Marine riser vortex-induced vibration suppression buoyancy block with spiral sphere array

Abstract

The invention discloses a marine riser vortex-induced vibration suppression buoyancy block with a spiral sphere array, and belongs to the technical field of ocean engineering equipment. Specifically, the buoyancy block assembly is of a closed cylinder structure formed by symmetrically splicing two buoyancy block half shells in the axial direction, three columns of spherical protrusions distributed in a spiral array mode are evenly arranged on the outer surface of the buoyancy block assembly in the circumferential direction at the interval of 120 degrees, and the thread pitch of the thread line is two times of the length of the buoyancy block. The spherical protrusions are closely arranged in the thread line direction, and the protruding height of the spherical protrusions is preferably 0.1 time of the outer diameter of the buoyancy block. Arc-shaped positioning rings are arranged at the two axial ends of the buoyancy block assembly so as to limit the axial movement of the buoyancy block assembly. While it is ensured that the buoyancy block device of the marine riser provides the buoyancy function, the marine riser vortex-induced vibration response can be restrained, and the resistance cannot generate a remarkable amplification effect.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore engineering equipment, and particularly to a buoyancy block for suppressing the vortex-induced vibration of a riser with a spiral sphere array. Background Art

[0002] In deep-sea oil and gas exploitation projects, the riser system, as the core equipment connecting the subsea wellhead and the offshore platform, its stable operation is crucial. The buoyancy block, as a key component of the riser system, provides the necessary buoyancy compensation through low-density composite materials, reduces the need for the platform to adjust its own buoyancy, and ensures that the riser maintains a reasonable axial load in the seawater environment. However, when the sea current flows through a cylindrical structure, vortex shedding alternates to generate periodic excitation forces, which easily form vortex-induced vibrations and cause the lateral vibration of the riser. Vortex-induced vibrations are prone to cause structural fatigue damage or even fracture failure, continuously threatening the operation safety and service life of the riser.

[0003] Most of the existing riser buoyancy blocks adopt a smooth surface design, such as patents CN206860107 U and CN208564465U, which cannot suppress vortex-induced vibrations. Although the flow field can be disturbed by adding a spiral fin device (such as patent CN116498803A), however, according to the research by Sheng Leixiang et al. in "CFD Analysis of the Flow Field around a Spiral Fin" (Shipbuilding of China, 2010, 51(01): 78-83), this type of structure will cause a significant increase in the flow resistance while reducing the lateral lift force, thereby causing an increase in the flow direction displacement of the riser and greatly amplifying the tension load received at the end. In addition, the spiral fin structure has engineering application drawbacks such as complex assembly processes and high manufacturing costs. The above technologies have not achieved an ideal balance between the flow field regulation efficiency and engineering practicability.

[0004] Therefore, those skilled in the art urgently need to provide a buoyancy block for suppressing the vortex-induced vibration of a riser with a spiral sphere array. While providing the buoyancy function, the buoyancy block can suppress the vortex-induced vibration response of the riser, and there will be no significant amplification effect on the resistance. Summary of the Invention

[0005] The purpose of the present invention is to provide a buoyancy block for suppressing the vortex-induced vibration of a riser with a spiral sphere array. While providing the buoyancy function, the buoyancy block can suppress the vortex-induced vibration response of the riser, and there will be no significant amplification effect on the resistance.

[0006] To achieve the above object, the present invention provides a buoyancy block for suppressing the vortex-induced vibration of a riser with a spiral sphere array, including a buoyancy block assembly, a riser, and an auxiliary tubular workpiece. Each of the buoyancy block assemblies internally limits a riser and an auxiliary tubular workpiece. A plurality of the risers and a plurality of auxiliary tubular workpieces are respectively connected end to end. The surface of the buoyancy block assembly is provided with spherical protrusions arranged in a spiral array with vortex-induced vibration suppression.

