Balance centering measurement and correction method for wind tunnel force measurement test

Abstract

The invention discloses a balance centering measurement and correction method for a wind tunnel force measurement test, and belongs to the technical field of wind tunnel force measurement. The problem that in the prior art, a traditional balance centering measurement and correction method is large in test result error due to the fact that the actual centering position and the theoretical centering position of a balance are inconsistent is solved. According to the invention, a wind tunnel test model is designed and processed, the positions of loading points are determined, each loading point is loaded, the angle of attack of a balance is adjusted through a support system, and then a normal force and a pitching moment are measured through the balance; according to the normal force and the pitching moment, force arms of the loading points at the fixed angle of attack are obtained, and the actual distance between each loading point and the balance calibration center in the flow direction is obtained through fitting; and obtaining the actual position of the balance center according to the difference between the actual distance and the theoretical distance from each loading point to the balance center along the flow direction. The method effectively improves the precision of the obtained balance center calibration position, and can be applied to a wind tunnel force measurement test.

Description

Technical Field

[0001] The invention relates to a balance centering measurement and correction method, in particular to a balance centering measurement and correction method for a wind tunnel force measurement test, and belongs to the technical field of wind tunnel force measurement. Background Art

[0002] Wind tunnel dynamometer test is an aerodynamic test conducted in a wind tunnel. It mainly measures the aerodynamic force of airflow on the aircraft test model or its components by installing a dynamometer test balance in the wind tunnel test model. Wind tunnel dynamometer test is crucial to the development of aircraft.

[0003] A force test balance, also known as a wind tunnel balance, is a force sensor specially used in wind tunnel tests. It is mainly used to measure the forces and moments acting on scaled aircraft models or components in wind tunnels. The lift, drag, side force, pitch moment, roll moment and yaw moment of the aircraft model or components are obtained through coordinate conversion between the balance axis system and the model axis system. The force test balance used in force measuring wind tunnel tests is a key equipment to ensure the accuracy of force measuring test data. In current force measuring wind tunnel tests, a common method is to use the theoretical centering of the balance as the actual centering of the balance to calculate the distance between the centering of the balance and the model torque reference point, and then obtain the relative relationship between the balance axis system and the model axis system. However, during the processing and manufacturing of the balance, there is a risk that the actual centering of the balance deviates from the theoretical centering due to processing tolerances and other reasons. Therefore, the existing methods cannot meet the needs of refined tests.

[0004] In summary, there is a need for a balance centering measurement and correction method for wind tunnel force measurement tests, which is used to accurately obtain aerodynamic moment data of an aircraft model and can measure the actual balance centering position. Summary of the invention

[0005] A brief overview of the present invention is provided below in order 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 key or important parts of the present invention, nor is it intended to limit the scope of the present invention. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] In view of this, in order to solve the problem of large errors in test results caused by inconsistency between the actual centering position of the balance and the theoretical centering position in the traditional balance centering measurement and correction method in the prior art, the present invention provides a balance centering measurement and correction method for wind tunnel force measurement test.

[0007] The technical solution is as follows: A method for measuring and correcting the balance centering of a wind tunnel force test comprises the following steps: S1. Design and process the wind tunnel test model, determine the loading point location, and define the actual and theoretical distances of the loading point from the balance center along the flow direction; S2. Install a support system in the wind tunnel test model and connect the force test model to the support system; S3. Install the force test model on a balance in the wind tunnel test model through a support system and level the balance; S4. Load each loading point, adjust the attack angle of the balance through the support system, and then measure the normal force and pitch moment through the balance; S5. According to the normal force and the pitching moment, the arm of the loading point under the fixed angle of attack is obtained, and the actual distance of each loading point from the balance center along the stream direction is obtained by fitting; S6. According to the difference between the actual distance and the theoretical distance of each loading point from the balance center along the flow direction, the actual position of the balance center is obtained.

