of Korea Patent Registration No. 10-1750761 (2017.06.20.) 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 using a method of covering air bubbles in the form of bubbles on the surface of a ship by installing an air nozzle on the bottom of the ship, but forming an air layer on the bottom of the ship. There was a problem in that the resistance reduction rate was lower than that of In addition, in order to increase the resistance reduction rate, an air layer is sometimes formed on the bottom surface of the ship bottom. However, a step for forming an air layer is not formed on the bottom surface of the ship bottom, and the air layer is properly formed due to the arrangement of the nozzles without considering the recirculation flow in the stage. There was a problem with not being able to do it.

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

The present invention has been made 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 generated due to viscous friction with seawater during ship operation. 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 that are not mentioned here are to those of ordinary skill in the art to which the present invention belongs from the description below. will be clearly understood.

In a ship comprising 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 on the bottom surface of the ship body. It includes a stepped portion concavely formed along the longitudinal direction of the main body, and the air supply unit includes a driving unit providing a driving force capable of flowing air and a jetting hole for injecting the air flowed from the driving unit into water. do.

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

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

In addition, the spray hole according to a preferred embodiment of the present invention is characterized in that it is provided inclined relative to the water surface.

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

By means of solving the above problems, the ship including the air lubrication system of the present invention injects air along the bottom surface of the hull to form an air layer, resulting in friction caused by viscous friction with seawater during operation of the ship. It is effective in providing a ship including an air lubrication system that reduces resistance.

In addition, in the ship including the air lubrication system of the present invention, the first row is formed at a distance separated from one end of the stepped portion by 9 times the height of the step, and the distance between the first and second rows is in the longitudinal direction of the stepped portion. There is an advantage in preventing collapse of the air layer due to recirculation flow by being formed with 1/3 of the length. That is, in the ship including the air lubrication system of the present invention, the air injected from the plurality of nozzles arranged in the first row and the air injected from the plurality of nozzles arranged in the second row are combined to form a balanced and stable air layer as a whole. There is an advantage.

In addition, by making the bending angle of the bent part 111 of the ship including the air lubrication system of the present invention inclined at 130 degrees relative 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 effects mentioned above, and the effects of the present invention not mentioned here will be clearly understood by those skilled in the art from the description below. .

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 stepped 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 stepped 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 how 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 how the injected air flows in the prior art.
5 is a view showing the result of analyzing the frictional resistance reduction rate of the ship body according to the inclination angle of the jet of the ship including the air lubrication system according to an embodiment of the present invention.

The 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 from general terms that are currently widely used as much as possible while considering the functions in the present invention, but these may vary depending on the intention of a person skilled in the art or precedent, the emergence of new technologies, 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, not simply the name of the term.

In the entire specification, when a part is said to "include" a certain component, it means that it may further include other components, not excluding other components unless otherwise stated.

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

The specific details, including the problem to be solved, the means for solving the problem, and the effect of the invention with respect to the present invention are included in the embodiments and drawings to be described below. Advantages and features of the present invention, and methods for achieving them, will become clear 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.

Referring to FIG. 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 inside 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 to load people, livestock, and materials and move on water, and may be a boat, ferry, steamship, warship, cargo ship, passenger ship, oil tanker, etc., but is not limited thereto.

At this time, the ship body 100 includes a stepped 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 stepped portion 110 may be formed to be rounded. More specifically, one end of the stepped portion 110 is provided with a bent portion 111 formed in a stepwise manner by being bent from the ship body 100, and the other end of the stepped 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 nozzle 220, which will be described later, flows along the stepped portion 110. In other words, the air injected from the nozzle 220 to be described later forms an air layer while flowing in a direction from the bent portion 111 toward 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 adjacent to the bottom surface inside the vessel body 100. At this time, the air supply unit 200 serves to supply air to the stepped portion 110 so that an air layer is formed in the stepped portion 110 .

In more detail, the air supply unit 200 includes a driving unit 210 that provides a driving force capable of flowing air and a nozzle 220 that injects the air flowed from the driving unit 210 into water. At this time, the drive unit 210 and the nozzle 220 may be connected through a pipe, and a supply unit (not shown) may be provided for supplying air to the drive unit 210.