[0007] Preferably, the buoyancy block assembly includes a buoyancy block half-shell, which is an arc-shaped shell. The inner side surface of the buoyancy block half-shell is evenly provided with auxiliary tubular workpiece channels, and the auxiliary tubular workpiece channels limit the auxiliary tubular workpieces. The inner side surface of the buoyancy block half-shell is also evenly provided with arc-shaped surfaces, which are located between two of the auxiliary tubular workpiece channels. A plurality of the arc-shaped surfaces are in contact with the outer wall of the riser to form a riser channel.

[0008] Preferably, both end faces of the buoyancy block half-shell are evenly provided with convex blocks and grooves, and the convex blocks and grooves are matched. The two buoyancy block half-shells are assembled into a cylindrical hollow structure through the cooperation of the convex blocks and grooves.

[0009] Preferably, through holes are opened on both end faces of the buoyancy block half-shell. After a bolt one passes through the through holes on the two assembled buoyancy block half-shells, it is connected together with a nut one and an elastic washer.

[0010] Preferably, flange plates are respectively fixedly connected to both ends of the riser, and two positioning ring assemblies are also connected to the outer wall of the riser. The two positioning ring assemblies are respectively limited at both ends of the buoyancy block assembly.

[0011] Preferably, the positioning ring assembly includes four arc-shaped positioning rings. The arc-shaped positioning ring includes a mating block one and a mating block two. Both the mating block one and the mating block two are provided with threaded holes, and the mating block one and the mating block two are matched. The mating block one and the mating block two overlap each other, and a bolt two passes through the threaded holes on the mating block one and the mating block two and is connected together with a nut two, thereby connecting the arc-shaped positioning rings in pairs.

[0012] Preferably, the arc-shaped positioning ring further includes an inner arc surface and a slot hole. The inner arc surface is in contact with the outer wall of the riser. Slot holes are provided at the bottoms of both ends of the arc-shaped positioning ring, and auxiliary tubular workpieces are limited between the slot holes of two adjacent arc-shaped positioning rings and the riser.

[0013] Preferably, auxiliary tubular workpiece through holes and connection holes are uniformly arranged on the flange. The auxiliary tubular workpiece passes through the auxiliary tubular workpiece channel and the auxiliary tubular workpiece through holes. Connecting pieces connect the adjacent two flanges end to end, thereby connecting several buoyancy block components together.

[0014] Preferably, three columns of spirally arranged spherical protrusions are uniformly arranged on the outer surface of the buoyancy block component along the circumferential direction. The pitch of the thread of the spherical protrusion is twice the length of the semi-shell of the buoyancy block. The surface of the spherical protrusion is coated with a fluoropolymer anti-biofouling coating, and the thickness of the fluoropolymer anti-biofouling coating is 50 μm - 100 μm.

[0015] Preferably, the inner angle of the arc-shaped positioning ring is 90°.

[0016] The advantages and positive effects of the buoyancy block for suppressing the vortex-induced vibration of the riser with a spiral sphere array according to the present invention are as follows: 1. The spirally arrayed spherical protrusions can effectively promote the early shedding of vortices, reduce the amplitude of the vortex-induced vibration of the riser, reduce the risk of fatigue damage, and improve the safety and reliability of the riser.

[0017] 2. Compared with the traditional spiral plate structure, the structure of the present invention is simple, the mold opening is easy, and the manufacturing cost and assembly difficulty are effectively reduced.

[0018] 3. The spherical protrusions spirally arrayed on the outer surface of the semi-shell of the buoyancy block adopt an integral molding process with a mold. Its integral structure has better stability and reliability in the deep-sea high-pressure environment, avoiding the problem of easy connection failure of the traditional structure.

[0019] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of a buoyancy block for suppressing the vortex-induced vibration of a riser with a spiral sphere array according to the present invention; Figure 2 is Figure 1 a schematic structural diagram of part A of Figure 3 is a schematic structural diagram of the semi-shell of the buoyancy block and the riser according to the present invention; Figure 4 is a schematic structural diagram of the semi-shell of the buoyancy block according to the present invention; Figure 5 is a schematic structural diagram of the arc-shaped positioning ring according to the present invention; Figure 6 is a schematic structural diagram of the riser, the arc-shaped positioning ring and the flange according to the present invention; Figure 7Schematic diagram for the installation of multiple buoyancy block components of the present invention.

