KR101901817B1 - Vortex induced motion reduction device for marine floating body - Google Patents

Abstract

According to the present invention, a vortex induced motion reduction device for a marine floating body is provided. The vortex induced motion reduction device for a marine floating body is applied to a column of a marine floating body to reduce a vortex caused by a tidal current to be generated in the marine floating body and an effect of vortex induced motion.

Description

TECHNICAL FIELD [0001] The present invention relates to an apparatus for reducing the vortex-induced motion of an offshore structure,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ocean structure, and more particularly, to an apparatus that can be added to an offshore structure to prevent vibration of an offshore structure caused by algae.

Work for offshore oil / gas drilling and production is prepared for marine structures, which are ships or platforms called "rigs". These offshore structures are installed on the deck, with superstructures such as drilling, production and storage equipment and operator residences.

The platform, which is an offshore structure, is either a fixed platform or a negative platform.

The fixed platform is fixed to the seabed by a supporting angle which is placed directly or indirectly on the seabed. While these fixed platforms are relatively stable, so-called compliant piled towers (CPTs), referred to as Baldpate towers, may be installed at depths of 1648 feet (about 500 m), but are generally relatively shallow Limited to a depth of about 500 feet (about 152 m).

On the other hand, subtype platforms are typically used at depths of more than about 500 feet (about 152 m) and can be suspended by a mooring line fixed to the seafloor, or by a power thruster located on one or both sides of the platform site). Subtype platforms have the advantage of being complicated to install due to wind or marine conditions, but the subtype platforms can be installed at deeper depths than the fixed platform and are easily transportable to other wells. Such subtype platforms include drill ship, semi-submersible platform and spar platform, tension-leg platform (TLP), and the like.

FIG. 1 is a perspective view of a conventional deep-sea semi-submersible platform in which a vortex-induced motion is generated at a deep draft. 1, four columns 20 supporting a deck 10 and an upper structure 12 are vertically installed, and a pontoon 30 interconnecting adjacent four columns 20, Respectively. The pontoons 30 are intended to provide a buoyancy capable of keeping the upper portion of the column 20, the deck 10 and the superstructure 12 on the surface of water below the water surface.

Hereinafter, the deep sea half submersible platform belonging to the negative type platform will be described as an example. The deep semi-submersible platform includes a plurality of columns supporting a lower portion of a deck on which the superstructure is installed, and a pontoon interconnecting adjacent columns among the plurality of columns. Here, the pontoon is submerged in seawater and provides buoyancy of a predetermined size.

On the other hand, the vortex induction motion refers to the motion generated by external force acting on the structure at a direction perpendicular to the incidence direction of the algae by periodic vortex shedding occurring behind the column when a relatively constant velocity algae is incident on the column of an offshore structure . In the case of a wave column motion with a relatively low draft, vortex induced motion is a major problem because the wave particle motion is disturbed by the wave motion, It does not.

However, in the case of an offshore structure having multiple columns at a depth of 40 m or more, the size of the wave particle motion is so small that it can hardly disturb the incoming algae, so that the vibration due to the algae is generated and the operation efficiency of the entire offshore structure is lowered.

On the other hand, in the case of the deep water semi-submersible platform, since a plurality of columns are formed in a long and slender shape, a vortex induced motion is apt to occur by algae. Therefore, in the case of the semi-submersible platform at deep draft, the vibration due to the algae is generated, which makes it difficult to control in terms of the balance and stability of the entire platform.

In addition, the vortex-induced motion causes a problem that adversely affects the fatigue life of the mooring line and the riser.

Japanese Unexamined Patent Publication No. 2000-168676 (published on June 20, 2000, entitled " Offshore Structures ")

It is an object of the present invention to provide an apparatus for reducing the vortex-induced movement of an offshore structure which can be added to a column of an offshore structure to reduce the influence of vortex and vortex- have.

It is to be understood that the present invention is not limited to the above-described subject matter, and another subject (s) not mentioned may be clearly understood by those skilled in the art from the following description .

