A Method for Measuring the Wing Torsion Angle of a Wind Tunnel Test Model

Abstract

The present invention discloses a method for measuring the wing twist angle of a wind tunnel test model, belonging to the technical field of wind tunnel tests. It solves the problem that the accuracy of the wind tunnel test results is relatively low due to the limitations of the measurement equipment in the traditional wing twist angle measurement method in the prior art; the present invention mounts the pressure measurement model in the wind tunnel through a support to complete the preparatory work for the subsequent dynamic pressure test; based on the fixed Mach number and Reynolds number in the same set of tests, by conducting high dynamic pressure and low dynamic pressure tests, collecting the pressures of the pressure measurement points on each section at multiple angles of attack, and calculating two sets of pressure coefficients and lift coefficients; obtaining the relationship between the ratio of the angle of attack and the dynamic pressure of the pressure measurement model and the lift coefficient of the pressure measurement model, and obtaining the coefficients of a linear function; substituting them into the calculation formula of the twist angle of the pressure measurement model to obtain the value of the twist angle of the pressure measurement model. The present invention effectively reduces the wing twist angle error, thereby improving the accuracy and reliability of the wind tunnel test results, and can be applied to measuring the wing twist angle.

Description

Technical Field

[0001] The present invention relates to a method for measuring the wing twist angle, and particularly to a method for measuring the wing twist angle of a wind tunnel test model, belonging to the technical field of wind tunnel tests. Background Art

[0002] During the wind tunnel test, the test scaled model is installed in the flow field center area of the wind tunnel test section through a support mechanism, and special equipment such as a balance or a scanning valve is used to measure the aerodynamic load received by the test model, so as to obtain the aerodynamic characteristics of the model. Generally, the angle of attack, sideslip angle and roll angle of the model are obtained by means of angle sensors and video measurements.

[0003] For an aircraft model in a wind tunnel test, especially a high aspect ratio aircraft model, the wing will produce elastic deformations when subjected to loads, including bending deformation and torsional deformation. Among them, when the wing undergoes torsional deformation, the local angle of attack of the wing changes, which will have a significant impact on the aerodynamic characteristics of the aircraft test model. In order to obtain the relationship between the accurate aerodynamic characteristics of the model and the model angle, it is necessary to obtain the twist angle of the test model wing so as to correct the aerodynamic data of the model.

[0004] In the prior art, the twist of the model wing is obtained by solving the photos of the aircraft model in the windy and windless states at different attitude angles collected by the deformation measurement camera of the binocular vision system. However, the existing method of measuring the wing deformation by the binocular vision system requires painting or pasting marking points on the surface of the test model, and at the same time has high requirements for the position and viewing angle of the camera. After the camera position is fixed, only the wing deformation within the viewing angle range of the camera can be measured. If the roll angle of the test model changes, it takes a lot of time to re-adjust and calibrate the camera position and viewing angle. In addition, it is impossible to accurately measure in the case of an occlusion at the measurement position or when the model vibrates.

[0005] In summary, a method for measuring the wing twist angle of a wind tunnel test model is needed. Summary of the Invention

[0006] A brief overview of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify the key or important parts of the present invention, nor is it intended to limit the scope of the present invention. Its purpose is only to present some concepts in a simplified form as a prelude to the more detailed description to be discussed later.

[0007] In view of this, in order to solve the problem of low accuracy of the wind tunnel test results caused by the limitations of the measurement equipment in the traditional wing twist angle measurement method in the prior art, the present invention provides a method for measuring the wing twist angle of a wind tunnel test model.

[0008] The technical solution is as follows: A method for measuring the wing twist angle of a wind tunnel test model, comprising the following steps:

[0009] S1. Mount the pressure measurement model in the wind tunnel through a support to complete the preparation work for subsequent dynamic pressure tests;

[0010] S2. Based on the fixed Mach number and Reynolds number in the same set of tests, by conducting high dynamic pressure tests and low dynamic pressure tests, collect the pressures of the pressure measurement points on each section at multiple angles of attack, and calculate two sets of pressure coefficients and lift coefficients;

[0011] S3. According to the two sets of pressure coefficients and lift coefficients, obtain the calculation formula for the twist angle of the pressure measurement model, and obtain the relationship between the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficient of the pressure measurement model, and obtain the coefficients of the linear function;

[0012] S4. Substitute the coefficients of the linear function into the calculation formula for the twist angle of the pressure measurement model to obtain the value of the twist angle of the pressure measurement model.

