A method for optimizing the arrangement of vortex-induced vibration device arrays

Abstract

The present invention proposes a method for optimizing the arrangement of an array of vortex-induced vibration devices, including: constructing a mathematical model of energy capture for multi-cylinder energy capture devices based on a method for analyzing fluid motion based on Stokes theory; constructing an optimization model for an array of multi-cylinder vortex-induced vibration energy capture devices based on the mathematical model of energy capture for multi-cylinder energy capture devices; presetting an objective function for the optimization model for the array of multi-cylinder vortex-induced vibration energy capture devices; and optimizing the optimization model for the array of multi-cylinder vortex-induced vibration energy capture devices based on the objective function using a genetic algorithm to obtain an optimal array layout of vortex-induced vibration devices. The present invention adopts a target optimization algorithm for the first time to optimize the arrangement of an array of multiple energy converters, and constructs a mathematical model for optimizing the arrangement of an array of multi-cylinder energy capture devices with energy capture size as the target, which has the advantages of being faster, more accurate, and more efficient than existing methods.

Description

Technical Field

[0001] The present invention belongs to the technical field of offshore vortex-induced vibration energy-harvesting array arrangement, and in particular relates to an array optimization arrangement method for vortex-induced vibration devices. Background Art

[0002] With the gradual consumption of traditional energy and the increasing awareness of carbon emissions, the development of new energy sources has received more and more attention from countries around the world. As one of the renewable energy sources, the development of ocean current energy has received much attention. At present, people's utilization of ocean current energy is mainly focused on the development and utilization of tidal energy, that is, by using underwater turbine power generation equipment to obtain energy from tidal currents with higher flow rates, but there are few studies on obtaining energy from low-speed ocean currents or rivers based on vortex-induced vibrations. However, in order to achieve commercial-scale power generation and cost control, the present invention optimizes the array arrangement of multiple energy converters to achieve the results of reducing costs and increasing efficiency.

[0003] At present, the capture of low-speed water kinetic energy based on vortex-induced vibration is mainly limited to the use of experimental and numerical simulation methods to study the capture of single energy converters composed of single cylinders, series-parallel double cylinders and multiple cylinders. Due to its high cost and low power output, a single energy converter has almost no economic value in practical applications. In large low-speed ocean current basins, the array arrangement of energy converters is an inevitable trend for the large-scale development of low-speed ocean current energy. However, due to the large number of parameters that affect the array arrangement, the economic and time costs of using numerical simulation or experimental methods are huge. Summary of the invention

[0004] The purpose of the present invention is to propose a method for optimizing the arrangement of an array of vortex-induced vibration devices, to adopt a target optimization algorithm for the first time to optimize the arrangement of an array of multiple energy converters, and to construct a mathematical model for optimizing the arrangement of an array of multi-cylindrical energy harvesting devices with energy harvesting size as the target.

[0005] To achieve the above object, the present invention provides a method for optimizing the arrangement of a vortex-induced vibration device array, comprising:

[0006] Based on the method of analyzing fluid motion based on Stokes theory, a mathematical model of energy harvesting of multi-cylinder energy harvesting device is constructed;

[0007] Based on the energy harvesting mathematical model of the multi-cylindrical energy harvesting device, an array optimization model of the multi-cylindrical vortex-induced vibration energy harvesting device is constructed;

[0008] Presetting the objective function of the multi-cylindrical vortex-induced vibration energy harvesting device array optimization model;

[0009] Based on the objective function, the genetic algorithm is used to optimize the array optimization model of the multi-cylindrical vortex-induced vibration energy harvesting device to obtain the optimal array layout of the vortex-induced vibration device.

[0010] Optionally, based on the method of analyzing fluid motion based on Stokes theory, constructing the energy harvesting mathematical model of the multi-cylinder energy harvesting device includes:

[0011] According to the method of analyzing fluid motion based on Stokes theory, a mathematical model of energy capture of vortex-induced vibration of a single cylinder is constructed based on the vortex-induced vibration device and regional seawater velocity data;

[0012] Based on the single cylindrical vortex-induced vibration energy harvesting mathematical model, the energy harvesting mathematical model of the multi-cylinder energy harvesting device is constructed.