As a means for solving the problem to be solved by the present invention described above,

An apparatus for reducing vortex-induced movement of an offshore structure according to a preferred embodiment of the present invention includes: at least one column for supporting a lower portion of an offshore structure; And a vortex abatement unit installed at an outer portion of the column; Wherein the vortex reduction unit comprises: a drum disposed on an outer peripheral surface of the column; And a plate extending outwardly of the drum to guide the flow of algae incident on the column and to transmit the flow in a predetermined direction; And < RTI ID = 0.0 > a < / RTI >

According to another aspect of the present invention, there is provided a rail system comprising: a rail installed on a part of an outer circumferential surface of a column or installed to surround an outer circumferential surface of the column and movably coupled to the drum, and moving the drum along an outer circumferential surface of the column, The method may further include the step of:

Further, as another embodiment, it is possible to further include an embodiment in which the drum can be moved along the branch rail or the rail by further including a branch rail branched from the rail and along the outer circumferential surface of the column.

Further, as another embodiment, a driver that is added to the inside or the outside of the drum to provide a driving force to the drum so that the drum can move along the rails or the branch rails; And a control unit for controlling the operation of the driving unit.

Further, as another embodiment, a position sensor may be added to the inside or the outside of the drum to measure the position of the drum; And the position sensor may be controlled by a control unit.

Further, as another embodiment, a sensor added to the inside or the outside of the drum to measure the flow velocity or hydraulic pressure of the algae flowing around the column; And the sensor may be controlled by a control unit.

Specific details of other embodiments are included in the " Detailed Description of the Invention "and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and / or features of the present invention and the manner of achieving them will be apparent by reference to various embodiments described in detail below with reference to the accompanying drawings.

However, the present invention is not limited to the configurations of the embodiments described below, but may be embodied in various other forms, and each embodiment disclosed in this specification is intended to be illustrative only, It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

According to the apparatus for reducing the vortex-induced movement of an offshore structure according to the preferred embodiment of the present invention having the above-described structure, the vortex and vortex generated in the offshore structure due to algae or the like are added to the column of the offshore structure, An apparatus for reducing the vortex-induced movement of an offshore structure that can reduce the effects of induced movement can be provided.

Figure 1 is a perspective view of a semi-submerged offshore platform or an offshore structure according to the prior art.
FIG. 2 is a conceptual diagram showing the direction of action of the vortex-induced motion by the algae and algae acting on marine structures floating on the sea.
3 is a perspective view showing a state where an apparatus for reducing vortex-induced movement of an offshore structure is added to a column according to a preferred embodiment of the present invention.
FIG. 4 is a perspective view illustrating an apparatus and a rail for reducing vortex-induced movement of an offshore structure according to a preferred embodiment of the present invention. FIG.
5 is a block diagram conceptually showing the configuration of a drum according to a preferred embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Before describing the present invention in detail, terms and words used herein should not be construed as being unconditionally limited in a conventional or dictionary sense, and the inventor of the present invention should not be interpreted in the best way It is to be understood that the concepts of various terms can be properly defined and used, and further, these terms and words should be interpreted in terms of meaning and concept consistent with the technical idea of the present invention.

That is, the terms used herein are used only to describe preferred embodiments of the present invention, and are not intended to specifically limit the contents of the present invention, It should be noted that this is a defined term.

Furthermore, in this specification, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise, and it should be understood that they may include singular do.

Where an element is referred to as "comprising" another element throughout this specification, the term " comprises " does not exclude any other element, It can mean that you can do it.

Further, when it is stated that an element is "inside or connected to" another element, the element may be directly connected to or in contact with the other element, A third component or means for fixing or connecting the component to another component may be present when the component is spaced apart from the first component by a predetermined distance, It should be noted that the description of the components or means of 3 may be omitted.

On the other hand, it should be understood that there is no third component or means when an element is described as being "directly connected" or "directly connected" to another element.