Here, the injection hole 220 may be provided in the bent portion 111 . That is, the air injected from the nozzle 220 flows in a direction from the bent portion 111 toward the round portion 112 to form an air layer in the stepped portion 110 . In this case, the air layer sprayed from the nozzle 220 is prevented from directly interfering with the fluid in the water by the bent portion 111, so that the air layer can be more uniformly formed in the stepped portion 110. For example, when the ship body 100 is operating in the left direction, the bent portion 111 is provided at the left end of the ship body 100, so that the air injected from the spray hole 220 is in the water. It is to minimize the interference with the fluid. In addition, the air ejected from the spray hole 220 by the round part 112 may maintain a speed while moving toward the other end of the stepped part 110 . For example, when the ship body 100 is operating in a leftward direction, the round part 112 is provided at the right end of the ship body 100, and the air injected from the spray hole 220 blows the round part 112. It is to minimize the decrease in the flow rate toward the part 112.

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

Here, the first row 221 is provided on the bent part 111 . In addition, the separation distance between the first row 221 and the second row 222 may be formed to be 1/3 of the length of the stepped portion 110 in the longitudinal direction. Accordingly, the air injected from the nozzles 220 provided in the first row 221 is merged with the air injected from the nozzles 220 provided in the second row 222 and recirculated flow (countercurrent) This does not occur and an air layer is formed up to the round portion 112 .

That is, the air injected from the nozzle 220 provided in the first row 221 forms an air layer, and then recirculation flow occurs at a point that is 1/3 of the length of the stepped portion 110 in the longitudinal direction. do. In this way, when the air injected from the injection port 220 provided in the first row 221 is recirculated, the air layer boundary collapses and the frictional resistance of the ship body 100 increases. To solve this problem, the separation distance between the first row 221 and the second row 222 is formed to be 1/3 of the length of the stepped portion 110 in the longitudinal direction.

Next, the first row 221 may be formed at a distance that is 9 times the step height H of the stepped portion 110 from the bent portion 111 . That is, the first row 221 may be formed at a distance separated from one end of the stepped portion 110 by 9 times the height of the stepped portion 110 . Therefore, since the reattachment distance of the recirculation flow can be determined in proportion to the step height (H) of the step portion 110, the first row 221 is the step height from one end of the step portion 110. It is formed at a distance 9 times greater than (H), and the distance between the first row 221 and the second row 222 is formed as 1/3 of the length of the stepped portion 110 in the longitudinal direction. In this way, there is an advantage in preventing collapse of the air layer due to recirculating flow.

Next, the distance between the nozzles 220 arranged in the first row 221 and the adjacent nozzles 220 may be 0.05 to 0.2 times the distance in the width direction of the ship body 100. At this time, when the distance between the nozzles 220 arranged in the first column 221 and the adjacent nozzles 220 is less than 0.05 times the distance in the width direction of the ship body 100, the nozzles ( 220), the time and cost required for manufacturing increase rapidly, and the distance between the nozzle 220 and the adjacent nozzle 220 decreases, so that the nozzle 220 and the adjacent nozzle 220 There is a problem in that the air layer is not formed parallel to the stepped portion 110 due to interference between injected air. In addition, when the distance between the nozzles 220 arranged in the first row 221 and the adjacent nozzles 220 exceeds 0.2 times the distance in the width direction of the ship body 100, the nozzles 220 ) and the adjacent spray hole 220 increases, so that the air sprayed from the spray hole 220 and the adjacent spray hole 220 does not form a balanced air layer as a whole. Therefore, the distance between the nozzles 220 arranged in the first row 221 and the adjacent nozzles 220 is 0.05 to 0.2 times the distance in the width direction of the ship body 100.

In addition, the distance between the nozzles 220 arranged in the second row 222 and the adjacent nozzles 220 is 0.2 to 0.3 times the distance in the width direction of the ship body 100. Can be formed. That is, the plurality of nozzles 220 arranged in the second column 222 have a larger separation distance between adjacent nozzles 220 than the plurality of nozzles 220 arranged in the first column 221 It will be. Accordingly, there is an advantage in that time and cost required for manufacturing the nozzle 220 can be reduced. In addition, the distance between the nozzles 220 arranged in the second column 222 and the adjacent nozzles 220 is 0.05 times the distance in the width direction of the ship body 100, the same as in the first column 221. to 0.2 times may also be formed.

