CN116498803A - Buoyancy device and system with vortex-induced vibration suppression performance - Google Patents

Abstract

The invention discloses a buoyancy device and a buoyancy system with vortex-induced vibration suppression performance. The buoyancy device comprises a buoyancy device body, wherein the buoyancy device body comprises two buoyancy half-tiles which are spliced with each other; three rows of identical spiral strakes are arranged on the surface of the buoyancy device body, the three rows of spiral strakes are uniformly distributed at 120 degrees, each row of spiral strakes comprises four fins with specific parameter profiles, and every two adjacent fins are arranged at intervals. According to the invention, the spiral strake structure is added on the buoyancy device body to inhibit vortex-induced vibration of the marine pipeline provided with the buoyancy device, namely, the formation of vortex is destroyed by the fins, so that the vortex-induced frequency is greatly reduced, the natural frequency of the marine pipeline is avoided, and the purpose of inhibiting the vortex-induced vibration of the marine pipeline is achieved.

Description

Buoyancy device and system with vortex-induced vibration suppression performance

Technical Field

The invention relates to the field of ocean engineering and technology, in particular to a buoyancy device and a buoyancy system with vortex-induced vibration inhibition performance.

Background

In marine engineering, many installations require the use of buoyancy devices. The buoyancy devices are of various types and are mainly divided into two main types, namely water and underwater. The water buoyancy device is mainly used for navigating and marking the floating body. The underwater distributed buoyancy device is mainly used for connecting a bridge pipeline between flexible riser systems, umbilical cables, cables or submarine equipment in the marine floating production system. Dynamic motion exists between the pipeline and the floating platform, namely, the floating platform can be driven to swing by sinking and floating motion or swing. Through installing distributed buoyancy device under water, the pipeline can form certain line type under water according to self weight to guarantee the safety of pipeline when dynamic application for the pipeline can not appear great tension and camber in the body motion range. For jumper pipes between subsea equipment, the primary function of the buoyancy means is to reduce the weight of the jumper.

Whether it be a subsea flexible riser or a subsea jumper, there are vortex-induced vibration problems caused by the bypassing of fluid around the column structure. When the natural frequency of the pipeline is close to the frequency of the external exciting force, the phenomenon of 'locking' of fluid-solid coupling vibration occurs, so that the amplitude is obviously increased, and the fatigue damage of the pipeline is caused. Once the pipe structure is broken, a great economic loss is generated. Buoyancy devices are also typical of column structures and therefore also suffer from vortex-induced vibration problems. At present, most buoyancy devices are of smooth cylinder structures and do not have the performance of inhibiting vortex-induced vibration, so that it is of great significance to design a buoyancy device with the performance of inhibiting vortex-induced vibration.

Disclosure of Invention

The invention aims to solve the technical problems and provides a buoyancy device and a buoyancy system with vortex-induced vibration inhibition performance. The buoyancy device can increase the buoyancy of the marine pipeline and inhibit vortex-induced vibration of the pipeline.

In a first aspect, the present application provides a buoyancy device with vortex-induced vibration suppression performance, which is implemented by adopting the following technical scheme.

A buoyancy device with vortex-induced vibration suppression performance comprises a buoyancy device body, wherein the buoyancy device body comprises two buoyancy half-watts which are spliced with each other; three rows of identical spiral strakes are arranged on the surface of the buoyancy device body, the three rows of spiral strakes are uniformly distributed at 120 degrees, and each row of spiral strakes comprises four fins which are arranged at intervals.

Further, the pitch length of the three-row spiral strake is 16 times of the outer diameter of the buoyancy half watt.

Further, the height of the fins in the spiral strake is 0.2 times of the outer diameter of the buoyancy half-watt; the pitch of the fins is 10 °; the included angle of the trapezoid cross section of the fin is 10 degrees; the width of the interval between two adjacent fins is 0.12 times of the outer diameter of the buoyancy half watt.

Further, each column of spiral strakes includes a top fin at both ends and two middle fins intermediate the two top fins.

Further, the bottom width of the top fin is 0.165 times the outer diameter of the buoyancy half watt; the bottom width of the middle fin is 0.23 times the outer diameter of the buoyancy half-watt.

Further, positioning components are arranged on the opposite splicing surfaces of the two buoyancy half-tiles.

Further, a plurality of bolt connection grooves are formed on the buoyancy device body.

