A measurement test method for the work done by the aerodynamic moment during the deployment of a folding rudder

Abstract

The invention discloses a measurement test method for the work done by the aerodynamic moment during the deployment of a folding rudder, belonging to the technical field of special wind tunnel tests. It solves the problem that the results obtained by the traditional folding rudder deployment performance measurement method in the prior art have a large error from the real aircraft. The invention conducts folding rudder deployment tests respectively under no wind load conditions and under wind load conditions. The effective driving moment during the folding rudder deployment process is measured by a balance, and the rudder surface rotation angle history under no wind load conditions and under wind load conditions is obtained through high-speed photography; thereby obtaining the relationship between the effective driving moment and the folding rudder deployment angle, integrating it to obtain the work done by the effective driving moment; obtaining the final angular velocity according to the moment when the folding rudder is fully deployed, and using the final kinetic energy of the folding rudder in place minus the work done by the effective driving moment to obtain the work done by the aerodynamic moment. The invention effectively improves the accuracy of the folding rudder deployment performance test and can be applied to the safety test of the folding rudder deployment.

Description

Technical Field

[0001] The present invention relates to a measurement test method for the work done by the aerodynamic moment during the deployment of a folding rudder, and belongs to the technical field of special wind tunnel tests. Background Art

[0002] In order to adapt to the strict constraints of space, the control rudders of aircraft are designed to be foldable to reduce the outer envelope size. During flight, the folding rudders of the aircraft are quickly deployed to enhance the control ability. Whether the folding rudders can be safely and smoothly deployed is a key assessment content in aircraft design, including whether the folding rudders can be normally deployed under the work done by aerodynamic resistance loads, and whether the impact loads when deployed in place under the work done by aerodynamic promoting loads will damage the rudder surface structure, etc.

[0003] In the prior art, wind tunnel tests are widely used as the most economical assessment method for the safety test of folding rudders. However, for the deployment assessment test of folding rudders, real models, folding rudders and their drive sources are required. Due to the limitation of the wind tunnel size, placing the real model in the wind tunnel results in too large a blockage ratio and the test cannot be carried out. The previous approach was to shorten and simplify the forebody of the real model, retain the real folding rudder installation part, and conduct a deployment test without driving force to obtain the deployment process of the rudder surface. However, the obtained results can only qualitatively analyze the deployment performance of the folding rudder because the oncoming flow where the folding rudder is located changes after the forebody of the real model is shortened and simplified, and the aerodynamic force it receives is inconsistent with that of the real model; or a scaled model is used to measure the rudder surface load to obtain the static load at different deployment angles, but this ignores the dynamic load during the deployment process of the folding rudder. The above methods are not applicable when accurately evaluating the folding deployment performance, and the obtained folding rudder deployment performance is inaccurate.

[0004] In summary, a measurement test method for the work done by the aerodynamic moment during the deployment of a folding rudder is needed. Summary of the Invention

[0005] 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 certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0006] In view of this, to solve the problem that the results obtained by the traditional folding rudder deployment performance measurement method in the prior art have a large error from the real aircraft, the present invention provides a measurement test method for the work done by the aerodynamic moment during the deployment of a folding rudder.

[0007] The technical solution is as follows: A measurement test method for the work done by the aerodynamic moment during the deployment of a folding rudder, comprising the following steps:

[0008] S1. Conduct the folding rudder deployment test under the condition of no wind load. Arrange the folding rudder model with a balance installed at the root. Measure the effective driving torque during the folding rudder deployment process through the balance. Use a high-speed photography tool to obtain the real-time folding rudder deployment angle. According to the obtained rudder surface rotation angle history under the condition of no wind load, obtain the relationship between the effective driving torque and the folding rudder deployment angle, and integrate the relationship to obtain the work done by the effective driving torque.

[0009] S2. Conduct the folding rudder deployment test under the condition of wind load. Arrange the folding rudder model without a balance installed. Use a high-speed photography tool to obtain the real-time folding rudder deployment angle, and obtain the rudder surface rotation angle history under the condition of no wind load. After digital filtering and smoothing preprocessing, perform polynomial fitting on it, and then take the first derivative of the folding rudder deployment angle history to obtain the angular velocity-time curve. According to the moment when the folding rudder deployment is in place, obtain the final angular velocity. Subtract the work done by the effective driving torque from the final kinetic energy when the folding rudder is in place to obtain the work done by the aerodynamic torque.

