JP6366124B2 - Floating structure - Google Patents

Description

  The present invention relates to a floating body structure, and more particularly to a floating body structure capable of improving the restoring force and reducing fluctuation.

  In recent years, offshore wind power generation has attracted attention from the viewpoint of the preservation of the global environment and the effective use of natural energy. The floating structure used for such offshore wind power generation is required to have a certain level of restoring force in order to reduce the steady inclination angle due to wind loads and to suppress unstable fluctuations. In general, the restoring force is formulated by GM (metacenter height) × drainage amount. In designing a floating structure, it is important how much GM can be increased for a certain amount of drainage.

  Here, GM (metacenter height) can be obtained by a calculation formula of GM = KB (buoyancy height) + BM (metacenter radius) −KG (center of gravity height). Therefore, in order to increase GM, (1) a method for increasing BM and (2) a method for increasing KB-KG are employed.

  Since “(1) BM enlargement method” is expressed as BM = I (water surface moment) / V (drainage volume), the water line is expanded by expanding the floating body in the vicinity of the water surface. This is a technique for increasing the surface moment I and increasing the BM (metacenter radius). For example, a semi-sub type floating structure corresponds to the floating structure using this technique (see Patent Document 1).

  “(2) Method of increasing KB-KG” is a method of increasing the distance between the buoyancy height KB and the center of gravity height KG and increasing “KB-KG” by forming the floating body vertically. is there. For example, a spar type floating structure corresponds to the floating structure using this technique (see Patent Document 2).

JP 2010-280301 A JP 2012-97713 A

  However, when “(1) Method for Enlarging BM” is adopted, there is a problem that the floating structure is greatly shaken because it is easily influenced by wave forces near the water surface. In addition, although the draft of the floating structure can be shallow, there is a problem that the area of the water line becomes too large and is subject to restrictions on installation and construction. In addition, when “(2) Method for Enlarging KB-KG” is adopted, there is a problem that the draft of the floating body becomes too deep and is subject to restrictions on installation and construction.

  The present invention was devised in view of the above-described problems, and an object thereof is to provide a floating structure capable of improving the restoring force and reducing the fluctuation based on the spar type floating structure. And

According to the present invention, in a floating structure having a single column-shaped column portion that can float in an upright state and can be connected to an upper structure disposed on the water, the columnar shape has a diameter larger than that of the column portion in the vicinity of the water line. The upper hull, the lower hull disposed at the lower end of the column portion and constituting a ballast tank and having a diameter larger than that of the column portion, and projecting radially outward over the entire circumference of the submerged portion of the upper hull. There is provided a floating structure characterized by having an overhanging portion which is a plate-like flange portion arranged to do so.

The overhang portion may have a cavity inside. Moreover, you may have the some fin erected on the upper surface of the said lower hull radially.

  According to the above-described floating structure according to the present invention, on the basis of a spar-type floating structure, an upper hull having an enlarged diameter in the vicinity of the waterline is formed, so that the water surface moment I is increased and BM (metacenter radius) ) Can be increased. Further, by forming a lower hull having a diameter expanded at the lower end of the column portion to form a ballast tank, the center of gravity of the floating structure can be lowered, and KG (center of gravity height) can be reduced. Furthermore, by connecting the upper hull and the lower hull described above at the column portion, the KB (floating center height) of the floating structure can be increased. Accordingly, the GM (metacenter height) obtained by the calculation formula of KB (buoyancy height) + BM (metacenter radius) −KG (center of gravity height) can be increased, and the restoring force of the floating structure is improved. be able to.

  Moreover, by forming the lower hull having a diameter expanded in the horizontal direction at the submerged portion, it is possible to increase the drag against the floating of the floating structure, and to reduce the vertical swing of the floating structure. Also, by forming the overhang on the outer periphery of the upper hull, the wave force received by the floating structure can be reduced, and the pitching and rolling of the floating structure can be reduced. it can. Therefore, it is possible to reduce the fluctuation of the floating structure.

