A method for zero-point monitoring and correction of a balance in a continuous wind tunnel force measurement test

Abstract

The present invention discloses a method for monitoring and correcting the zero point of a balance in a continuous wind tunnel force test, and belongs to the technical field of aircraft wind tunnel tests. The method solves the problem in the prior art that in order to ensure the accuracy of the test data, the compressor needs to be frequently shut down to collect windless test data, which greatly affects the efficiency of the continuous wind tunnel test; and solves the problem in the prior art that the collected balance strain cannot be corrected for zero point changes. The present invention realizes accurate correction of the zero point of the force test balance through the installation of the wind tunnel test support system and the wind tunnel test model, the collection of windless and windy test data, and the calculation of the balance zero point correction value based on time changes, and then calculates the six-element force and moment of the aerodynamic load on the test model. The present invention can significantly improve the efficiency of the continuous wind tunnel test, reduce the time for collecting the balance zero point and deadweight, significantly improve the accuracy and reliability of the continuous wind tunnel force test data, and can be applied to the wind tunnel force test.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft wind tunnel tests, and in particular to a method for monitoring and correcting the zero point of a continuous wind tunnel force measurement test balance. Background Art

[0002] Wind tunnel force test is an aerodynamic test conducted in a wind tunnel. It mainly measures the aerodynamic force of the airflow on the aircraft test model or its components by installing a force test balance in the wind tunnel test model. This test is crucial to the development of aircraft, and mainly includes full aircraft (missile) force test, half-model force test, component force test, external force test, hinge torque test, etc. In the development process of aircraft, wind tunnel force test is the test type with the highest proportion and the largest test volume, accounting for about 60% to 70% of all wind tunnel tests in the model development process.

[0003] Continuous wind tunnels are generally recirculation type, which maintains a stable flow in the wind tunnel by increasing the airflow pressure through a compressor or fan drive. Compared with temporary wind tunnels, it has the ability to operate continuously for a long time, has a higher test efficiency, and can complete all test states under the same model conditions in one start. Therefore, the force balance and data acquisition need to be stable and reliable throughout the test process. The accuracy and effectiveness of the data collected are the prerequisites for ensuring the efficient operation of the continuous wind tunnel.

[0004] A force test balance, also known as a wind tunnel balance, is a force sensor specifically used in wind tunnel tests. Currently, most of them are multi-component strain gauge balances, which are mainly used to measure the lift, drag, side force, pitch moment, roll moment and yaw moment, etc. exerted on scaled aircraft models or components in wind tunnels.

[0005] In the process of wind tunnel test, it is generally necessary to carry out windless test and windy test. When the model posture in the wind tunnel windless state is consistent with the model posture in the windy state, it is assumed that the balance load generated by gravity in the wind tunnel windy state (calculated by subtracting the balance zero point from the balance strain in the windy state) is equal to the balance load generated by gravity in the wind tunnel windless state (calculated by subtracting the balance zero point from the balance strain in the windless state), so the aerodynamic force on the test model can be obtained by subtracting the total load measured by the balance in the windy state from the total load measured by the balance in the windless state. The premise for the balance load generated by gravity in the wind tunnel windy state and the balance load generated by gravity in the wind tunnel windless state to be equal is that the zero point of the balance is stable or the zero point used to calculate the current load of the balance is the true zero point of the balance at the current moment (the zero point is the reading when the model is not installed on the balance).

[0006] The force test balance used in the force measurement wind tunnel test is a key device to ensure the accuracy of the force measurement test data. During the wind tunnel test, the model and the balance are located in the test section flow field, the environment is complex, and the pressure, temperature, vibration, etc. of the balance environment change in real time over time. Therefore, each strain element of the balance will have uncontrollable zero drift over time. In the current force measurement wind tunnel test, the common method is to carry out a windless test in time before blowing, shorten the time interval between the windless test and the wind test, and reduce the impact of the zero drift of the balance on the data. Since the aerodynamic load changes in real time during the test, it is impossible to judge the change of the zero point of the balance, and it cannot be used continuously for a long time. Once the zero point of the balance changes significantly and is not discovered and re-collected in time, the accuracy of the data obtained during the test will have a large deviation and cannot be corrected. Therefore, the existing force measurement wind tunnel test has the problem of frequently stopping the test to collect windless test data during the test, and the shutdown and startup of the wind tunnel compressor takes a lot of time, which greatly affects the efficiency of the continuous wind tunnel test. At the same time, for the data deviation caused by the change of the zero point of the balance during the test, due to the lack of data rules for the change of the zero point of the balance, there is a problem that the strain collected by the balance cannot be corrected, and the reliability and accuracy of the test data cannot be guaranteed. Summary of the invention