[0013] Optionally, the energy harvesting mathematical model of the multi-cylindrical energy harvesting device is:

[0014]

[0015] Among them, P z (t) is the total energy of vortex-induced vibration absorbed by the energy-harvesting device system, P VIV (t) is the kinetic energy of the energy-harvesting device itself, P pz (t) is the potential energy absorbed by the energy harvesting device, ρ is the density, C y is the lateral lift of vibration, U 2 is the incoming flow velocity, f is the frequency of the cylinder in water, y max is the amplitude of the vortex-induced vibration of the cylinder, D is the diameter of the cylinder, L is the length of the cylinder, g is the acceleration of gravity, A is the maximum amplitude, t is the vortex-induced vibration time, is the phase difference between vortex-induced vibration and displacement, and ξ is the vortex number generated by vortex-induced vibration.

[0016] Optionally, the objective function of the multi-cylindrical vortex-induced vibration energy harvesting device array optimization model is:

[0017] maxf=q(x1,y1,x2,y2...)

[0018] Among them, q is the interaction coefficient for evaluating the quality of the array, x i is the horizontal coordinate of the cylinder, y i is the ordinate of the cylinder, i=1, 2,...

[0019] Optionally, optimizing the multi-cylindrical vortex-induced vibration energy harvesting device array optimization model using a genetic algorithm includes:

[0020] According to the multi-cylindrical vortex-induced vibration energy harvesting device array, the genetic algorithm parameters are set; wherein the genetic algorithm parameters include: the scale of the vortex-induced vibration energy harvesting device, the number of device optimization iterations, the energy interaction rate between devices, and the energy conversion mutation rate of the device;

[0021] According to the set genetic algorithm parameters, fitness calculation is performed, and individuals are selected from them to perform energy interaction between different vortex-induced vibration devices through the energy interaction rate between devices, thereby obtaining new interactive individuals; wherein the individual represents a single device in the vortex-induced vibration energy capture device;

[0022] According to the obtained new interactive individuals, according to the objective function, the device energy conversion mutation rate operation is performed on the population individuals, and the best performing individuals are obtained by mixing and sorting, that is, the maximum value of the vortex-induced vibration energy harvesting device array;

[0023] Determine whether the best performing individual has reached the preset number of device optimization iterations, otherwise recalculate the fitness;

[0024] The optimal vortex-induced vibration device array layout in the field of multi-cylindrical vortex-induced vibration energy capture device array is determined based on the final best performing individual.

[0025] Optionally, the method for calculating the fitness is:

[0026]

[0027] Among them, V k ′、V k ″ represents the individuals to be mutated and after mutation; f best is the optimal fitness value of all individuals in this generation population, R a is a random number between 0 and 1, and f′ is the fitness value of the individual to be mutated in this generation of population.

[0028] Optionally, the interaction coefficient for evaluating the quality of the array is:

[0029]

[0030] Where N is the number of energy harvesting devices, P z is the energy captured by multiple cylindrical vortex induced vibration energy harvesting devices in an array arrangement, P0 is the energy captured by a single cylindrical vortex induced vibration energy harvesting device, j is the number of vortex induced vibration energy harvesting devices, k0 is the vortex number k0 of the wake, β is the empirical coefficient, and ε is the turbulence dissipation rate.

[0031] The present invention has the following beneficial effects:

[0032] The present invention proposes a method for optimizing the arrangement of a vortex-induced vibration device array. First, a mathematical model of energy capture of a multi-cylinder energy capture device is constructed; based on the mathematical model of energy capture of the multi-cylinder energy capture device, an optimization model of the array of a multi-cylinder vortex-induced vibration energy capture device is constructed; an objective function is set; and a genetic algorithm is used to optimize the optimization model of the array of a multi-cylinder vortex-induced vibration energy capture device to obtain an optimal vortex-induced vibration device array layout. The present invention adopts a target optimization algorithm for the first time to optimize the arrangement of an array of multiple energy converters, and constructs a mathematical model of optimal arrangement of an array of a multi-cylinder energy capture device with energy capture size as the target. Compared with existing methods, it has the advantages of being faster, more accurate, and more efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0034] Figure 1 is a structural block diagram of an energy capture device according to an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of a flow chart of a method for optimizing the arrangement of a vortex-induced vibration device array according to an embodiment of the present invention;