[0008] Furthermore, in S1, the loading points are designed and processed on the back of the symmetric surface of the wind tunnel test model, and the loading points located around the balance center are defined as j, and the theoretical distance of the jth loading point from the balance center along the flow direction is , the distance between the jth loading point and the balance center along the normal direction is , the actual distance between the jth loading point and the balance center along the flow direction is , j=1, 2, 3, ..., n, when the loading point is in front of the balance center, >0, >0, when the loading point is behind the balance centering, <0, <0.

[0009] Furthermore, the step S4 specifically includes the following steps: S41. Load a weight at the loading point directly below the balance center, adjust the balance angle of attack through the support system, and record the normal force and pitching moment measured by the balance when the angle of attack is between -2° and 2° and the sideslip angle is 0°; S42. Load a weight at the loading point in front of the balance centering, adjust the balance angle of attack through the support system, and record the normal force and pitching moment measured by the balance at an angle of attack of -2° to 2° and a sideslip angle of 0°; S43. Load weights at the loading point behind the balance centering, adjust the balance angle of attack through the support system, and record the normal force and pitching moment measured by the balance when the angle of attack is -2° to 2° and the sideslip angle is 0°.

[0010] Furthermore, the S5 specifically includes the following steps: S51. At each angle of attack selected from -2° to 2°, according to the collected normal force and pitch moment, obtain the moment arm of the loading point at the fixed angle of attack; S52. According to the arm of the loading point at all fixed angles of attack, a curve of the relationship between the arm and the angle of attack is obtained, and then the actual distance of each loading point from the balance center along the stream direction is obtained; In S51, the force arm of the loading point at the fixed angle of attack It is expressed as: ; ; ; Where i is the angle of attack number, i=1, 2, 3, 4, 5, G is the weight of the weight, is the balance angle of attack, is the i-th balance angle of attack, is the balance pitching moment at a fixed angle of attack, is the balance normal force at a fixed angle of attack; In S52, the relationship curve between the force arm and the angle of attack is It is expressed as: .

[0011] Furthermore, the step S6 specifically includes the following steps: S61. According to the actual distance and theoretical distance of each loading point from the balance center along the flow direction, the difference between the actual distance and theoretical distance of the jth loading point from the balance center along the flow direction is obtained. ; S62. Average the difference between the actual distance and the theoretical distance of all loading points from the balance center in the flow direction to obtain the average value of the difference, add the average value of the theoretical balance center position and the difference to obtain the actual balance center position; In S61, the difference between the actual distance and the theoretical distance of the jth loading point from the balance center along the flow direction is It is expressed as: .

[0012] The beneficial effects of the present invention are as follows: the present invention determines the position of the loading point through early design and processing of the wind tunnel test model, then arranges the test environment, connects various components to the model, loads each loading point, adjusts the angle of attack of the balance through the support system, and then measures the normal force and pitching moment at each angle of attack through the balance; according to the normal force and the pitching moment, the force arm of the loading point at the fixed angle of attack is obtained, and the actual distance of each loading point from the balance center along the flow direction is obtained by fitting; finally, according to the difference between the actual distance of each loading point from the balance center along the flow direction and the theoretical distance, the actual position of the balance center is obtained; based on the accurate actual position of the balance center, the present invention improves the accuracy of the corrected wind tunnel force measurement test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 A schematic diagram of a flow chart of a balance centering measurement and correction method for a wind tunnel force measurement test; Figure 2 This is a schematic diagram of loading for wind tunnel force test; Figure 3 This is a top view of the loading point arrangement.

[0014] Figure numerals: 1. Wind tunnel test model; 2. Balance; 3. Support system; 4. Weight. DETAILED DESCRIPTION