Further, a plurality of hoisting holes are formed in the end face of the buoyancy device body.

In a second aspect, the present application provides a buoyancy system with vortex-induced vibration suppression performance, which is implemented by adopting the following technical solutions.

A buoyancy system with vortex-induced vibration suppression performance comprises the buoyancy device and a pipeline provided with a spiral strake.

Further, the pitch length of the spiral strakes arranged on the pipeline provided with the spiral strakes is 16 times of the outer diameter of the pipeline; the fin height is 0.25 times of the outer diameter of the buoyancy half-watt; the pitch of the fins is 10 °; the included angle of the trapezoidal cross section of the fin is 10 °.

The present application has the following advantageous effects.

The buoyancy device meets the actual engineering requirements, is practical and feasible, has the advantages of light weight, easy mold forming and manufacturing, high-efficiency and quick installation, and capability of effectively inhibiting vortex-induced vibration of the pipeline and less increase of pipeline resistance on the basis of guaranteeing the buoyancy performance of the buoyancy device, and provides reliable guarantee for the development of marine pipelines.

Drawings

FIG. 1 is a schematic structural view of a buoyancy device having vortex induced vibration suppression properties according to the present invention;

FIG. 2 is a schematic view of the buoyancy half-watt structure of the present invention;

FIG. 3 is a schematic illustration of the fin angle on a buoyancy half watt intended to embody the present invention;

FIG. 4 is an assembled schematic view of a conventional buoyancy device mounted on a bare pipe;

FIG. 5 is an assembled schematic view of a conventional buoyancy device mounted on a pipeline with a spiraling strake mounted thereon;

FIG. 6 is a schematic diagram of an assembly of a buoyancy device with vortex-induced vibration suppression capability mounted on a pipe mounting a spiral strake;

FIG. 7 is a graph of drag coefficient versus flow rate;

FIG. 8 is a graph of amplitude versus flow rate;

FIG. 9 is a graph of amplitude suppression efficiency versus flow rate;

FIG. 10 is a cloud view of a vortex core with a conventional buoyancy device mounted on a bare pipe;

FIG. 11 is a cloud of vortex nuclei for a conventional buoyancy device mounted on a pipeline with a spiraling deck;

FIG. 12 is a cloud of vortex nuclei of a pipe having a spiral strake mounted thereon with buoyancy means for suppressing vortex induced vibration.

1, buoyancy half-watt; 2. a top fin; 3. an intermediate fin; 4. a hoisting hole; 5. a bolt connecting groove; 6. a positioning groove; 7. positioning the boss; 8. a bare pipe; 9. a conventional buoyancy device; 10. a pipeline for installing the spiral strakes; 11. a buoyancy device having vortex-induced vibration suppressing performance.

Detailed Description

The invention will be further described with reference to the drawings and examples.

As shown in fig. 1-3, a buoyancy device with vortex-induced vibration suppression performance comprises a buoyancy device body comprising two buoyancy half-tiles 1. The buoyancy half tile 1 is semi-cylindrical, a semi-circular groove extending along the axial direction is formed in the middle of the buoyancy half tile, and an embedded groove is formed in the middle of the groove by expanding. The two buoyancy half tiles 1 are mutually spliced to form a cylinder, a channel for the marine pipeline to penetrate is formed in the center of the cylinder, and the two embedded grooves are spliced to be used for embedding the marine pipeline clamp.

In order to improve convenience and accuracy of the split of the two buoyancy half tiles 1, the positioning assembly is arranged on the opposite split surfaces of the two buoyancy half tiles 1 and comprises a positioning groove 6 and a positioning boss 7. Specifically, as shown in fig. 2, the positioning assembly may be configured in the following manner: the positioning groove 6 and the positioning boss 7 are respectively positioned on the splicing surfaces of different sides of the same buoyancy half tile 1. When the buoyancy half tile 1 is wrapped on the clamp of the marine pipeline, the positioning boss 7 is inserted into the positioning groove 6 and is connected with the screw connecting groove 5 through a bolt, so that the buoyancy device is fastened on the clamp of the marine pipeline. There are many examples of clip structures, and this patent will not be described.

The end face of the buoyancy device body is provided with a plurality of lifting holes 4 for lifting the buoyancy device.

