A test method for measuring unsteady aerodynamic force during wing deployment

Abstract

A method for measuring the unsteady aerodynamic force of wing deployment belongs to the technical field of special aerodynamic wind tunnel tests. The invention includes step 1, measuring the moment of inertia of the wing; step 2, measuring the wind test data; step 3, calculating the inertial load; step 4, deducting the inertial load to obtain the pure aerodynamic load; the purpose of the invention is to solve the problem that the deployment trajectory under windy conditions and no wind conditions in the existing wing deployment wind tunnel test is quite different, and the existing data processing method causes large errors. The invention can be applied to any deployment trajectory condition, and has a wide range of applications. At the same time, it can accurately deduct the inertial force during the wing deployment process to obtain pure unsteady aerodynamic force; the moment of inertia of the wing can be directly measured using the existing test conditions, and the cost of the test device modification can be reduced to the maximum extent. The overall cost of the method improvement implementation process is low. Not only that, it also greatly improves the test efficiency and saves time.

Description

Technical Field

[0001] The invention relates to a test method for measuring unsteady aerodynamic force of a wing deployment, and belongs to the technical field of special tests of aviation aerodynamic wind tunnels. Background Art

[0002] With the demand for missile development, more and more missiles with folding wings are being developed. The aerodynamic force of the missile will undergo large and rapid changes during the folding wing deployment process. It is necessary to carry out corresponding wind tunnel tests in the wind tunnel test to assess the deployment performance of the folding wing surface under the action of aerodynamic force. At the same time, during the rapid deployment of the folding wing, the unsteady aerodynamic force acting on the wing will change dramatically. It is necessary to accurately obtain the unsteady aerodynamic force in this process to evaluate the impact of the unsteady aerodynamic force on the missile's flight attitude.

[0003] The aerodynamic torque that the wing is subjected to during the deployment process is a key target that needs to be obtained. Previous experiments did not accurately extract it. Instead, they directly used the balance force as the final result and then compared the change in torque. Or, they divided the entire folding angle into several measuring points, and smoothly connected the force and torque of the measuring points to obtain the change in the aerodynamic force of the missile body during the entire deployment process. However, this method cannot obtain the influence of unsteady dynamic loads and has inherent deficiencies.

[0004] With the development of test refinement, the demand for accurate extraction of pure unsteady aerodynamic loads is getting higher and higher. The data processing method of the existing rudder / wing deployment process aerodynamic measurement test is usually as follows: first, the dynamic signal of the balance is collected during the rudder / wing deployment process under windless conditions as the initial reading of the balance; then, the dynamic signal of the balance is collected during the rudder / wing deployment process under windy conditions as the final reading of the balance; finally, the two are subtracted one by one to deduct the influence of the inertial load and extract the aerodynamic load.

[0005] For a certain missile, the driving torque for the wing to unfold is the elastic force provided by the elastic torsion spring. The trajectory of the wing unfolding is determined by the elastic force and the aerodynamic force. Since the effects of elasticity and aerodynamic force are equivalent, there may be obvious differences in the movement trajectory of the wing under windless conditions and windy conditions. The initial / final balance readings cannot be subtracted one by one. Obviously, the above data processing method is no longer applicable.

[0006] Therefore, it is urgent to propose a new type of unsteady aerodynamic measurement test method for wing deployment to solve the above technical problems. Summary of the invention

[0007] The purpose of the present invention is to solve the problem that the deployment trajectory under windy conditions and no wind conditions in the existing wing deployment wind tunnel test is quite different, and the existing data processing method causes large errors. 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.

[0008] The technical solution of the present invention:

[0009] A test method for measuring unsteady aerodynamic force of missile wing deployment, comprising the steps of 1, measuring the rotational inertia of the missile wing;

[0010] Wing deployment measurement test in windless conditions, real-time load measured by balance , the angle measuring device measures the rotation angle of the missile wing , at this time the real-time load measured by the balance is the inertia load of the wing, see the following formula:

[0011] ;

[0012] Where: For time, is the real-time load measured by the balance, is the moment of inertia of the wing about the axis of rotation, is the rotation angle, that is, the rotation angle of the wing centerline, is the derivative of the rotation angle with respect to time, i.e., the angular velocity, is the derivative of angular velocity with respect to time, i.e. angular acceleration;

[0013] Then the moment of inertia of the wing about the axis of rotation is calculated by the following formula:

[0014] ;

[0015] Step 2, measurement of blowing test data;