In addition, 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. there is. Therefore, the air injected from the plurality of nozzles 220 arranged in the first row 221 and the air injected from the plurality of nozzles 220 arranged in the second row 222 are combined to form a balanced overall There is an advantage that a stable air layer can be formed.

Next, referring to (a) of FIG. 4 , the spray hole 220 may be inclined with respect to the water surface. That is, the spray hole 220 is 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 sprayed from the spray hole 220, and the boundary layer is clearly formed. . In addition, the air injected from the nozzles 220 arranged in the first row 221 flows while the air injected from the nozzles 220 arranged in the second row 222 minimizes interference with each other. There is an advantage in that the air layer can be stably formed.

In comparison, as shown in FIG. 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 inclined with respect to the water surface.

Next, the bent portion 111 may be inclined at an angle of 130 degrees with respect to the water surface. That is, the bending angle R of the bending portion 111 is formed at 130 degrees based on the longitudinal direction of the ship body 100. Accordingly, the recirculation area of the air injected from the nozzles 220 arranged in the first column 221 is reduced, and the nozzles arranged in the second column 222 before being changed to the form of air bubbles ( 220, there is an advantage in that the frictional resistance reduction rate of the ship body 100 can be improved as a stable air layer is formed while the air injected from the ship body 100 is combined. That is, the air injected from the nozzles 220 arranged in the first row 221 minimizes recirculation to form a thin air layer and flows to the wake, thereby improving the frictional resistance reduction rate of the ship body 100 will be.

In more detail, referring to FIG. 5, as a result of numerical analysis by setting the bending angle R of the bending part 111 to 45 degrees, 90 degrees, and 130 degrees based on the water surface, the bending part 111 When the bending angle R of is 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 bending part 111 inclined at 130 degrees with respect to the water surface, it is possible to further reduce the frictional resistance of the ship body 100. At this time, the bottom of the ship body 100 is 7.59 m long, 1.70 m wide, and 0.035 m high at the lower center of the flat plate having a length of 8.19 m, a width of 1.71 m, and a height of 0.06 m. The stepped portion 110 is formed, The experiment was conducted under the conditions of Fr = 0.173 and Re = 1.1*10^7. Further, in the analytical test, the value of the flow coefficient Cq was 0.149, and the spraying 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 inlet speed (V), the width (B) of the ship bottom plate part, and the step height (H). In addition, the step height of the stepped portion 110 is 0.035 m, and the length of the stepped portion 110 in the longitudinal direction is fixed at 7.59 m. In addition, the nozzle 220 was formed to have a circular cross section, and a total of 16 were arranged in each row, each having a diameter of 0.0445 m and an interval of 0.89 m.

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

As such, it will be understood that the technical configuration of the present invention described above can be implemented in other specific forms without changing the technical spirit or essential features of the present invention by those skilled in the art to which the present invention belongs.

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

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

Claims (5)

ship body; and
Including; an air supply unit provided inside the ship body,
The ship body,
Including; a step portion formed concavely along the longitudinal direction of the ship body on the bottom surface of the ship body,
The air supply unit,
a driving unit that provides a driving force capable of moving air; and
Including; a spray hole for spraying the air flowed from the driving unit into water,
The nozzle is plural,
Arranged along a virtual first column formed along the width direction of the ship body and a virtual second column formed parallel to the first column and spaced apart by a predetermined interval,
The plurality of nozzles arranged in the first column and the plurality of nozzles arranged in the second column are alternately arranged with each other,
The separation distance between the first row and the second row is formed by 1/3 of the length of the step portion in the longitudinal direction,
The distance between the nozzles arranged in the first row and the adjacent nozzles is 0.05 to 0.2 times the distance in the width direction of the ship body,
The distance between the nozzles arranged in the second row and the adjacent nozzles is 0.2 to 0.3 times the distance in the width direction of the ship body,
One end of the stepped portion is provided with a bent portion formed in a stepwise manner by being bent from the ship body,
The bent portion is a vessel including an air lubrication system, characterized in that provided inclined at an angle of 130 degrees relative to the water surface. delete delete delete delete

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