The buoyancy device body is provided with three rows of identical spiral strakes on the surface, the three rows of spiral strakes are uniformly distributed at 120 degrees, the three rows of spiral strakes are composed of two rows of top fins 2 and two rows of middle fins 3, the two rows of middle fins 3 are located in the middle of the two rows of top fins 2, the fins are arranged at intervals, and the top fins 2 and the middle fins 3 are in similar quadrangular frustum of a pyramid. The spiral strake structure is designed on the buoyancy device, so that the buoyancy of the marine pipeline can be effectively increased, and vortex-induced vibration of the pipeline and the buoyancy device can be restrained. The fins are arranged at intervals, so that the dragging force caused by the spiral strake can be reduced.

The CFD/CSD fluid-solid coupling analysis is carried out by adopting FLUENT commercial software, so that the better appearance structural parameters of the fin on the buoyancy device are optimized, the fin on the buoyancy device has better vortex-induced vibration inhibiting effect, and meanwhile, the resistance is less increased. Specifically, the outer diameter of the buoyancy half tile 1 is set to be D, the length of the pitch P of the three-row spiral strake is set to be 16D, and the heights of the top fin 2 and the middle fin 3 are both 0.2D; the slopes α of the top fin 2 and the middle fin 3 are 10 °, the included angles β of the trapezoid cross sections of the top fin 2 and the middle fin 3 are 10 °, and the interval width between the adjacent two fins is 0.12D. The bottom width of the top fin 2 is 0.165D, and the bottom width of the middle fin 3 is 0.23D. According to the fin pitch and the fin inclination, resistance caused by the spiral strake can be effectively reduced under the condition that the inhibiting effect of vortex induced vibration is not affected.

The buoyancy device is made of polyethylene materials, and the buoyancy half-tile shell and fins on the outer surface of the shell are integrally formed by adopting a die.

The application also provides a buoyancy system with vortex-induced vibration suppression performance, which comprises the buoyancy device and a pipeline provided with the spiral strake. The height of the fins of the spiral strake installed on the pipeline provided with the spiral strake is 0.25D, the screw pitch is 16 times of the outer diameter of the pipeline, and parameters such as the inclination and the included angle of the fins are consistent with those of the fins on the surface of the buoyancy device.

The working mechanism of the invention is as follows:

the conventional buoyancy device itself is a smooth cylinder structure, the buoyancy device is distributed on a marine hose or a subsea jumper, and the distributed smooth buoyancy device cylinder structure can cause certain vortex-induced vibration amplitude. The speed interval of the fluid environment where the marine hose or the submarine jumper is installed is a subcritical or supercritical interval. In the subcritical range, vortex shedding has definite natural frequency, and vortex-induced resonance phenomenon is very easy to occur. The fin on the buoyancy device can damage the vortex structure and break up the vortex, so that the shedding frequency of the vortex is greatly reduced, the fin is far away from the natural frequency of the structure, and the generation of vortex-induced resonance is avoided. Meanwhile, the fins have a certain inclination and are distributed at intervals, so that certain resistance can be reduced. The buoyancy device is made of polyethylene material, has the advantage of light weight, and has negligible weight of fins added on the buoyancy device and almost no influence on the performance of the buoyancy device.

FIG. 4 is a structural outline view of the bare pipe 8 with a conventional buoyancy device 9 mounted thereon; FIG. 5 is a structural outline view of a conventional buoyancy device 9 mounted on a conduit 10 for mounting a spiraling panel; fig. 6 is a structural outline view of a pipe 10 to which a spiral strake is attached, to which a buoyancy device 11 having vortex-induced vibration suppressing performance is attached. The flow speed capable of enabling the marine pipeline to generate vortex-induced resonance is selected, CFD/CSD bidirectional fluid-solid coupling analysis is carried out through FLUENT software, the results of resistance coefficient, transverse flow amplitude and the like of the marine pipeline with the buoyancy device under the condition that the buoyancy device with the fin is additionally arranged and the buoyancy device without the fin are obtained, and the vortex-induced vibration amplitude suppression efficiency of the buoyancy device with the fin can be judged through comparing the amplitude.

