A cylindrical double-degree-of-freedom flow-induced vibration experimental device based on rolling disk design

Abstract

The present invention discloses a cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disc design, comprising a main body support, a central axis, a mass pound, a disc assembly and two tension spring assemblies; the disc assembly is sleeved on the upper end of the central axis, the main body support is sleeved on the disc assembly, the two tension spring assemblies are respectively mounted on the upper surface and the lower surface of the main body support, and the tension spring assembly is connected to the central axis, and the lower end of the central axis is mounted on the mass pound. The present invention realizes double-degree-of-freedom movement in the cylindrical plane through the rolling disc design, reduces the friction damping of the experimental mechanism during the flow-induced vibration of the cylinder, improves the accuracy of the experimental results, and provides support for model experiments to study the flow-induced vibration characteristics of risers. The present invention can be used for riser design in marine engineering.

Description

Technical Field

[0001] The invention relates to a cylindrical double-freedom flow-induced vibration experimental device based on a rolling disc design, and belongs to the field of marine riser flow-induced vibration model tests. Background Art

[0002] The riser in marine engineering is an important component that connects the offshore oil and gas platform to the seabed oil and gas wellhead. However, due to the action of the ocean current, the riser is prone to vortex-induced vibration, that is, the pipe body continues to vibrate regularly to varying degrees. This vibration can cause fatigue damage to the riser, so the flow-induced vibration characteristics of the riser have always been an important research direction in the field of marine engineering.

[0003] In order to study the laws and mechanisms of flow-induced vibration, model tests are a major research method. Through model tests, the vortex shedding, hydrodynamics and vibration response characteristics of the riser under different flow velocities can be simulated, providing a reference for practical engineering design and numerical simulation. Due to the limitations of experimental conditions, a spring-constrained rigid cylindrical model is usually used to simulate the double-degree-of-freedom flow-induced vibration of the marine riser plane.

[0004] However, the current experimental device has some problems in simulating the double-degree-of-freedom flow-induced vibration of a cylinder. These problems include large friction resistance of the planar mechanism, plane instability, and time-consuming installation. The way to deal with these problems directly affects the setting of the hydrodynamic influencing parameters in the flow-induced vibration of the riser, thereby affecting the correct simulation of the flow-induced vibration mechanism of the riser.

[0005] To solve these problems, the experimental device needs to be improved and optimized. Possible improvement directions include reducing friction resistance, improving plane stability, simplifying the installation process, etc. By improving the experimental device, the flow-induced vibration behavior of the riser at different flow rates can be simulated more accurately, providing more reliable experimental data for a deeper understanding of the riser vibration mechanism. This is of great significance for the design and safety assessment of marine engineering. Summary of the invention

[0006] The invention aims to solve the problems of large friction resistance, unstable plane and time-consuming installation of planar mechanisms, and further proposes a cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disc design.

[0007] The technical solution adopted by the present invention to solve the above problems is: a cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disc design, comprising a main body bracket, a central axis, a mass pound, a disc assembly and two tension spring assemblies; the disc assembly is sleeved on the upper end of the central axis, the main body bracket is sleeved on the disc assembly, the two tension spring assemblies are respectively installed on the upper surface and the lower surface of the main body bracket, and the tension spring assembly is connected to the central axis, and the lower end of the central axis is installed on the mass pound.

[0008] Furthermore, the disc assembly includes a lower splint, an upper splint, a disc and a plurality of rolling steel balls; the disc is arranged between the lower splint and the upper splint, and the disc is mounted on the central axis, a plurality of rolling steel balls are arranged between the lower surface of the upper splint and the upper surface of the disc, and a plurality of rolling steel balls are arranged between the lower surface of the disc and the upper surface of the lower splint.

[0009] Furthermore, the disc assembly also includes a universal wheel and a top plate, the universal wheel is arranged at the top end of the central axis, and the top end of the central axis contacts the lower surface of the top plate through the universal wheel, the top plate is fixed to the main bracket through a support, and the top plate is located above the disc.