It is a front view of the floating structure according to the first embodiment of the present invention. It is explanatory drawing of the floating body structure shown in FIG. 1, (A) is AA arrow sectional drawing in FIG. 1, (B) is BB arrow sectional drawing in FIG. 1, (C) is FIG. CC sectional view taken on the line in FIG. It is a figure which shows the floating body structure which concerns on other embodiment of this invention, (A) is 2nd embodiment, (B) is 3rd embodiment, (C) is 4th embodiment, (D) is 1st embodiment. 5 shows a fifth embodiment. It is an external view of the floating body structure which concerns on 4th embodiment, (A) is an overhead view, (b) has shown the elevation view. It is a figure which shows the floating body structure which concerns on 6th embodiment of this invention, (A) is a front view, (B) is BB arrow sectional drawing in FIG. 5 (A), (C) is FIG. The CC arrow directional cross-sectional view in A) is shown.

  Hereinafter, a floating structure according to an embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1 is a front view of the floating structure according to the first embodiment of the present invention. 2 is an explanatory view of the floating structure shown in FIG. 1, (A) is a cross-sectional view taken along the line AA in FIG. 1, (B) is a cross-sectional view taken along the line BB in FIG. ) Shows a cross-sectional view taken along the line CC in FIG. In each figure, the hollow portion that can constitute the ballast tank is indicated by an alternate long and short dash line.

  As shown in FIG. 1 and FIGS. 2A to 2C, the floating structure 1 according to the first embodiment of the present invention includes an upper structure 2 that can float in an upright state and is disposed on water. An upper hull 4 having a single columnar column 3 that can be connected, and having a diameter larger than that of the column 3 near the water line, and a lower hull that is disposed at the lower end of the column 3 to form a ballast tank and has a diameter larger than that of the column 3 5 and a plate-like projecting portion 6 projecting radially outward from the outer periphery of the submerged portion of the upper hull 4.

  The floating structure 1 is, for example, a floating structure for offshore wind power generation, and the upper structure 2 is configured by, for example, a windmill having a support column 21, a nacelle 22, and a blade 23. The support column 21 is erected on a connecting portion 31 formed at the upper end portion of the column portion 3. The nacelle 22 has a generator inside, and generates electric power by the rotation of the blade 23. The blade 23 is driven to rotate by wind power. Although not shown, a solar panel may be disposed on the support column 21. The wind power generation facility described above is merely an example of the upper structure 2 installed in the floating structure 1, and the upper structure 2 includes a wind condition observation device such as an anemometer and an anemometer, a solar power generation device, Equipment such as a lighting device and a wireless communication device may be used.

  The column portion 3 is a substantially cylindrical central axis for constituting the spar type floating body structure 1. The inside of the column portion 3 is formed in a cavity and constitutes a part of a buoyancy body that gives buoyancy to the floating structure 1. Moreover, a pump room, a machine room, etc. are arrange | positioned inside the column part 3 as needed. In the pump room, a pump for processing the pouring and discharging of ballast water is arranged, and in the machine room, an auxiliary generator functioning as an internal power source and various control devices are arranged.

  Since the floating structure 1 according to the present embodiment is based on a spar type, only one (single) column portion 3 is arranged. The size and length of the diameter of the column part 3 are set according to conditions such as the depth of the sea area where the floating structure 1 is disposed, the required amount of drainage, and the sizes of the upper hull 4 and the lower hull 5. A part of the column portion 3 may be used as a ballast tank (including both fixed and variable).

  The upper hull 4 includes, for example, a center hull 41 connected to the column portion 3 and a plurality of horizontal braces 42 extending radially from the submerged portion of the center hull 41, as shown in FIG. And an outer hull 43 arranged at the tip of the horizontal brace 42. In FIG. 2A, the portion arranged in the submerged portion is displayed in gray.

  The center hull 41 is a member that supports the horizontal brace 42 and is formed in the vicinity of the water line of the column portion 3 and has a columnar shape or a prism shape that is larger in diameter than the column portion 3.

  The horizontal brace 42 is a member that connects the center hull 41 and the outer hull 43. Since the horizontal brace 42 receives a load by wave force when arranged on the water line, it is preferably arranged in the submerged portion. Further, by sinking the horizontal brace 42 in the water, the weight can be supported by buoyancy, and the support load can be reduced as compared with the case where it is arranged in the air. Further, the inside of the horizontal brace 42 may be formed as a hollow and used as a ballast tank (including both fixed and variable). In addition, although the illustrated horizontal braces 42 are radially arranged from the center hull 41, the number is not limited thereto.

  The outer hull 43 is a rectangular parallelepiped buoyancy body disposed at the tip of the horizontal brace 42. The inside of the outer hull 43 is used as a ballast tank (including both fixed and variable). The shape of the outer hull 43 is not limited to a rectangular parallelepiped shape, and may be a spherical shape or a spheroid shape.