[0036] Figure 3 A schematic diagram of an optimized arrangement of an array of vortex-induced vibration devices according to an embodiment of the present invention;

[0037] Figure 4 Schematic diagram of energy capture curve of a multi-cylindrical energy capture device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0040] This embodiment proposes a method for optimizing the arrangement of a vortex-induced vibration device array. First, a vortex-induced vibration device in this embodiment is described. Figure 1 ,include:

[0041] Vortex-induced vibration power generation device, the energy capture device consists of three parts: a vibrating cylinder, a transmission mechanism and an energy transmission device;

[0042] Vibrating cylinder: used to capture ocean current energy. When ocean current flows through the cylinder, vortex-induced vibration effect occurs, causing the cylinder to vibrate.

[0043] Transmission mechanism: spring, damper and support frame. The vibrating cylinder is fixed on the seabed through the support frame. The spring and damper are used to transfer the energy of the cylinder vibration to the generator side.

[0044] Energy transmission device: gear belt and generator, the vibration transmitted by the transmission mechanism drives the gear to rotate the generator rotor, thereby converting the mechanical energy generated by the cylinder vibration into electrical energy;

[0045] When low-speed water flows through the cylinder, a vortex-induced vibration effect is generated, causing the cylinder to vibrate up and down, converting the kinetic energy of the water into mechanical energy of the up and down vibration of the cylinder, which is then transmitted to the generator rotor by the transmission mechanism to drive the generator to operate, thereby realizing the energy transfer process from water energy to mechanical energy and then to electrical energy.

[0046] like Figure 2 As shown, the vortex induced vibration device array optimization layout method is based on the vortex induced vibration regular array arrangement. By constructing a multi-cylinder energy harvesting device energy capture mathematical model, a genetic algorithm is adopted, and by setting the vortex induced vibration device position adjustment range, the vortex induced vibration device position is optimized in the vicinity of the vortex induced vibration device regular array. The global optimal arrangement of the vortex induced vibration device array is achieved, the utilization rate of the wake between the vortex induced vibration devices is increased, the overall power generation of the vortex induced vibration device is improved, and the layout of the vortex induced vibration device is more effective.

[0047] The method for optimizing the arrangement of a vortex-induced vibration device array proposed in this embodiment specifically includes:

[0048] Based on the method of analyzing fluid motion based on Stokes theory, a mathematical model of energy harvesting of multi-cylinder energy harvesting device is constructed;

[0049] Based on the mathematical model of multi-cylindrical energy harvesting device, an array optimization model of multi-cylindrical vortex-induced vibration energy harvesting device is constructed;

[0050] Preset the objective function of the multi-cylindrical vortex-induced vibration energy harvesting device array optimization model;

[0051] Based on the objective function, the genetic algorithm is used to optimize the array optimization model of the multi-cylinder vortex-induced vibration energy harvesting device to obtain the optimal array layout of the vortex-induced vibration device.

[0052] Furthermore, based on the method of analyzing fluid motion based on Stokes theory, the energy harvesting mathematical model of the multi-cylinder energy harvesting device is constructed, including:

[0053] According to the method of analyzing fluid motion based on Stokes theory, a mathematical model of energy capture of vortex-induced vibration of a single cylinder is constructed based on the vortex-induced vibration device and regional seawater velocity data;

[0054] Based on the mathematical model of energy harvesting by vortex-induced vibration of a single cylinder, a mathematical model of energy harvesting by a multi-cylinder energy harvesting device is constructed.

[0055] Specifically, in this embodiment, constructing the energy harvesting mathematical model of the multi-cylinder energy harvesting device includes the following steps:

[0056] The Stokes theory is used to analyze the movement of fluid, and the mathematical model of multi-cylinder vortex-induced vibration energy conversion is derived based on the mathematical model of single-cylinder water-machine-electricity energy conversion.

