KR20150126452A - A ship for reducing vibromotive force - Google Patents

A ship for reducing vibromotive force Download PDF

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Publication number
KR20150126452A
KR20150126452A KR1020140053289A KR20140053289A KR20150126452A KR 20150126452 A KR20150126452 A KR 20150126452A KR 1020140053289 A KR1020140053289 A KR 1020140053289A KR 20140053289 A KR20140053289 A KR 20140053289A KR 20150126452 A KR20150126452 A KR 20150126452A
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South Korea
Prior art keywords
working gas
propeller
hull
receiving membrane
gas receiving
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Application number
KR1020140053289A
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Korean (ko)
Inventor
이정훈
전명호
허갑
김윤식
김진학
박지환
박형길
이경준
한재문
Original Assignee
삼성중공업 주식회사
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Application filed by 삼성중공업 주식회사 filed Critical 삼성중공업 주식회사
Priority to KR1020140053289A priority Critical patent/KR20150126452A/en
Priority to JP2016564165A priority patent/JP6275872B2/en
Priority to PCT/KR2015/004354 priority patent/WO2015167263A1/en
Priority to CN201580024060.XA priority patent/CN106458307B/en
Publication of KR20150126452A publication Critical patent/KR20150126452A/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/18—Propellers with means for diminishing cavitation, e.g. supercavitation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/28—Other means for improving propeller efficiency
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
    • B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
    • B63H5/16—Arrangements on vessels of propulsion elements directly acting on water of propellers characterised by being mounted in recesses; with stationary water-guiding elements; Means to prevent fouling of the propeller, e.g. guards, cages or screens

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Vibration Prevention Devices (AREA)

Abstract

Disclosed is a ship for reducing propeller cavitation organic vibromotive force. According to an embodiment of the present invention, the ship for reducing propeller cavitation organic vibromotive force comprises: a hull wherein a propeller is provided; and a working gas accommodated membrane pad coupled to the hull adjacent to the propeller, wherein working gas generating a reflected wave to raise a destructive interference phenomenon with an incident wave generated in case of rotation of the propeller is accommodated in one side.

Description

A ship for reducing vibromotive force,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a propeller cavitation organic exciter power reduction type ship, and more particularly, to a propeller cavitation organic exciter power reduction type ship improved in structure for reducing excitation power.

When the propeller provided at the rear of the ship rotates in water, the water flows to the propeller blade surface, causing a difference in hydraulic pressure between the front and back surfaces of the propeller blade surface. The propulsion generated in this way allows the ship to be operated at sea.

On the other hand, when the propeller is operated for the operation of the ship, that is, when the propeller is rotated in water, a fluctuating pressure is generated in the water due to the propeller as the rotating body. The fluctuating pressure thus generated increases the excitation force to the hull, (Including noise).

Particularly, when cavitation occurs in the water by the propeller, vibration of the hull is severely generated because the excitation force is further increased.

This is because when the pressure in the water is low, the gas contained in the water escapes from the water and collects at a low pressure. As a result, bubbles are generated in the water, and when the bubbles reach the high pressure part, Thereby generating a fluctuating pressure.

In order to solve the problem of increased excitation force due to such fluctuating pressure, it is necessary to design the shape and size of the propeller blade itself differently, to improve the shape of the rear of the ship, to attach a separate reinforcing material for preventing noise and vibration, Or by applying various methods such as attaching a guide device for guiding the flow of the water flowing in the propeller, reducing the size of the propeller, or the like. However, it is practically effective to reduce the excitation force it's difficult.

The vibration problem including the noise transmitted to the hull by the propeller is increased when the propeller is operated. For example, when the ship is a cruise ship, such as a cruise ship or a warship, .

Accordingly, the present applicant has filed with the Korean Intellectual Property Office (KIPO) a number of technologies for reducing the excitation force by forming an air layer in the form of an air bubble on the surface of the hull adjacent to the propeller.

However, most of the prior art attempts to use the air layer, including the last-filed technology, require air to be continuously injected using a compressor to form an air layer, so that due to the installation and operation of the compressor and its related components Energy consumption and so on. Therefore, research and development are urgently needed to solve this problem.

Prior Art _1; Japanese Patent Application Laid-Open No. 8-188192 Prior Art _2; Japanese Unexamined Patent Application Publication No. 2009-274705

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a propeller which can prevent vibrations from occurring in the hull due to an increased excitation force when the propeller is operated, Which is capable of preventing the burden of the propeller cavitation.

