New tip loss correction calculation method based on shen tip loss model

Abstract

The application proposes a new tip loss correction calculation method based on the Shen tip loss model, including: step 1: reading user input parameters; step 2: coupling the Shen tip loss correction model to the wind turbine simulation tool OpenFAST; step 3: calculating the general correction factor according to the user input parameters; step 4: according to the tip loss correction requirement, selecting one of the Shen tip loss correction model and the Prandtl model in the wind turbine simulation tool OpenFAST, and combining the general correction factor to correct the stress and displacement of the tip position under high tip speed ratio, and completing the tip loss correction calculation. The application couples the Shen tip loss correction model to OpenFAST, proposes a new tip loss correction calculation method, and calculates the stress and displacement of the tip position more accurately under high tip speed ratio, filling the gap of OpenFAST in this field.

Description

Technical Field

[0001] This invention relates to a novel tip loss correction calculation method based on the Shen tip loss model, belonging to the field of wind turbine aerodynamic design and optimization technology. Background Technology

[0002] OpenFAST is an open-source software tool for the integrated design and analysis of wind turbines, widely used in the simulation and optimization of aerodynamics, structural dynamics, and control systems in the wind power industry. This tool primarily uses blade element momentum theory to calculate the aerodynamic performance of wind turbine blades, and introduces the Prandtl tip loss correction model to account for the impact of tip effects on aerodynamic performance. However, its calculation accuracy has certain limitations at high tip speed ratios, which can easily lead to inaccurate aerodynamic performance predictions.

[0003] To address this issue, the Shen tip loss correction model was developed. Compared with traditional correction models, the Shen correction model can more accurately describe the generation and drag near the tip, thereby improving the accuracy of aerodynamic performance prediction for wind turbines under this operating condition.

[0004] The key point of this invention is to couple the Shen tip loss correction model into OpenFAST, optimizing the aerodynamic calculation capabilities of the existing tool to achieve more accurate simulation and analysis under high tip speed ratio conditions. This innovation not only fills a gap in OpenFAST's capabilities in this field but also provides new technical support for the design and performance optimization of large blades, especially floating wind turbines. Summary of the Invention

[0005] This invention addresses the technical problem that the OpenFAST wind turbine simulation tool has limited calculation accuracy under high tip speed ratios, leading to inaccurate aerodynamic performance predictions. Therefore, it proposes a novel tip loss correction calculation method based on the Shen tip loss model.

[0006] The technical solution adopted by this invention to solve the above problems is as follows: This invention proposes a novel tip loss correction calculation method based on the Shen tip loss model, including:

[0007] Step 1: Read user input parameters;

[0008] Step 2: Couple the Shen tip loss correction model into the wind turbine simulation tool OpenFAST;

[0009] Step 3: Calculate the general correction factor based on the user input parameters;

[0010] Step 4: Based on the tip loss correction requirements, select either the Shen tip loss correction model or the Prandtl model in the wind turbine simulation tool OpenFAST. Combine the general correction factor to correct the force and displacement of the tip position under the high tip speed ratio condition, and complete the tip loss correction calculation.

[0011] Optionally, the user input parameters in step 1 include blade inflow parameters, airfoil parameters, lift and drag coefficients corresponding to the airfoil parameters, number of blades, blade rotation speed, blade radius, blade geometry, blade element node position, number of blades, blade inflow angle, and blade local velocity components.

[0012] Optionally, the steps for obtaining the general correction factor in step 3 include:

[0013] Step 3.1: Read the inflow air parameters, airfoil parameters, and lift and drag coefficients corresponding to the airfoil parameters, initialize the fan speed, and calculate the average inflow air velocity;

[0014] Step 3.2: Calculate the tip speed ratio λ based on the average inflow velocity, blade rotation speed, and blade radius;

[0015] Step 3.3: Calculate the tip loss correction constant based on the leaf geometry, leaf element node position, and number of leaves;

[0016] Step 3.4: Calculate the universal correction factor based on the tip loss correction constant and the blade inflow angle;

[0017] The formula for calculating the average air velocity is:

[0018]

[0019] In formula (1), V0 is the average inflow velocity, V xi The local velocity component of the blade along the thrust direction corresponds to the blade, and B is the number of blades;

[0020] The formula for calculating the tip speed ratio λ is:

[0021]

[0022] In formula (2), Ω is the blade rotation speed and R is the blade radius;

[0023] The formula for calculating the tip loss correction constant is:

[0024]

[0025] In formula (3), t is the tip loss correction constant and r is the span of the node to be calculated in the blade;

[0026] The formula for calculating the correction factor is:

[0027]

[0028] In formula (4), f is a general correction factor and Φ is the blade inflow angle.