[0013] Further, in S3, it specifically includes the following steps:

[0014] S31. According to the local angle of attack of the pressure measurement model section that is the same under the same Mach number, the same Reynolds number, and different dynamic pressures, obtain the relationship between the local angle of attack of the pressure measurement model section in the high dynamic pressure test and the low dynamic pressure test and the twist angle of the pressure measurement model section;

[0015] S32. According to the relationship between the twist angle of the pressure measurement model section and the dynamic pressure and lift, obtain the calculation formula for the twist angle of the pressure measurement model;

[0016] S33. According to the fact that the lift coefficient of the pressure measurement model is the same under the same Mach number and the same Reynolds number, obtain the relationship between the lift coefficients of the pressure measurement model in the high dynamic pressure test and the low dynamic pressure test;

[0017] S34. According to the results obtained in steps S31 to S33, obtain the relationship between the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficient of the pressure measurement model;

[0018] S35. Perform linear regression calculations on the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficients of each section of the pressure measurement model at multiple angles of attack in the two test states of high dynamic pressure and low dynamic pressure, and fit to obtain the coefficients of the linear function, that is, the slope a and the constant term b;

[0019] In S31, the relationship between the local angle of attack of the pressure measurement model section and the twist angle of the pressure measurement model section is expressed as:

[0020] ;

[0021] ;

[0022] Among them, is the local angle of attack of the pressure measurement model profile, is the angle of attack of the pressure measurement model during high dynamic pressure tests, is the angle of attack of the pressure measurement model during low dynamic pressure tests, is the model profile torsion angle during high dynamic pressure tests, is the model profile torsion angle during low dynamic pressure tests;

[0023] In the above S32, the calculation formula for the torsion angle of the pressure measurement model is expressed as:

[0024] ;

[0025] Among them, is the slope of the linear function, is the lift coefficient of the pressure measurement model, is the constant term of the linear function, is the dynamic pressure;

[0026] In the above S33, the relationship between the lift coefficients of the pressure measurement model during high and low dynamic pressure tests is expressed as:

[0027] ;

[0028] Among them, is the lift coefficient of the pressure measurement model during high dynamic pressure tests, is the lift coefficient of the pressure measurement model during low dynamic pressure tests.

[0029] In the above S34, the relationship between the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficient of the pressure measurement model is:

[0030] ;

[0031] ;

[0032] Among them, is the angle of attack of the pressure measurement model during high dynamic pressure tests, is the angle of attack of the pressure measurement model during low dynamic pressure tests, is the dynamic pressure during high dynamic pressure tests, is the dynamic pressure during low dynamic pressure tests.

[0033] The beneficial effects of the present invention are as follows: The present invention does not require specific and additional deformation measurement equipment, is not restricted by factors such as the model support method and model layout, and is not sensitive to model vibration. It can directly obtain the model torsion angle using the pressure measurement data on the wing surface, thereby obtaining more accurate test results, improving the accuracy and reliability of the wind tunnel test results, and reducing the test cost and time. The present invention can be applied to different test models with various support methods and can measure the torsion angle of the model in any attitude. During the normal wind tunnel pressure measurement test, the present invention can simultaneously obtain the torsion angle of the model wing, thereby realizing the accurate measurement and correction of the subsequent aerodynamic characteristics of the model and obtaining more accurate wind tunnel test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the present invention and form a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0035] Figure 1 It is a schematic flow chart of a method for measuring the torsion angle of the wing of a wind tunnel test model;

[0036] Figure 2 It is a schematic diagram of the distribution of pressure measurement points on the wing of the pressure measurement model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] In order to make the technical solutions and advantages in the embodiments of the present invention clearer and more understandable, the following further describes the exemplary embodiments of the present invention in detail with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than an exhaustive list of all embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0038] Refer to Figure 1 - Figure 2 This embodiment is described in detail. A method for measuring the torsion angle of the wing of a wind tunnel test model specifically includes the following steps:

[0039] S1. Install the pressure measurement model in the wind tunnel through support to complete the preparation work for the subsequent dynamic pressure test;

[0040] S2. Based on the fixed Mach number and Reynolds number in the same group of tests, by conducting high dynamic pressure tests and low dynamic pressure tests, collect the pressures of the pressure measurement points on each section at multiple angles of attack, and calculate two sets of pressure coefficients and lift coefficients;

[0041] Specifically: The high dynamic pressure test refers to the test conducted under the condition of a higher dynamic pressure q at a fixed Mach number and Reynolds number; the low dynamic pressure test refers to the test conducted under the condition of a lower dynamic pressure q at a fixed Mach number and Reynolds number;

[0042] S3. Based on two sets of pressure coefficients and lift coefficients, obtain the calculation formula for the torsion angle of the pressure measurement model, and obtain the relationship between the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficient of the pressure measurement model, and obtain the coefficients of the linear function;

[0043] S4. Substitute the coefficients of the linear function into the calculation formula for the torsion angle of the pressure measurement model to obtain the value of the torsion angle of the pressure measurement model.

[0044] Furthermore, in step S3, it specifically includes the following steps:

[0045] S31. Based on the local angle of attack of the pressure measurement model profile that is consistent under the same Mach number, the same Reynolds number, and different dynamic pressures, obtain the relationship between the local angle of attack of the pressure measurement model profile and the torsion angle of the pressure measurement model profile in the high-dynamic-pressure test and the low-dynamic-pressure test;

[0046] S32. Based on the relationship between the torsion angle of the pressure measurement model profile and dynamic pressure and lift, obtain the calculation formula for the torsion angle of the pressure measurement model;

[0047] S33. Based on the fact that the lift coefficient of the pressure measurement model is consistent under the same Mach number and the same Reynolds number, obtain the relationship between the lift coefficients of the pressure measurement model in the high-dynamic-pressure test and the low-dynamic-pressure test;

[0048] S34. Based on the results obtained in steps S31 to S33, obtain the relationship between the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficient of the pressure measurement model;

[0049] S35. Perform linear regression calculations on the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficients of each profile of the pressure measurement model at multiple angles of attack in the high-dynamic-pressure and low-dynamic-pressure test states for each profile, and fit to obtain the coefficients of the linear function, namely the slope a and the constant term b;

[0050] In step S31, the relationship between the local angle of attack of the pressure measurement model profile and the torsion angle of the pressure measurement model profile is expressed as:

[0051] ;

[0052] ;

[0053] Among them, is the local angle of attack of the pressure measurement model profile, is the angle of attack of the pressure measurement model in the high-dynamic-pressure test, is the angle of attack of the pressure measurement model in the low-dynamic-pressure test, is the torsion angle of the model profile in the high-dynamic-pressure test, is the torsion angle of the model profile in the low-dynamic-pressure test;

[0054] In step S32, the calculation formula for the torsion angle of the pressure measurement model is expressed as:

[0055] ;

[0056] Among them, is the slope of the linear function, is the lift coefficient of the pressure measurement model, is the constant term of the linear function, is the dynamic pressure;

[0057] In the said S33, the relational expression of the lift coefficient of the pressure measurement model during the high dynamic pressure test and the low dynamic pressure test is expressed as:

[0058] ;

[0059] Among them, is the lift coefficient of the pressure measurement model during the high dynamic pressure test, is the lift coefficient of the pressure measurement model during the low dynamic pressure test.

[0060] In the said S34, the relational expression between the ratio of the angle of attack of the pressure measurement model and the dynamic pressure and the lift coefficient of the pressure measurement model is:

[0061] ;

[0062] ;

[0063] Among them, is the angle of attack of the pressure measurement model during the high dynamic pressure test, is the angle of attack of the pressure measurement model during the low dynamic pressure test, is the dynamic pressure during the high dynamic pressure test, is the dynamic pressure during the low dynamic pressure test.