[0021] Reference numerals 1. Buoyancy block component; 101. Buoyancy block half shell; 102. Spherical protrusion; 103. Through hole; 104. Bolt 1; 105. Nut 1; 106. Elastic washer; 107. Bump; 108. Groove; 109. Arc surface; 110. Auxiliary tubular workpiece channel; 111. Riser pipe channel 2. Auxiliary tubular workpiece; 3. Riser pipe; 4. Flange; 401. Connection hole; 5. Arc positioning ring; 501. Threaded hole; 502. Nut 2; 503. Inner arc surface; 504. Slot hole; 505. Fitting block 1; 506. Fitting block 2 Detailed implementation manners

[0022] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the terms "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. In case of inconsistency, the meaning described in this specification or the meaning obtained according to the content recorded in this specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0024] The following will describe the embodiments of the present invention in detail with reference to the drawings.

[0025] As Figures 1 - 7As shown in the figure, a buoyancy block for suppressing the vortex-induced vibration of a riser with a spiral sphere array includes a buoyancy block assembly 1, a riser 3, and an auxiliary tubular workpiece 2. The riser 3 and the auxiliary tubular workpiece 2 are internally limited in each buoyancy block assembly 1. A number of risers 3 and a number of auxiliary tubular workpieces 2 are respectively connected end to end. The surface of the buoyancy block assembly 1 is provided with spherical protrusions 102 arranged in a spiral array for suppressing vortex-induced vibration.

[0026] Specifically, the working principle of the spherical protrusions 102 for suppressing vortex-induced vibration is as follows: The spherical protrusions arranged in a spiral array can effectively disrupt the vortex shedding around the riser 3 and break the periodic shedding law of the traditional smooth surface Karman vortex street. According to the relevant theories of vortex shedding and structural vibration in fluid mechanics, when the vortex shedding frequency is close to the natural frequency of the riser 3, resonance is likely to occur, leading to large-amplitude vibration. However, the spherical protrusions 102 can change the shedding vortex frequency, making it far from the structural natural frequency, thereby effectively avoiding large amplitudes of the riser 3 due to resonance and realizing the suppression of vortex-induced vibration.

[0027] The buoyancy block assembly 1 includes a buoyancy block half-shell 101, and the buoyancy block half-shell 101 is an arc-shaped shell. Auxiliary tubular workpiece channels 110 are uniformly arranged on the inner side surface of the buoyancy block half-shell 101, and the auxiliary tubular workpiece 2 is limited in the auxiliary tubular workpiece channels 110.

[0028] Arc-shaped surfaces 109 are also uniformly arranged on the inner side surface of the buoyancy block half-shell 101. The arc-shaped surfaces 109 are located between two auxiliary tubular workpiece channels 110, and a number of arc-shaped surfaces 109 are in contact with the outer wall of the riser 3 to form a riser channel 111.

[0029] Convex blocks 107 and grooves 108 are uniformly arranged on both end faces of the buoyancy block half-shell 101. The convex blocks 107 and the grooves 108 are matched, and the two buoyancy block half-shells 101 are assembled into a cylindrical hollow structure through the cooperation of the convex blocks 107 and the grooves 108.

[0030] Through holes 103 are provided on both end faces of the buoyancy block half-shell 101. After a bolt 104 passes through the through holes 103 on the two assembled buoyancy block half-shells 101, it is connected together with a nut 105 and an elastic washer 106.

[0031] Specifically, the through holes 103 penetrate from both end faces of the buoyancy block half-shell 101 to the arc-shaped surfaces.

[0032] Flange plates 4 are respectively fixedly connected to both ends of the riser 3, and two positioning ring assemblies are also connected to the outer wall of the riser 3. The two positioning ring assemblies are respectively limited at both ends of the buoyancy block assembly 1.

[0033] Specifically, the two ends of the riser 3 are connected to the flange plates 4 by welding.

