Wind turbine CFD equivalent test method and system for phase-locked wind tunnel measurement

Abstract

The application provides a wind turbine CFD equivalent test method for phase-locked wind tunnel measurement, obtains a rotating wind turbine blade number, a rotating speed, a spatial resolution of a target entity measurement device, a time resolution, a phase division box and a measurement uncertainty, reversely determines an initial space-time resolution of CFD according to a blade passing frequency and an instrument measurement parameter, converts original flow fields of different resolution CFD into instrument observable data by using a same measurement transfer operator, compares differences of equivalent measurement results of adjacent resolution levels with a comprehensive measurement uncertainty of a physical instrument, automatically determines a lowest measurement equivalent CFD resolution, and executes subsequent wind turbine equivalent wind tunnel tests by using the resolution.

Description

Technical Field

[0001] This invention relates to the fields of wind engineering, wind turbine aerodynamics, computational fluid dynamics, and wind tunnel measurement technology, specifically a CFD equivalent test method for wind turbines oriented towards phase-locked wind tunnel measurement. Background Technology

[0002] The rotor diameter and swept area of ​​large horizontal axis wind turbines continue to increase, and full-scale physical wind tunnel tests are limited by factors such as test section size, blockage ratio, Reynolds number similarity, model manufacturing, rotor drive, and the arrangement of measurement equipment. Using CFD to construct numerical or virtual wind tunnels allows for the acquisition of high-dimensional flow field information such as velocity, pressure, vorticity, and loads within the computational domain, and therefore has been widely used in the study of wind turbine aerodynamic performance and wake characteristics.

[0003] However, the raw flow field obtained from CFD is not equivalent to the instrument measurement results in a physical wind tunnel. Physical PIV, LDV, hot-wire, scanning lidar, or force / torque measurement devices all have limited measurement volume, spatial resolution, time response, sampling frequency, phase synchronization accuracy, calibration relationships, and measurement uncertainties. Directly using the instantaneous values ​​of CFD grid nodes or single points as "wind tunnel measurements" ignores the observable range and transfer characteristics of physical instruments, leading to inconsistencies between numerical results and physical experimental data at the definition level.

[0004] Existing virtual instrumentation or synthetic measurement techniques typically simulate the observation process of a certain type of instrument on an existing CFD flow field. On the other hand, conventional CFD grid independence or time-step independence analyses are usually based on the original field variables, overall aerodynamic forces, or numerical residuals. When the target task is phase-locked wake measurement of a rotating wind turbine, the turbine speed, number of blades, and blade passage frequency introduce unique time scales. The target PIV phase binning, measurement window, and measurement uncertainty directly determine "the degree of resolution required to be experimentally meaningful." Existing methods lack a closed-loop technical solution that uses the target entity's wind tunnel measurement capabilities to determine the initial CFD configuration and uses the resolvability of the physical instrument as the stopping criterion for whether further improvements in numerical resolution are necessary. Summary of the Invention

[0005] To address the problem that existing CFD numerical tests of wind turbines primarily rely on empirical settings or traditional grid independence analysis for computational grids, time steps, and data output frequencies, making it difficult to establish a correspondence with the actual spatial resolution, temporal resolution, and measurement uncertainty of physical wind tunnel measurement instruments, this invention proposes an equivalent CFD test method for wind turbines oriented towards phase-locked wind tunnel measurements. This method achieves a synergistic match between CFD numerical resolution and physical wind tunnel measurement capabilities. The technical solution provided by this invention is as follows: Firstly, a CFD equivalent test method for wind turbines oriented towards phase-locked wind tunnel measurements includes the following steps: S1, acquire the number of blades, rotor angular velocity, and target wind tunnel measurement task of the rotating wind turbine. The target wind tunnel measurement task includes at least the spatial resolution scale, time resolution scale, comprehensive measurement uncertainty, and phase bin parameters of the target entity measurement device. S2, determine the blade passing frequency based on the number of blades and rotor angular velocity, and combine the phase box parameters, spatial resolution scale and time resolution scale to determine the initial CFD spatial resolution, initial CFD time step and result output parameters of the target measurement area; S3, perform unsteady CFD calculations on the rotating wind turbine according to the nth-level CFD configuration to obtain the original flow field of the nth-level target measurement area; S4, using the measurement transfer operator corresponding to the target entity measurement device to perform spatial measurement scale action and time or phase sampling action on the original flow field to obtain the nth level equivalent measurement data; S5, while keeping the wind turbine geometry, test conditions and target wind tunnel measurement tasks unchanged, improve the spatial resolution and / or temporal resolution of the target measurement area to form the (n+1)th level CFD configuration, and obtain the (n+1)th level equivalent measurement data through the same measurement transfer operator; S6. Based on the difference between the equivalent measurement data of level n and level n+1 and the comprehensive measurement uncertainty of the target entity measurement device, a measurement equivalence criterion is formed. When the measurement equivalence criterion is greater than a preset threshold, the CFD resolution is further increased. When the measurement equivalence criterion is not greater than the preset threshold, the lowest resolution level is determined from the CFD configurations that satisfy the measurement equivalence criterion as the minimum measurement equivalent CFD resolution. S7. Perform the wind turbine CFD equivalent test corresponding to the target wind tunnel measurement task using the minimum measurement equivalent CFD resolution, and output wind tunnel equivalent measurement data consistent with the observable definition of the target entity measurement device through the measurement transfer operator.

