A rotating flow local scour test research device and method

Abstract

The application provides a rotating flow local scour test research device and method, which comprises a water circulation system and a control system, the water circulation system comprises a water tank, a water storage pool, a communication pipeline for connecting the water storage pool and the water tank, a water pump and a rotating mechanism in the water tank; the rotating mechanism comprises a rotating table on the bottom surface of the water tank and a driving part for driving the rotating table, a foundation model is fixed on the rotating table, and bed sand is laid on the rotating table; the communication pipeline is provided with an adjusting valve for adjusting the water flow, and a lifting baffle for adjusting the water level is arranged in the water tank; the local scouring situation of the wind power foundation near the fixed seabed in the actual situation is simulated by laying the bed sand after fixing the foundation model on the rotating table, and the water level, the flow rate and the rotating table speed of the current water tank are controlled according to the time history data of the tidal level, the tidal current speed and the direction near the foundation position, so as to finely depict the influence of the tidal level and the tidal current time history on the local scouring characteristics.

Description

Technical Field

[0001] This invention relates to the field of offshore wind power, and in particular to a rotating flow local scour test apparatus and method. Background Technology

[0002] As offshore wind farm projects gradually extend into deeper waters, the hydrodynamics of the sites are increasingly freed from the influence of nearshore topography, and the swirling flow characteristics of tidal currents are becoming more pronounced. Currently, local scour test flumes can only construct unidirectional and reciprocating flow conditions, and cannot simulate swirling flow conditions. Therefore, the academic and engineering communities lack a comprehensive understanding of the depth, development process, and extent of local scour of wind turbine foundations under the influence of swirling flow. Furthermore, most current local scour test flumes cannot simultaneously control the water level and flow velocity within the flume, and can only simulate the local scour characteristics under extreme tidal currents. Consequently, they cannot accurately characterize the impact of tidal level and tidal current duration on local scour characteristics. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the technical problem to be solved by the present invention is to provide a rotating flow local scouring test research device and method.

[0004] This invention discloses a rotating flow local scour test apparatus, comprising a water circulation system and a control system. The water circulation system includes a water tank, a reservoir, a connecting pipe for connecting the reservoir and the water tank, a water pump, and a rotating mechanism located within the water tank. The rotating mechanism includes a rotating platform located on the bottom of the water tank and a drive unit for driving the rotating platform to rotate. A base model is fixed on the rotating platform, and bed sand is laid on the rotating platform. The connecting pipe is equipped with a regulating valve for adjusting the water flow rate, and a lifting baffle for adjusting the water level is provided within the water tank. The control system is used to control the operation of the water circulation system.

[0005] Preferably, the control system includes a controller, which is communicatively connected to the lifting baffle, the regulating valve, and the drive unit; the controller controls the opening degree of the lifting baffle, the opening degree of the regulating valve, and the rotational speed of the drive unit respectively based on the time-series data of the predetermined water level in the water tank, the predetermined water flow rate, and the predetermined rotational speed of the rotating table.

[0006] Preferably, the rotating flow local scour test research device includes a monitoring system communicatively connected to the control system. The monitoring system includes a water level gauge for measuring the water level in the tank and a flow meter located in the connecting pipe. The controller obtains the current water level in the tank through the water level gauge and controls the opening of the lifting baffle based on the difference between the current water level and the predetermined water level. The controller obtains the current water flow velocity in the tank through the flow meter and controls the opening of the regulating valve based on the difference between the current water flow velocity and the predetermined water flow velocity.

[0007] Preferably, the rotating flow local scour test research device further includes a processing system, which is communicatively connected to the control system; the processing system is used to receive time history data of tide level, tidal velocity and direction near a predetermined position at sea, and, based on geometric similarity and water flow motion similarity, to obtain time history data of predetermined water level in the tank, predetermined water flow velocity and predetermined rotating table speed and send them to the controller.

[0008] Preferably, the diameter of the rotating platform is greater than the predetermined local scour horizontal range, and the depth of the rotating platform is greater than the depth of the predetermined local scour pit.

[0009] Preferably, the bottom surface of the water tank is provided with a receiving groove for the rotating platform, and the bed sand laid inside the rotating platform is flush with the bottom surface of the water tank.

[0010] This invention also proposes a test method for studying localized scour of rotating flow, using any of the aforementioned test apparatus for studying localized scour of rotating flow, comprising the following steps:

[0011] Collect basic actual information about the seabed, including basic data of the predetermined location on the seabed, seabed geological information, and time history data of tide level, tidal current velocity and direction;

[0012] Based on the aforementioned basic data, the dimensions of the rotary table and the basic model fixed on the rotary table are determined through geometric similarity relationships.

[0013] Based on the seabed geological information, the particle size and specific gravity of the sand laid on the rotating platform were determined by the similarity criteria of starting and settling velocity.