[0010] Furthermore, a plurality of steel ball grooves are provided on the lower surface of the upper clamping plate and the upper surface of the lower clamping plate along the circumferential direction of the disc, and a rolling steel ball is provided in each of the steel ball grooves.

[0011] Furthermore, each of the tension spring assemblies includes four tension springs and four spring brackets. The four tension springs are evenly distributed around the central axis along the circumferential direction. The inner end of the tension spring is connected to the central axis, and the outer end of the tension spring is connected to the main body bracket through the spring bracket.

[0012] Furthermore, the main support includes a support mechanism and a fixing mechanism. The support mechanism is square in shape and includes four support beams. The four support beams are respectively a first support beam, a second support beam, a third support beam and a fourth support beam. The third support beam and the fourth support beam are parallel to each other. The fixing mechanism is arranged between the third support beam and the fourth support beam, and both are fixedly connected to the third support beam and the fourth support beam.

[0013] Furthermore, the fixing mechanism includes four parallel fixed beams, the four fixed beams include two upper fixed beams and two lower fixed beams, both ends of the two upper fixed beams are fixedly connected to the upper surfaces of the third support beam and the fourth support beam, both ends of the two lower fixed beams are fixedly connected to the lower surfaces of the third support beam and the fourth support beam, the two upper fixed beams correspond to the corresponding two lower fixed beams up and down, the four fixed beams are all located on the inner side of the first support beam and the second support beam, and there are gaps between the two upper fixed beams and between the two lower fixed beams, the upper clamping plate in the disc assembly is fixed between the two upper fixed beams and located at the lower part of the two upper fixed beams, the lower clamping plate in the disc assembly is fixed between the two lower fixed beams and located at the upper part of the two lower fixed beams, and the upper clamping plate and the lower clamping plate correspond to each other up and down.

[0014] Furthermore, a gasket is provided between the upper clamping plate and the two upper fixed beams, and a gasket is provided between the lower clamping plate and the two lower fixed beams.

[0015] Furthermore, the cylindrical double-degree-of-freedom flow-induced vibration experimental device based on the rolling disk design also includes a cylindrical shell and a vortex-induced vibration suppression device, and the two ends of the cylindrical shell are detachably provided with a cylindrical top cover and a cylindrical bottom cover, a mass pound is provided inside the cylindrical shell, and a vortex-induced vibration suppression device is provided outside the cylindrical shell.

[0016] The beneficial effects of the present invention are:

[0017] 1. The present invention realizes double-degree-of-freedom movement in the plane of the cylinder through the rolling disk design, reduces the friction damping of the experimental device during the flow-induced vibration of the cylinder, improves the accuracy of the experimental results, can better simulate the flow-induced vibration of the cylinder with double degrees of freedom, and provides support for the model experiment of studying the flow-induced vibration characteristics of the riser.

[0018] 2. The present invention enables the universal wheel to contact the lower surface of the top plate through the adjusting bolt, thereby improving the plane stability and reliability of the mass pound when performing plane motion.

[0019] 3. The connection design of the present invention can facilitate the installation of the flow-induced vibration suppression device. The structure is simple to install and the cylindrical model specimen in the experiment can be quickly and conveniently replaced, thereby shortening the adjustment time of the natural frequency, mass ratio, diameter and suppression device of the test model, thereby reducing the preparation time of the experiment and improving the experimental efficiency.

[0020] 4. The present invention can synchronously observe the motion trajectory and force conditions of the cylinder in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a front view of the cylindrical double-degree-of-freedom flow-induced vibration experimental device of the present invention;

[0022] Figure 2 It is a partial exploded view of the cylindrical double-degree-of-freedom flow-induced vibration experimental device of the present invention;

[0023] Figure 3 This is a front view of the cylindrical double-degree-of-freedom flow-induced vibration experimental device of the present invention. Figure 1 ;

[0024] Figure 4 This is a front view of the cylindrical double-degree-of-freedom flow-induced vibration experimental device of the present invention. Figure 2 ;

[0025] Figure 5 It is a top view of the cylindrical double-degree-of-freedom flow-induced vibration experimental device of the present invention.

