Blade modal damping distribution calculation method, medium and system

Abstract

The invention discloses a distribution calculation method for modal damping of a blade, a medium and a system. The method comprises the following steps: 1) acquiring modal frequencies of the blade under each order and converting the modal frequencies into angular frequencies; 2) obtaining intermediate parameters alpha 1 and alpha 2 according to Rayleigh damping setting on the basis of the first-order angular frequency and the second-order angular frequency; 3) on the basis of the intermediate parameters alpha 1 and alpha 2, according to Rayleigh damping setting, obtaining Rayleigh damping corresponding to a mode of more than three orders; and 4) setting the modal damping of the blade in the whole machine model according to the Rayleigh damping. According to the method, calculation analysis of each order of the modal frequency of the blade is utilized, the damping ratio of the changed modal structure can be estimated by using the Rayleigh damping model, so that load distortion of the blade in the simulation process is avoided, the simulation reasonability of the blade load and the whole machine load is ensured, and the divergence problem of the long flexible blade is solved.

Description

Technical Field

[0001] The present invention mainly relates to the field of wind power technology, and in particular to a distribution calculation method, medium and system for blade modal damping. Background Art

[0002] As a clean and renewable energy, wind energy has huge reserves and is increasingly valued by countries around the world. With the increase in the capacity of wind turbines, the diameter of the wind rotor increases, the height of wind turbines from the ground increases, the length of the blades increases, and the blades become more and more flexible. In simulation, the blades are more likely to diverge, and the loads of the whole machine and blades are abnormal, which leads to distortion of the simulation load.

[0003] At present, the blades in the wind power industry are becoming longer and longer. As the power of a single unit increases, the blades are also becoming longer and longer. This requires the analysis and solution of the divergence problem that often occurs in the blade calculation simulation. By using the Rayleigh damping model to estimate the damping ratio of the modal structure, the blade divergence problem is solved, ensuring that the blade divergence problem is solved during the calculation of the blade and the whole machine model. Therefore, in general, the adjustment of the damping ratio of the blade modal structure can well meet the solution of the divergence problem in the blade iteration process, and more reasonably check the structural strength of the blade and the whole machine components.

[0004] At present, the setting method of blade modal damping is based on the damping constants provided by the blade manufacturer, which are usually 0.8%, 0.5%, 0.3% and other constants. As the blades become longer and longer, the modal damping of the blades becomes smaller and smaller, resulting in the blades becoming more and more prone to divergence problems during the simulation calculation process, and the loads of various components increase abnormally. Summary of the invention

[0005] In view of the technical problems existing in the prior art, the present invention provides a distribution calculation method, medium and system for blade modal damping that solve the divergence problem of long flexible blades.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0007] A method for calculating the distribution of blade modal damping comprises the steps of:

[0008] 1) Obtain the modal frequencies of the blades at each order and convert them into angular frequencies;

[0009] 2) Based on the angular frequencies of the first and second orders, the intermediate parameter α is obtained according to the Rayleigh damping setting 1 and α 2 ;

[0010] 3) Based on the intermediate parameter α 1 and α 2, according to the Rayleigh damping setting, the Rayleigh damping corresponding to the third-order and above modes is obtained;

[0011] 4) Set the blade modal damping in the blade machine model according to the Rayleigh damping.

[0012] Preferably, in step 1), the modal frequencies of the blades at various orders include flapping frequencies and swing frequencies.

[0013] Preferably, in step 1), the specific formula for converting the modal frequency into the angular frequency is:

[0014] ω=2πf;

[0015] Where ω is the angular frequency and f is the frequency.

[0016] Preferably, the specific process of step 2) is:

[0017]

[0018] where ω 1 is the first mode angular frequency; ω 2 is the second mode angular frequency; ζ 1 is the first mode damping ratio; ζ 2 is the second mode damping ratio; the damping ratio below the second order is a fixed value given by the blade manufacturer.

[0019] Preferably, the first modal damping ratio ζ 1 and the second mode damping ratio ζ 2 Both are 0.3%.

[0020] Preferably, in step 3), based on the intermediate parameter α 1 and α 2 According to the Rayleigh damping setting, the specific formula of Rayleigh damping corresponding to the third-order and above modes is:

[0021]

[0022] where ζ n is the Rayleigh damping in the n-order mode; ω n is the angular frequency of the nth mode.