[0029] Optionally, step 4, which involves selecting the Shen tip loss correction model to correct the force and displacement at the tip position under high tip speed ratio conditions, includes the following steps:

[0030] Step 4.1: Calculate the Shen correction factor g based on the number of blades and the tip speed ratio λ;

[0031] Step 4.2: Calculate the tip loss correction factor F based on the Shen correction factor g and the general correction factor;

[0032] Step 4.3: Correct the force and displacement of the blade tip position under high tip speed ratio conditions based on the tip loss correction factor F;

[0033] The formula for calculating the Shen correction factor g is:

[0034] g = e -0.125(Bλ-21)+0.1 (5);

[0035] The formula for calculating the tip loss correction factor F is:

[0036]

[0037] Optionally, in step 4, the Prandtl model is selected to correct the force and displacement at the blade tip position under the high tip speed ratio condition. Specifically, this includes:

[0038] By inputting a general correction factor into the Prandtl model and combining it with the simulation function of the wind turbine simulation tool OpenFAST, the force and displacement at the blade tip position under high tip speed ratio conditions are corrected.

[0039] The beneficial effects of this invention are:

[0040] 1. This invention couples the Shen tip loss correction model into OpenFAST and proposes a new tip loss correction calculation method, which calculates the force and displacement of the tip position more accurately under high tip speed ratio conditions, filling the gap in OpenFAST in this field.

[0041] 2. This invention couples the Shen tip loss correction model to OpenFAST and integrates it with other simulation software, enabling it to be applied to multiple fields for accurate prediction of aerodynamic performance, providing new technical support for the design and performance optimization of large blades, especially floating wind turbines. Attached Figure Description

[0042] Figure 1 A flowchart of a novel tip loss correction calculation method based on the Shen tip loss model provided by this invention;

[0043] Figure 2 A comparison diagram of tip displacements in two different directions, flapping and twitching, calculated using the Shen tip loss model and the Wilson tip loss model, provided for this invention.

[0044] Figure 3 A comparison diagram of the blade stress obtained by the tip loss-free result, the Wilson tip loss model calculation result, and the Shen tip loss model calculation result provided by this invention. Detailed Implementation

[0045] Combination Figure 1 This embodiment will be described as follows: Figure 1 As shown, the steps of the novel tip loss correction calculation method based on the Shen tip loss model described in this embodiment include:

[0046] S1: Couple the Shen tip loss correction model to the wind turbine simulation tool OpenFAST and read user input data;

[0047] User input parameters include blade inflow parameters, airfoil parameters, lift and drag coefficients corresponding to the airfoil parameters, number of blades, blade rotation speed, blade radius, blade geometry, blade element node position, number of blades, blade inflow angle, and blade local velocity components.

[0048] S2: Read the inflow air parameters and airfoil parameters of the blades and their corresponding lift and drag coefficients, initialize the fan speed, and calculate the average inflow air velocity.

[0049] The formula for calculating the average air velocity is:

[0050]

[0051] In formula (1), V0 is the average inflow velocity, V xi The local velocity component of the blade along the thrust direction corresponds to the blade, and B is the number of blades;

[0052] S3: Calculate the tip speed ratio λ;

[0053] The formula for calculating the tip speed ratio λ is:

[0054]

[0055] In formula (2), Ω is the blade rotation speed and R is the blade radius.

[0056] S4: Calculate the tip loss correction constant;

[0057] The tip loss correction constant can also be applied to other tip loss correction methods. The formula for calculating the tip loss correction constant is:

[0058]

[0059] In formula (3), t is the tip loss correction constant and r is the span of the node to be calculated in the blade.

[0060] S5: Calculate the general correction factor;

[0061] The universal correction factor is related to leaf geometry, leaf element node position, and leaf number. The formula for calculating the universal correction factor is:

[0062]

[0063] In formula (4), f is a general correction factor and Φ is the blade inflow angle.

[0064] S6: Select either the Shen tip loss correction model or the Prandtl model in the wind turbine simulation tool OpenFAST to correct the force and displacement at the tip position under high tip speed ratio conditions and complete the tip loss correction calculation.

[0065] Among them, the Shen tip loss correction model corrects the force and displacement of the tip position under high tip speed ratio conditions, specifically including: calculating the Shen correction factor g;

[0066] The formula for calculating the Shen correction factor g is:

[0067] g = e -0.125(Bλ-21)+0.1 (5);

[0068] Calculate the tip loss correction factor F;

[0069] The formula for calculating the tip loss correction factor F is:

[0070]

[0071] The Prandtl model corrects the forces and displacements at the blade tip position under high tip speed ratio conditions, specifically including:

[0072] By inputting a general correction factor into the Prandtl model and combining it with the simulation function of the wind turbine simulation tool OpenFAST, the force and displacement at the blade tip position under high tip speed ratio conditions are corrected.