[0026] Description of the numbers in the figure:

[0027] 1. Tension spring; 2. Universal wheel; 3. Top plate; 4. Spring bracket; 5. Integral bracket; 6. Lower splint; 7. Middle shaft; 8. Upper splint; 9. Disc; 10. Fixing pin hole; 11. Cylindrical bottom cover; 12. Cylindrical outer shell; 13. Mass pound; 14. Rolling steel ball; 51. First fixed beam; 52. Second fixed beam; 53. Third fixed beam; 54. Fourth fixed beam; 55. First bracket beam; 56. Second bracket beam; 57. Third bracket beam; 58. Fourth bracket beam. DETAILED DESCRIPTION

[0028] Specific implementation method 1: Combination Figures 1 to 5 The present embodiment is described. The cylindrical double-degree-of-freedom flow-induced vibration experimental device designed based on a rolling disc in the present embodiment includes a main support 5, a central axis 7, a mass pound 13, a disc assembly and two tension spring assemblies.

[0029] The main support 5 is fixed to the outer wall edge of the circulating water tank by a G-clamp to ensure that when the mass pound 13 starts to move during the experiment, the main support 5 is prevented from vibrating, thereby ensuring the stability of the main support 5.

[0030] The disc assembly is sleeved on the upper end of the central axis 7, and the main body bracket 5 is sleeved on the disc assembly.

[0031] The length of the middle axis 7 is set according to the actual water level of the water tank to ensure that the mass pound 13 is completely submerged in the water and the upper surface of the mass pound 13 is greater than 250mm from the water surface, thereby reducing the influence of water surface fluctuations on the movement of the mass pound 13. At the same time, the outer diameter of the middle axis 7 is 250mm to reduce the influence of water surface wave resistance on the experiment.

[0032] The two extension spring assemblies are respectively mounted on the upper surface and the lower surface of the main support 5, and the extension spring assembly is connected to the central axis 7, and the lower end of the central axis 7 is mounted on the mass pound 13. The extension spring assembly is additionally provided with a three-force balance.

[0033] Specific implementation method 2: Combination Figures 1 to 5To explain this embodiment, the disc assembly in this embodiment includes a lower clamping plate 6, an upper clamping plate 8, a disc 9 and a plurality of rolling steel balls 14. The disc 9 is arranged between the lower clamping plate 6 and the upper clamping plate 8. In order to reduce the mass of the disc 9 itself as much as possible, the disc 9 is made of a lighter material. In this embodiment, the disc 9 is made of PVC material. In order to enhance the strength and surface smoothness of the disc 9, a layer of aluminum alloy shell is added to the upper and lower surfaces of the disc 9. The surfaces of the upper clamping plate 8 and the lower clamping plate 6 facing the disc 9 are polished to reduce the friction resistance of the disc 9 when it moves. The disc 9 is mounted on the central shaft 7, and a plurality of rolling steel balls 14 are arranged between the lower surface of the upper clamping plate 8 and the upper surface of the disc 9, and a plurality of rolling steel balls 14 are arranged between the lower surface of the disc 9 and the upper surface of the lower clamping plate 6. .

[0034] Specific implementation method three: Combination Figures 1 to 5 To explain this embodiment, the disc assembly described in this embodiment also includes a universal wheel 2 and a top plate 3. The universal wheel 2 is arranged at the top end of the central axis 7, and the top end of the central axis 7 contacts the lower surface of the top plate 3 through the universal wheel 2, ensuring that the disc 9 and the central axis 7 will not tilt or other problems during the translation process. The central axis 7 is also provided with an adjusting bolt, through which the top plate 3 is closely contacted with the universal wheel 2 in the disc assembly, further enhancing the stability of the disc 9 and the central axis 7 during planar motion. The top plate 3 is made of highly transparent tempered glass, which is convenient for better observation and recording of the moving motion trajectory of the mass pound 13. The top plate 3 is fixedly connected to the upper surfaces of the two upper fixed beams through pillars and fixed with bolts. The top plate 3 is located above the disc 9.