[0006] Preferably, the target entity measuring device is a phase-locked particle image velocimetry (PIV) device; the spatial resolution scale is determined by the PIV interrogation window, the laser sheet thickness, or the equivalent measurement volume; and the phase binning parameters are determined by the number of rotor azimuth bins or the phase synchronization accuracy.

[0007] Preferably, the measurement transfer operator includes at least: spatial integration or weighted averaging of the PIV interrogation window or equivalent measurement volume; temporal application of exposure, sampling interval or instrument time response; and phase binning and phase averaging according to the rotor azimuth angle.

[0008] Preferably, the measurement equivalence criterion is: ,in For the (n+1)th level equivalent measurement data, For the nth level equivalent measurement data, To comprehensively measure uncertainty, when The system determines that the corresponding CFD configuration meets the measurement equivalence requirements, where K is a preset threshold.

[0009] Preferably, at least one higher resolution level is established for verification; when the verification result still meets the measurement equivalence criterion, the lowest resolution level that first meets the criterion is determined as the minimum measurement equivalent CFD resolution.

[0010] Preferably, when the target operating condition is the yaw fan operating condition, the position of the target measurement window is determined based on the wake center position calculated by the previous stage CFD, and the local densification range of the target measurement area is updated with the position of the target measurement window.

[0011] Preferably, the wind tunnel equivalent measurement data includes at least one of phase-locked velocity, velocity deficit, vortex core position, phase-averaged turbulence statistics, thrust or torque, and is stored together with the minimum measurement equivalent CFD resolution, target entity measurement device parameters, phase settings, and comprehensive measurement uncertainty.

[0012] Secondly, a CFD equivalent test method for wind turbines oriented towards phase-locked wind tunnel measurement includes a task and instrument parameter input module, a CFD resolution inverse calculation module, a CFD configuration and solution module, a measurement transfer operator module, a measurement equivalence determination module, an adaptive encryption module, and an equivalent test data output module; wherein, each module is configured to collaboratively execute the above method.

[0013] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention pre-configures the physical wind tunnel measurement capability as the CFD configuration input, so that the CFD grid, time step and output frequency are no longer determined solely by experience or numerical residuals, but directly correspond to the spatial, temporal and phase resolution requirements of the target measurement task.

[0014] This invention uses the same measurement transfer operator to compare different CFD resolution levels, avoiding excessive encryption caused by direct comparison of high-dimensional original fields, where numerical differences exist but are indistinguishable by the target instrument.

[0015] This invention constructs a further encrypted stopping criterion based on the comprehensive measurement uncertainty of physical instruments, which can select the minimum necessary CFD spatiotemporal resolution without reducing the resolvability of the target wind tunnel measurement, thereby reducing the consumption of computational resources.

[0016] For phase-locked measurement of rotating wind turbines, this invention incorporates the blade passage frequency, rotor azimuth angle, and instrument time response into the time step constraint, thereby coupling the CFD time resolution with the rotating aerodynamic characteristics and the phase measurement requirements of the physical test.