Likewise, other expressions that describe the relationship between the components, such as "between" and "immediately", or "neighboring to" and "directly adjacent to" .

In this specification, terms such as "one side", "other side", "one side", "other side", "first", "second" Is used to clearly distinguish one element from another element, and it should be understood that the meaning of the element is not limited by such term.

It is also to be understood that terms related to positions such as "top", "bottom", "left", "right" in this specification are used to indicate relative positions in the drawing, Unless an absolute position is specified for these positions, it should not be understood that these position-related terms refer to absolute positions.

Furthermore, in the specification of the present invention, the terms "part", "unit", "module", "device" and the like mean a unit capable of handling one or more functions or operations, Or software, or a combination of hardware and software.

In this specification, the same reference numerals are used for the respective components of the drawings to denote the same reference numerals even though they are shown in different drawings, that is, the same reference numerals throughout the specification The symbols indicate the same components.

In the drawings attached to the present specification, the size, position, coupling relationship, and the like of each constituent element of the present invention may be partially or exaggerated or omitted or omitted for the sake of clarity of description of the present invention or for convenience of explanation May be described, and therefore the proportion or scale may not be rigorous.

Further, in the following description of the present invention, a detailed description of a configuration that is considered to be unnecessarily blurring the gist of the present invention, for example, a known technology including the prior art may be omitted.

Figure 1 is a perspective view of a semi-submerged offshore platform or an offshore structure according to the prior art.

1, there are shown four columns 20 supporting a deck 10 and an upper structure 12, and a pontoon 30 interconnecting adjacent four columns 20, A detailed description of each component and the entirety of FIG. 1 has been already described in the Background of the Invention section, and therefore, a repeated description thereof will be omitted.

FIG. 2 is a conceptual diagram showing the direction of action of the vortex-induced motion by the algae and algae acting on marine structures floating on the sea.

2, a right side arrow C is shown on the left side of the drawing, and a column 50 and a pontoon 60 are shown on the right side of the drawing. Arrows M ).

In Fig. 2, the direction of the arrow C indicates the flow of seawater, that is, the direction of the alga (C).

The structure includes a column 50 supporting a deck and an upper structure (not shown) of the offshore structure, and a pontoon 60 connecting the lower portion of each column and generating buoyancy to float the deck and upper structure on the surface of the water.

At this time, if the algae C in the same direction as the arrow C acts on the offshore structure having the above-described structure, the vortex inducing motion occurs in the direction of the arrow M. Here, the direction of the arrow M is viewed in the direction of the line perpendicular to the arrow C indicating the direction of the alga, and the arrow M means the direction of the vortex-induced action M.

The occurrence of the vortex-induced motion will be described in more detail. Periodic vortex shedding or Karman vortex occurs as the alga (C) incident on the column 50 is flow-separated around the column (50). Further, the vortex shedding or the Karman vortex may cause vortex-induced motion in the offshore structure and adversely affect the fatigue life of the mooring line or riser connected to the offshore structure.

There arises a need to apply structures and devices capable of reducing the vortex shedding or the Karman vortex to an offshore structure or a marine platform for the same reason as described above.

3 is a perspective view showing a state where an apparatus for reducing vortex-induced movement of an offshore structure is added to a column according to a preferred embodiment of the present invention.

Referring to FIG. 3, an apparatus for reducing vortex-induced movement of an offshore structure according to a preferred embodiment of the present invention is an apparatus for reducing eddy currents generated in a marine structure installed on the sea, At least one column (70); And a puddle abatement unit installed at an outer portion of the column (70); , The vortex reduction unit comprising: a drum (100) disposed on an outer circumferential surface of the column (70); And a plate (150) extending outwardly of the drum (100) and guiding the flow of the alga (C) incident on the column (70) in a predetermined direction; And a control unit. Hereinafter, detailed description will be given of each of the components listed above.

