A physical-numerical hybrid scale model test method for floating wind turbine
By using a physical-numerical hybrid scaled-down model testing method, the incompatibility between aerodynamic and hydrodynamic similarity criteria in floating wind turbine model testing was solved, achieving accurate load simulation and test reliability, reducing costs and optimizing the design cycle.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CRRC DALIAN CO LTD
- Filing Date
- 2024-12-27
- Publication Date
- 2026-06-26
AI Technical Summary
In existing floating wind turbine model tests, the aerodynamic and hydrodynamic similarity criteria are incompatible, resulting in large simulation errors at scale. It is difficult to accurately simulate aerodynamic loads in water tank tests, and traditional water tank tests have significant limitations and cannot meet the requirements of large-scale tests.
A physical-numerical hybrid scaled-down model test method was adopted, dividing the floating wind turbine into two parts: a physical model and a numerical model. A measurement system composed of three-dimensional force sensors and six-dimensional force sensors, and a loading system composed of a six-rotor propeller and a six-degree-of-freedom platform, were used to realize real-time interaction and closed-loop control of the load. Combined with computer for data transmission and loading, a more adaptable scaling criterion was established.
It enables independent scaling of aerodynamic and hydrodynamic loads, reduces testing costs, improves testing accuracy and reliability, significantly shortens design cycle and cost, and can more realistically simulate the dynamic response of floating wind turbines.
Smart Images
Figure CN119878463B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of offshore wind power generation technology and relates to a physical-numerical hybrid scaled model test method for floating wind turbines. Background Technology
[0002] Offshore wind power is an important renewable energy source, playing a crucial role in optimizing energy structure and mitigating climate change. With advancements in technology and the economy, global wind power equipment is increasingly trending towards larger scale and offshore deployment. A floating offshore wind turbine comprises blades, a nacelle, a tower, a floating platform, and a mooring system. The floating platform is connected to the seabed via the mooring system to mitigate the movement of the floating body caused by environmental loads such as wind, waves, and currents, adapting to varying water depths and soil conditions. Compared to floating oil and gas platforms in marine engineering, floating wind turbines must withstand greater aerodynamic loads. Therefore, when analyzing the dynamic response of floating wind turbines, the coupling of aerodynamic forces should be considered in addition to hydrodynamic and mooring forces. The most widely used method for obtaining the dynamic response of floating wind turbines is to establish motion control equations based on potential flow, blade element momentum, and multibody dynamics theory, combined with automatic control algorithms, to conduct aerodynamic-hydraulic-servo-elastic coupling numerical simulations. However, uncertainties exist in floating wind turbines under highly nonlinear conditions, requiring highly reliable model tests to verify and correct the numerical simulation results.
[0003] Compared to stationary offshore wind turbines, floating wind turbines exhibit more significant dynamic responses, making the simultaneous and accurate simulation of aerodynamic and hydrodynamic forces crucial in model testing. However, due to the incompatibility between Reynolds number and Froude number, aerodynamic and hydrodynamic similarity cannot be simultaneously satisfied. Most existing floating wind turbine model tests are tank tests, simulating equivalents based on the Froude number similarity criterion, simulating only major aerodynamic loads, such as the impeller axial thrust at steady wind speeds, which introduces certain errors into the tests. Furthermore, the limited water depth in laboratory tanks makes large-scale tests difficult, and the poor wind generation quality in tanks can lead to distorted wind field simulations that affect wave morphology, thus presenting certain limitations. Therefore, resolving the incompatibility of similarity criteria in floating wind turbine model testing and the problem of accurate simulation of scaled-down aerodynamic loads are urgent issues to be addressed in this field.
[0004] Chinese patent application CN117386568A discloses a real-time hybrid model testing method for multi-fan driven offshore floating wind turbines. This invention proposes dividing the hybrid model into a platform physical substructure and a wind turbine numerical substructure. The physical substructure refers to the floating wind turbine platform model, while the numerical substructure uses a computer to numerically simulate the wind turbine's aerodynamic loads. At each time step, force commands derived from the numerical substructure are applied to the platform physical substructure via the multi-fan drive system. Motion feedback from the floating platform test is then fed back to the numerical substructure for calculating subsequent time steps. This invention enables accurate simulation of aerodynamic loads under the Froude scaling law, which is beneficial for laboratory-scale wind turbine load simulation and exhibits better static and dynamic response performance. However, this patented technology uses traditional water tank tests to simulate hydrodynamic loads, which cannot overcome the limitations of traditional water tank tests.