[0035] Specific implementation method four: Combination Figures 1 to 5 To explain this embodiment, a plurality of steel ball grooves of equal size are evenly spaced along the circumferential direction of the disc 9 on the lower surface of the upper clamping plate 8 and the upper surface of the lower clamping plate 6 described in this embodiment. A rolling steel ball 14 of equal size adapted to the steel ball groove is provided in each of the steel ball grooves, so that the disc 9 can move freely in the plane between the upper clamping plate 8 and the lower clamping plate 6, reducing the friction damping during the flow-induced vibration of the cylinder, more accurately simulating the flow-induced vibration of the cylinder, and improving the accuracy of the experimental results. At the same time, it also ensures that the rolling steel ball 14 will not roll off. During the experiment, lubricant needs to be added to the steel ball groove to further reduce the friction resistance of the disc 9 during movement and ensure the accuracy of the experimental data. The rolling steel ball 14 is in contact with the disc 9.

[0036] Specific implementation method five: Combination Figures 1 to 5To describe this embodiment, each of the tension spring assemblies in this embodiment includes four tension springs 1 and four spring brackets 4. The four tension springs 1 are evenly distributed around the central axis 7 in the circumferential direction. Moreover, the tension springs 1 are distributed along the downstream direction and the cross-stream direction respectively to ensure accurate measurement of the force exerted on the cylinder. The spring bracket 4 is arranged in the middle of each bracket beam of the main bracket 5. The inner end of the tension spring 1 is connected to the central axis 7 through a connecting frame, and the outer end of the tension spring 1 is connected to the main bracket 5 through a spring bracket 4. And the four tension springs 1 of each tension spring assembly form a plane, which is parallel to the plane of the main bracket 5.

[0037] This simulates the natural frequency of the riser movement. To ensure that the tension spring 1 remains in a tensioned state when the mass 13 moves, the original length of the spring L K The requirements are as follows:

[0038]

[0039] Wherein, L is the distance from the spring support 4 to the central axis 7, and D is the diameter of the cylinder.

[0040] Specific implementation method six: Combination Figures 1 to 5 To explain this embodiment, the main support 5 described in this embodiment includes a support mechanism and a fixing mechanism. The main support 5 is constructed of 80×40 aluminum profiles. The support mechanism is a 1.2m×1.2m square frame. The support mechanism includes four support beams, which are the first support beam 55, the second support beam 56, the third support beam 57 and the fourth support beam 58, and the lengths of all of them are 1200mm. The four support beams are connected by angle irons, and the angle irons are connected to the aluminum profile support beams by bolts. The third support beam 57 and the fourth support beam 58 are parallel to each other. The first support beam 55 and the second support beam 56 are installed in the direction of the water flow; the third support beam 57 and the fourth support beam 58 are installed perpendicular to the water flow.

[0041] The fixing mechanism is arranged between the third support beam 57 and the fourth support beam 58, and is fixedly connected to the third support beam 57 and the fourth support beam 58. The third support beam 57 and the fourth support beam 58 are at the same distance from the outer wall of the water tank. The main body support 5 is fixed to the outer wall edge of the circulating water tank by clamping the two ends of the third support beam 57 and the fourth support beam 58 with a G-shaped clamp.