The column 70 is a structure for supporting the lower portion of the deck on which the upper structure is installed. Although the column 70 is shown in Figures 3 and 4 attached to the present invention as being cylindrical, it is only a conceptual illustration of the shape of the column 70, which is based on one embodiment of the column 70 , It should be noted that in the practice of the present invention in accordance with the technical idea of the present invention, the column 70 is not necessarily limited to being cylindrical. It should be noted that in the practice of the present invention, the form of the column 70 is not critical.

The drum 100 is attached to a portion of a surface or an outer surface of a column 70 of an offshore platform or an offshore structure and a plate 150 described below is added to be disposed adjacent the outer circumferential surface of the column 70 to be.

The plate 150 is configured such that the alga C incident on the column 70 flows along the surface or the outer circumferential surface of the column 70 and flows away from the column 70 to prevent the occurrence of vortexes, And serves to guide the flow of the algae C entering the column 70 to the outside in the set direction.

Here, the set direction means that the algae are guided in the rear direction of the column when the algae are viewed forward from a part incident on the column. In addition, the set direction may be adjusted depending on the purpose of execution or environment.

Here, it is preferable that the plate 150 is made of a soft material such as fabric or rubber. It is also desirable that the plate made of a soft material has a neutral buoyancy, but the buoyancy of the upper portion may be prevented by making the lower portion heavier and the upper portion buoyant.

When the drum 100 is moved, the plate 150 is stored in the drum 100. After the drum 150 is moved to the designated position, 0.0 > 100, < / RTI >

Further, in order to move the drum 100, a rail 80 and a branch rail 90 may be disposed on the column 70, which will be described in detail with reference to FIG.

The controller 110 may further include a driver 110, a sensor unit 130, and a controller 140, both inside and outside the drum 100, Will be described in detail with reference to FIG.

FIG. 4 is a perspective view illustrating an apparatus and a rail for reducing vortex-induced movement of an offshore structure according to a preferred embodiment of the present invention. FIG.

Referring to FIG. 4, an apparatus and a rail for reducing the vortex-induced movement of an offshore structure according to a preferred embodiment of the present invention, as compared to the configuration shown in FIG. 3, (90) is added, and the plate (150) is not shown. Hereinafter, a detailed description will be added to each of the components listed above.

The description of the column 70, the drum 100, and the plate 150 has already been described with reference to FIG. 3, and therefore will not be described here. It should be noted that the plate 150 is not shown in the view of FIG. 4 to clearly show that the rail 80 and the branch rail 90 have been added in comparison with the view of FIG. It should be noted that the embodiment of FIG. 4 does not omit the plate 150, but only the plate 150 is not shown.

The rail 80 is installed along the outer circumferential surface of the column 70 for the purpose of moving the drum 100 along the surface of the column 70. 4, the rail 80 is illustrated as being installed in the horizontal direction of the column 70, but the direction in which the rail 80 is installed is necessarily limited to the horizontal direction of the column 70 It is not. The rail 80 may be installed in a direction different from that shown in FIG.

The branch rail 90 is a rail provided along the outer peripheral surface of the column 70 so as to be branched from the rail 80 so that the drum 100 can be moved in a direction different from the rail 80 Is installed. 4 shows that the diverging rail 90 is installed perpendicularly to the column 70 in a direction perpendicular to the rail 80 because the diverging rail 90 must be in the vertical direction of the column 70 But is not intended to be limited to being installed. The branch rail 90 may be installed in a direction different from that shown in FIG.

5 is a block diagram conceptually showing the configuration of a drum according to a preferred embodiment of the present invention.

Referring to FIG. 5, a drum 100 according to an embodiment of the present invention includes a driver 110, a sensor unit 130, and a controller 140. Hereinafter, a detailed description will be added to each of the components listed above.

The driver 110 is provided for providing a driving force to the drum 100 in moving the drum 100 along the rail 80 or the branch rail 90. At this time, an encoder for measuring the number of revolutions of the driver 110 may be provided integrally with the driver 110. Of course, an encoder may be separately provided outside the driver 110. However, considering the specificity of the environment in which the present invention is implemented, it is more easily realized that the driver 110 and the encoder are integrally provided. It is assumed that there will be.