[0015] In order to make the technical solutions and advantages of the embodiments of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0016] refer to Figure 1 and Figure 2 The present embodiment is described in detail, a balance centering measurement and correction method for a wind tunnel force measurement test, specifically comprising the following steps: S1. Design and process the wind tunnel test model, determine the loading point location, and define the actual and theoretical distances of the loading point from the balance center along the flow direction; S2. Install a support system in the wind tunnel test model and connect the force test model to the support system; S3. Install the force test model on a balance in the wind tunnel test model through a support system and level the balance; Specifically: connect the balance to the support system, preliminarily level the balance, connect and wire the balance and the data acquisition system and other components in the force test model, install the force test model on the balance and level it again; S4. Load each loading point, adjust the attack angle of the balance through the support system, and then measure the normal force and pitch moment through the balance; S5. According to the normal force and the pitching moment, the arm of the loading point under the fixed angle of attack is obtained, and the actual distance of each loading point from the balance center along the stream direction is obtained by fitting; S6. According to the difference between the actual distance and the theoretical distance of each loading point from the balance center along the flow direction, the actual position of the balance center is obtained.

[0017] Furthermore, in S1, the loading points are designed and processed on the back of the symmetric surface of the wind tunnel test model, and the loading points located around the balance center are defined as j, and the theoretical distance of the jth loading point from the balance center along the flow direction is , the distance between the jth loading point and the balance center along the normal direction is , the actual distance between the jth loading point and the balance center along the flow direction is , j=1, 2, 3, ..., n, when the loading point is in front of the balance center, >0, >0, when the loading point is behind the balance centering, <0, <0; Specifically, in this embodiment, there are 3 loading points, j=1, 2, 3, and the loading point located directly below the balance center is defined as 1, i.e., the first loading point, the loading point located in front of the balance center is defined as 2, i.e., the second loading point, and the loading point located behind the balance center is defined as 3, i.e., the third loading point. The theoretical distances of the three loading points from the balance center along the flow direction are recorded as follows: , , , the distances of the three loading points from the balance center along the normal direction are , , The actual distances of the three loading points from the balance center along the flow direction are , , .

[0018] Furthermore, the step S4 specifically includes the following steps: S41. Load a weight at the loading point directly below the balance center, adjust the balance angle of attack through the support system, and record the normal force and pitching moment measured by the balance when the angle of attack is between -2° and 2° (the angle of attack in this range is 1° apart) and the sideslip angle is 0°; S42. Load a weight at the loading point in front of the balance centering, adjust the balance angle of attack through the support system, and record the normal force and pitching moment measured by the balance when the angle of attack is between -2° and 2° (the angle of attack in this range is 1° apart) and the sideslip angle is 0°; S43. Load weights at the loading point behind the balance centering, adjust the balance angle of attack through the support system, and record the normal force and pitching moment measured by the balance when the angle of attack is between -2° and 2° (the angle of attack interval within this range is 1°) and the sideslip angle is 0°.

[0019] Furthermore, the S5 specifically includes the following steps: S51. At each angle of attack selected from -2° to 2°, according to the collected normal force and pitch moment, obtain the moment arm of the loading point at the fixed angle of attack; S52. According to the arm of the loading point at all fixed angles of attack, a curve of the relationship between the arm and the angle of attack is obtained, and then the actual distance of each loading point from the balance center along the stream direction is obtained; In S51, the force arm of the loading point at the fixed angle of attack It is expressed as: ; ; ; Where i is the angle of attack number, i=1, 2, 3, 4, 5, G is the weight of the weight, is the balance angle of attack, is the i-th balance angle of attack, is the balance pitching moment at a fixed angle of attack, is the balance normal force at a fixed angle of attack; In S52, the relationship curve between the force arm and the angle of attack is It is expressed as: ; Specifically, the force arm of the loading point at a fixed angle of attack includes the force arm of the first loading point at a fixed angle of attack , the moment arm of the second loading point at a fixed angle of attack , the force arm of the third loading point at a fixed angle of attack .

[0020] Furthermore, the step S6 specifically includes the following steps: S61. According to the actual distance and theoretical distance of each loading point from the balance center along the flow direction, the difference between the actual distance and theoretical distance of the jth loading point from the balance center along the flow direction is obtained. ; S62. Average the difference between the actual distance and the theoretical distance of all loading points from the balance center in the flow direction to obtain the average value of the difference, add the average value of the theoretical balance center position and the difference to obtain the actual balance center position; In S61, the difference between the actual distance and the theoretical distance of the jth loading point from the balance center along the flow direction is It is expressed as: .