[0017] This invention restricts the formal results to the observable data space of the target instrument, and simultaneously outputs instrument parameters, measurement uncertainty and minimum measurement equivalent CFD resolution metadata, which is beneficial for comparing CFD results with physical wind tunnel data in the same way. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall process of the method of the present invention; Figure 2 This is a schematic diagram of the two-way closed-loop relationship between target instrument parameters, CFD configuration, measurement transfer operator and uncertainty criterion; Figure 3 This is a schematic diagram of the CFD equivalent test principle of a wind turbine for phase-locked wind tunnel measurement. Figure 4 This is a schematic diagram showing the measurement equivalence criteria relationship under different CFD resolutions; Figure 5 This is a schematic diagram of the system composition of the present invention; Figure 6 This is a schematic diagram illustrating the determination of CFD spatiotemporal resolution under phase-locked measurement constraints. Figure 7 This is a schematic diagram of wind tunnel equivalent data generation based on the measurement transfer operator; Figure 8 This is a flowchart for determining the minimum measurement equivalent CFD resolution and adaptive encryption. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0020] To make the above-mentioned objectives, features and effects of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] This invention provides a CFD equivalent test method for wind turbines based on phase-locked wind tunnel measurements, such as... Figure 1 As shown, firstly, the time resolution required for phase-locking measurement is determined based on the number of wind turbine blades, rotor speed, blade passing frequency, and the number of target phase sub-boxes. This constrains the CFD time step, data writing interval, and phase sampling frequency. Simultaneously, based on the spatial resolution, measurement window, and target measurement area of ​​the target measuring instruments such as the PIV, the local grid scale and refinement range of the CFD are determined in reverse, ensuring that the spatial and temporal resolution of the numerical calculation matches the measurement capabilities of the physical wind tunnel. After obtaining the raw CFD flow field, a measurement transfer operator, incorporating spatial response, time response, phase locking, instrument response, and measurement uncertainty, is constructed to convert the raw CFD flow field into equivalent measurement data corresponding to the observable measurements of the target physical wind tunnel instruments, rather than directly using the raw CFD point values ​​as the wind tunnel test results. Furthermore, for multiple CFD configurations with progressively increasing spatiotemporal resolution, the same measurement transfer operator is used to obtain the corresponding virtual measurement results. The relationship between the changes in virtual measurement results at adjacent resolutions and the overall measurement uncertainty of the target physical instrument is compared. When the changes in virtual measurement results caused by further increasing the CFD spatiotemporal resolution no longer exceed the preset measurement equivalence threshold, further encryption is stopped, and the minimum measurement equivalence CFD resolution that meets the target wind tunnel measurement capability requirements is determined. Through the above method, a synergistic constraint relationship can be established between wind turbine rotation characteristics, physical wind tunnel measurement capability, and CFD spatiotemporal resolution. While ensuring the effectiveness of wind tunnel equivalent measurements, invalid numerical encryption exceeding the actual resolvable capability of the physical instrument is reduced, computational resource consumption is decreased, and a unified CFD configuration basis is provided for subsequent wind turbine phase-locked wake tests and similar wind tunnel equivalent tests.

[0022] The basic principle of this invention is to introduce the actual measurement capabilities of a physical wind tunnel measuring instrument into the modeling, calculation, and accuracy determination process of wind turbine CFD numerical experiments. This allows the spatial resolution, temporal resolution, and data output method of the CFD to be determined not only based on computational experience, residual convergence, or traditional grid independence analysis, but also by the reverse constraints of the physical wind tunnel measurement task to be reproduced. A unified measurement transfer operator is used to convert the original CFD flow field into equivalent measurement results that can be actually observed by the physical instrument. Finally, the comprehensive measurement uncertainty of the physical instrument itself is used to determine whether it is still necessary to further improve the CFD resolution. This establishes a closed-loop correspondence between "wind turbine physical characteristics - wind tunnel measurement capabilities - CFD spatiotemporal resolution - instrument observable results - measurement uncertainty determination," as follows: Figure 2 As shown.