  As shown in FIG. 2A, a certain gap is formed between adjacent outer hulls 43. In this way, by disposing the outer hull 43 in a distributed manner on the circumference, a part of the wave can enter inside through the gap of the outer hull 43, and the load received by the wave force can be reduced. . Further, the work ship can be brought close to the vicinity of the center hull 41 using the clearance of the outer hull 43, and the column section 3 provided with the machine room and the like can be easily accessed. Can be reduced.

  Further, by disposing the outer hull 43 as a buoyant body at a position away from the column portion 3 constituting the central axis of the floating structure 1, the water surface moment I is increased and the BM (metacenter radius) is increased. can do. The volume of the outer hull 43 and the separation distance of the outer hull 43 from the column portion 3 (that is, the length of the horizontal brace 42) are set according to the restoring force required for the floating structure 1.

  As shown in FIGS. 1 and 2C, the lower hull 5 is a substantially disc-shaped heavy object (weight) disposed at the lower end of the column portion 3. The interior of the lower hull 5 is divided into a plurality of spaces by, for example, a plurality of partition plates arranged radially, and each constitutes a ballast tank. The ballast tank may be a fixed ballast having a constant weight, or may be a variable ballast whose weight can be adjusted by pouring and draining seawater.

  Thus, by arranging a heavy object at the lower end of the column portion 3, the center of gravity of the floating structure 1 can be lowered, and KG (center of gravity height) can be reduced. Further, by arranging the lower hull 5 that is flattened in the horizontal direction in the submerged portion, it is possible to increase the drag generated when the floating structure 1 tries to move in the vertical direction. Shaking (Heaving) can be reduced.

  Further, the lower hull 5 may have a plurality of fins 51 erected radially on the upper surface. By disposing a plurality of fins 51 that are spread out in a substantially vertical direction on the submerged lower hull 5, it is possible to increase the drag generated when the floating structure 1 tries to rotate around the column portion 3. The yawing of the structure 1 can be reduced. Conditions such as the number and area of the fins 51 can be arbitrarily set according to the amount of drainage of the floating structure 1 and the installation environment.

  The overhang portion 6 is a plate-like flange portion formed on the outer periphery of the submerged portion of the outer hull 43. Increasing the drag generated when the floating structure 1 is inclined by wind load or wave force by forming the overhanging portion 6 that is flattened in a substantially horizontal direction on the outer hull 43 constituting the buoyancy body. Thus, the pitching and rolling of the floating structure can be reduced. The overhanging amount of the overhanging part 6 can be arbitrarily set according to the amount of drainage of the floating structure 1 or the installation environment.

  The floating structure 1 shown in FIG. 1 includes a plurality of diagonal braces 7 that connect the outer hull 43 and the lower hull 5, and a middle brace 8 that is formed in an annular shape by connecting the adjacent diagonal braces 7. Have. The oblique brace 7 and the middle brace 8 function as a reinforcing material that supports the outer hull 43.

  For example, the lower end of the oblique brace 7 is connected to the support fitting 71 disposed on the upper surface of the central portion of the lower hull 5, and the upper end is connected to the lower surface of the outer hull 43. Therefore, the diagonal braces 7 are arranged radially from the lower end toward the upper end. The lower end of the diagonal brace 7 may be connected to the peripheral surface of the column portion 3, and the upper end of the diagonal brace 7 may be connected to the horizontal brace 42. As shown in FIG. 2 (B), the inside of the diagonal brace 7 may be formed in a hollow and used as a ballast tank.

  The middle brace 8 is a member that improves rigidity as a structure of the oblique brace 7 by connecting the adjacent oblique braces 7. Therefore, as shown in FIG. 2B, the middle braces 8 are arranged in a polygonal shape according to the number of the diagonal braces 7. The number of the diagonal braces 7 and the arrangement position (height) of the middle braces 8 can be arbitrarily set according to the strength required for the outer hull 43. A plurality of middle braces 8 may be arranged in the vertical direction.