[0016] Wing deployment measurement test in windy conditions, real-time load measured by balance , the angle measuring device measures the rotation angle of the missile wing , at this time the real-time load measured by the balance is the inertial load of the wing and the aerodynamic load of the missile as a whole;

[0017] Step 3, calculation of inertia load;

[0018] Mesh the wing and calculate the inertial force generated by the entire wing in the X-axis direction , the inertial force generated by the entire wing in the Y-axis direction , and the moment of inertia of the entire wing about the axis of rotation ;

[0019] Step 4, deduction of inertial load;

[0020] The calculated inertial load is deducted from the real-time load measured by the balance to obtain the pure aerodynamic load, as shown in the following formula:

[0021] ;

[0022] ;

[0023] ;

[0024] is the aerodynamic force in the X-axis direction, is the aerodynamic force in the Y-axis direction, is the total load in the X-axis direction, is the total load in the Y-axis direction, is the aerodynamic moment in the Z-axis direction, is the total moment in the Z direction.

[0025] Preferably: after the wing is divided into grids, the mass blocks of the part of the wing divided in each grid are , the distance from the center of rotation is ;

[0026] The mass blocks of the parts of the wing divided in each grid Inertial force generated in the X-axis direction for:

[0027] ;

[0028] The mass blocks of the parts of the wing divided in each grid Inertial force in the Y-axis direction for:

[0029] ;

[0030] The inertial force generated by the entire wing in the X-axis direction for:

[0031] ;

[0032] The inertial force generated by the entire wing in the Y-axis direction for:

[0033] ;

[0034] The moment of inertia of the entire wing about the axis of rotation for:

[0035] ;

[0036] in, It is the angle between the line connecting the mass block at the i-th point and the center of rotation relative to the theoretical center line of the entire wing.

[0037] Preferably, the specific steps of meshing the missile wing are as follows:

[0038] Step 3.1, conduct a test under windless conditions to obtain inertial force;

[0039] Step 3.2, dividing the mass blocks on the three-dimensional digital model;

[0040] Step 3.3, calculate the inertial force of the entire wing;

[0041] Step 3.4, compare the calculated value of the inertia force with the experimental value to see if they are within the allowable range of the experimental error. If not, double the number of grids and repeat steps 3.2 to 3.4. If yes, the grid division is completed.

[0042] The present invention has the following beneficial effects:

[0043] 1. The present invention can be applied to any deployment trajectory condition, has a wide range of applications, and can accurately deduct the inertial force during the wing deployment process to obtain pure unsteady aerodynamic force;

[0044] 2. The present invention can directly use the existing test conditions to measure the moment of inertia of the missile wing, and reduce the cost of the test device modification to the maximum extent. The overall cost of the method improvement implementation process is low. Not only that, it also greatly improves the test efficiency and saves time;

[0045] 3. The present invention performs appropriate grid division on the moving parts on the three-dimensional digital model, obtains the mass of each component and the distance from the center of rotation, and then obtains the inertial force and moment generated by the entire moving part in each direction through integration. The above measures are used to achieve the purpose of accurately calculating the inertial load, and then obtain the pure aerodynamic load. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Schematic diagram of the wing rotation process in Example 1, wherein (a) is a schematic diagram of the wing deployment state, (b) is a schematic diagram of the wing rotation state, and (c) is a schematic diagram of the wing closed state;

[0047] Figure 2 is a schematic diagram of the rotation angle of the missile wing in the first embodiment;

[0048] Figure 3 is a schematic diagram of a coarse grid mass block in the mass block division in the first embodiment;

[0049] Figure 4 It is a flow chart of the specific division steps of meshing the missile wing in the first embodiment. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0051] The connection mentioned in the present invention is divided into fixed connection and detachable connection. The fixed connection (i.e., non-detachable connection) includes but is not limited to conventional fixed connection methods such as folding connection, rivet connection, bonding connection and welding connection. The detachable connection includes but is not limited to conventional detachable methods such as threaded connection, snap connection, pin connection and hinge connection. When the specific connection method is not clearly defined, it is assumed that at least one connection method can always be found in the existing connection methods to achieve the function. Those skilled in the art can choose according to their needs. For example: welding connection is selected for fixed connection, and hinge connection is selected for detachable connection.

[0052] Embodiment 1: Combination Figure 1-Figure 4 This embodiment describes a test method for measuring the unsteady aerodynamic force of the wing deployment. Under wind conditions, the real-time load measured by the balance includes two parts: the inertial load caused by the wing deployment movement and the aerodynamic load acting on the entire missile. The wing deployment angle is measured during the wind blowing process. The schematic diagram of the wing rotation process is shown in the figure. Figure 1 shown.