[0007] In order to solve the problem that the compressor needs to be frequently shut down to collect windless test data in order to ensure the accuracy of the test data in the prior art, which greatly affects the efficiency of the continuous wind tunnel test. In order to solve the problem that the collected balance strain cannot be corrected for zero point changes in the prior art, the present invention provides a method for monitoring and correcting the zero point of a balance in a continuous wind tunnel force measurement test.

[0008] The technical solution is as follows: A method for monitoring and correcting the zero point of a continuous wind tunnel force test balance comprises the following steps:

[0009] S1: The wind tunnel test support system is installed in the wind tunnel;

[0010] S2: The wind tunnel test model and force test balance are installed in the wind tunnel, and the balance zero point is collected ;

[0011] S3: Complete the test preparation;

[0012] S4: Conduct a windless test, combined with the zero point of the balance in S2 , obtain the windless state strain value of the force test balance And the deadweight value of the wind tunnel test model ;

[0013] S5: Wind tunnel start-up, collecting strain values ​​of the force test balance when the wind tunnel compressor is idling , while recording the current time ;

[0014] S6: Conduct a wind test to obtain the strain value of the force test balance under wind conditions and collection time;

[0015] S7: Perform balance monitoring strain collection. During the S6 wind test, adjust the compressor to the idle state every 15 minutes to obtain the strain value of the intermittent idle state of the force test balance. and current time ;

[0016] S8: Based on the strain value of the force test balance in S5 at the idle state of the wind tunnel compressor and the strain value of the intermittent idle state of the force test balance in S7 Get the strain change value of the force test balance collected at each moment , the strain change value of the force test balance Combined with the moment in S5 With S7 Obtain the curve of the balance zero point changing with time, and the strain value of the force test balance in S6 under windy conditions and current time Through local weighted linear regression, the zero point correction value of the force test balance of different trains is obtained by fitting the zero point change curve of the balance over time. ;

[0017] S9: Based on the zero point correction value of the force test balance of different vehicles in S8 and the deadweight value of the wind tunnel test model in S4 , the six-element forces and moments of the aerodynamic loads on the test model after zero-point correction are calculated.

[0018] Further, in S3, the test preparation work includes: installation and debugging of test equipment, inspection and testing of wind tunnel control system, surface treatment and inspection of wind tunnel test model and inspection and testing of data acquisition system.

[0019] Furthermore, in S4, the deadweight value of the wind tunnel test model is pass:

[0020] ;

[0021] get.

[0022] Furthermore, in S4, the windless state strain value of the force test balance is It is obtained by collecting the voltage values ​​of each element of the force test balance under the dead weight of the wind tunnel test model.

[0023] Furthermore, S5 specifically includes:

[0024] S51. The wind tunnel compressor is started, and the speed is adjusted to the idle speed. At the same time, the wind tunnel compressor blade angle is adjusted to a non-working state;

[0025] S52. Adjust the wind tunnel body conditions to the normal state;

[0026] S53. When the angle of attack of the wind tunnel test model is in the range of -4°~4° and the sideslip angle is 0°, the strain value of the force test balance at the idle state of the wind tunnel compressor is collected at every 1° angle of attack. , while recording the current time .

[0027] Furthermore, the balance strain change values ​​collected at each moment in S8 pass:

[0028] ;

[0029] get.