Another object of the installation of the actuator 110 may be to provide the power required for the embodiment in which the plate 150 is embodied so as to be housed or moved inside the drum 100. [

The sensor unit 130 may include at least one sensor according to an embodiment of the present invention.

The control unit 140 is provided for the purpose of controlling the driver 110 and controlling various sensors included in the drum 100 and the sensor unit 130 and acquiring measurement data. Here, the various sensors include a position sensor capable of measuring the position of the drum 100, a drum 100, a sensor capable of measuring the flow rate of algae flowing around the column 70, And a sensor capable of measuring the temperature.

Further, it is preferable that the control unit 140 is further provided with a communication function. The reason why the communication function is added to the maker 140 or the drum 100 is that the information such as the position of the drum 100 measured through the sensor unit 130, The information on the amount of rotation of the driver 110 may be transmitted to the outside of the drum 100 for processing and may be more advantageous for the implementation of the present invention and for the operation of the offshore structure.

Although not shown in the drawings of the present invention including FIG. 5, a power supply unit for supplying power required for operation of the drum 100, the driver 110, the sensor unit 130, and the controller 140 is further required . The power supply unit may be provided in the form of a battery in the drum 100 or may be provided with a separate external power supply unit to supply power from the external power supply unit to the drum 100 through a power supply line It can also be implemented in the form of. At this time, in a form of the external power source device, a solar panel is provided on the deck of the offshore structure or on the column 70, and the power line is connected from the solar panel to the drum 100, For example, the power is supplied to the elements. As an example of the external power supply device, although a solar panel is used, other power supply devices may be applied depending on the purpose or environment of operation.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

In addition, since the present invention can be embodied in various other forms, the present invention is not limited by the above description, and the above description is intended to be a complete description of the present invention, It is to be understood that only those of ordinary skill in the art are provided for a complete disclosure of the scope of the present invention and that the present invention is only defined by the claims of the claims.

10: Deck
12: Superstructure
20: Column
30: The pontoon
50: Column
60: pontoon
70: Column
80: Rail
90: branch rail
100: Drums
110:
130:
140:
150: Plate
C: Birds
M: direction of vortex-induced motion

Claims (6)

An apparatus for reducing eddy currents in an offshore structure,
At least one column supporting the underside of the ocean structure;
A vortex reduction unit installed at a part of the column to reduce vortex and vortex induced motion caused by algae in the offshore structure; / RTI >
Wherein the vortex reduction unit comprises:
A drum disposed on an outer circumferential surface of the column; And
The plate of soft material has a neutral buoyancy, the bottom is resistant to buoyancy, and the buoyancy is provided at the top to prevent the shape from changing by algae, and the drum Wherein the plate is housed in the drum when the plate is moved and then the plate is unfolded out of the drum after the drum is moved to a designated position so that the plates extend outwardly of the drum, A plate for guiding the flow of the algae in a predetermined direction;
A rail installed on a part of the outer circumferential surface of the column or installed to surround the outer circumferential surface of the column and movably coupled to the drum and moving the drum along the outer circumferential surface of the column in correspondence with the tide entering the column;
And a branch rail branched from the rail and along the outer circumferential surface of the column,
Characterized in that the drum can be moved along the branch rail or the rail,
Which is added to the inside or outside of the drum,
A driver for providing a driving force to the drum to allow the drum to move along the rail or the branch rail; And
Further comprising a control unit for controlling the operation of the driver. ≪ RTI ID = 0.0 > 11. < / RTI > delete delete delete The method according to claim 1,
Which is added to the inside or outside of the drum,
A position sensor for measuring the position of the drum; Respectively,
Wherein the position sensor is controlled by the control unit,
A sensor attached to the inside or the outside of the drum to measure the flow velocity or hydraulic pressure of the algae flowing around the column; Respectively,
Characterized in that the sensor is controlled by the control unit.



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