[0023] For rotating wind turbines, the time resolution of phase-locked wind tunnel measurements is primarily constrained by the periodic rotational characteristics of the turbine itself. Let the number of wind turbine blades be B, and the rotor angular velocity be Ω. Then, the blade passage frequency formed by the blades passing through a fixed observation position can be expressed as: .in, Characterizing the primary characteristic frequencies as the rotating blades periodically pass through the measurement area. When the target wind tunnel test employs phase-locked VIV or other phase-synchronous measurement methods, a complete rotation cycle of the rotor is divided into... If there are several phase intervals, then the angular interval between adjacent target phases is: .

[0024] To ensure that CFD calculations can distinguish flow changes between adjacent target phases and obtain a sufficient number of numerical sampling points within each phase interval, each phase interval is required to have at least [number of sampling points]. If there are 10 numerical sampling points, then the CFD time step satisfies: Therefore, the CFD time step is no longer solely determined by the Courant number or solver stability, but is further constrained by the target wind tunnel phase-locked measurement requirements while still satisfying numerical stability. Simultaneously, based on the target instrument's sampling frequency, phase triggering method, and subsequent data statistics requirements, the CFD data writing interval and phase sampling frequency are determined, ensuring that the numerical output fully covers the time scale and phase information required for the target wind tunnel measurement.

[0025] In terms of spatial resolution, physical point-in-velocity (PIV), laser velocimetry, hot-wire probes, or other measuring devices all have finite spatial measurement scales, rather than mathematically infinitesimal point measurements. Taking PIV as an example, its actual measurement results are affected by the measurement window, the correlated region of the particle image, the thickness of the laser sheet, and spatial averaging effects. Therefore, let the equivalent spatial resolution of the target entity measurement system be... Within a single physical measurement unit, at least the following are required: If there are 1 CFD computation unit, then the local CFD grid scale in the target measurement area can satisfy: .in, The parameters are pre-defined based on the target measurement accuracy, flow structure scale, and computational resource conditions. For areas with large local gradients, such as the near-wake of the wind turbine, tip vortices, and shear layers, local mesh refinement areas can be set in conjunction with the target PIV measurement plane or measurement volume, without needing to perform uniform refinement to the same degree across the entire computational domain.

[0026] After completing the CFD calculations, this invention does not directly use the velocity, pressure, or load values ​​at the calculation nodes as equivalent results of the wind tunnel test. Instead, it constructs a measurement transfer operator corresponding to the target entity wind tunnel instrument. Let the high-dimensional original flow field obtained from CFD calculation be... Then the virtual measurement result M corresponding to the target instrument is represented as: Measurement transfer operator This is used to describe the transformation relationship between the original CFD flow field and the observable measurement of the target instrument. It can include at least one or more of the following: spatial response, time response, phase response, instrument dynamic response, calibration relationship, and data filtering. The measurement uncertainty of the target instrument is used as the measurement capability parameter corresponding to the measurement transfer process for subsequent measurement equivalence determination.

[0027] Specifically, the spatial response is used to simulate the limited measurement volume, measurement window, and spatial averaging effect of the physical instrument; the time response is used to simulate the sampling frequency, exposure time, integration time, and time averaging process; the phase response is used to perform phase binning and phase locking based on the rotor angular position; and the instrument response is used to characterize the frequency response, calibration relationship, and data filtering characteristics of the actual sensor. Through the above transformation, the raw CFD flow field is mapped to the data space that the physical wind tunnel instrument can actually obtain.

[0028] This embodiment illustrates a measurement transfer operator. Implementation method: Let the original CFD flow field be... First, based on the measurement position, measurement window, or measurement volume of the target instrument, the original CFD flow field is spatially mapped to obtain:

[0029] in, The measurement area corresponding to the physical instrument. This is the spatial response weighting function. Subsequently, based on the target instrument's sampling frequency, integration time, and phase-locking condition, the following is applied: Time sampling and phase processing are performed. For phase-locked measurements, one rotor cycle is divided into... There are several phase intervals, with the phase spacing being:

[0030] CFD data that meet the same phase condition are sampled or averaged to form virtual measurement data corresponding to the target physical instrument. Finally, the above data is transformed according to the calibration relationship, frequency response, and data filtering rules of the target instrument to obtain the final virtual instrument observable measurement M.