[0014] Based on the time history data of the tidal level, tidal velocity and direction, the time history data of the predetermined water level, predetermined water velocity and predetermined rotating table speed are determined by geometric similarity and water flow motion similarity relationship.

[0015] The controller receives time-history data of the predetermined water level in the water tank, the predetermined water flow velocity, and the predetermined rotation speed of the rotating platform, and controls the lifting baffle, the regulating valve, and the drive unit respectively to simulate the local scouring situation of the basic rotating flow.

[0016] As described above, the present invention relates to a rotating flow local scour test research device and method. By fixing a foundation model on a rotating platform and laying bed sand, and then driving the rotating platform, the local scour situation near a wind turbine foundation fixed on the seabed by tidal currents of various directions in actual conditions is simulated. Furthermore, based on the time history data of tidal level, tidal current velocity and direction near the foundation location, the data are converted into predetermined water level in a water tank, predetermined water flow velocity and predetermined rotation speed of the rotating platform. Then, the current water level in the water tank, water flow velocity and rotation speed of the rotating platform are correlated to meticulously characterize the influence of tidal level and tidal current time history on local scour characteristics. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a rotating flow local scouring test device according to the present invention.

[0018] Figure 2 This is another schematic diagram of a rotating flow local scouring test device according to the present invention.

[0019] Figure 3 This is a schematic diagram of the rotating mechanism in this invention.

[0020] Explanation of reference numerals in the attached figures:

[0021] 10. Water tank; 20. Water storage tank; 30. Connecting pipe; 40. Water pump; 51. Rotary table; 52. Servo motor; 53. Force transmission shaft; 60. Basic model; 70. Regulating valve; 71. Lifting baffle; 80. Controller; 81. Water level gauge; 82. Flow meter. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0023] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0024] like Figure 1-3As shown, this invention provides an embodiment of a rotating flow local scour test research device, including a water circulation system and a control system. The water circulation system includes a water tank 10, a water storage tank 20, a connecting pipe 30 for connecting the water storage tank 20 and the water tank 10, a water pump 40, and a rotating mechanism located within the water tank 10. The rotating mechanism includes a rotating platform 51 located on the bottom surface of the water tank 10 and a drive unit for driving the rotating platform 51 to rotate. A base model 60 is fixed on the rotating platform 51, and bed sand is laid on the rotating platform 51. The connecting pipe 30 is provided with a function to regulate the water flow rate. The system includes a regulating valve 70 and a lifting baffle 71 for regulating the water level in the water tank 10. The control system includes a controller 80, which is communicatively connected to the lifting baffle 71, the regulating valve 70, and the drive unit. The controller 80 controls the lifting baffle 71, the regulating valve 70, and the drive unit respectively according to the time-series data of the predetermined water level, the predetermined water flow speed, and the predetermined rotation speed of the rotating table 51, so that the water level in the water tank 10 reaches the predetermined water level at the predetermined time point, the water flow speed reaches the predetermined water flow speed, and the rotation speed of the rotating table 51 reaches the predetermined rotation speed.

[0025] This invention simulates the local scouring effect of tidal currents on wind turbine foundations fixed on the seabed by fixing a foundation model on a rotating platform 51 and laying bed sand, then driving the platform to rotate. The controller 80 converts time-history data of tidal level, tidal current velocity, and direction near the foundation location into predetermined water level in the tank, predetermined flow velocity, and predetermined rotating platform speed, controlling the current water level, flow velocity, and rotating platform speed in the tank 10. This allows for a detailed depiction of the influence of tidal level and tidal current time-history on local scouring characteristics. The foundation model can be a single-pile foundation, a multi-pile foundation, a suction cylinder foundation, or a gravity foundation. In this embodiment, the foundation model is a single-pile foundation model for wind turbines.

[0026] Specifically, when the water pump 40 is running, the water tank 10 continuously draws water from the reservoir 20. The water then flows back into the water tank 10 through the inlet pipe, the water tank 10, and the outlet pipe, thus achieving water circulation. The water circulation system allows for adjustments to the water level in the water tank 10 by raising and lowering the baffle 71, adjusting the flow rate in the water tank 10 by adjusting the opening of the flow regulating valve 70, and adjusting the direction of water flow in the water tank 10 by rotating the rotary table 51. Ultimately, the flow of water in the water tank 10 simulates tidal levels, tidal currents, and multi-directional tidal currents.