[0005] Chinese patent application CN116011193A discloses a hybrid model test method for offshore wind turbines of various basic types, including the following steps: (1) determining the test scale ratio and processing the physical model; (2) selecting an indoor wave pool and calibrating wave conditions; (3) hoisting the physical model and actuator to the site; (4) setting up an optical measurement system; and (5) iterative calculation of the blade element momentum model in aerodynamics and conducting the overall test. Through the information interaction between the blade element momentum model, the physical model, and the actuator at the truncated section, the load and motion response of the actual wind turbine can be reflected. However, this patented technology requires different trusses for different wind turbine models due to the large mass of the multi-degree-of-freedom loading brake, and the method does not consider the gyroscopic effect of offshore wind turbines. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a physical-numerical hybrid scaled model test method for floating wind turbines. The test method provided by this invention can accurately capture the dynamic response of key structures and solve a series of problems such as incompatibility of scaling criteria and the resulting scale effects. This method can more accurately simulate aerodynamic and hydrodynamic loads, ensuring the realism and reliability of floating wind turbine model tests, and providing theoretical guidance and technical support for the construction of offshore floating wind turbine generators.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0008] A hybrid physical-numerical scaled-down model test method for floating wind turbines is disclosed. This method models the floating wind turbine into two parts: a physical model and a numerical model, based on scaling criteria. In addition to the physical and numerical models, the test platform includes a measurement system composed of three-dimensional and six-dimensional force sensors, and a loading system composed of a six-rotor propeller and a six-degree-of-freedom platform. The measured signals from the measurement system are interacted with the calculation results of the numerical model in real time via a computer. The loading system then applies the signals, ultimately achieving the construction and closed-loop control of the hybrid test platform.
[0009] First, a multi-body / multi-physics collaborative scaling criterion for the floating wind turbine is established based on dimensional analysis, and a physical and numerical model is designed according to the scaling criterion. Second, the physical model of the floating wind turbine is bolted together with a measurement system composed of sensors and a loading system composed of a six-degree-of-freedom platform and six-rotor propellers. The measurement system is connected to a computer via a data acquisition system and data cable, and then the computer is connected to the loading system to transmit loading signals, ultimately building a physical-numerical hybrid experimental platform. Third, load calculations for different working conditions are performed based on the numerical model. The physical model is loaded through the loading system, and the shear force and bending moment information at the bottom of the tower are measured by the measurement system, and the measured data is transmitted to the computer. Finally, the computer transmits the measured data at the bottom of the tower to the numerical floating body, thereby calculating the additional floating body motion generated by the tower's action on the platform, and feeding it back to the numerical wind turbine, thus achieving load recalculation. Closed-loop control is then achieved by applying the loading system to the physical model. Relevant information from the experimental process is extracted through a visual monitoring interface according to actual needs. Specifically, the following steps are included:
[0010] Step (1) establishes a multi-body / multi-physics collaborative scaling criterion for the floating wind turbine, and divides the overall structure of the floating wind turbine into a physical model and a numerical model, specifically:
[0011] Step 1.1: Equivalent the aerodynamic load to the wind turbine thrust and the hydrodynamic load to the floating body motion. Based on the dimensional analysis theory, derive the load-structure-response similarity law and establish the multi-body / multi-physics field collaborative scaling criterion for floating wind turbines to ensure that the response of the scaled model can be returned to the original scaled model through the scaling criterion.
[0012] Step 1.2: Determine the scaling ratio based on the established scaling criteria and the prototype size of the floating wind turbine, and design the physical and numerical models of the floating wind turbine. The physical model includes blades, nacelle, tower and connecting structure, and the numerical model includes numerical floating body and numerical wind turbine.
[0013] Step (2) integrates the physical model, numerical model, loading system, and measurement system to build a hybrid physical-numerical test platform for floating wind turbines, specifically as follows:
[0014] Step 2.1: Connect the hardware of the test platform. Connect the physical model, measurement system and loading system respectively through connection structures such as flanges. The measurement system includes a three-dimensional force sensor and a six-dimensional force sensor. The loading system includes a six-rotor propeller and a six-degree-of-freedom motion platform.
[0015] Step 2.2: Establish the data transmission channel of the test platform, integrate the sensor data interface, numerical model calculation result file and the input terminal of the loading system into the same information storage device of the computer, and establish a closed-loop data transmission channel of "measurement system-numerical model-loading system-physical model-measurement system" through the computer.