According to an aspect of the present invention, there is provided a hull comprising: a hull having a propeller; And a working gas receiving membrane pad which is coupled to the hull adjacent to the propeller and receives a working gas for generating a reflected wave for causing destructive interference with an incident wave generated when the propeller rotates, Ships may be provided.

The material of the working gas receiving membrane pad may be a material whose acoustic impedance is similar to that of water.

The material of the working gas receiving membrane pad may be rubber, and the working gas may be air.

The working gas accommodating membrane pad may include: a pad body detachably coupled to the hull; And a working gas bag formed on one side of the pad body and sealed with the working gas.

The working gas receiving membrane pad may be coupled to the hull wall on the upper side of the propeller.

The work gas receiving membrane pads may be coupled to a plurality of wall surfaces of the hull adjacent to the propeller.

The working gas sizes of the working gas receiving membrane pads coupled to a plurality of wall surfaces of the hull can be different from each other.

When the propeller generates and controls vibration components of N (N is a natural number) frequency band, the N working gas receiving membrane pads may be attached to the wall surface of the hull adjacent to the propeller.

According to the present invention, it is possible to prevent vibrations from occurring in the hull due to an increase in excitation force when the propeller is operated, and in particular to reduce the energy consumption due to the installation and operation of the compressor, .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a structural view of a propeller area of a propeller cavitation organic exciter force reduction type ship according to a first embodiment of the present invention; FIG.
2 is an enlarged view of the area A in Fig.
FIG. 3 is a schematic rear view of the region A of FIG. 1, showing the state where the propeller is not shown.
Fig. 4 is a chart for measuring the impedance of water, rubber, and air.
5 is a view for explaining the principle of incident wave and reflected wave.
6 is a view of a working gas receiving membrane pad for illustrating equation (1).
Fig. 7 is a view showing a state where a working gas receiving membrane pad is installed in a region on the upstream side of the propeller, and shows a plurality of variable pressure measuring points.
Figure 8 is a graphical representation of the efficiency of a working gas receiving membrane pad relative to the frequency of the propeller.
Figure 9 is a graph summarizing the results of the 150 Hz band for the working gas receiving membrane pads corresponding to Figure 7;
FIG. 10 is a rear view of a ship designing reduction type ship according to a second embodiment of the present invention, in which the working gas receiving membrane pads are installed at various positions.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

FIG. 1 is a structural view of a propeller region of a propeller cavitation propulsion reduction type ship according to a first embodiment of the present invention, FIG. 2 is an enlarged view of region A of FIG. 1, and FIG. And is a schematic rear structural view showing a state in which the propeller is not shown.

Referring to these drawings, the propeller cavitation organic exciter power reduction type ship according to the present embodiment can prevent vibrations from occurring in the hull due to an increase in excitation force when the propeller 120 is operated, and in particular, And includes a hull 110 and a working gas receiving membrane pad 130 coupled to the hull 110 to prevent the burden of energy consumption due to installation and operation of the related parts.

At the rear of the hull 110, a propeller 120 for propelling the hull 110 is provided. A rudder 125 for adjusting the traveling direction of the ship is provided around the propeller 120. The rudder 125 may be a normal rudder or a bulb rudder.

For reference, the ship to which the present invention is applied may include all of marine vessels, warships, fishing vessels, carriers, drillships, cruise ships, special work ships, and the like, as well as floating marine structures. Therefore, the scope of right of the present embodiment can not be limited to a specific ship.

As described above, when the propeller 120 is operated, that is, when the propeller 120 is rotated in water, a fluctuating pressure is generated in the water due to the propeller 120 as a rotating body. ), Which causes vibration (including noise) in the hull.

The vibration transmitted to the hull 110 may be a serious problem, for example, as a cruise ship or a warship such as a warship, and should be prevented.

In other words, the vibrating force is increased due to the fluctuating pressure generated in the water during the operation of the propeller 120 to prevent the vibration of the hull 110 from being generated. For this purpose, in this embodiment, the working gas receiving membrane pad 130 ) Is applied.

As will be described in detail below, the working gas receiving membrane pad 130 applied to the vessel of the present embodiment has a completely different form from the structures forming the air layer, which is a conventional air bubble shape.