[0042] Specific implementation method seven: Combination Figures 1 to 5This embodiment is described. The fixing mechanism described in this embodiment includes four parallel fixed beams. The four fixed beams are aluminum profiles, including two upper fixed beams (i.e., the first fixed beam 51 and the second fixed beam 52) and two lower fixed beams (i.e., the third fixed beam 53 and the fourth fixed beam 54). The two ends of the two upper fixed beams are fixedly connected to the upper surfaces of the third support beam 57 and the fourth support beam 58; the two ends of the two lower fixed beams are fixedly connected to the lower surfaces of the third support beam 57 and the fourth support beam 58. The two upper fixed beams correspond to the corresponding two lower fixed beams one by one. The four fixed beams are all located on the inner side of the first support beam 55 and the second support beam 56, and there are gaps between the two upper fixed beams and between the two lower fixed beams. The upper clamping plate 8 in the disc assembly is fixed between the two upper fixed beams by bolt connection and is located at the lower part of the two upper fixed beams. The lower clamping plate 6 in the disc assembly is fixed between the two lower fixed beams by bolt connection and is located at the upper part of the two lower fixed beams. The upper clamping plate 8 and the lower clamping plate 6 correspond to each other one by one.

[0043] Specific implementation method eight: Combination Figures 1 to 5 To explain this embodiment, a gasket is installed between the upper clamping plate 8 and the two upper fixed beams, and a gasket is installed between the lower clamping plate 6 and the two lower fixed beams. By using the gaskets between the fixed beams and the upper and lower clamping plates, the upper and lower clamping plates can clamp the disc 9, so that when the mass pound 13 moves, the disc 9 will not vibrate up and down.

[0044] Specific implementation method nine: Combination Figures 1 to 5 To explain the present embodiment, the cylindrical double-degree-of-freedom flow-induced vibration experimental device based on the rolling disk design described in the present embodiment also includes a cylindrical shell 12 and a vortex-induced vibration suppression device. The two ends of the cylindrical shell 12 are detachably provided with a cylindrical top cover and a cylindrical bottom cover 11. A mass pound 13 is provided inside the cylindrical shell 12. By installing mass pounds 13 of different masses to change the mass ratio of the cylinder, it is convenient to experiment with cylinders with different parameters. A vortex-induced vibration suppression device is provided outside the cylindrical shell 12. Fixed pin holes 10 are processed on the cylindrical top cover and the cylindrical bottom cover 11 to facilitate the installation of the vortex-induced vibration suppression device and prevent the threads at the connection between the cylindrical shell 12 and the upper and lower covers from loosening.

[0045] The upper surfaces of the four support beams of the main support 5 are also provided with symmetrically distributed lifting rings to facilitate lifting the experimental device to replace the rigid cylindrical shell 12 and the mass pound 13 of different outer diameters, and a vortex-induced vibration suppression device can also be installed.

[0046] The experimental device of the present invention can also observe the motion trajectory and force conditions of the cylinder in real time and synchronously through the built-in sensors and optical balls.

[0047] How it works

[0048] The specific operation process of the cylindrical double-degree-of-freedom flow-induced vibration experimental device designed by the present invention based on the rolling disk design is as follows:

[0049] Step 1, install the tension spring 1 according to the specific needs of the experiment, and adjust the bolts set on the upper clamping plate 8 and the lower clamping plate 6 to clamp the disc 9, and then lift the main support 5.

[0050] Step 2, adjust the length of the center axis 7, pull out the fixing pin, and remove the cylindrical bottom cover 11 and the cylindrical outer shell 12.

[0051] Step 3, according to the specific needs of the experiment, install the mass scale 13, and install the cylindrical bottom cover 11 and the cylindrical outer shell 12.

[0052] Step 4: Install the vortex-induced vibration suppression device outside the cylindrical shell 12 and fix it with fixing pins.

[0053] Step 5, sink the experimental device into the water in the tank and prepare for the experiment.

[0054] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disk design, characterized by: The invention comprises a main frame (5), a central axis (7), a mass pound (13), a disc assembly and two tension spring assemblies; the disc assembly is sleeved on the upper end of the central axis (7), the main frame (5) is sleeved on the disc assembly, the two tension spring assemblies are respectively mounted on the upper surface and the lower surface of the main frame (5), and the tension spring assembly is connected to the central axis (7), and the lower end of the central axis (7) is mounted on the mass pound (13); the disc assembly comprises a universal wheel (2), a top plate (3) and a disc (9), the top plate (3) is fixed to the main frame (5) by a support, and the top plate (3) is located above the disc (9), the disc (9) is sleeved on the central axis (7), the universal wheel (2) is arranged at the top end of the central axis (7), and the top end of the central axis (7) contacts with the lower surface of the top plate (3) through the universal wheel (2) to ensure the stability of the disc (9) and the central axis (7) when moving in a plane.