[0016] Step (3), the data interaction and closed-loop control of the physics-numerical hybrid experimental platform, specifically includes:
[0017] A computer-controlled six-degree-of-freedom motion platform applies floating motion to a physical model, while a six-rotor thruster applies wind turbine thrust to the physical model. A measurement system records and transmits the measurement data in real time to the computer, which receives signals from the data acquisition board in the measurement system. These acquired signals are used as input to the numerical model for calculations, yielding the additional floating motion under the tower base load. The computer then sends the numerical model calculation results to the loading system. Based on the numerical model calculation results, the real-time loading signals of the six-degree-of-freedom motion platform and the six-rotor thruster are adjusted, and the measurement system records the load data at the bottom of the tower, achieving data interaction and closed-loop control of the physics-numerical hybrid experimental platform.
[0018] Step (4), information monitoring and extraction during the physical-numerical hybrid experiment, specifically includes:
[0019] The operational status of the hybrid physics-numerical test platform is monitored through a visual interface. Furthermore, this visual interface is used to monitor the operational status of the hybrid physics-numerical test platform in real time and display information such as the motion data of the floating body and the aerodynamic load data of the wind turbine. The necessary information is extracted in real time, and the extracted information is analyzed and processed to evaluate the dynamic response performance of the floating wind turbine.
[0020] The beneficial effects of this invention are:
[0021] (1) This invention divides the overall structure of the floating wind turbine into two parts: a physical model and a numerical model. The physical model includes a scaled-down model of the wind turbine consisting of blades, nacelle, and tower, which is the actual structure subjected to aerodynamic and hydrodynamic loads. The numerical model is a system that performs real-time calculations of equivalent loads based on a computer and scaling criteria. It can calculate the motion response of the floating body under the action of waves and tower bottom loads, as well as the turbine thrust of the blades at different wind speeds and rotational speeds. At each time step, the turbine thrust and floating body motion at that moment are calculated by the numerical model and applied to the physical model through a loading system. The load data at the bottom of the tower is recorded by a measurement system and transmitted to the numerical model through a computer, forming a real-time interactive and closed-loop control of the floating wind turbine's physical-numerical hybrid test data.
[0022] (2) This invention uses a physical-numerical hybrid test to convert aerodynamic loads and hydrodynamic loads into wind turbine thrust and floating body motion respectively, thereby achieving independent scaling of aerodynamic loads and hydrodynamic loads. This solves the problem of incompatibility of scaling of the two types of loads in pool tests, gets rid of the limitations of traditional pool tests, and establishes a more adaptable scaling criterion.
[0023] (3) The experimental method proposed in this invention uses a low-cost numerical model, which can reconstruct the numerical wind turbine and numerical float at a very low experimental cost. This has a significant effect on the design of the blades and float of the floating wind turbine. Designers can use the experimental method proposed in this invention to optimize the design of the floating wind turbine, which significantly reduces the product design cycle and design cost. Attached Figure Description
[0024] Figure 1 This is a three-dimensional model of the floating wind turbine tower of the present invention;
[0025] Figure 2 This is a three-dimensional model of the floating wind turbine nacelle of the present invention;
[0026] Figure 3 This is a three-dimensional model of the floating wind turbine connection structure of the present invention;
[0027] Figure 4 This is a schematic diagram of the overall system layout of the present invention. Detailed Implementation
[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0029] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.
[0030] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0031] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0032] The invention will be further described below with reference to the accompanying drawings. A method for testing a hybrid physical-numerical scaled model of a floating wind turbine, the specific implementation of which includes the following steps:
[0033] Step (1) Establishment of the multibody / multiphysics scaling criterion for floating wind turbines, specifically:
[0034] By employing similarity theory and dimensional analysis, the scaling ratios of various physical quantities in the hybrid experiment were determined, thereby deriving the target parameters. For example, dimensional analysis yielded the conversion coefficients between the scaled-down model and the prototype for physical quantities such as length, area, volume, mass, time, frequency, velocity, acceleration, force, torque, and moment of inertia. This allowed the determination of target parameters for the physical model, including tower thickness, nacelle-blade mass and center of gravity position, equivalent rotor thrust, and floating body motion.