[0031] Simultaneously, the overall measurement uncertainty is determined based on the measurement accuracy, calibration error, and repeatability characteristics of the target instrument. The overall measurement uncertainty This data is used for subsequent CFD measurement equivalence determination. Therefore, this invention does not directly use the instantaneous velocity, pressure, or load values ​​at the CFD grid nodes as the equivalent results of the wind tunnel test. Instead, it uses a unified measurement transfer operator to convert the original CFD flow field into wind tunnel equivalent data corresponding to the measurement characteristics of the target entity's wind tunnel instruments.

[0032] For example, when the target instrument is a phase-locked PIV, the three-dimensional transient CFD velocity field can be converted into equivalent PIV velocity data within a specific measurement plane, a specific phase, and a specific spatial window. The result can be expressed as follows: , When the target instrument is a hot-wire velocimetry device, a velocity-time series consistent with the hot-wire sampling frequency, probe volume, and time response can be obtained through corresponding measurement operators. When the target device is a wind tunnel force or torque measurement system, the data can be obtained according to the corresponding measurement coordinate system, time averaging method, and data processing rules. In addition, observable measurements such as thrust coefficient and power coefficient are also included. Therefore, the "wind tunnel equivalent measurement data" in this invention refers to the numerical results constrained by the measurement characteristics of the target entity instrument, rather than a simple extraction or direct output of the original CFD flow field data.

[0033] To determine the required CFD resolution for the target wind tunnel measurement task, this invention further establishes a multi-resolution hierarchical comparison mechanism. This involves sequentially constructing CFD configurations with progressively increasing spatiotemporal resolution. The corresponding original CFD flow fields were obtained respectively. Applying the exact same target measurement transfer operator to CFD flow fields at different resolutions. To ensure consistency in measurement location, measurement volume, sampling frequency, phase conditions, and data filtering methods, the following results were obtained. , and .

[0034] The variation in results between adjacent CFD configurations within the target instrument's observable space was then calculated: ,as well as For velocity fields, vector fields, or multi-point measurement data, the difference can also be calculated using root mean square error, normalization norm, regional average difference, maximum difference, or other indicators that can reflect the degree of change in the target measurement quantity, rather than being limited to a single scalar absolute difference.

[0035] Let the overall measurement uncertainty of the wind tunnel measurement system for the target entity be... Then define the measurement equivalence judgment parameter: , And set a predetermined measurement equivalent threshold K. When and At this point, it was determined that the changes in the virtual measurement results of the target caused by further increasing the spatiotemporal resolution of CFD had already entered the range limited by the resolvability of the physical instrument itself. Under this condition, even if the grid scale or time step was further reduced, the resulting changes in numerical results would hardly constitute an increment with practical measurement significance for the wind tunnel measurement task of the target entity, therefore further densification could be stopped.

[0036] If the above measurement equivalence criteria are not met, the CFD resolution is further increased based on the type of error that did not meet the requirements. For example, when the spatial measurement results differ significantly, further local mesh refinement is implemented in the target measurement area; when the phase or time variation differs significantly, the time step is further reduced, the phase sampling density is increased, or the data writing frequency is increased. After the adjustments are completed, a new CFD configuration is generated and run again, repeating the process of "CFD solution - measurement transfer - result comparison - uncertainty determination" until the measurement equivalence conditions are met, such as... Figure 4 As shown.

[0037] Among multiple progressively increasing CFD configurations, this invention defines the lowest spatiotemporal resolution configuration that first satisfies the preset measurement equivalence conditions as the minimum measurement equivalent CFD resolution. This resolution represents the minimum computational configuration required to achieve equivalent CFD numerical results in terms of physical wind tunnel measurement capabilities, under specific conditions of wind turbine, measurement location, target instrument, and measurement task. This does not mean that the original CFD flow field has reached absolute convergence in a mathematical sense, but rather that the changes in observable results resulting from further increasing the CFD resolution are below the level that the target entity instrument can effectively distinguish.

[0038] like Figure 3 As shown, this invention uses a physical wind tunnel phase-locked measurement target and rotating wind turbine parameters as pre-inputs for CFD equivalent experiments. The physical measurement target includes at least the measurement area and spatial resolution. Time resolution Overall measurement uncertainty and the number of phase sub-boxes The wind turbine parameters should include at least the number of blades B, the rotor angular velocity Ω, and the blade passing frequency derived therefrom. The above parameters are first used to back-calculate the CFD time step, local mesh scale, and result output frequency, and then transferred through the target measurement operator. The raw CFD flow field is converted into virtual PIV measurement results. The differences between measurement results at adjacent CFD resolution levels are compared with... Comparisons were made to determine whether to continue improving the spatiotemporal resolution of CFD.