Fig. 7-9 are graphs of drag coefficient versus vortex-induced vibration amplitude versus suppression efficiency versus flow rate for the three device configurations of fig. 4-6. As can be seen from FIG. 7, the structural resistance coefficients of the invention designed by adopting the parameters are all smaller than 1.6, and the invention meets the engineering requirements. As can be seen from fig. 8, only the spiral strake is mounted on the bare pipe 8, and a certain vortex-induced vibration suppressing effect is provided. The vortex-induced vibration transverse amplitude is further suppressed when the buoyancy device is replaced with a finned buoyancy device. As can be seen from fig. 9, under the condition that only the spiral strake is installed on the bare pipe 8, the suppression efficiency is significantly reduced with an increase in flow rate, and the overall suppression efficiency is 89%. When the buoyancy device is replaced by the buoyancy device with fins, the inhibition efficiency is more than 90% at each flow rate, and the comprehensive inhibition efficiency is 97%.

Fig. 10 to 12 are respectively a vortex core cloud image of a conventional buoyancy device 9 mounted on a bare pipeline 8, a vortex core cloud image of a conventional buoyancy device 9 mounted on a pipeline 10 mounted with a spiral strake, and a vortex core cloud image of a buoyancy device 11 having vortex-induced vibration suppression performance mounted on a pipeline 10 mounted with a spiral strake. As can be seen from fig. 10, with the bare pipe 8 plus conventional buoyancy means 9, the rear of the pipe creates a complete vortex core. As can be seen from fig. 11, after the spiral strake is installed, the vortex cores around the pipe are broken up. As is more apparent from fig. 12, after the buoyancy device with fins is installed on the pipeline, the vortex core in the area where the buoyancy device is located is broken, and the structure of the vortex is destroyed, so that the vortex shedding frequency of the vortex becomes very small and is far away from the natural frequency of the structure, thereby playing a role in inhibiting vortex induced vibration.

The embodiments of the present invention are all preferred embodiments of the present invention, and are not intended to limit the scope of the present invention in this way, therefore: all equivalent changes in structure, shape and principle of the invention should be covered in the scope of protection of the invention.

Claims (10)

1. The utility model provides a buoyancy device with vortex-induced vibration suppression performance, includes buoyancy device body, its characterized in that: the buoyancy device body comprises two buoyancy half tiles (1) which are spliced with each other; three rows of identical spiral strakes are arranged on the surface of the buoyancy device body, the three rows of spiral strakes are uniformly distributed at 120 degrees, and each row of spiral strakes comprises four fins which are arranged at intervals.

2. A buoyancy device having vortex-induced vibration suppression properties according to claim 1, wherein: the pitch length of the three-row spiral strake is 16 times of the outer diameter of the buoyancy half watt (1).

3. A buoyancy device having vortex-induced vibration suppression properties according to claim 1, wherein: the height of the fins in the spiral strake is 0.2 times of the outer diameter of the buoyancy half watt (1); the pitch of the fins is 10 °; the included angle of the trapezoid cross section of the fin is 10 degrees; the width of the interval between two adjacent fins is 0.12 times of the outer diameter of the buoyancy half watt (1).

4. A buoyancy device having vortex-induced vibration suppression properties according to claim 1, wherein: each column of spiral strake comprises a top fin (2) at two ends and two middle fins (3) positioned in the middle of the two top fins (2).

5. A buoyancy device having vortex-induced vibration suppression properties as claimed in claim 4 wherein: the bottom width of the top fin (2) is 0.165 times of the outer diameter of the buoyancy half watt (1); the width of the bottom end of the middle fin (3) is 0.23 times of the outer diameter of the buoyancy half watt (1).

6. A buoyancy device having vortex-induced vibration suppression properties according to any one of claims 1 to 5, wherein: the opposite splicing surfaces of the two buoyancy half tiles (1) are provided with positioning components.

7. A buoyancy device having vortex-induced vibration suppression properties according to any one of claims 1 to 5, wherein: a plurality of bolt connecting grooves (5) are formed on the buoyancy device body.

8. A buoyancy device having vortex-induced vibration suppression properties according to any one of claims 1 to 5, wherein: the end face of the buoyancy device body is provided with a plurality of lifting holes (4).

9. A buoyancy system having vortex-induced vibration suppression properties, characterized by: a pipeline comprising a buoyancy device according to any one of claims 1 to 8 and a mounting spiral strake.

10. A buoyancy system with vortex-induced vibration suppression according to claim 9, wherein: the pitch length of the spiral strakes arranged on the pipeline provided with the spiral strakes is 16 times of the outer diameter of the pipeline; the fin height is 0.25 times of the outer diameter of the buoyancy half watt (1); the pitch of the fins is 10 °; the included angle of the trapezoidal cross section of the fin is 10 °.