In other words, since the working gas receiving membrane pad 130 applied in the present embodiment is only a structure in which the air is confined, there is no need to install or operate the relevant parts including the compressor which should be used in the past .

Therefore, it is possible to fundamentally prevent the burden of installing and operating the compressor and related parts, and energy consumption.

The working gas receiving membrane pad 130 in this role is coupled to the hull 110 adjacent to the propeller 120 as shown in Figure 1 and is connected to the hull 110 as it is generated during rotation of the propeller 120, And has a shape in which a reflected wave is generated to cancel an incident wave, and a working gas is accommodated in one side.

In particular, the working gas receiving membrane pads 130 may be joined to the wall surface of the hull 110 on the upper side of the propeller 120. As an example, the work gas receiving membrane pads 130 are shown attached to the upper chamber of the propeller 120 in the figure.

Specifically, the working gas receiving membrane pad 130 includes a pad body 131 detachably coupled to the hull 110, and a working gas pocket 131 formed at one side of the pad body 131 to receive the working gas, (132).

In this embodiment, the material of the working gas receiving membrane pad 130 may be rubber, and the working gas may be air.

However, the scope of the rights of the present embodiment is not limited thereto. That is, if the material of the working gas receiving membrane pad 130 is a material similar to rubber, it is sufficient, and the working gas may be applied to various gases as long as it is not a liquid.

The pad body 131 forming the working gas receiving membrane pad 130 is a flat structure made of a rubber material and is utilized as a part detachably coupled to the hull 110.

The pad body 131 may be coupled to the hull 110 through a variety of structures and methods.

For example, the pad body 131 can be coupled to the hull 110 in various manners such as a bolt-nut coupling method, a fitting method, and a welding method in which an insert metal plate is welded. Therefore, the scope of the right of the present embodiment can not be limited to the manner in which the pad body 131 is coupled.

In this embodiment, the pad body 131 may have a rectangular shape, but the shape of the pad body 131 may be rectangular, circular, triangular, or the like. Therefore, the right range of the present embodiment can not be limited to the shape of the pad body 131. [

The working gas bag 132 is formed inside the pad body 131 and has a shape swollen to one side of the pad body 131.

Although the working gas pocket 132 has a circular shape in the present embodiment, the shape of the working gas pocket 132 may also be various polygonal shapes such as a triangle shape and a square shape. Therefore, Can not be.

As described above, the working gas bag 132 is filled with air as a working gas.

The working gas filled in the working gas pocket 132 is formed integrally with the working gas receiving membrane pad 130 when the working gas receiving pocket 132 is formed, It does not.

Hereinafter, the principle of reducing the exciting force due to the working gas receiving membrane pad 130 in which the working gas is hermetically sealed will be described in detail with reference to FIG. 4 to FIG.

Fig. 4 is a graph showing the impedance of water, rubber and air, Fig. 5 is a view for explaining the principle of an incident wave and a reflected wave, Fig. 6 is a drawing of a working gas receiving membrane pad, 7 is a view showing a state in which a working gas receiving membrane pad is installed in a region immediately upstream of the propeller, and FIG. 8 is a graph showing a plurality of fluctuation pressure measuring points, and FIG. 8 is a graph showing the efficiency of a working gas receiving membrane pad based on the frequency of the propeller Fig. 9 is a graph summarizing the results of the 150 Hz band for the working gas receiving membrane pads corresponding to Fig. 7, and Fig. 10 is a graph showing the result of the 150 Hz band for the working gas receiving membrane pads corresponding to Fig. Fig. 6 is a view showing a state in which a working gas accommodating membrane pad is installed at various positions as a structural view. Fig.

Referring to these drawings, referring first to FIG. 4, an acoustic impedance (which means an acoustical resistance) of rubber, which is a material of the working gas receiving membrane pad 130 of the present embodiment, , While it is almost infinitely greater than air.

Typically, when sound waves propagate in a specific medium and a medium having a different impedance is encountered, a transmission phenomenon and a reflection phenomenon occur. Since the impedance of seawater and rubber is similar, only the reflection phenomenon occurs without reflection at the boundary between sea water and rubber.