[0039] like Figure 6As shown, the CFD temporal resolution is constrained by the wind turbine rotation characteristics, phase binning requirements, and minimum number of samples per phase, while the spatial resolution is constrained by the target PIV measurement window and the spatial measurement resolution. The temporal and spatial constraints together form the initial equivalent CFD configuration, ensuring that the grid, time step, write frequency, and local refinement range directly correspond to the target wind tunnel measurement capabilities.

[0040] like Figure 7 As shown, the high-dimensional raw flow fields such as U, V, W, and p obtained from CFD calculations are not directly used as wind tunnel test measurement results, but are instead transferred through the measurement transfer operator. After processing for spatial response, time response, phase response, instrument response, and measurement uncertainty, observable data for the physical instrument are generated. Phase-locked PIV, velocity probe / hot wire, and force / torque measurements can all be constructed according to their respective measurement characteristics. This results in the formation of a wind tunnel equivalent test dataset containing information on operating conditions, measurement locations, sampling frequencies, and uncertainty elements.

[0041] like Figure 8 As shown, for CFD configurations that are progressively upgraded use the same target instrument measurement operator. ,get Calculate the differences between adjacent measurement results. and And the uncertainty is comprehensively measured by the target entity instrument. Normalization is performed to obtain and When both judgment variables are not greater than the preset equivalent measurement threshold K, further encryption is stopped and the minimum configuration that meets the condition is determined. Otherwise, the iteration continues by refining the local mesh, reducing the time step, increasing the number of phase samples, or adjusting the data writing frequency. The core of this criterion is to compare the virtual measurement results after the same measurement operator is applied, rather than simply comparing the original CFD field or solving the residuals.

[0042] Example 1: A scaled-down wind tunnel test of a 10MW three-bladed horizontal axis wind turbine is used as an example. The full-size reference rotor diameter is 220m, and the model rotor diameter is 2.2m when using a 1:100 geometric scaled-down model. Assuming the model rotor angular velocity Ω = 62.83 rad / s (approximately 600 r / min) and the number of blades B = 3, the blade passing frequency is approximately 30Hz. The target measurement task is to perform phase-locked VIV measurements at 1D, 3D, and 5D sections downstream of the rotor. The following values ​​are only used to illustrate the criterion execution logic of this invention and do not indicate that a physical wind tunnel comparison test has been completed.

[0043]

[0044] The target PIV is configured with 72 rotor azimuth phase sub-cells, so the width of each phase sub-cell is 5°. The equivalent spatial resolution scale of the PIV is taken as... Equivalent time resolution scale The overall uncertainty of speed measurement is taken as Set the spatial oversampling coefficient. Phase oversampling coefficient This results in a local initial mesh size of no more than 1.25 mm; the upper limit of the time step corresponding to the phase constraint is approximately 0.694 ms. After synthesizing the PIV time response, an initial time step of 0.5 ms can be selected.

[0045]

[0046]

[0047] Establish first-level configuration The local grid size for the PIV target measurement area is 1.25 mm, and the time step is 0.5 ms; Level 2 Local mesh size 0.90 mm, time step 0.35 ms; Level 3 The local mesh size is 0.65 mm, and the time step is 0.25 ms. Except for the spatiotemporal resolution, the geometry, boundary conditions, fan speed, turbulence model, and phase definition remain consistent across all levels.

[0048] The same PIV measurement transfer operator is applied to the raw CFD flow field for each stage. This operator first performs spatial averaging within the equivalent interrogation window and laser sheet thickness range, then performs temporal averaging based on the target PIV exposure / time response, and finally performs phase averaging based on 72 rotor azimuth phase bins to obtain the phase-locked velocity field of each measurement plane.

[0049] Assuming the equivalent velocities at the center of the 3D wake in a certain phase are respectively =6.842m / s =6.795m / s =6.781m / s, then:

[0050]

[0051] Under the condition that the threshold is 1, It cannot meet the measurement equivalence requirements. With a higher level The difference is less than the target PIV velocity measurement uncertainty, therefore It can be used as a candidate minimum measurement equivalent resolution; when improved robustness is required, it can be re-established. A review will be conducted. Then, [the process will be adopted]. The corresponding local mesh, time step, and result output settings execute the remaining phase and wind speed conditions without increasing the entire computational domain. The resolution.