[0030] Furthermore, S9 specifically includes:

[0031] S91. Zero point correction value of force test balance according to different trains in S8 , correct the zero-point voltage of each test vehicle during air blowing, specifically through:

[0032] ;

[0033] Correction, where Indicates the corrected zero voltage value of the current test vehicle;

[0034] S92. According to the corrected zero-point voltage value, the total six-element force and moment measured by the force test balance are obtained. The specific formula is:

[0035] ;

[0036] in, The total six-element force and moment measured by the force test balance, Indicates the collected voltage values ​​of each element of the force test balance;

[0037] S93. Based on the total six-element forces and moments measured by the force test balance, deduct the deadweight value of the wind tunnel test model in S4 , the specific formula is:

[0038] ;

[0039] in, It represents the six-element force and moment of the aerodynamic load on the test model after zero point correction.

[0040] The beneficial effects of the present invention are as follows:

[0041] 1. The present invention can significantly improve the efficiency of continuous wind tunnel testing and reduce the time for collecting the zero point and deadweight of the balance;

[0042] Taking the drag coefficient as an example, under normal circumstances, when the balance strain changes by 1με / v, the deviation of the drag coefficient can exceed 0.0001 when the Mach number is 0.4 (the accuracy of the advanced indicator of the national military standard drag coefficient is ±0.0001). To ensure the accuracy of the test data, the compressor needs to be shut down at least every 30 minutes to collect windless data (a total of about 10 minutes). This method takes 2 minutes to collect the balance monitoring strain once every 15 minutes, saving more than 50% of the time for collecting the balance zero point and deadweight.

[0043] 2. The present invention can significantly improve the accuracy and reliability of continuous wind tunnel force measurement test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] 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:

[0045] Figure 1 This is a flow chart of the zero point monitoring and correction method for the continuous wind tunnel force test balance;

[0046] Figure 2 Schematic diagram of balance strain monitoring and fitting. DETAILED DESCRIPTION

[0047] 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.

[0048] Example: Combination Figure 1 - Figure 2 This embodiment describes a method for monitoring and correcting the zero point of a continuous wind tunnel force test balance, the method comprising:

[0049] S1: The wind tunnel test support system is installed in the wind tunnel;

[0050] Specifically, for the tail support test, the test support is connected to the middle bracket of the test section; for the side wall support test, the half-mold balance adapter is connected to the side wall window rotating mechanism of the test section.

[0051] S2: The wind tunnel test model and force test balance are installed in the wind tunnel, and the balance zero point is collected ;

[0052] Specifically, i is a positive integer, indicating the strain element number of the balance;

[0053] According to different test types and support forms, select different installation and zero point acquisition sequences. For example, for the full machine (bullet) force test, the steps are as follows:

[0054] S21. Connect the force test balance to the support system, perform preliminary leveling of the force test balance, and perform wiring and routing of the force test balance, data acquisition system, etc.;

[0055] S22. The dynamometer test balance is placed at the roll angle positions of 0°, ±90°, and 180° through the scimitar system roll angle mechanism, and the zero voltage of the balance is collected and recorded;

[0056] S23. The zero point of the balance can be obtained by averaging the four sets of data collected at different roll angles of each element of the force test balance. ;

[0057] S24. After the zero point is collected, the test model is installed on the force test balance and leveled.

[0058] For component force test, external force test, hinge moment test, etc., the steps are as follows:

[0059] S25. Connect the main body of the wind tunnel test model except the force test balance and components to the test support system and level it;

[0060] S26. Install the force test balance on the wind tunnel test model, and connect and wire the force test balance, data acquisition system, etc.;

[0061] S27. Collect the zero point of the force test balance 10 times and average it to get the zero point of the balance ;

[0062] S28. Install the model components, rudder surfaces, etc. on the force test balance.

[0063] For the half-mold force test, the steps are as follows:

[0064] S29. Connect the force test balance to the half-mold support adapter, and wire and route the force test balance, data acquisition system, etc.;

[0065] S210. Level the force test balance, collect the zero point of the force test balance 10 times and average them to get the zero point of the balance. ;

[0066] S211. Install the wind tunnel test model on the force test balance and level it.