[0035] Step (2): Based on the established scaling criteria, design and fabricate the physical model, specifically as follows:
[0036] The physical model includes the blades, nacelle, tower, and connecting structures between components of the floating wind turbine. After establishing the scaling criteria, the scaling ratio needs to be determined based on the prototype size and test conditions. This invention uses a 1:40 scale to create the physical model, which satisfies the following similarity conditions: 1) Geometric similarity: The physical model should be scaled down proportionally to the prototype size; 2) Dynamic similarity: After creating the physical model based on geometric similarity, reinforcement and counterweight are applied at appropriate locations to ensure that its weight, center of gravity, and moment of inertia satisfy similarity rules. The tower of the physical model is shown below. Figure 1 As shown, the cabin is as follows Figure 2 As shown, the connection structure is as follows Figure 3 As shown.
[0037] Step (3): Based on the established scaling criteria, design and establish a numerical model, specifically as follows:
[0038] The numerical model includes a numerical wind turbine and a numerical floating body. The numerical wind turbine is modeled and solved using blade element-momentum theory, and combined with the established scaling criterion, it aims to output "wind turbine thrust" when "wind speed-floating body motion" is input at the current time step. The numerical floating body is modeled and solved using three-dimensional potential flow theory and the Morrison equation, and combined with the established scaling criterion, it aims to output "floating body motion" when "wave information-tower base shear force and bending moment" is input at the current time step.
[0039] Step (4) establishes the loading system of the floating wind turbine physical-numerical hybrid test platform, specifically as follows:
[0040] To apply the wind turbine thrust and floating body motion calculated by the numerical model to the physical model, a loading system for a hybrid test platform was established. This system consists of a six-rotor thruster and a six-degree-of-freedom platform. The six-rotor thruster was modified on a ZD850 UAV frame. Through secondary development and control of the Pixhawk 4 flight control system, independent control of the six motor speeds was achieved, thereby precisely loading the wind turbine thrust calculated from the numerical wind turbine model. The MG6-10 / 12EP six-degree-of-freedom motion platform was used to load the floating body motion calculated from the numerical floating body model. The software was installed on the same computer to achieve synchronous control of both, thus forming the loading system for the hybrid physical-numerical test platform for floating wind turbines.
[0041] Step (5) establishes the measurement system of the floating wind turbine physical-numerical hybrid test platform, specifically as follows:
[0042] To obtain the actual thrust applied to the top of the physical model and the shear force and bending moment experienced at the bottom, a measurement system for a hybrid test platform was established. The system consists of a three-dimensional force sensor, a six-dimensional force sensor, and a data acquisition system. The three-dimensional force sensor is a NaiChuang FC3D80, the six-dimensional force sensor is a Kunwei KWR200E, and the data acquisition system is a Donghua DH5922D dynamic signal testing and analysis system. The three-dimensional and six-dimensional force sensors were connected to the data acquisition system via data cables, and the data acquisition system was then connected to a computer via data cables, thus establishing the measurement system.
[0043] Step (6) involves constructing a hybrid physical-numerical experimental platform for the floating wind turbine, specifically as follows:
[0044] To integrate the physical model, numerical model, loading system, and measurement system into a coupled closed-loop system, a hybrid physical-numerical test platform for floating wind turbines needs to be constructed. The construction of this platform mainly involves two parts: the hardware installation of the model and sensors, and the establishment of data transmission channels. After assembling the tower-nacelle-blades into a physical model, the three-dimensional force sensors and six-dimensional force sensors of the measurement system are installed at the top and bottom of the physical model, respectively, and connected to the six-rotor propeller and the six-degree-of-freedom platform, respectively, using bolt connections to achieve hardware installation. The established numerical model is installed in the computer, and a data transmission communication channel is established with the measurement system and loading system. Data interaction and closed-loop control are implemented in the computer, specifically a data transmission loop of "numerical model - loading system - physical model - measurement system - numerical model." These steps enable real-time interaction between the various parts of the hybrid test platform at each time step. The overall system layout is as follows. Figure 4 As shown.
[0045] Step (7), monitoring and extraction of test information, specifically includes:
[0046] The operational status of the physical-numerical hybrid test platform can be monitored through a visual interface. Furthermore, it displays information such as the motion of the numerical floating body and the aerodynamic loads on the numerical wind turbine, extracts necessary information in real time, and analyzes and processes the extracted information to evaluate the dynamic response performance of the floating wind turbine.
[0047] In summary, this invention proposes a physical-numerical hybrid testing method for offshore floating wind turbines. By combining physical and numerical models, it develops a physical-numerical hybrid testing technology for floating wind turbines. In the experiment, it accurately realizes the real-time dynamic coupling effect of the numerical and physical models, and establishes an effective testing method and process that can make up for the shortcomings of existing model testing methods and can accurately and reliably predict the motion and dynamic response of floating wind turbines.