[0053] The curve of the deployment angle changing with time is differentiated to obtain the curve of the angular velocity changing with time, and then the curve of the angular acceleration changing with time is differentiated with respect to time. The mass and moment of inertia of the wing are known, and the inertial load is calculated using the rigid body motion dynamics equation. The real-time load measured by the balance minus the calculated inertial load is the required pure unsteady aerodynamic load, which specifically includes:

[0054] Step 1, measurement of the wing moment of inertia;

[0055] Wing deployment measurement test in windless conditions, real-time load measured by balance , the angle measuring device measures the rotation angle of the missile wing , at this time the real-time load measured by the balance is the inertia load of the wing, see the following formula:

[0056] ;

[0057] Where: For time, is the real-time load measured by the balance, is the moment of inertia of the wing about the axis of rotation, is the rotation angle, that is, the rotation angle of the wing centerline, is the derivative of the rotation angle with respect to time, i.e., the angular velocity, is the derivative of angular velocity with respect to time, i.e. angular acceleration;

[0058] Then the moment of inertia of the wing about the axis of rotation is calculated by the following formula:

[0059] ;

[0060] Step 2, measurement of blowing test data;

[0061] Wing deployment measurement test in windy conditions, real-time load measured by balance , the angle measuring device measures the rotation angle of the missile wing , at this time the real-time load measured by the balance is the inertial load of the wing and the aerodynamic load of the missile as a whole;

[0062] Step 3, calculation of inertia load;

[0063] Mesh the wing and calculate the inertial force generated by the entire wing in the X-axis direction , the inertial force generated by the entire wing in the Y-axis direction , and the moment of inertia of the entire wing about the axis of rotation ;

[0064] Step 4, deduction of inertial load;

[0065] The calculated inertial load is deducted from the real-time load measured by the balance to obtain the pure aerodynamic load, as shown in the following formula:

[0066] ;

[0067] ;

[0068] ;

[0069] is the aerodynamic force in the X-axis direction, is the aerodynamic force in the Y-axis direction, is the total load in the X-axis direction, is the total load in the Y-axis direction, is the aerodynamic moment in the Z-axis direction, is the total moment in the Z direction.

[0070] After the missile wing is meshed, the mass block of the part of the missile wing divided in each mesh is , the distance from the centroid is ;

[0071] The mass blocks of the parts of the wing divided in each grid Inertial force generated in the X-axis direction for:

[0072] ;

[0073] The mass blocks of the parts of the wing divided in each grid Inertial force in the Y-axis direction for:

[0074] ;

[0075] The inertial force generated by the entire wing in the X-axis direction for:

[0076] ;

[0077] The inertial force generated by the entire wing in the Y-axis direction for:

[0078] ;

[0079] The moment of inertia of the entire wing about the axis of rotation for:

[0080] ;

[0081] in, It is the angle between the line connecting the mass block at the i-th point and the center of rotation relative to the theoretical center line of the entire wing.

[0082] The specific steps of meshing the missile wing are as follows:

[0083] Step 3.1, conduct a test under windless conditions to obtain inertial force;

[0084] Step 3.2, mass block division is performed on the three-dimensional digital model, that is, first, the mass block is divided on the three-dimensional digital model, and then the rough grid is divided, such as Figure 3 The figure shows a schematic diagram of a rough grid mass block in the mass block division. It can be divided into four grids first. The four grids are respectively set as mass block m1, mass block m2, mass block m3 and mass block m4. Correspondingly, is the angle between the first point mass block and the line connecting the center of rotation relative to the theoretical center line of the entire wing, is the angle between the second point mass block and the line connecting the center of rotation relative to the theoretical center line of the entire wing, is the angle between the third point mass block and the line connecting the center of rotation relative to the theoretical center line of the entire wing and The angle between the fourth point mass block and the line connecting the center of rotation and the theoretical center line of the entire wing;

[0085] Step 3.3, calculate the inertial force of the entire wing, that is, calculate the inertial force of the entire wing in the X and Y axis directions according to the rotation angle curve under windless conditions;

[0086] Step 3.4, compare the calculated value of the inertial force with the test value to see if they are within the allowable range of the test error. If not, double the number of grids and repeat steps 3.2 to 3.4, that is, double the number of grids again, and then calculate the inertial force of the entire wing in the X and Y axis directions according to the rotation angle curve under windless conditions, and analyze the difference between the two inertial forces in the X and Y axis directions. If it exceeds the allowable range of the test error, continue to double the number of grids and perform two more inertial force difference analyses. If yes, that is, if it is within the allowable range of the test error, use this grid as the final grid and the grid division is completed.