[0027] Of course, before using the monitoring system to simulate the water flow in the tank 10, the predetermined water level data, predetermined water flow velocity data, and predetermined rotational speed of the rotating platform 51 need to be set in the controller 80. Therefore, preferably, the rotating flow local scour test research device of this embodiment also includes a processing system that is communicatively connected to the control system. In actual engineering, the processing system is used to receive time history data of tidal level, tidal velocity, and direction near a predetermined position at sea, and calculates and outputs time history data of predetermined tank water level, predetermined water flow velocity, and predetermined rotating platform speed in the tank 10 to the controller 80 based on geometric similarity and water flow motion similarity relationship. The controller 80 controls the opening degree of the lifting baffle (71), the opening degree of the regulating valve (70), and the rotational speed of the drive unit according to the time history data, thereby realizing the control of the current tank water level, current water flow velocity, and rotating platform speed. Since the relevant calculations based on geometric similarity and water flow motion similarity relationship are existing technologies in this field, they will not be described in detail here.

[0028] In this embodiment, the drive unit of the rotary table 51 is a servo motor 52, and the rotary table 51 is connected to the servo motor 52 via a force transmission shaft 53. The rotational speed of the rotary table 51 is directly controlled by rotating the servo motor 52. It should be noted that, in order to ensure the watertightness of the bottom of the water tank, sealing measures are provided at the contact points between the rotary table 51, the force transmission shaft 23, and the water tank 10.

[0029] In practice, the controller 80 obtains the actual water level in the water tank 10 through the water level gauge 81. Based on the difference between the actual water level and the current predetermined water level, it sends a control signal to the motor driving the lifting baffle 71, thereby correcting the water level. Similarly, the controller 80 can also obtain the water flow velocity through the flow meter 82. Based on the difference between the flow velocity and the current predetermined flow velocity, it controls the flow regulating valve 70 to correct the water flow velocity. This ensures that the actual water level in the water tank 10 is closer to the predetermined water level, and the water flow velocity is more closely aligned with the predetermined flow velocity.

[0030] The average flow velocity V within the tank can be calculated using the following formula:

[0031]

[0032] In the formula, Q is the flow rate data collected by the flow meter; h is the water level data collected by the water level gauge; and B is the width of the water tank.

[0033] To avoid the experimental results being affected by the rotation table 51 being located on the bottom surface of the water tank 10, a receiving groove for the rotation table 51 is provided on the bottom surface of the water tank 10. The upper surface of the bed sand laid inside the rotation table 51 is flush with the bottom surface of the water tank 10, and the rotation table 51 is in contact with the inner peripheral wall of the receiving groove.

[0034] Of course, in order to make the actual scouring of the single pile foundation within the water tank 10 more accurate, the upper surface area of ​​the rotating platform 51 is larger than the predetermined local scouring horizontal range, and the depth of the rotating platform 51 is larger than the depth of the predetermined local scouring pit. The depth of the rotating platform 51 is the distance between the upper and lower surfaces of the bed sand (that is, the upper surface of the rotating platform 51).

[0035] The predetermined local scour horizontal range and the predetermined local scour pit depth can be calculated based on the actual situation of the single pile foundation on the seabed through geometric similarity, water flow similarity, etc., which will not be elaborated here.

[0036] This invention also proposes an embodiment of a method for testing localized scour of rotating currents, employing the aforementioned test apparatus for localized scour of rotating currents, comprising the following steps: S1, collecting actual information on subsea monopile foundations, including monopile foundation data at predetermined locations on the seabed, seabed geological information, and time history data of tidal level, tidal current velocity, and direction; S2, based on the monopile foundation data, determining the dimensions of the rotating platform 51 and the foundation model fixed on the rotating platform 51 through geometric similarity relationships; S3, based on the seabed geological information, determining the dimensions of the rotating platform 51 and the foundation model fixed on the rotating platform 51 through similarity criteria of starting and settling velocities. S4. Determine the particle size and specific gravity of the bed sand laid on the rotating platform 51; S5. Based on the time history data of tidal level, tidal flow velocity and direction, determine the time history data of the water level of the predetermined water tank 10, the predetermined water flow velocity and the predetermined rotation speed of the rotating platform 51 through geometric similarity and water flow motion similarity relationship; S6. Controller 80 receives the time history data of the water level of the predetermined water tank 10, the predetermined water flow velocity and the predetermined rotation speed of the rotating platform 51, and controls the lifting baffle 71, the regulating valve 70 and the drive unit respectively to simulate the local scouring of the rotating flow of a single pile foundation.

[0037] It should be noted that in actual operation, when the swirling current locally scours the monopile foundation fixed on the seabed, it is essentially equivalent to the presence of seawater tidal currents in all directions around the monopile foundation. In this embodiment, since the foundation model is fixed to the rotating platform and the bed sand is also laid on the rotating platform, before the platform rotates, the water flow in the tank only occurs in a single direction relative to the foundation model and the bed sand. After the platform rotates, it rotates relative to the water in the tank, and the water in the tank, relative to the foundation model and the bed sand, is equivalent to flowing in all directions. Therefore, the direction of seabed tidal currents can be simulated by the rotational speed of the platform.