[0073] This invention couples the Shen tip loss correction model into OpenFAST and proposes a new tip loss correction calculation method. This method can more accurately calculate the force and displacement at the tip position under high tip speed ratio conditions, filling the gap in OpenFAST in this field.

[0074] Example

[0075] Combination Figure 2-3 This embodiment will be described in detail. To verify the technical effect of the present invention, the following experiment was conducted in this embodiment:

[0076] This embodiment uses a DTU-10MW wind turbine model at a wind speed of 11.4 m / s and a rotational speed of 9.6 rpm. The Wilson tip loss model and the Shen tip loss model are used to calculate the tip displacement in two different directions: flapping and swaying. The results are as follows: Figure 2 As shown, the blade tip displacement calculated by the two tip loss correction models under the same working conditions differs.

[0077] The normal and tangential forces at different blade span positions were calculated using the Wilson and Shen tip loss models for tip speed ratios of 7.86 and 11.2, respectively. Values ​​were calculated at 10%, 22%, 31%, 53%, 60%, 93%, and 95% of the blade span. The results without tip loss, the Wilson tip loss model, and the Shen tip loss model were compared. Figure 3 As shown. By calculating the normal and tangential forces at different span positions of a 10MW wind turbine blade under different tip speed ratios, it is concluded that under small tip speed ratios, the calculation results of the Wilson tip loss model and the Shen tip loss model are basically consistent. Under large tip speed ratios, the calculation results of the Shen tip loss model are closer to the actual blade forces than those of the Wilson tip loss model.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A method for calculating tip loss correction based on the Shen tip loss model, characterized in that, The steps of the novel tip loss correction calculation method based on the Shen tip loss model include: Step 1: Read user input parameters; Step 2: Couple the shen tip loss correction model into the wind turbine simulation tool OpenFAST; Step 3: Calculate the general correction factor based on the user input parameters; Step 3, obtaining the general correction factor, includes the following steps: Step 3.1: Read the inflow air parameters, airfoil parameters, and lift and drag coefficients corresponding to the airfoil parameters, initialize the fan speed, and calculate the average inflow air velocity; Step 3.2: Calculate the tip speed ratio based on the average inflow velocity, blade rotation speed, and blade radius. ; Step 3.3: Calculate the tip loss correction constant based on the blade geometry, leaf element node position, and number of blades; Step 3.4: Calculate the universal correction factor based on the tip loss correction constant and the blade inflow angle; The formula for calculating the average air velocity is: （1）； In formula (1), For the average inflow velocity, The local velocity component of the blade along the thrust direction corresponds to the blade, and B is the number of blades; Tip speed ratio The calculation formula is: （2）； In formula (2), For blade rotation speed, Where is the blade radius; The formula for calculating the tip loss correction constant is: （3）； In formula (3), This is the correction constant for tip loss. Let be the span of the node to be calculated in the blade; The formula for calculating the general correction factor is: （4）； In formula (4), As a general correction factor, The blade inlet angle; Step 4: Based on the tip loss correction requirements, select either the Shen tip loss correction model or the Prandtl model in the wind turbine simulation tool OpenFAST. Combine the general correction factor to correct the force and displacement of the tip position under the high tip speed ratio, and complete the tip loss correction calculation. Step 4 involves selecting the Shen tip loss correction model to correct the force and displacement at the tip position under high tip speed ratio conditions. This includes: Step 4.1: Based on the number of blades and the tip speed ratio The Shen correction factor g is calculated. Step 4.2: Calculate the tip loss correction factor F based on the Shen correction factor g and the general correction factor; Step 4.3: Correct the force and displacement of the blade tip position under high blade tip speed ratio based on the blade tip loss correction factor F; The formula for calculating the Shen correction factor g is: （5）； The formula for calculating the tip loss correction factor F is: （6）。 2. The tip loss correction calculation method based on the Shen tip loss model according to claim 1, characterized in that, In step 1, the user input parameters include blade inflow parameters, airfoil parameters, lift and drag coefficients corresponding to the airfoil parameters, number of blades, blade rotation speed, blade radius, blade geometry, blade element node position, number of blades, blade inflow angle, and blade local velocity components.

3. The tip loss correction calculation method based on the Shen tip loss model according to claim 1, characterized in that, Step 4 involves selecting the Prandtl model to correct the forces and displacements at the blade tip position under high tip speed ratio conditions. Specifically, this includes: The general correction factor is input into the Prandtl model, and the force and displacement at the blade tip position under high tip speed ratio conditions are corrected by combining the simulation function of the wind turbine simulation tool OpenFAST.

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