[0021] Although the present invention has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the invention thus described. In addition, it should be noted that the language used in this specification is selected primarily for readability and teaching purposes, rather than for explaining or defining the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is illustrative, not restrictive, with respect to the scope of the present invention, which is defined by the appended claims.

Claims

1. A method for measuring and correcting the balance centering in a wind tunnel force test, characterized in that: The following steps are involved: S1. Design and process the wind tunnel test model, determine the loading point location, and define the actual and theoretical distances of the loading point from the balance center along the flow direction; S2. Install a support system in the wind tunnel test model and connect the force test model to the support system; S3. Install the force test model on a balance in the wind tunnel test model through a support system and level the balance; S4. Load each loading point, adjust the attack angle of the balance through the support system, and then measure the normal force and pitch moment through the balance; S5. According to the normal force and the pitching moment, the arm of the loading point under the fixed angle of attack is obtained, and the actual distance of each loading point from the balance center along the stream direction is obtained by fitting; S6. According to the difference between the actual distance and the theoretical distance of each loading point from the balance center along the flow direction, the actual position of the balance center is obtained.

2. The balance centering measurement and correction method for wind tunnel force test according to claim 1 is characterized in that: In S1, the loading points are designed and processed on the back of the symmetric surface of the wind tunnel test model, and the loading points located around the balance center are defined as j, and the theoretical distance of the jth loading point from the balance center along the flow direction is , the distance between the jth loading point and the balance center along the normal direction is , the actual distance between the jth loading point and the balance center along the flow direction is , j=1, 2, 3, ..., n, when the loading point is in front of the balance center, >0, >0, when the loading point is behind the balance centering, <0, <0.

3. The balance centering measurement and correction method for wind tunnel force test according to claim 2 is characterized in that: The S4 specifically includes the following steps: S41. Load a weight at the loading point directly below the balance center, adjust the balance angle of attack through the support system, and record the normal force and pitching moment measured by the balance when the angle of attack is between -2° and 2° and the sideslip angle is 0°; S42. Load a weight at the loading point in front of the balance centering, adjust the balance angle of attack through the support system, and record the normal force and pitching moment measured by the balance at an angle of attack of -2° to 2° and a sideslip angle of 0°; S43. Load weights at the loading point behind the balance centering, adjust the balance angle of attack through the support system, and record the normal force and pitching moment measured by the balance when the angle of attack is -2° to 2° and the sideslip angle is 0°.

4. The method for measuring and correcting the balance centering in a wind tunnel force test according to claim 3 is characterized in that: The S5 specifically includes the following steps: S51. At each angle of attack selected from -2° to 2°, according to the collected normal force and pitch moment, obtain the moment arm of the loading point at the fixed angle of attack; S52. According to the arm of the loading point at all fixed angles of attack, a curve of the relationship between the arm and the angle of attack is obtained, and then the actual distance of each loading point from the balance center along the stream direction is obtained; In S51, the force arm of the loading point at the fixed angle of attack It is expressed as: ； ； ； Where i is the angle of attack number, i=1, 2, 3, 4, 5, G is the weight of the weight, is the balance angle of attack, is the i-th balance angle of attack, is the balance pitching moment at a fixed angle of attack, is the balance normal force at a fixed angle of attack; In S52, the relationship curve between the force arm and the angle of attack is It is expressed as: 。 5. The method for measuring and correcting the balance centering in a wind tunnel force test according to claim 4 is characterized in that: The S6 specifically includes the following steps: S61. According to the actual distance and theoretical distance of each loading point from the balance center along the flow direction, the difference between the actual distance and theoretical distance of the jth loading point from the balance center along the flow direction is obtained. ; S62. Average the difference between the actual distance and the theoretical distance of all loading points from the balance center in the flow direction to obtain the average value of the difference, add the average value of the theoretical balance center position and the difference to obtain the actual balance center position; In S61, the difference between the actual distance and the theoretical distance of the jth loading point from the balance center along the flow direction is It is expressed as: 。

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