[0010] Further, in S1, the effective driving torque is the torque measured by the balance , and the rudder surface rotation angle history under the condition of no wind load is , with the unit of radian;

[0011] The effective driving torque is expressed as:

[0012] ;

[0013] ;

[0014] Among them, the unit of the effective driving torque is N·m, the unit of the torque measured by the balance is N·m, is the theoretical driving torque of the driving source, with the unit of N·m, is the frictional torque during the rotation process, with the unit of N·m, is the moment of inertia of the moving part around the rotation axis, with the unit of kg·m², is the angular acceleration under the condition of no wind load, that is, the second derivative of the folding rudder deployment angle with respect to time, with the unit of rad / s²;

[0015] According to the effective driving torque , obtain the relationship between the effective driving torque and the folding rudder deployment angle. Through the integration algorithm, obtain the work done by the effective driving torque , with the unit of joule;

[0016] The work done by the effective driving torque is expressed as:

[0017] 。

[0018] Further, in S2, the angle-of-rotation history of the rudder surface under wind load conditions is , with the unit of radian. Digital filtering and smoothing methods are used for its preprocessing, and 6th-degree polynomial curve fitting is performed to obtain the mathematical expression of the unfolding angle of the folding rudder varying with time. Taking the first derivative of it gives the function of angular velocity varying with time. According to the moment when the folding rudder is fully unfolded, the final angular velocity is calculated. By subtracting the work done by the effective driving torque from the final kinetic energy, the work done by the aerodynamic torque is obtained;

[0019] The mathematical expression of the unfolding angle of the folding rudder varying with time is expressed as:

[0020] ;

[0021] where is time, with the unit of / second, are respectively the constant terms of the 6th-degree polynomial curve fitting, and the moment when the folding rudder is fully unfolded has the unit of / second;

[0022] The function of angular velocity varying with time is expressed as:

[0023] ;

[0024] where represents taking the first derivative of the angle-of-rotation history of the rudder surface under wind load conditions;

[0025] The final angular velocity is expressed as:

[0026] ;

[0027] The work done by the aerodynamic torque is expressed as:

[0028] ;

[0029] where the work done by the aerodynamic torque has the unit of joule.

[0030] The beneficial effects of the present invention are as follows: By taking the work done by aerodynamic torque as the evaluation index, the present invention effectively avoids the problem that it is difficult to simultaneously simulate the aerodynamic torque and the unfolding angle history during the unfolding process of the folding rudder of the shortened simplified test model of the forebody, and can accurately evaluate the true unfolding performance of the folding rudder. Under the condition of no wind load, the present invention uses a balance measurement method to obtain the effective driving torque, which can accurately deduct the influence of the rotational friction torque of the folding rudder. When processing the unfolding test data under the condition of wind load, the angular velocity at the moment when the folding rudder reaches the unfolding position is introduced to calculate the work done by the aerodynamic torque, which can effectively avoid the large deviation of the second derivative of the angle-time curve and the error influence of the data fluctuation in the intermediate process, and improve the measurement accuracy. The measurement results of the present invention can quickly and accurately evaluate the rationality of the driving torque and test the anti-impact load capacity of the folding rudder, avoid problems during flight, improve safety, and save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the present invention and constitute 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 of the present invention. In the drawings:

[0032] Figure 1 It is a schematic flow chart of a measurement test method for the work done by the aerodynamic torque during the unfolding of a folding rudder;

[0033] Figure 2 It is a schematic diagram of the forces acting during the unfolding process of the folding rudder;

[0034] Figure 3 It is a schematic diagram for solving the work done by the effective driving torque;

[0035] Figure 4 It is a schematic flow chart of an embodiment of a measurement test method for the work done by the aerodynamic torque during the unfolding of a folding rudder. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] 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.

[0037] Refer to Figures 1 - 4 This embodiment is described in detail. A measurement test method for the work done by the aerodynamic torque during the unfolding of a folding rudder specifically includes the following steps:

[0038] S1. Conduct a folding rudder deployment test under no wind load conditions. Arrange a folding rudder model with a balance installed at the root. Measure the effective driving torque during the folding rudder deployment process through the balance. Use a high-speed photography tool to obtain the real-time folding rudder deployment angle. According to the obtained rudder surface rotation angle history under no wind load conditions, obtain the relationship between the effective driving torque and the folding rudder deployment angle, and integrate the relationship to obtain the work done by the effective driving torque.