  The floating structure 1 is connected to a plurality of mooring lines 9 fixed to the seabed and stays in a predetermined sea area. For example, as shown in FIG. 1, the upper end of the mooring line 9 is fixed to the outer surface of the outer hull 43, and the lower end of the mooring line 9 is inserted into a mooring pipe 91 disposed in the overhanging portion 6. Fixed to the sea floor. By connecting the mooring line 9 to the outer hull 43 located at a position separated from the column part 3, it is possible to increase the drag force against the yawing that the floating structure 1 tries to rotate.

  Therefore, the mooring line 9 can keep the floating structure 1 in a predetermined sea area, and can reduce bowing, swaying, and swaying. The mooring line 9 may be fixed to the overhanging portion 6 or the oblique brace 7.

  By the way, the restoring force is generally formulated by GM (metacenter height) × drainage amount. GM (metacenter height) is GM = KB (buoyancy height) + BM (metacenter radius) −KG (center of gravity height) It can be obtained by the calculation formula of Therefore, in the floating structure 1 according to the first embodiment described above, (1) by forming the upper hull 4, the water surface moment I is increased to increase the BM (metacenter radius), and (2) the lower hull 5. To lower the center of gravity of the floating structure 1 to reduce the KG (center of gravity height). (3) By connecting the upper hull 4 and the lower hull 5 with the column portion 3, the KB (floating) of the floating structure 1 is formed. I try to increase my heart height. Therefore, the numerical value of GM (metacenter height) can be increased, and the restoring force of the floating structure 1 can be improved.

  Moreover, according to the floating structure 1 which concerns on 1st embodiment mentioned above, having formed the lower hull 5 can reduce the vertical swing (Heaving) of the floating structure 1, and formed the overhang | projection part 6. Therefore, the pitching and rolling of the floating structure 1 can be reduced. By forming the fins 51, the yawing of the floating structure 1 can be reduced, and the floating structure can be reduced. It is possible to reduce the shaking of the object 1.

  Next, a floating structure 1 according to another embodiment of the present invention will be described. Here, FIG. 3 is a figure which shows the floating body structure which concerns on other embodiment of this invention, (A) is 2nd embodiment, (B) is 3rd embodiment, (C) is 4th embodiment. Form, (D) shows the fifth embodiment. 4A and 4B are external views of a floating structure according to the fourth embodiment, where FIG. 4A shows an overhead view and FIG. 4B shows a top view. FIG. 5: is a figure which shows the floating body structure which concerns on 6th embodiment of this invention, (A) is a front view, (B) is BB arrow sectional drawing in FIG. 5 (A), (C). FIG. 5 shows a cross-sectional view taken along the line CC in FIG. In addition, in each figure, about the same component as 1st embodiment mentioned above, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  The floating structure 1 according to the second embodiment shown in FIG. 3A is obtained by omitting the middle brace 8 of the floating structure 1 according to the first embodiment described above, and is shown in FIG. The floating structure 1 according to the third embodiment is obtained by omitting the oblique braces 7 and the middle braces 8 of the floating structure 1 according to the first embodiment described above. Thus, the reinforcing structure of the upper hull 4 (for example, the outer hull 43) can be designed as necessary using the diagonal brace 7 and the middle brace 8.

  The floating structure 1 according to the fourth embodiment illustrated in FIG. 3C is obtained by omitting the fins 51 of the floating structure 1 according to the first embodiment described above. For example, if the mooring line 9 can sufficiently reduce yawing, the fins 51 can be omitted. Here, in order to promote understanding of the structure of the floating structure 1, an overhead view of the floating structure 1 according to the fourth embodiment is shown in FIG. 4A, and an elevation view is shown in FIG. 4B. . In addition, in each figure, the figure of a part of support bracket 71 and the column part 3 (part above the center hull 41) is abbreviate | omitted for convenience of explanation. The shape of the floating structure 1 shown in FIGS. 4A and 4B is 3D modeling in which a planar portion is displayed as a mesh.

  The floating structure 1 according to the fifth embodiment shown in FIG. 3 (D) has a connecting bridge 44 that spans the water surface between the center hull 41 and the outer hull 43. By arranging such a connecting bridge 44, even when the floating structure 1 is floated, that is, when the horizontal brace 42 is submerged, the center hull 41 and the outer hull 43 can be moved back and forth. It is possible to reduce the time required for movement during maintenance. The connecting bridge 44 includes, for example, a floor plate that connects the center hull 41 and the outer hull 43, and handrails that are arranged on both sides of the floor plate.