[0034] The positioning ring assembly includes four arc-shaped positioning rings 5. The arc-shaped positioning ring 5 includes a first mating block 505 and a second mating block 506. Threaded holes 501 are provided in both the first mating block 505 and the second mating block 506, and the first mating block 505 and the second mating block 506 are matched with each other. The first mating block 505 and the second mating block 506 are lapped together, and after a second bolt passes through the threaded holes 501 in the first mating block 505 and the second mating block 506, they are connected together with a second nut 502, thereby connecting the arc-shaped positioning rings 5 to each other in pairs.

[0035] The arc-shaped positioning ring 5 further includes an inner arc surface 503 and a slot hole 504. The inner arc surface 503 is in contact with the outer wall of the riser 3. Slot holes 504 are provided at the bottoms of both ends of the arc-shaped positioning ring 5, and an auxiliary tubular workpiece 2 is limited between the slot holes 504 of two adjacent arc-shaped positioning rings 5 and the riser 3. Specifically, the size of the inner arc surface 503 matches the size of the outer wall of the riser 3, so that two positioning ring assemblies can be clamped at both ends of the buoyancy block assembly 1.

[0036] Auxiliary tubular workpiece through holes and connection holes 401 are uniformly provided on the flange 4. The auxiliary tubular workpiece 2 passes through the auxiliary tubular workpiece 2 channel and the auxiliary tubular workpiece through hole. Connecting pieces connect two adjacent flanges 4 end to end, thereby connecting a plurality of buoyancy block assemblies 1 together.

[0037] Specifically, the auxiliary tubular workpieces 2 are connected together after a plurality of buoyancy block assemblies 1 are assembled.

[0038] Specifically, the connecting piece can adopt a bolt assembly, thereby connecting two adjacent flanges 4 end to end.

[0039] Three rows of helically arranged spherical protrusions 102 are uniformly provided on the outer surface of the buoyancy block assembly 1 in the circumferential direction. The pitch of the thread of the spherical protrusion 102 is twice the length of the buoyancy block half shell 101. A fluoropolymer anti-biofouling coating is coated on the surface of the spherical protrusion 102, and the thickness of the fluoropolymer anti-biofouling coating is 50 μm - 100 μm. Specifically, the spherical protrusions 102 are closely arranged along the thread direction, and the protruding height is preferably 0.1 times the outer diameter D of the buoyancy block half shell.

[0040] Specifically, the buoyancy block half shell 101 and the spherical protrusions 102 on the surface are made of polyurethane elastomer, and the polyurethane elastomer has the characteristics of high pressure resistance and high buoyancy.

[0041] The inner angle of the arc-shaped positioning ring 5 is 90°. Specifically, four arc-shaped positioning rings 5 are assembled into an integral ring structure.

[0042] The usage process of the present invention is as follows. During installation, the riser pipe 3 is horizontally mounted on a support platform with a rotating function, and the distance between the support components is adjusted to fit the length of the pipe section to ensure that the axis of the pipe body of the riser pipe 3 coincides with the tooling reference line.

[0043] After the riser pipe 3 is positioned, a lifting tooling with a magnetic attraction or a chuck is used to grasp the buoyancy block half shell 101. The two buoyancy block half shells 101 are aligned along the outer wall of the riser pipe 3 and positioned by the cooperation of the convex block 107 and the groove 108. Then, a bolt 104 is inserted into the through hole 103 to complete the connection of the two buoyancy block half shells 101. After the buoyancy block assembly 1 is installed, two groups of positioning ring assemblies are installed closely against the two end faces of the buoyancy block half shell 101 to limit the axial displacement of the buoyancy block assembly 1.

[0044] After the buoyancy block assembly 1 is installed, the assembled buoyancy block assembly 1 and the riser pipe 3 are lowered section by section on the platform deck. The flange plates provided at both ends of the riser pipe 3 are provided with connection holes 401, and the adjacent riser pipes 3 are connected and fixed by cooperating with corresponding connecting pieces, such as bolt assemblies, so as to achieve the purpose of extending the overall length of the riser pipe 3.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A buoyancy block for suppressing the vortex-induced vibration of a riser with a spiral sphere array, characterized in that: It includes buoyancy block assemblies, risers, and auxiliary tubular workpieces. Inside each of the buoyancy block assemblies, a riser and an auxiliary tubular workpiece are limited. A number of the risers and a number of the auxiliary tubular workpieces are respectively connected end to end. On the surface of the buoyancy block assembly, spherical protrusions arranged in a spiral array with vortex-induced vibration suppression are provided.