For example, as shown in FIG. 5, the incident wave generated in the operation of the propeller 120 passes through the rubber layer, which is the wall surface of the working gas pocket 132, and then flows into the work gas filled in the working gas pocket 132, And is reflected by the phase opposite to the incident wave, that is, it is formed as a reflected wave. This reflected wave causes a destructive interference phenomenon with the incident wave, so that the incident wave generated in the operation of the propeller 120 is canceled. By such a phenomenon, the exciting force is reduced and the occurrence of vibration of the ship 110 can be reduced.

I will explain this again. The spherical pressure wave generated by the cavitation during the operation of the propeller 120, that is, the incident wave, can be propagated omnidirectionally.

In this case, when the working gas receiving membrane pads 130 filled with air are installed on the surface of the hull 110 around the propeller 120, the working gas pockets 132 of the working gas receiving membrane pads 130 The incident incident wave passes through the rubber layer, which is the wall surface of the working gas pocket 132, but is reflected by the working gas filled in the working gas pocket 132, i.e., air, in a phase opposite to that of the incident wave.

When the incident wave is formed as a reflected wave that is reflected by the opposite phase and strikes against the air, the reflected wave meets an incident wave incident on the workpiece receiving membrane pad 130, causing a destructive interference phenomenon with the incident wave.

As a result, the fluctuating pressure transmitted from the outside of the working gas receiving membrane pad 130 to the hull 110 is reduced, and when the fluctuating pressure is reduced, the exciting force is reduced. Therefore, 110 are reduced.

On the other hand, such a reduction performance is limited to a specific frequency band of the propeller as shown in the following equation (1).

[Equation 1]

Figure pat00001

Here, f is the propeller of a reduced frequency, c a (= 340m / s ) and c w (= 1500m / s), respectively for air and water sound speed ρ a (= 1.02 kg / m 3), ρ w (= 1024kg / m 3 ) denote the density of air and seawater, and a and b mean the inner diameter and outer diameter of the working gas receiving membrane pads 130a to 130c, respectively, when they are regarded as equivalent spheres.

A model test was carried out to verify these items. That is, as shown in FIG. 7, one working gas receiving membrane pad 130 having a reducing effect in the frequency band of 150 Hz is designed (or attached) to the wall surface of the hull 110 on the STBD region side, P2, P3, and P4, as well as vibrations were measured in the transom region, which is a steel plate supporting above the stern of the hull 110. In addition,

8, the horizontal axis (x axis) indicates the frequency, and the vertical axis (y axis) indicates the amount of increase / decrease after attachment of the work gas accommodating membrane pad 130 to the workpiece accommodating pad 130. In the vicinity of 135 Hz Work gas accommodating Membrane pads (130) Increase in pressure and vibration after installation Although the increase in pressure and vibration is noticeable, a remarkable reduction effect appears in the vicinity of the design frequency of 150 Hz.

FIG. 9 summarizes the results of the 150 Hz band. Referring to FIG. 9, the fluctuating pressures at the positions P2, P3 and P4 located outside the working gas receiving membrane pad 130 are reduced by an average of about 70% As a result, the vibration level is also remarkably reduced by 70% or more.

According to the present embodiment having the structure and function as described above, it is possible to prevent vibrations from being generated in the hull 110 by increasing the excitation force at the time of operating the propeller 120, and more particularly, It is possible to fundamentally prevent obstacles such as installation of components and burden of energy consumption due to operation.

As a result, it is possible to effectively prevent vibration from being generated in the hull 110. Thus, for example, in the case of a ship for which a quiet operation is to be premised, such as a cruise ship or a warship, The noise-containing vibration problem can be appropriately solved.

In particular, the structure according to the present embodiment is different from the structure of the present embodiment in that the shape and size of the blade 120 itself of the propeller 120 are designed differently, the shape of the tail of the ship is improved, a separate reinforcing material for blocking noise and vibration is padded, A method of improving noise and vibration by reducing various loss such as attaching a guide device for guiding the flow of water flowing from the propeller 120 or reducing the size of the propeller 120 Technically differentiated. In addition, since the present technology provides a margin for eliminating the restraint condition of vibration in the propeller design by shielding the excitation force, it is possible to greatly increase the size of the propeller 120, It is expected.

FIG. 10 is a rear view of a ship designing reduction type ship according to a second embodiment of the present invention, in which the working gas receiving membrane pads are installed at various positions.