[0052] Example 2: Under the condition that the wind turbine yaw angle is not zero, the wake center shifts laterally with the downstream distance. First, a coarse wake center trajectory is obtained using a CFD configuration that satisfies the initial measurement constraints. Then, the measurement window for each downstream section is determined based on the target PIV measurement plane size and safety margin. The local mesh refinement area shifts or expands, while other locations in the computational domain maintain lower resolution. Subsequently, the same PIV measurement transfer operator and uncertainty criterion are used to determine the corresponding operating condition. This method ensures that the encrypted region is determined by the area visible to the target entity, rather than the entire wake computation domain. .

[0053] Example 3: When the target device is a hot-wire velocimeter, the measurement transfer operator may include spatial averaging within the probe's sensitive length, the probe's frequency response function, sampling frequency, and calibration curve; when the target device is a scanning lidar, the measurement transfer operator may include velocity projection along the line-of-sight direction, weighted average of the probe volume, and scanning dwell time; when the target device is a six-component balance, the force / torque obtained by integrating the CFD surface pressure and viscous stress can be further converted into equivalent observables according to the balance coordinate system, sampling period, and calibration matrix. For the above measuring devices, the method of "comparing the difference between equivalent measurement results at adjacent CFD resolution levels with the corresponding instrument's overall measurement uncertainty" can be used to determine the measurement. .

[0054] Example 4: A wind turbine CFD equivalent test system for performing the above method, such as Figure 5 As shown, it includes: a task and instrument parameter input module for reading wind turbine parameters and target measurement tasks; a CFD resolution inverse calculation module for generating initial CFD spatiotemporal constraints based on blade passing frequency, phase resolution, and instrument metrology parameters; a CFD configuration and solution module for generating and executing CFD calculations for rotating wind turbines at different resolution levels; a measurement transfer operator module for converting the original flow field into observable data for the target instrument; a measurement equivalence determination module for comparing the differences between equivalent measurement results at adjacent resolution levels with the overall measurement uncertainty of the target instrument; an adaptive encryption module for increasing the spatial and / or temporal resolution of the target measurement area when the criteria are not met; and an equivalent test data output module for outputting data after determining the required parameters. The output includes equivalent wind tunnel measurement data and corresponding metadata.

[0055] Example 5: The computer-readable storage medium of this example stores a computer program that, when executed by a processor, implements the steps in the wind turbine CFD equivalent test method for phase-locked wind tunnel measurement in Example 1.

[0056] The computer-readable storage medium in this embodiment can be an internal storage unit of the terminal, such as the terminal's hard disk or memory; the computer-readable storage medium in this embodiment can also be an external storage device of the terminal, such as a plug-in hard disk, smart memory card, secure digital card, flash memory card, etc. equipped on the terminal; furthermore, the computer-readable storage medium can include both the terminal's internal storage unit and external storage devices.

[0057] The computer-readable storage medium of this embodiment is used to store computer programs and other programs and data required by the terminal. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0058] Example 6: The computer device of this example includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the wind turbine CFD equivalent test method for phase-locked wind tunnel measurement in Example 1.

[0059] In this embodiment, the processor can be a central processing unit, or other general-purpose processors, digital signal processors, application-specific integrated circuits, off-the-shelf programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc. The memory can include read-only memory and random access memory, and provides instructions and data to the processor. A portion of the memory can also include non-volatile random access memory. For example, the memory can also store device type information.