[0064] Although the present invention has been described based on a limited number of embodiments, those skilled in the art in this technical field understand that, within the scope of the present invention thus described, other embodiments can be envisioned. In addition, it should be noted that the language used in this specification is mainly selected for the purpose of readability and teaching, rather than for the purpose of explaining or limiting the subject matter of the present invention. Therefore, many modifications and variations are obvious to those of ordinary skill in the art in this technical field without departing from the scope and spirit of the appended claims. For the scope of the present invention, the disclosure of the present invention is illustrative rather than restrictive, and the scope of the present invention is defined by the appended claims.

Claims

1. A method for measuring the wing twist angle of a wind tunnel test model, characterized in that It includes the following steps: S1. Install the pressure measurement model in the wind tunnel through supports to complete the preparation for subsequent dynamic pressure tests; S2. Based on the fixed Mach number and Reynolds number in the same set of tests, by conducting high-dynamic pressure tests and low-dynamic pressure tests, collect the pressures at the pressure measurement points on each section at multiple angles of attack, and calculate two sets of pressure coefficients and lift coefficients; S3. According to the two sets of pressure coefficients and lift coefficients, obtain the calculation formula for the torsion angle of the pressure measurement model, and obtain the relationship between the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficient of the model, and obtain the coefficients of the linear function; S4. Substitute the coefficients of the linear function into the calculation formula for the torsion angle of the pressure measurement model to obtain the value of the torsion angle of the pressure measurement model; In the above S3, it specifically includes the following steps: S31. According to the same Mach number, the same Reynolds number, and the consistent local angle of attack of the pressure measurement model section under different dynamic pressures, obtain the relationship between the local angle of attack of the pressure measurement model section and the torsion angle of the pressure measurement model section in the high-dynamic pressure test and the low-dynamic pressure test; S32. According to the relationship between the torsion angle of the pressure measurement model section and the dynamic pressure and lift, obtain the calculation formula for the torsion angle of the pressure measurement model; S33. According to the consistent lift coefficient of the pressure measurement model under the same Mach number and the same Reynolds number, obtain the relationship between the lift coefficients of the pressure measurement model in the high-dynamic pressure test and the low-dynamic pressure test; S34. According to the results obtained in steps S31 to S33, obtain the relationship between the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficient of the pressure measurement model; S35. Conduct a linear regression calculation on the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficient of each section of the pressure measurement model at multiple angles of attack in the two test states of high-dynamic pressure and low-dynamic pressure, and fit to obtain the coefficients of the linear function, namely the slope a and the constant term b; In the above S31, the relationship between the local angle of attack of the pressure measurement model section and the torsion angle of the pressure measurement model section is expressed as: (α local -α model,2 )-(α local -α model,1 ) = ε2 - ε1 -(α model,2 -α model,1 ) = ε2 - ε1 where α local is the local angle of attack of the pressure measurement model profile, α model,1 is the angle of attack of the pressure measurement model during the high dynamic pressure test, α model,2 is the angle of attack of the pressure measurement model during the low dynamic pressure test, ε1 is the model profile torsion angle during the high dynamic pressure test, and ε2 is the model profile torsion angle during the low dynamic pressure test; In the above S32, the calculation formula for the torsion angle of the pressure measurement model is expressed as: ε = -(a × C L + b) × q where a is the slope of the linear function, C L is the lift coefficient of the pressure measurement model, b is the constant term of the linear function, and q is the dynamic pressure; In the above S33, the relationship between the lift coefficients of the pressure measurement model in the high-dynamic pressure test and the low-dynamic pressure test is expressed as: C L,1 = C L,2 Among them, C L,1 is the lift coefficient of the pressure measurement model during the high dynamic pressure test, and C L,2 is the lift coefficient of the pressure measurement model during the low dynamic pressure test; In the above S34, the relationship between the ratio of the angle of attack and dynamic pressure of the pressure measurement model and the lift coefficient of the pressure measurement model is: α model,2 -α model,1 = ε1 - ε2 = -(a×C L,1 + b)×q1 + (a×C L,2 + b)×q2 Among them, α model,1 is the angle of attack of the pressure measurement model during the high dynamic pressure test, and α model,2 is the angle of attack of the pressure measurement model during the low dynamic pressure test. q1 is the dynamic pressure during the high dynamic pressure test, and q2 is the dynamic pressure during the low dynamic pressure test.

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