[0023] The present invention also discloses a distribution calculation system for blade modal damping, comprising:

[0024] The first program module is used to obtain the modal frequencies of the blades at each order and convert them into angular frequencies;

[0025] The second program module is used to obtain the intermediate parameter α based on the angular frequency of the first and second orders according to the Rayleigh damping setting 1 and α 2 ;

[0026] The third program module is used to 1 and α 2 , according to the Rayleigh damping setting, the Rayleigh damping corresponding to the third-order and above modes is obtained;

[0027] The fourth program module is used to set the blade modal damping in the blade whole machine model according to Rayleigh damping.

[0028] The present invention further discloses a computer program product, comprising a computer program, wherein the computer program executes the steps of the method described above when executed by a processor.

[0029] The present invention also discloses a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described above are executed.

[0030] The present invention further discloses a computer device, comprising a memory and a processor connected to each other, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the steps of the method described above are executed.

[0031] Compared with the prior art, the advantages of the present invention are:

[0032] The present invention utilizes the calculation and analysis of each order of blade modal frequency and can estimate the damping ratio of the modified modal structure by using the Rayleigh damping model, thereby achieving the goal of no load distortion in the blade during the simulation process, ensuring the rationality of the blade load and the whole machine load simulation, and thus solving the divergence problem of long and flexible blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the blade-damping arrangement in the present invention.

[0034] Figure 2 It is a schematic diagram of the damping ratio setting of the balde whole machine model in the present invention.

[0035] Figure 3 This is a comparison diagram of blade modal damping and blade load divergence in the present invention.

[0036] Figure 4 The figure is a flow chart of the distributed computing method in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0038] like Figure 4 As shown, the distribution calculation method of blade modal damping provided by the embodiment of the present invention includes the steps of:

[0039] 1) According to the balde software, the modal frequencies of the blades at each order are calculated, including the first-order blade flapping frequency, the first-order swing array frequency, the second-order blade flapping frequency, the second-order swing array frequency, etc., and the corresponding modal frequencies of the blades at each order are converted into angular frequencies; the specific conversion formula is:

[0040] ω=2πf;

[0041] Where ω is the angular frequency and f is the frequency.

[0042] 2) According to the IEC61400-6-2020 standard, the high-order modal damping adopts the Rayleigh damping setting, through the first modal angular frequency ω 1 、The second mode angular frequency ω 2 , the first mode damping ratio ζ 1 and the second mode damping ratio ζ 2 Get the key parameter α 1 and α 2 , specifically:

[0043]

[0044] where ω 1 is the first mode angular frequency; ω 2 is the second mode angular frequency; ζ 1 is the first mode damping ratio; ζ 2 is the second mode damping ratio; the damping ratio below the second order is a fixed value (0.3%) given by the blade manufacturer.

[0045] 3) Calculate the Rayleigh damping corresponding to the higher-order mode (above the second-order mode) based on the key parameters, specifically:

[0046]

[0047] where ζ n is the Rayleigh damping in the n-order mode; ω n is the angular frequency of the nth mode.

[0048] like Figure 1 As shown in the figure, taking a large blade as an example, the blade Rayleigh damping is set as follows:

[0049]

[0050]

[0051] Usually, the first-order and second-order modes of the blade use constants recommended by the blade manufacturer, and the modes above the second order use high-order Rayleigh damping settings to solve the divergence problem that occurs during the blade simulation process.

[0052] 4) Set the blade modal damping in the blade machine model according to the Rayleigh damping.

[0053] Calculate the damping ratio of each mode through step 2), and set the damping ratio into the model in the balde machine model, such as Figure 2 As shown in the figure, Damping Ratio is the damping ratio; Name is the name; Modal Frequency is the modal frequency.

[0054] In specific applications, Figure 3 The blade modal damping is compared with the blade load divergence shown in the figure, where the black is the fixed damping ratio and the red is the Rayleigh damping set by the above method. It can be seen from the comparison that the divergence problem of the blade in the simulation calculation process can be solved by setting the Rayleigh damping of the high-order mode.

[0055] The present invention utilizes the calculation and analysis of each order of blade modal frequency and can estimate the damping ratio of the modified modal structure by using the Rayleigh damping model, thereby achieving the goal of no load distortion in the blade during the simulation process, solving the rationality of the simulation of blade load and whole machine load, and thus solving the divergence problem of long and flexible blades.