[0039] S2. Conduct a folding rudder deployment test under wind load conditions. Arrange a folding rudder model without a balance installed. Use a high-speed photography tool to obtain the real-time folding rudder deployment angle, and obtain the rudder surface rotation angle history under no wind load conditions. After performing digital filtering and smoothing preprocessing, perform polynomial fitting on it, and then take the first derivative of the folding rudder deployment angle history to obtain the angular velocity-time curve. Obtain the final angular velocity according to the moment when the folding rudder is fully deployed. Subtract the work done by the effective driving torque from the final kinetic energy when the folding rudder is in place to obtain the work done by the aerodynamic torque.

[0040] Specifically, refer to Figure 2 , is the aerodynamic torque. The forces acting on the folding rudder during the deployment process include driving torque, aerodynamic torque, inertial torque, and frictional torque, etc. Since the real folding rudder and the drive source are used for the test, the work done by the driving torque, frictional torque, and inertial torque is consistent with the real model. According to the principle of energy conservation, as long as the work done by the aerodynamic torque of the folding rudder deployment of the shortened and simplified test model of the forebody is ensured to be consistent with the real model, the real deployment performance of the folding rudder can be fully reflected.

[0041] The situation where the work done by the aerodynamic torque of the folding rudder deployment of the shortened and simplified test model of the forebody is consistent with the real model is expressed as:

[0042] ;

[0043] ;

[0044] ;

[0045] Among them, is the work done by the aerodynamic torque of the shortened and simplified test model of the forebody, is the work done by the aerodynamic torque of the real model, is the folding rudder deployment angle of the shortened and simplified test model of the forebody, is the aerodynamic torque of the shortened and simplified test model of the forebody, is the folding rudder deployment angle of the real model, is the aerodynamic torque of the real model.

[0046] Although the unfolding process of the test model and its aerodynamic moments are inconsistent with the actual ones, as long as the work done by the aerodynamic moments is equal, the assessment requirements can be met. Therefore, the work done by the aerodynamic moments of the test model is the most important measurement index for evaluating whether the simulation conditions of the wind tunnel test meet the assessment requirements. In this embodiment, during the folding rudder unfolding test, the work done by the aerodynamic moments during the unfolding process of the folding rudder of the shortened simplified model of the forebody is accurately measured;

[0047] The effective driving moment is the theoretical driving moment minus the friction moment value. The friction moment is the driving moment lost due to mechanical friction during the rotation of components. Engineering experience shows that the ratio of the friction moment to the theoretical driving moment can reach 25%, so it cannot be ignored and needs to be deducted.

[0048] Furthermore, in S1, the effective driving moment is the moment measured by the balance , and the effective driving moment is the value obtained by subtracting the friction moment from the theoretical driving moment. The angle of the rudder surface rotation process under the condition of no wind load is , and its unit is radian (rad);

[0049] The effective driving moment is expressed as:

[0050] ;

[0051] ;

[0052] Among them, the unit of the effective driving moment is Newton-meter (N·m), the unit of the moment measured by the balance is Newton-meter (N·m), is the theoretical driving moment of the driving source, and its unit is Newton-meter (N·m), is the friction moment during the rotation process, and its unit is Newton-meter (N·m), is the moment of inertia of the moving part around the rotating shaft, and its unit is kilogram-meter squared (kg·m²), is the angular acceleration under the condition of no wind load, that is, the second derivative of the folding rudder unfolding angle with respect to time, and its unit is radian per second squared (rad / s²);

[0053] After measuring the effective driving moment, the relationship between the effective driving moment and the folding rudder unfolding angle is obtained, and the work done by the effective driving moment is obtained through the integral algorithm , and its unit is joule (J);

[0054] The work done by the effective driving moment is expressed as:

[0055] .

[0056] Further, in S2, the angle-of-rotation history of the rudder surface under wind load conditions is , with the unit of radian (rad). Digital filtering and smoothing methods are used to preprocess it, and a sixth-degree polynomial curve fitting is performed to obtain a mathematical expression for the unfolding angle of the folding rudder changing with time. Taking the first derivative of it gives a function of the angular velocity changing with time. According to the moment when the folding rudder is fully unfolded, the final angular velocity is calculated. By subtracting the work done by the effective driving torque from the final kinetic energy, the work done by the aerodynamic torque is obtained;

[0057] The mathematical expression for the unfolding angle of the folding rudder changing with time is expressed as:

[0058] ;

[0059] Among them, is time, with the unit of second (s), are respectively the constant terms of the sixth-degree polynomial curve fitting, and the moment when the folding rudder is fully unfolded has the unit of second (s), and the angular velocity corresponding to the moment when the folding rudder is fully unfolded has the unit of radian per second (rad / s);

[0060] The function of the angular velocity changing with time is expressed as:

[0061] ;

[0062] Among them, represents taking the first derivative of the angle-of-rotation history of the rudder surface under wind load conditions;

[0063] The final angular velocity is expressed as:

[0064] ;

[0065] The work done by the aerodynamic torque is expressed as:

[0066] ;

[0067] Among them, the unit of the work done by the aerodynamic torque is joule (J).