[0087] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present invention will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.

[0088] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A test method for measuring the unsteady aerodynamic force of a wing deployment, characterized in that: include: Step 1, measurement of the wing moment of inertia; The wing deployment measurement test is carried out under windless conditions. The real-time load M(t) measured by the balance is the inertial load of the wing, and the angle measuring device measures the rotation angle θ(t) of the wing. At this time, the real-time load M(t) measured by the balance is the inertial load of the wing, as shown in the following formula: Where: t is time, M(t) is the real-time load measured by the balance, I is the moment of inertia of the wing around the axis of rotation, is the derivative of the rotation angle with respect to time, i.e., the angular velocity, is the derivative of angular velocity with respect to time, i.e. angular acceleration; Then the moment of inertia of the wing about the axis of rotation is calculated by the following formula: Step 2, measurement of blowing test data; The wing deployment measurement test is carried out under windy conditions, the real-time load M(t) measured by the balance, and the angle measurement device measures the rotation angle θ(t) of the wing. At this time, the real-time load M(t) measured by the balance is the inertial load of the wing and the aerodynamic load of the missile as a whole; Step 3, calculation of inertia load; Grid the wing and calculate the inertial force F generated by the entire wing in the X-axis direction xI 、The inertial force F generated by the entire wing in the Y-axis direction yI , and the moment of inertia M of the entire wing about the axis of rotation xI ; Step 4, deduction of inertial load; The calculated inertial load is deducted from the real-time load measured by the balance to obtain the pure aerodynamic load, as shown in the following formula: F xa =F xT -F xI F ya =F yT -F yI M xa =M xT -M xI F xa is the aerodynamic force in the X-axis direction, F ya is the aerodynamic force in the Y-axis direction, F xT is the total load in the X-axis direction, F yT is the total load in the Y-axis direction, M xa is the aerodynamic moment in the Z-axis direction, M xT is the total moment in the Z-axis direction; After the wing is meshed, the mass block of the part of the wing divided in each mesh is m i , the distance from the center of rotation is r i ; The mass m of the part of the wing divided in each grid i Inertial force F generated in the X-axis direction xi for: The mass m of the part of the wing divided in each grid i The inertial force F generated in the Y-axis direction yi for: The inertial force F generated by the entire wing in the X-axis direction xI for: The inertial force F generated by the entire wing in the Y-axis direction yI for: The moment of inertia of the entire wing about the axis of rotation is M xI for: Among them, Δθ i is the angle between the mass block at point i and the line connecting the center of rotation relative to the theoretical center line of the entire wing; The specific steps of meshing the missile wing are as follows: Step 3.1, conduct a test under windless conditions to obtain inertial force; Step 3.2, mass block division is performed on the three-dimensional digital model, that is, first, the mass block is divided on the three-dimensional digital model, and then the rough grid division is performed, first divided into 4 grids, and the four grids are respectively set as mass block m1, mass block m2, mass block m3 and mass block m4, correspondingly, Δθ1 is the angle between the first point mass block and the rotation center line relative to the theoretical center line of the entire wing, Δθ2 is the angle between the second point mass block and the rotation center line relative to the theoretical center line of the entire wing, Δθ3 is the angle between the third point mass block and the rotation center line relative to the theoretical center line of the entire wing, and Δθ4 is the angle between the fourth point mass block and the rotation center line relative to the theoretical center line of the entire wing; Step 3.3, calculate the inertial force of the entire wing, that is, calculate the inertial force of the entire wing in the X and Y axis directions according to the rotation angle curve under windless conditions; Step 3.4, compare the calculated value of the inertial force with the test value to see if they are within the allowable range of the test error. If not, double the number of grids and repeat steps 3.2 to 3.4, that is, double the number of grids again, and then calculate the inertial force of the entire wing in the X and Y axis directions according to the rotation angle curve under windless conditions, and analyze the difference between the two inertial forces in the X and Y axis directions. If it exceeds the allowable range of the test error, continue to double the number of grids and perform two more inertial force difference analyses. If yes, that is, if it is within the allowable range of the test error, use this grid as the final grid and the grid division is completed.

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