[0057] In the embodiment of the present invention, the mathematical model of single cylinder vortex-induced vibration energy conversion is specifically expressed as follows:

[0058]

[0059] Based on the energy conversion mathematical model of a single cylinder, the present invention derives the energy conversion mathematical model of multi-cylinder vortex-induced vibration for the first time. The energy capture mathematical model of the multi-cylinder energy capture device is specifically expressed as follows:

[0060]

[0061] The interaction coefficient q for evaluating the quality of the array is specifically expressed as follows:

[0062]

[0063] Where: N is the number of energy harvesting devices, P z is the energy captured by multiple cylindrical vortex-induced vibration energy harvesting devices in an array arrangement; P0 is the energy captured by a single cylindrical vortex-induced vibration energy harvesting device. Similarly, the interaction coefficient q z To reflect the energy conversion efficiency of the vortex-induced vibration of each cylinder in the array arrangement.

[0064] In the example of the present invention, an optimization model of the array of multi-cylindrical vortex-induced vibration energy harvesting devices is established based on the mathematical model of energy conversion of multi-cylindrical energy harvesting devices. The cylindrical vortex-induced vibration energy harvesting device 1 is installed at (0, 0), and the design parameters include the coordinates of other devices related to the multi-cylindrical vortex-induced vibration energy harvesting device 1. For an array of N vortex-induced vibration energy harvesting devices, the optimal value is N-1, and the coordinates of each energy harvesting device include two components of the horizontal and vertical coordinates. Therefore, the dimension of the problem is D=2(N-1), and the maximum goal of the array of multi-cylindrical vortex-induced vibration energy harvesting devices is to capture the low-speed water flow energy to the maximum extent within a predetermined area. Therefore, the objective function is the array q factor, and the mathematical model of its optimization problem can be expressed as:

[0065] Objective function maxf = q(x1, y1, x2, y2...)

[0066] Wherein: q is a function of the position of the vortex-induced vibration energy harvesting device, and the origin is the fixed position of the vortex-induced vibration energy harvesting device 1.

[0067] The multi-cylinder vortex-induced vibration energy harvesting device array optimization model is a mathematical model that combines fluid-solid coupling, feedback control and intelligent genetic algorithm. When defining the multi-cylinder vortex-induced vibration energy harvesting device array optimization model, this embodiment considers how to harvest energy through the vortex-induced vibrations induced by multiple cylindrical structures in the fluid. This model usually includes the simulation of the flow field, the dynamic response of the structure, and the calculation of the energy conversion efficiency. Through the study of a three-dimensional single cylinder, combined with the speed feedback and displacement feedback control laws, a neural network is used to map the flow field information to the feedback gain size, and a genetic algorithm is used to optimize the neural network parameters, thereby realizing active control of the cylindrical vortex-induced vibration at different flow rates.

[0068] Furthermore, the genetic algorithm is used to optimize the array optimization model of the multi-cylinder vortex-induced vibration energy harvesting device, such as Figure 2 As shown, including:

[0069] According to the multi-cylindrical vortex-induced vibration energy harvesting device array, the genetic algorithm parameters are set; wherein the genetic algorithm parameters include: the scale of the vortex-induced vibration energy harvesting device, the number of device optimization iterations, the energy interaction rate between devices, and the energy conversion mutation rate of the device;

[0070] According to the set genetic algorithm parameters, fitness calculation is performed, and individuals are selected from them to perform energy interaction between different vortex-induced vibration devices through the energy interaction rate between devices, thereby obtaining new interaction individuals; wherein the individual represents a single device in the vortex-induced vibration energy capture device;

[0071] According to the obtained new interactive individuals, according to the objective function, the energy conversion mutation rate of the population individuals is operated, and the best performing individuals are obtained by mixing and sorting, that is, the maximum value of the vortex-induced vibration energy harvesting device array;

[0072] Determine whether the best performing individual has reached the preset number of device optimization iterations, otherwise recalculate the fitness;

[0073] The optimal vortex induced vibration device array layout in the field of multi-cylindrical vortex induced vibration energy harvesting device array is determined based on the final best performing individual.