2. The buoyancy block for suppressing the vortex-induced vibration of a riser with a spiral sphere array according to claim 1, wherein: The buoyancy block assembly includes a buoyancy block half-shell, which is an arc-shaped shell. On the inner side surface of the buoyancy block half-shell, auxiliary tubular workpiece channels are uniformly provided, and the auxiliary tubular workpiece channels limit the auxiliary tubular workpieces. On the inner side surface of the buoyancy block half-shell, arc-shaped surfaces are also uniformly provided. The arc-shaped surfaces are located between two of the auxiliary tubular workpiece channels. A number of the arc-shaped surfaces are in contact with the outer wall of the riser to form a riser channel.

3. The buoyancy block for suppressing the VIV of the riser with a spiral sphere array according to claim 2, characterized in that: On both end faces of the buoyancy block half-shell, bumps and grooves are uniformly provided. The bumps and grooves are matched. Two of the buoyancy block half-shells are assembled into a cylindrical hollow structure through the cooperation of the bumps and grooves.

4. A buoyancy block for suppressing the vortex-induced vibration of a riser with a spiral sphere array according to claim 3, characterized in that: Through holes are provided on both end faces of the buoyancy block half-shell. After a bolt one passes through the through holes on two assembled buoyancy block half-shells, it is connected together with a nut one and an elastic washer.

5. The buoyancy block for suppressing the VIV of the riser with a spiral sphere array according to claim 4, characterized in that: Flange plates are respectively fixedly connected to both ends of the riser. Two positioning ring assemblies are also connected to the outer wall of the riser. The two positioning ring assemblies are respectively limited at both ends of the buoyancy block assembly.

6. The buoyancy block for suppressing the VIV of the riser with a spiral sphere array according to claim 5, characterized in that: The positioning ring assembly includes four arc-shaped positioning rings. The arc-shaped positioning ring includes a mating block one and a mating block two. Threaded holes are provided on both the mating block one and the mating block two. The mating block one and the mating block two are matched. The mating block one and the mating block two are lapped together. After a bolt two passes through the threaded holes on the mating block one and the mating block two, it is connected together with a nut two, thereby connecting the arc-shaped positioning rings in pairs.

7. The buoyancy block for suppressing the vortex-induced vibration of a riser with a spiral sphere array according to claim 6, characterized in that: The arc-shaped positioning ring further includes an inner arc surface and a slot hole. The inner arc surface is in contact with the outer wall of the riser. Slot holes are provided at the bottoms of both ends of the arc-shaped positioning ring. An auxiliary tubular workpiece is limited between the slot holes of two adjacent arc-shaped positioning rings and the riser.

8. The buoyancy block for suppressing the VIV of the riser with a spiral sphere array according to claim 5, characterized in that: Auxiliary tubular workpiece through holes and connection holes are uniformly provided on the flange plate. The auxiliary tubular workpiece passes through the auxiliary tubular workpiece channel and the auxiliary tubular workpiece through hole. Connecting pieces connect the adjacent two flange plates end to end, thereby connecting a number of buoyancy block assemblies together.

9. The buoyancy block for suppressing the VIV of the riser with a spiral sphere array according to claim 2, wherein: On the outer surface of the buoyancy block assembly, three columns of spherical protrusions arranged in a spiral are uniformly provided along the circumferential direction; the pitch of the thread line of the spherical protrusion is twice the length of the buoyancy block half-shell; a fluoropolymer anti-biofouling coating is coated on the surface of the spherical protrusion, and the thickness of the fluoropolymer anti-biofouling coating is 50μm - 100μm.

10. The buoyancy block for suppressing the vortex-induced vibration of a riser having a spiral sphere array according to claim 7, characterized in that: The inner angle of the arc-shaped positioning ring is 90°.

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