2. According to claim 1, a cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disk design is characterized by: The disc assembly further comprises a lower clamping plate (6), an upper clamping plate (8) and a plurality of rolling steel balls (14); the disc (9) is arranged between the lower clamping plate (6) and the upper clamping plate (8); a plurality of rolling steel balls (14) are arranged between the lower surface of the upper clamping plate (8) and the upper surface of the disc (9); and a plurality of rolling steel balls (14) are arranged between the lower surface of the disc (9) and the upper surface of the lower clamping plate (6).

3. The cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disk design according to claim 2 is characterized by: A plurality of steel ball grooves are provided on the lower surface of the upper clamping plate (8) and the upper surface of the lower clamping plate (6) along the circumferential direction of the disc (9), and a rolling steel ball (14) is provided in each of the steel ball grooves.

4. The cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disk design according to claim 1, characterized in that: Each of the tension spring assemblies comprises four tension springs (1) and four spring brackets (4). The four tension springs (1) are evenly distributed around the central axis (7) in a circumferential direction. The inner ends of the tension springs (1) are connected to the central axis (7), and the outer ends of the tension springs (1) are connected to the main body bracket (5) via the spring brackets (4).

5. The cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disk design according to claim 2, characterized in that: The main frame (5) comprises a frame mechanism and a fixing mechanism. The frame mechanism is square in shape and comprises four frame cross beams. The four frame cross beams are respectively a first frame cross beam (55), a second frame cross beam (56), a third frame cross beam (57) and a fourth frame cross beam (58). The third frame cross beam (57) and the fourth frame cross beam (58) are parallel to each other. The fixing mechanism is arranged between the third frame cross beam (57) and the fourth frame cross beam (58), and is fixedly connected to the third frame cross beam (57) and the fourth frame cross beam (58).

6. The cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disk design according to claim 5, characterized in that: The fixing mechanism comprises four parallel fixed beams, the four fixed beams comprising two upper fixed beams and two lower fixed beams, the two upper fixed beams having two ends fixedly connected to the upper surfaces of the third support beam (57) and the fourth support beam (58), the two lower fixed beams having two ends fixedly connected to the lower surfaces of the third support beam (57) and the fourth support beam (58), the two upper fixed beams corresponding to the corresponding two lower fixed beams in the upper and lower directions, the four fixed beams are all located inside the first support beam (55) and the second support beam (56), and there are gaps between the two upper fixed beams and between the two lower fixed beams, the upper clamping plate (8) in the disc assembly is fixed between the two upper fixed beams and located at the lower parts of the two upper fixed beams, the lower clamping plate (6) in the disc assembly is fixed between the two lower fixed beams and located at the upper parts of the two lower fixed beams, and the upper clamping plate (8) and the lower clamping plate (6) correspond to each other in the upper and lower directions.

7. The cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disk design according to claim 6, characterized in that: A gasket is provided between the upper clamping plate (8) and the two upper fixed cross beams, and a gasket is provided between the lower clamping plate (6) and the two lower fixed cross beams.

8. The cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disk design according to claim 1 is characterized by: The cylindrical double-degree-of-freedom flow-induced vibration experimental device based on a rolling disk design also includes a cylindrical shell (12) and a vortex-induced vibration suppression device, wherein the two ends of the cylindrical shell (12) are detachably provided with a cylindrical top cover and a cylindrical bottom cover (11), a mass pound (13) is provided inside the cylindrical shell (12), and the vortex-induced vibration suppression device is provided outside the cylindrical shell (12).

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