[0074] Specifically, the basic idea of ​​this embodiment is to start from the initial population, select individuals using the natural law of survival of the fittest, and generate a new generation of populations through hybridization and mutation, evolving generation by generation until the goal is met.

[0075] The population initialization is implemented as follows:

[0076]

[0077] Where: R a A random number between 0 and 1.

[0078] The adaptive crossover rate and mutation rate used are defined as:

[0079]

[0080]

[0081] Where: P c1 , P c2 is the maximum and minimum crossover probability; P m1 , P m2 represents the maximum and minimum mutation probability; t and T represent the current iteration number and the termination iteration number respectively; f avg It is the average fitness value of all individuals in the current population; f is the larger fitness value of the individuals to be crossed in the current population; f′ represents the fitness value of the individuals to be mutated in the current population.

[0082] In order to compute real-coded genetic operators, non-uniform crossover operators and non-uniform mutation operators are used. The latter is defined as follows:

[0083]

[0084] When the fitness value of the individual to be mutated is close to the optimal fitness, the change made to the original individual is small, and the non-uniform mutation operator is defined as:

[0085]

[0086] Where: V k ′、V k ″ represents the individuals to be mutated and after mutation; f best It is the optimal fitness value of all individuals in this generation population.

[0087] In this embodiment, the objective function of the vortex-induced vibration device array is calculated to obtain the objective function value of the vortex-induced vibration device array;

[0088] Compare the objective function value of the vortex-induced vibration device array with the maximum value of the objective function value of the vortex-induced vibration device array to obtain the maximum value of the two; the maximum value of the two is the maximum value of the objective function value of the vortex-induced vibration device array.

[0089] Figure 3The array of multi-cylinder vortex-induced vibration devices is optimized and arranged. The algorithm optimizes and calculates to generate a white energy band. The best individuals after optimization are all in the energy band. The optimization results verify the three-dimensional wake energy capture characteristics of multi-cylinder vortex-induced vibration arranged in vortex-induced vibration. This arrangement is distributed in a "geese formation", making full use of the wake vortex generated by the vortex-induced vibration of the upstream cylindrical energy capture device, and capturing more water flow energy through the interaction between the wake vortex and the downstream cylinder.

[0090] Figure 4 This is the energy capture curve of the multi-cylinder energy capture device. The array arrangement of 2 cylinders has a faster convergence speed, while the array arrangement of 8 cylinders has a higher evolutionary starting point. In the calculation of the captured energy of each arrangement scheme, the convergence speed is fast at the beginning, and the captured energy tends to be stable as the number of devices increases. Within the arrangement range, as the number of energy capture devices in the array optimization arrangement increases, the captured energy increases nonlinearly, and the increase rate gradually slows down. This is because when the arrangement range is fixed, although the number of energy capture devices increases, it also means that the interference between the cylinders is more complicated, the vibration of the downstream cylinder is significantly affected by the upstream, the amplitude is reduced, the energy capture efficiency is reduced, and the energy capture density naturally decreases rapidly with the increase in the number of energy capture devices.

[0091] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for optimizing the arrangement of a vortex-induced vibration device array, characterized in that: include: Based on the method of analyzing fluid motion based on Stokes theory, a mathematical model of energy harvesting of multi-cylinder energy harvesting device is constructed; The energy harvesting mathematical model of the multi-cylinder energy harvesting device is: Among them, P z (t) is the total energy of vortex-induced vibration absorbed by the energy-harvesting device system, P VIV (t) is the kinetic energy of the energy-harvesting device itself, P pz (t) is the potential energy absorbed by the energy harvesting device, ρ is the density, C y is the lateral lift of vibration, U 2 is the incoming flow velocity, f is the frequency of the cylinder in water, y max is the amplitude of the vortex-induced vibration of the cylinder, D is the diameter of the cylinder, L is the length of the cylinder, g is the acceleration of gravity, A is the maximum amplitude, t is the vortex-induced vibration time, is the phase difference between vortex-induced vibration and displacement, ξ is the vortex number generated by vortex-induced vibration; Based on the energy harvesting mathematical model of the multi-cylindrical energy harvesting device, an array optimization model of the multi-cylindrical vortex-induced vibration energy harvesting device is constructed; Presetting the objective function of the multi-cylindrical vortex-induced vibration energy harvesting device array optimization model; Based on the objective function, the genetic algorithm is used to optimize the array optimization model of the multi-cylindrical vortex-induced vibration energy harvesting device to obtain the optimal array layout of the vortex-induced vibration device.