[0038] This method simulates a local area of ​​the seabed where a single pile foundation is fixed by laying bed sand after fixing the foundation model on a rotating platform. Furthermore, by controlling the water level, water flow velocity, and rotating platform speed in the water tank, the local scouring characteristics of the tide level and tidal history are simulated. The simulation process is simple and detailed.

[0039] In actual experiments, data on monopile foundations can be obtained from monopile foundation design data, including the form and dimensions of the monopile foundation. Seabed geological information can be obtained through on-site investigation or by consulting relevant seabed geological data.

[0040] For the scouring test research device, the water level and flow rate in the tank can be calibrated first when the regulating valve 70 is at different opening degrees and the lifting baffle 71 is at different heights.

[0041] During the test, the adjustable baffle 71 is raised to the initial water level height required to simulate the tidal flow time history. When the pump 40 is started, the regulating valve 70 can be controlled to slowly release water to the initial water level speed required to simulate the tidal flow time history. At this time, the water flow velocity should not cause bed sediment to be stirred up. When simulating the local rotating flow of a single pile foundation in the flume, local scour data are collected.

[0042] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for studying localized scour in rotating flow, implemented using a device for studying localized scour in rotating flow; the device includes a water circulation system and a control system, characterized in that: The water circulation system includes a water tank (10), a water storage tank (20), a connecting pipe (30) for connecting the water storage tank (20) and the water tank (10), a water pump (40), and a rotating mechanism located in the water tank (10); the rotating mechanism includes a rotating platform (51) located on the bottom surface of the water tank (10) and a drive unit for driving the rotating platform (51) to rotate; a base model (60) is fixed on the rotating platform (51), and bed sand is laid on the rotating platform (51); the connecting pipe (30) is provided with a regulator for adjusting the water flow rate. The system includes a regulating valve (70), a lifting baffle (71) for adjusting the water level in the water tank (10), and a control system for controlling the operation of the water circulation system. The control system includes a controller (80), which is communicatively connected to the lifting baffle (71), the regulating valve (70), and the drive unit. The controller (80) controls the opening degree of the lifting baffle (71), the opening degree of the regulating valve (70), and the rotational speed of the drive unit according to the time history data of the predetermined water level in the water tank, the predetermined water flow rate, and the predetermined rotational speed of the rotating table. The experimental method for studying localized scouring of rotating flow includes the following steps: Collect basic actual information about the seabed, including basic data of the predetermined location on the seabed, seabed geological information, and time history data of tide level, tidal current velocity and direction; Based on the aforementioned basic data, the dimensions of the rotary table (51) and the basic model fixed on the rotary table (51) are determined through geometric similarity relationships. Based on the seabed geological information, the particle size and specific gravity of the bed sand laid on the rotating platform (51) are determined by the similarity criteria of starting and settling velocity. Based on the time history data of the tidal level, tidal velocity and direction, the time history data of the predetermined water level, predetermined water velocity and predetermined rotating table speed are determined by geometric similarity and water flow motion similarity relationship. The controller (80) receives time history data of the predetermined water level in the water tank, the predetermined water flow velocity, and the predetermined rotation speed of the rotating table, and controls the lifting baffle (71), the regulating valve (70), and the drive unit respectively to simulate the local scouring of the basic rotating flow.

2. The experimental method for studying local scouring of rotating flow according to claim 1, characterized in that, It also includes a monitoring system that is communicatively connected to the control system. The monitoring system includes a water level gauge (81) for measuring the water level in the water tank and a flow meter (82) located in the connecting pipe (30). The controller (80) obtains the current water level in the water tank through the water level gauge (81) and controls the opening of the lifting baffle (71) based on the difference between the current water level in the water tank and the predetermined water level data. The controller (80) obtains the current water flow velocity in the water tank through the flow meter (82) and controls the opening of the regulating valve (70) based on the difference between the current water flow velocity in the water tank and the predetermined water flow velocity data.

3. The experimental method for studying local scouring of rotating flow according to claim 1, characterized in that, It also includes a processing system, which is communicatively connected to the control system; the processing system is used to receive time history data of tide level, tidal velocity and direction near a predetermined position on the seabed, and to obtain time history data of predetermined water level, predetermined water velocity and predetermined rotational speed in the water tank (10) based on geometric similarity and water flow motion similarity relationship, and to transmit the time history data to the controller (80).

4. The experimental method for studying local scouring of rotating flow according to claim 1, characterized in that, The upper surface area of ​​the rotating platform (51) is greater than the predetermined local scour horizontal range, and the depth of the rotating platform (51) is greater than the depth of the predetermined local scour pit.

5. The experimental method for studying local scouring of rotating flow according to claim 1, characterized in that, The bottom surface of the water tank (10) is provided with a receiving groove for the rotating platform (51), and the surface of the upper layer of bed sand laid in the rotating platform (51) is flush with the bottom surface of the water tank (10).

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