[0068] Although the present invention has been described in terms of a limited number of embodiments, those skilled in the art, having the benefit of the foregoing description, will appreciate that other embodiments can be devised within the scope of the invention as thus described. Additionally, it should be noted that the language used in this specification has been principally selected for readability and instructional purposes and not to limit or define the inventive subject matter. Accordingly, many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the appended claims. For the scope of the present invention, the disclosure herein is illustrative and not restrictive, and the scope of the invention is defined by the appended claims.

Claims

1. A test method for measuring the work done by the aerodynamic torque of a folding rudder, characterized in that: The following steps are involved: S1. Conduct a folding rudder deployment test under windless conditions, deploy a folding rudder model with a balance installed at the root, measure the effective driving torque during the folding rudder deployment process using the balance, use a high-speed photography tool to obtain the real-time folding rudder deployment angle, and obtain the relationship between the effective driving torque and the folding rudder deployment angle based on the obtained rudder surface rotation angle history under windless conditions, and integrate the relationship to obtain the work done by the effective driving torque; S2. Conduct a folding rudder deployment test under wind load conditions, set up a folding rudder model without a balance, use a high-speed photography tool to obtain the real-time folding rudder deployment angle, obtain the rudder surface rotation angle history under wind load conditions, perform polynomial fitting on it after digital filtering and smoothing pre-processing, and then perform a derivative on the folding rudder deployment angle history to obtain the angular velocity versus time curve, obtain the terminal angular velocity according to the moment when the folding rudder is fully deployed, and obtain the aerodynamic torque work by subtracting the effective driving torque work from the terminal kinetic energy when the folding rudder is fully deployed; In S1, the effective driving torque M xyx That is, the moment M measured by the balance xtp , the rudder surface rotation angle history under no wind load conditions is θ k , whose unit is radians; Effective driving torque M xyx It is expressed as: M xyx =M xnh -M xmc Among them, the effective driving torque M xyx The unit is Newton meter, the torque measured by the balance is M xtp The unit is Newton meter, M xnh is the theoretical driving torque of the driving source, its unit is Newton meter, M xmc is the friction torque during rotation, with the unit of N·m, and I is the moment of inertia of the moving part around the axis of rotation, with the unit of kg·m 2 , is the angular acceleration under no wind load conditions, that is, the second derivative of the folding rudder deployment angle with respect to time, and its unit is radian / second2; According to the effective driving torque M xyx , we can get the relationship between the effective driving torque and the folding rudder deployment angle F(θ k ), the work done by the effective driving torque W is obtained by the integration algorithm yx , whose unit is joule; The work done by the effective driving torque W yx It is expressed as: W yx =∫M xyx dth k =∫F(θ k )dθ k In S2, the rudder surface rotation angle history under wind load conditions is θ f , whose unit is radian, is pre-processed by digital filtering and smoothing method, and a 6th-order polynomial curve fitting is performed to obtain the mathematical expression of the change of the folding rudder deployment angle with time. The angular velocity function with time is obtained by taking a derivative. According to the time t when the folding rudder is deployed, end , calculate the final angular velocity ω end , using the final kinetic energy minus the work done by the effective driving torque, we get the work done by the aerodynamic torque; The mathematical expression of the change of the folding rudder deployment angle over time is expressed as: <h2 style=";text-align:left;direction:ltr">θ<h2 style=";text-align:left;direction:ltr"> f <h2 style=";text-align:left;direction:ltr"> =b0+b1t+b2t<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +b3t<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> +b4t<h2 style=";text-align:left;direction:ltr"> 4 <h2 style=";text-align:left;direction:ltr"> +b5t<h2 style=";text-align:left;direction:ltr"> 5 <h2 style=";text-align:left;direction:ltr"> +b6t<h2 style=";text-align:left;direction:ltr"> 6 Among them, t is time, and its unit is / second. b0, b1, b2, b3, b4, b5, and b6 are the constants of the 6th-order polynomial curve fitting. The moment when the folding rudder is fully deployed is t end The unit is / second; The angular velocity changes with time as a function of: in, Indicates the rudder surface rotation angle history θ under wind load conditions f Take a derivative; Final angular velocity ω end It is expressed as: Aerodynamic torque work W q It is expressed as: Among them, the aerodynamic torque does work W q The unit is joule.

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