2. The method for optimizing the arrangement of a vortex-induced vibration device array according to claim 1, characterized in that: Based on the method of analyzing fluid motion based on Stokes theory, the energy harvesting mathematical model of the multi-cylinder energy harvesting device is constructed, including: According to the method of analyzing fluid motion based on Stokes theory, a mathematical model of energy capture of vortex-induced vibration of a single cylinder is constructed based on the vortex-induced vibration device and regional seawater velocity data; Based on the single cylindrical vortex-induced vibration energy harvesting mathematical model, the energy harvesting mathematical model of the multi-cylinder energy harvesting device is constructed.

3. The method for optimizing the arrangement of a vortex-induced vibration device array according to claim 1, characterized in that: The objective function of the multi-cylinder vortex-induced vibration energy harvesting device array optimization model is: maxf=q(x1,y1,x2,y2...x n ,y n ) Among them, q is the interaction coefficient for evaluating the quality of the array, x n is the horizontal coordinate of the cylinder, y n is the ordinate of the cylinder, and n is the number of cylinders.

4. The method for optimizing the arrangement of a vortex-induced vibration device array according to claim 1, characterized in that: The optimization process of the multi-cylinder vortex-induced vibration energy harvesting device array optimization model using a genetic algorithm includes: According to the multi-cylindrical vortex-induced vibration energy harvesting device array, the genetic algorithm parameters are set; wherein the genetic algorithm parameters include: the scale of the vortex-induced vibration energy harvesting device, the number of device optimization iterations, the energy interaction rate between devices, and the energy conversion mutation rate of the device; According to the set genetic algorithm parameters, fitness calculation is performed, and individuals are selected from them to perform energy interaction between different vortex-induced vibration devices through the energy interaction rate between devices, thereby obtaining new interactive individuals; wherein the individual represents a single device in the vortex-induced vibration energy capture device; According to the obtained new interactive individuals, according to the objective function, the device energy conversion mutation rate operation is performed on the population individuals, and the best performing individuals are obtained by mixing and sorting, that is, the maximum value of the vortex-induced vibration energy harvesting device array; Determine whether the best performing individual has reached the preset number of device optimization iterations, otherwise recalculate the fitness; The optimal vortex-induced vibration device array layout in the field of multi-cylindrical vortex-induced vibration energy capture device array is determined based on the final best performing individual.

5. The method for optimizing the arrangement of a vortex-induced vibration device array according to claim 4, characterized in that: Implementing a genetic algorithm using real-number coded genetic operators; wherein the real-number coded genetic operators are calculated using non-uniform crossover operators and non-uniform mutation operators; The non-uniform mutation operator is: Among them, V k ′、V k ″ represents the individuals to be mutated and after mutation; f best is the optimal fitness value of all individuals in this generation population, R a is a random number between 0 and 1, and f′ is the fitness value of the individual to be mutated in this generation of population.

6. The method for optimizing the arrangement of a vortex induced vibration device array according to claim 3, characterized in that: The interaction coefficient for evaluating the quality of the array is: Where N is the number of energy harvesting devices, P z is the energy captured by multiple cylindrical vortex induced vibration energy harvesting devices in an array arrangement, P0 is the energy captured by a single cylindrical vortex induced vibration energy harvesting device, j is the number of vortex induced vibration energy harvesting devices, k0 is the vortex number of the wake, β is the empirical coefficient, and ε is the turbulence dissipation rate.

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