  Moreover, the floating structure 1 according to the fifth embodiment may include an auxiliary floor plate 45 extending outward from the outer hull 43 in addition to the connecting bridge 44 as illustrated. By arranging the auxiliary floor plate 45 on the outer hull 43, an operator can get on and off the outer hull 43 via the auxiliary floor plate 45 at the time of maintenance or the like, and convenience can be improved. In other words, in the present embodiment, the worker can get on and off the floating structure 1 from either the center hull 41 or the outer hull 43, and can arbitrarily enter a place where the worker gets on or off according to the work content or the progress of the work. Can be selected.

  The floating structure 1 according to the sixth embodiment shown in FIGS. 5A to 5C is a simplified structure of the upper hull 4. Specifically, the upper hull 4 has a polygonal column shape whose diameter is expanded from the column portion 3. For example, the diameter (width) of the upper hull 4 is preferably about the same as the diameter (width) of the lower hull 5, but can be arbitrarily changed according to the amount of drainage of the floating structure 1, the installation environment, and the like. The shape of the upper hull 4 is not limited to the polygonal column shape, and may be a columnar shape.

  As shown in FIGS. 5A and 5B, a plate-like overhanging portion 6 protruding radially outward is disposed on the outer periphery of the submerged portion of the upper hull 4. You may make it use the inside of the overhang | projection part 6 as a hollow, and use as a ballast tank (a fixed or variable is included). In FIG. 5A, for convenience of explanation, the draft line is virtually illustrated by a one-dot chain line.

  As shown in FIG. 5C, the lower hull 5 in the sixth embodiment has a flat octagonal prism shape, and the inside thereof is divided by partition plates arranged radially, and each room has Used as a ballast tank (including both fixed and variable). Eight fins 51 are arranged radially on the upper surface of the lower hull 5.

  The floating structure 1 according to the sixth embodiment can be easily designed and reinforced because the upper hull 4 does not have the outer hull 43 that is dispersedly arranged in a floating island shape as in the first embodiment. There is little need for a structure (oblique brace 7 or middle brace 8), and a robust buoyancy body that is structurally easy to manufacture can be easily formed.

  In the floating structure 1 according to the second embodiment to the sixth embodiment described above, similarly to the floating structure 1 according to the first embodiment, the water hull surface is formed by forming the upper hull whose diameter is increased in the vicinity of the water line. The moment I can be increased to increase the BM (metacenter radius), and the lower hull 5 having an enlarged diameter is formed at the lower end of the column portion 3 to form a ballast tank, whereby the center of gravity of the floating structure 1 is lowered and KG ( The center of gravity (height of the center of gravity) can be reduced, and by connecting the upper hull 4 and the lower hull 5 with the column portion 3, the KB (buoyancy height) of the floating structure can be increased. ) + BM (metacenter radius) −KG (metacenter height) calculated by the calculation formula can be increased, and the restoring force of the floating structure can be improved.

  Moreover, according to the floating structure 1 which concerns on 2nd embodiment-6th embodiment mentioned above, the lower hull 5 expanded in the horizontal direction by the submerged part similarly to the floating structure 1 which concerns on 1st embodiment. By forming, the resistance against the vertical swing of the floating structure 1 can be increased, and by forming the protruding portion on the outer periphery of the upper hull, the wave force received by the floating structure 1 in all directions can be reduced. Further, it is possible to reduce the vertical shaking (Heaving), pitching (Pitching), and rolling (Rolling) of the floating structure 1 and to reduce the shaking of the floating structure 1.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Floating structure 2 Upper structure 3 Column part 4 Upper hull 5 Lower hull 6 Overhang part 7 Diagonal brace 8 Middle brace 41 Center hull 42 Horizontal brace 43 Outer hull 44 Connecting bridge 51 Fin

Claims (3)

In a floating structure having a single column-shaped column portion that can float in an upright state and can connect an upper structure disposed on water,
A columnar upper hull having a diameter larger than that of the column portion in the vicinity of the water line;
A lower hull arranged at the lower end of the column portion and constituting a ballast tank and having a diameter larger than that of the column portion;
An overhanging portion which is a plate-like flange portion arranged so as to protrude radially outward over the entire circumference of the submerged portion of the upper hull;
The floating structure characterized by having.   The floating structure according to claim 1, wherein the projecting portion has a cavity inside. The floating structure according to claim 1, further comprising a plurality of fins erected radially on an upper surface of the lower hull.