[0056] The present invention also discloses a distribution calculation system for blade modal damping, comprising:

[0057] The first program module is used to obtain the modal frequencies of the blades at each order and convert them into angular frequencies;

[0058] The second program module is used to obtain the intermediate parameter α based on the angular frequency of the first and second orders according to the Rayleigh damping setting 1 and α 2 ;

[0059] The third program module is used to 1 and α 2 , according to the Rayleigh damping setting, the Rayleigh damping corresponding to the third-order and above modes is obtained;

[0060] The fourth program module is used to set the blade modal damping in the blade whole machine model according to Rayleigh damping.

[0061] The present invention further discloses a computer program product, including a computer program, wherein the computer program executes the steps of the above method when executed by a processor. The present invention further discloses a computer readable storage medium, wherein a computer program is stored thereon, wherein the computer program executes the steps of the above method when executed by a processor. The present invention further discloses a computer device, including a memory and a processor connected to each other, wherein a computer program is stored on the memory, wherein the computer program executes the steps of the above method when executed by the processor.

[0062] The system, product, medium and device of the present invention all correspond to the above method and also have the advantages described in the above method.

[0063] The present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned method embodiment when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. Computer-readable storage media include: any entity or device that can carry computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. The memory is used to store computer programs and / or modules, and the processor implements various functions by running or executing computer programs and / or modules stored in the memory, and calling data stored in the memory. The memory may include high-speed random access memory and may also include non-volatile memory, such as a hard disk, an internal memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0064] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A method for calculating the distribution of blade modal damping, characterized in that: Includes steps: 1) Obtain the modal frequencies of the blades at each order and convert them into angular frequencies; 2) Based on the angular frequencies of the first and second orders, the intermediate parameters α1 and α2 are obtained according to the Rayleigh damping setting; 3) Based on the intermediate parameters α1 and α2, the Rayleigh damping corresponding to the third-order and above modes is obtained according to the Rayleigh damping setting; 4) Set the blade modal damping in the blade machine model according to the Rayleigh damping.

2. The method for calculating the distribution of blade modal damping according to claim 1, characterized in that: In step 1), the modal frequencies of the blades at each order include flapping frequencies and swing frequencies.

3. The method for calculating the distribution of blade modal damping according to claim 2, characterized in that: In step 1), the specific formula for converting the modal frequency to the angular frequency is: ω=2πf; Where ω is the angular frequency and f is the frequency.

4. The method for calculating the distribution of blade modal damping according to claim 1, 2 or 3, characterized in that: The specific process of step 2) is: Where ω1 is the first modal angular frequency; ω2 is the second modal angular frequency; ζ1 is the first modal damping ratio; ζ2 is the second modal damping ratio; the damping ratio below the second order is a fixed value given by the blade manufacturer.

5. The method for calculating the distribution of blade modal damping according to claim 4, characterized in that: The first modal damping ratio ζ1 and the second modal damping ratio ζ2 are both 0.3%.

6. The method for calculating the distribution of blade modal damping according to claim 1, 2 or 3, characterized in that: In step 3), based on the intermediate parameters α1 and α2, the specific formula of Rayleigh damping corresponding to the third-order and above modes is obtained according to the Rayleigh damping setting: where ζ n is the Rayleigh damping in the n-order mode; ω n is the angular frequency of the nth mode.

7. A distribution calculation system for blade modal damping, characterized in that: include: The first program module is used to obtain the modal frequencies of the blades at each order and convert them into angular frequencies; A second program module is used to obtain intermediate parameters α1 and α2 according to Rayleigh damping settings based on the angular frequencies at the first and second orders; The third program module is used to obtain the Rayleigh damping corresponding to the third-order and higher modes according to the Rayleigh damping setting based on the intermediate parameters α1 and α2; The fourth program module is used to set the blade modal damping in the blade whole machine model according to Rayleigh damping.

8. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are performed.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the computer program performs the steps of the method according to any one of claims 1 to 6.

10. A computer device comprising a memory and a processor connected to each other, wherein a computer program is stored in the memory, characterized in that: When the computer program is executed by a processor, the computer program performs the steps of the method according to any one of claims 1 to 6.

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