[0048] The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art, under the guidance of this invention, can make various modifications and variations without departing from the spirit and scope of the claims, and all of these fall within the protection scope of this invention.
Claims
1. A physical-numerical hybrid scaled-down model test method for a floating wind turbine, characterized in that, The experimental method models the floating wind turbine into two parts: a physical model and a numerical model. In addition to the physical and numerical models, the experimental platform also includes a measurement system and a loading system. The measured signals from the measurement system and the calculation results from the numerical model are interacted in real time via a computer. The loading system is used to load the signals, ultimately achieving the construction and closed-loop control of the hybrid experimental platform. The method includes the following steps: Step (1): Establish the multi-body / multi-physics field collaborative scaling criterion for floating wind turbines based on the dimensional analysis method, and divide the overall structure of floating wind turbines into physical models and numerical models; Step (2): Integrate the physical model, numerical model, loading system, and measurement system to build a hybrid physical-numerical test platform for the floating wind turbine. Connect the measurement system to the computer through the data acquisition system, and then connect the computer to the loading system to transmit the loading signal, thus building the hybrid physical-numerical test platform; specifically: Step 2.1: Connect the hardware of the test platform, and connect the physical model to the measurement system and the loading system respectively. The measurement system includes a three-dimensional force sensor and a six-dimensional force sensor, and the loading system includes a six-rotor thruster and a six-degree-of-freedom motion platform. Step 2.2: Establish the data transmission channel of the test platform, integrate the sensor data interface, numerical model calculation result file and the input terminal of the loading system into the computer, and establish a closed-loop data transmission channel of "measurement system-numerical model-loading system-physical model-measurement system" through the computer; Step (3), data interaction and closed-loop control of the physics-numerical hybrid experimental platform; Load calculations for different working conditions are performed based on the numerical model. The physical model is loaded through a loading system, and the shear force and bending moment information at the bottom of the tower are measured through a measurement system. The measured data is then transmitted to the computer. The computer transmits the measured data of the tower to the numerical floating body, calculates the additional floating body motion generated by the tower's action on the platform, and feeds it back to the numerical wind turbine to achieve load recalculation. Closed-loop control is achieved by applying the loading system to the physical model. Step (4): Information monitoring and extraction during the physical-numerical hybrid experiment.
2. The method for physical-numerical hybrid scaled model testing of a floating wind turbine according to claim 1, characterized in that, The specific steps (1) are as follows: Step 1.1: Equivalent the aerodynamic load to the wind turbine thrust and the hydrodynamic load to the floating body motion. Based on the dimensional analysis theory, derive the load-structure-response similarity law and establish the multi-body / multi-physics field collaborative scaling criterion for floating wind turbines to ensure that the response of the scaled model can be returned to the original scaled model through the scaling criterion. Step 1.2: Determine the scaling ratio based on the established scaling criteria and the prototype size of the floating wind turbine, and design the physical and numerical models of the floating wind turbine. The physical model includes blades, nacelle, tower and connecting structure, and the numerical model includes numerical floating body and numerical wind turbine.
3. The method for physical-numerical hybrid scaled model testing of a floating wind turbine according to claim 1, characterized in that, The specific steps (3) are as follows: Step (3), the data interaction and closed-loop control of the physics-numerical hybrid experimental platform, specifically includes: The computer controls a six-degree-of-freedom motion platform to apply floating motion to the physical model, controls a six-rotor thruster to apply wind turbine thrust to the physical model, and the measurement system records the measurement data in real time and sends it to the computer, while the computer receives signals from the data acquisition board in the measurement system. The collected signals are used as input to the numerical model for calculation to obtain the motion of the additional floating body under the load at the bottom of the tower. The numerical model calculation results are then sent to the loading system via a computer. The calculation results based on the numerical model change the real-time loading signals of the six-degree-of-freedom motion platform and the six-rotor thruster. The load data at the bottom of the tower is recorded by the measurement system, realizing data interaction and closed-loop control of the physical-numerical hybrid test platform.
4. The method for physical-numerical hybrid scaled-down model testing of a floating wind turbine according to claim 1, characterized in that, The specific steps (4) are as follows: The operation status of the physical-numerical hybrid test platform is monitored through a visual interface. The visual interface is used to monitor the operation status of the physical-numerical hybrid test platform in real time and display the motion data of the floating body and the aerodynamic load data of the wind turbine. The extracted information is extracted, analyzed and processed in real time to evaluate the dynamic response performance of the floating wind turbine.