[0067] S3: Complete the test preparation;

[0068] S4: Conduct a windless test, combined with the zero point of the balance in S2 , obtain the windless state strain value of the force test balance And the deadweight value of the wind tunnel test model ;

[0069] Specifically, a windless test is carried out, and the model attitude angle range of the windless test is determined according to the model attitude angle range required for the wind test in the current model state, ensuring that the windless state strain value of the force test balance in the entire wind test attitude angle range is obtained. And the deadweight value of the wind tunnel test model .

[0070] S5: Wind tunnel start-up, collect strain values ​​of the force test balance when the wind tunnel compressor is idling , while recording the current time ;

[0071] S6: Conduct a wind test to obtain the strain value of the force test balance under wind conditions and collection time;

[0072] Specifically, the wind test mainly carries out the wind test under the current model state according to the wind tunnel test outline, and collects the strain of each element of the balance. , wind tunnel flow field data, model attitude angle data, etc. Generally, 0.5 seconds of data are collected at each attitude angle and averaged, and the time when data collection is completed is recorded at the same time.

[0073] S7: Perform balance monitoring strain collection. During the S6 wind test, adjust the compressor to the idle state every 15 minutes to obtain the strain value of the intermittent idle state of the force test balance. and current time ;

[0074] Specifically, j represents the number of collections.

[0075] S8: Based on the strain value of the force test balance in S5 at the idle state of the wind tunnel compressor and the strain value of the intermittent idle state of the force test balance in S7 Get the strain change value of the force test balance collected at each moment , the strain change value of the force test balance Combined with the moment in S5 With S7 Obtain the curve of the balance zero point changing with time, and the strain value of the force test balance in S6 under windy conditions and current time Through local weighted linear regression, the zero point correction value of the force test balance of different trains is obtained by fitting the zero point change curve of the balance over time. Specific fitting conditions are as follows: Figure 2 shown.

[0076] S9: Based on the zero point correction value of the force test balance of different vehicles in S8 and the deadweight value of the wind tunnel test model in S4 , the six-element forces and moments of the aerodynamic loads on the test model after zero-point correction are calculated.

[0077] In S3, the test preparation work includes: installation and debugging of test equipment, inspection and testing of wind tunnel control system, surface treatment and inspection of wind tunnel test model, and inspection and testing of data acquisition system.

[0078] In S4, the deadweight value of the wind tunnel test model pass:

[0079] ;

[0080] get.

[0081] In S4, the strain value of the force test balance in the windless state It is obtained by collecting the voltage values ​​of each element of the force test balance under the dead weight of the wind tunnel test model.

[0082] S5 specifically includes:

[0083] S51. The wind tunnel compressor is started, and the speed is adjusted to the idle speed. At the same time, the wind tunnel compressor blade angle is adjusted to a non-working state;

[0084] S52. Adjust the wind tunnel body conditions to the normal state;

[0085] Specifically, the tunnel conditions include the wall panel angles, FLAP pieces, opening and closing ratios, etc. of the wind tunnel test section. The commonly used states refer to the tunnel conditions that are most used during the wind tunnel test, so as to minimize the time for changing tunnel conditions during the test.

[0086] S53. When the angle of attack of the wind tunnel test model is in the range of -4°~4° and the sideslip angle is 0°, the strain value of the force test balance at the idle state of the wind tunnel compressor is collected at every 1° angle of attack. , while recording the current time .

[0087] Balance strain change values ​​collected at each moment in S8 pass:

[0088] ;

[0089] get.

[0090] S9 specifically includes:

[0091] S91. Zero point correction value of force test balance according to different trains in S8 , correct the zero-point voltage of each test vehicle during air blowing, specifically through:

[0092] ;

[0093] Correction, where Indicates the corrected zero voltage value of the current test vehicle;

[0094] S92. According to the corrected zero-point voltage value, the total six-element force and moment measured by the force test balance are obtained. The specific formula is:

[0095] ;

[0096] in, The total six-element force and moment measured by the force test balance, Indicates the collected voltage values ​​of each element of the force test balance;

[0097] S93. Based on the total six-element forces and moments measured by the force test balance, deduct the deadweight value of the wind tunnel test model in S4 , the specific formula is:

[0098] ;

[0099] in, It represents the six-element force and moment of the aerodynamic load on the test model after zero point correction.