[0060] Those skilled in the art will clearly understand that each implementation can be achieved using software plus the necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A CFD equivalent test method for wind turbines based on phase-locked wind tunnel measurements, characterized in that, Includes the following steps: S1, acquire the number of blades, rotor angular velocity, and target wind tunnel measurement task of the rotating wind turbine. The target wind tunnel measurement task includes at least the spatial resolution scale, time resolution scale, comprehensive measurement uncertainty, and phase bin parameters of the target entity measurement device. S2, determine the blade passing frequency based on the number of blades and rotor angular velocity, and combine the phase box parameters, spatial resolution scale and time resolution scale to determine the initial CFD spatial resolution, initial CFD time step and result output parameters of the target measurement area; S3, perform unsteady CFD calculations on the rotating wind turbine according to the nth-level CFD configuration to obtain the original flow field of the nth-level target measurement area; S4, using the measurement transfer operator corresponding to the target entity measurement device to perform spatial measurement scale action and time or phase sampling action on the original flow field to obtain the nth level equivalent measurement data; S5, while keeping the wind turbine geometry, test conditions and target wind tunnel measurement tasks unchanged, improve the spatial resolution and / or temporal resolution of the target measurement area to form the (n+1)th level CFD configuration, and obtain the (n+1)th level equivalent measurement data through the same measurement transfer operator; S6. Based on the difference between the equivalent measurement data of level n and level n+1 and the comprehensive measurement uncertainty of the target entity measurement device, a measurement equivalence criterion is formed. When the measurement equivalence criterion is greater than a preset threshold, the CFD resolution is further increased. When the measurement equivalence criterion is not greater than the preset threshold, the lowest resolution level is determined from the CFD configurations that satisfy the measurement equivalence criterion as the minimum measurement equivalent CFD resolution. S7. Perform the wind turbine CFD equivalent test corresponding to the target wind tunnel measurement task using the minimum measurement equivalent CFD resolution, and output wind tunnel equivalent measurement data consistent with the observable definition of the target entity measurement device through the measurement transfer operator.

2. The CFD equivalent test method for wind turbines based on phase-locked wind tunnel measurement according to claim 1, characterized in that, The target entity measurement device is a phase-locked particle image velocimetry (PIV) device; the spatial resolution scale is determined by the PIV interrogation window, the thickness of the laser sheet, or the equivalent measurement volume; and the phase sub-bin parameters are determined by the number of rotor azimuth sub-bins or the phase synchronization accuracy.

3. The wind turbine CFD equivalent test method for phase-locked wind tunnel measurement according to claim 2, characterized in that, The measurement transfer operator includes at least: spatial integration or weighted averaging of the PIV interrogation window or equivalent measurement volume; temporal application of exposure, sampling interval or instrument time response; and phase binning and phase averaging according to the rotor azimuth angle.

4. The CFD equivalent test method for wind turbines based on phase-locked wind tunnel measurement according to claim 1, characterized in that, The measurement equivalence criterion is: ,in For the (n+1)th level equivalent measurement data, For the nth level equivalent measurement data, To comprehensively measure uncertainty, when The system determines that the corresponding CFD configuration meets the measurement equivalence requirements, where K is a preset threshold.

5. The CFD equivalent test method for wind turbines based on phase-locked wind tunnel measurement according to claim 4, characterized in that, Establish at least one higher resolution level for verification; when the verification result still meets the measurement equivalence criterion, the lowest resolution level that first meets the criterion is determined as the minimum measurement equivalent CFD resolution.

6. The CFD equivalent test method for wind turbines based on phase-locked wind tunnel measurement according to claim 1, characterized in that, When the target operating condition is the yaw fan operating condition, the position of the target measurement window is determined based on the wake center position obtained from the previous CFD calculation, and the local densification range of the target measurement area is updated with the position of the target measurement window.

7. The CFD equivalent test method for wind turbines based on phase-locked wind tunnel measurement according to claim 1, characterized in that, The wind tunnel equivalent measurement data includes at least one of the following: phase-locked velocity, velocity deficit, vortex core position, phase-averaged turbulence statistics, thrust or torque, and is stored together with the minimum measurement equivalent CFD resolution, target entity measurement device parameters, phase settings, and comprehensive measurement uncertainty.

8. A CFD equivalent test method for wind turbines based on phase-locked wind tunnel measurements, characterized in that, It includes a task and instrument parameter input module, a CFD resolution inverse calculation module, a CFD configuration and solution module, a measurement transfer operator module, a measurement equivalence determination module, an adaptive encryption module, and an equivalent test data output module; wherein each module is configured to collaboratively execute the method described in any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the wind turbine CFD equivalent test method for phase-locked wind tunnel measurement as described in any one of claims 1-7.

10. A computer device comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the wind turbine CFD equivalent test method for phase-locked wind tunnel measurement as described in any one of claims 1-7.

Images