Referring to this figure, referring to Equation 1 and FIG. 6, it can be seen that the reduced frequency band f is in inverse proportion to the air volume (radius, a), and the working gas receiving membrane pads 130a to 130c It is possible to apply to only one frequency band per one.

However, there are often two or more frequency bands that need to be controlled when operating a ship. That is, in operating a ship, there is a case where the frequency component of N frequency bands (N is a natural number) or more is controlled rather than one frequency band corresponding to the rotation speed (rpm) of the propeller 120. Here, the vibration component (or the vibrating component) is transmitted to the hull 110 during rotation of the propeller 120 to vibrate the hull 110, and the magnitude of the vibration component may vary from frequency to frequency.

In this case, since N different frequency bands can not be controlled through only one working gas receiving membrane pads 130a to 130c, the number of working gas receiving membrane pads 130a to 130c is increased by the number N of applied frequency bands, Should be used.

In other words, if N frequency bands need to be controlled, N work gas receiving membrane pads (not shown) must be attached to the wall surface of the hull 110 adjacent to the propeller 120 and used.

For example, FIG. 10 shows a total of three working gas receiving membrane pads 130a to 130c coupled to a plurality of wall surfaces of the hull 110 adjacent to the propeller 120 for three frequency band controls, such as 130 Hz, 140 Hz and 150 Hz Indicates the situation.

At this time, the working gas sizes of the working gas receiving membrane pads 130a to 130c coupled to a plurality of wall surfaces of the hull 110, that is, the working gas pockets 132a to 132c, may be different from each other.

As a result, regardless of whether one or a plurality of work gas receiving membrane pads 130a to 130c are installed, the exciting force of the hull 110 can be remarkably reduced by the principle of canceling interference.

That is, even if a large number of working gas receiving membrane pads 130a to 130c are applied as in the present embodiment, the excitation force is increased during operation of the propeller 120 to prevent vibration from occurring in the hull 110, It is possible to prevent the obstacles such as the installation of the compressor and the related parts and the burden of energy consumption due to the operation.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

110: Hull 120: Propeller
125: rudder 130: working gas receiving membrane pad
131: Pad body 132: Working gas pocket

Claims (8)

A hull with a propeller; And
And a working gas accommodating membrane pad which is coupled to the hull adjacent to the propeller and receives a working gas for generating a reflected wave for causing a destructive interference phenomenon with an incident wave generated when the propeller rotates, . The method according to claim 1,
Wherein the material of the working gas receiving membrane pad is a material whose acoustic impedance is similar to that of water. The method according to claim 1,
The material of the working gas receiving membrane pad is rubber,
Wherein the working gas is air. The method according to claim 1,
The working gas receiving membrane pads,
A pad body detachably coupled to the hull; And
And a working gas pocket formed on one side of the pad body to seal the working gas. The method according to claim 1,
Wherein the working gas receiving membrane pad is coupled to the hull wall surface on the upper side of the propeller. The method according to claim 1,
Wherein the working gas receiving membrane pads are coupled to a plurality of wall surfaces of the hull adjacent to the propeller. The method according to claim 6,
Wherein a working gas size of the working gas receiving membrane pads coupled to a plurality of wall surfaces of the hull is different from each other. The method according to claim 6,
Wherein the N number of the working gas receiving membrane pads are attached to the wall surface of the hull adjacent to the propeller when the propeller generates and controls vibration components of N (N is a natural number) frequency band.
KR1020140053289A 2014-05-02 2014-05-02 A ship for reducing vibromotive force KR20150126452A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
KR1020140053289A KR20150126452A (en) 2014-05-02 2014-05-02 A ship for reducing vibromotive force
JP2016564165A JP6275872B2 (en) 2014-05-02 2015-04-29 Propeller cavitation induced vibration reduction type ship
PCT/KR2015/004354 WO2015167263A1 (en) 2014-05-02 2015-04-29 Ship for reducing propeller cavitation-induced excitation force
CN201580024060.XA CN106458307B (en) 2014-05-02 2015-04-29 For reducing the ship of exciting force caused by propeller cavitation

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110536833A (en) * 2017-02-27 2019-12-03 通用电气公司 The downstream surface feature that screw current acoustics of decaying interacts

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110536833A (en) * 2017-02-27 2019-12-03 通用电气公司 The downstream surface feature that screw current acoustics of decaying interacts

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