[0100] 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 monitoring and correcting the zero point of a continuous wind tunnel force test balance, characterized in that: The method comprises the following steps: S1: The wind tunnel test support system is installed in the wind tunnel; S2: The wind tunnel test model and force test balance are installed in the wind tunnel, and the balance zero point is collected ; S3: Complete the test preparation; S4: Conduct a windless test, combined with the zero point of the balance in S2 , obtain the windless state strain value of the force test balance And the deadweight value of the wind tunnel test model ; S5: Wind tunnel start-up, collect strain values ​​of the force test balance when the wind tunnel compressor is idling , while recording the current time ; S6: Conduct a wind test to obtain the strain value of the force test balance under wind conditions and collection time; S7: Perform balance monitoring strain collection. During the S6 wind test, adjust the compressor to the idle state every 15 minutes to obtain the strain value of the intermittent idle state of the force test balance. and current time ; S8: Based on the strain value of the force test balance in S5 at the idle state of the wind tunnel compressor and the strain value of the intermittent idle state of the force test balance in S7 Get the strain change value of the force test balance collected at each moment , the strain change value of the force test balance Combined with the moment in S5 With S7 Obtain the curve of the balance zero point changing with time, and the strain value of the force test balance in S6 under windy conditions and current time Through local weighted linear regression, the zero point correction value of the force test balance of different trains is obtained by fitting the zero point change curve of the balance over time. ; S9: Based on the zero point correction value of the force test balance of different vehicles in S8 and the deadweight value of the wind tunnel test model in S4 , the six-element forces and moments of the aerodynamic loads on the test model after zero-point correction are calculated.

2. The method for monitoring and correcting the zero point of a continuous wind tunnel force test balance according to claim 1, characterized in that: In S3, the test preparation work includes: installation and debugging of test equipment, inspection and testing of wind tunnel control system, surface treatment and inspection of wind tunnel test model, and inspection and testing of data acquisition system.

3. The method for monitoring and correcting the zero point of a continuous wind tunnel force test balance according to claim 1, characterized in that: In S4, the deadweight value of the wind tunnel test model pass: ； get.

4. The method for monitoring and correcting the zero point of a continuous wind tunnel force test balance according to claim 1, characterized in that: In S4, the strain value of the force test balance in the windless state It is obtained by collecting the voltage values ​​of each element of the force test balance under the dead weight of the wind tunnel test model.

5. The method for monitoring and correcting the zero point of a continuous wind tunnel force test balance according to claim 1, characterized in that: S5 specifically includes: S51. The wind tunnel compressor is started, and the speed is adjusted to the idle speed. At the same time, the wind tunnel compressor blade angle is adjusted to a non-working state; S52. Adjust the wind tunnel body conditions to the normal state; S53. When the angle of attack of the wind tunnel test model is in the range of -4°~4° and the sideslip angle is 0°, the strain value of the force test balance at the idle state of the wind tunnel compressor is collected at every 1° angle of attack. , while recording the current time .

6. The method for monitoring and correcting the zero point of a continuous wind tunnel force test balance according to claim 1, characterized in that: Balance strain change values ​​collected at each moment in S8 pass: ； get.

7. The method for monitoring and correcting the zero point of a continuous wind tunnel force test balance according to claim 1, characterized in that: S9 specifically includes: S91. Zero point correction value of force test balance according to different trains in S8 , correct the zero-point voltage of each test vehicle during air blowing, specifically through: ； Correction, where Indicates the corrected zero voltage value of the current test vehicle; S92. According to the corrected zero-point voltage value, the total six-element force and moment measured by the force test balance are obtained. The specific formula is: ； in, It represents the total six-element force and moment measured by the force test balance. Indicates the collected voltage values ​​of each element of the force test balance; S93. Based on the total six-element forces and moments measured by the force test balance, deduct the deadweight value of the wind tunnel test model in S4 , the specific formula is: ； in, It represents the six-element force and moment of the aerodynamic load on the test model after zero point correction.

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