Continuous force measurement wind tunnel test method based on differential pressure type pressure scanning valve

Abstract

The invention discloses a continuous force measurement wind tunnel test method based on a differential pressure type pressure scanning valve, and belongs to the technical field of wind tunnel tests. In order to solve the problem that a test result can be introduced by a reference pressure error measured by reference pressure measurement equipment, the method comprises the steps that a differential pressure type pressure scanning valve is installed in an aircraft model, and a reference pressure channel and a last measurement channel of the differential pressure type pressure scanning valve are connected with a wind tunnel plenum chamber static pressure air pipeline; measuring the pressure at the same position with a wind tunnel static pressure sensor; calculating the range of the differential pressure type pressure scanning valve; performing a wind tunnel test, and synchronously acquiring the pressure of each surface pressure measuring hole, the wind tunnel total pressure and the wind tunnel plenum chamber static pressure of the aircraft model in different states; whether the difference value between the wind tunnel plenum chamber static pressure collected by the last channel of the differential pressure type pressure scanning valve and the wind tunnel plenum chamber static pressure collected by the wind tunnel static pressure sensor meets the measurement precision or not is judged based on the range of the differential pressure type pressure scanning valve; and performing test data processing on the effective test data, and calculating the coefficient of the wind tunnel flow field pressure hole.

Description

Technical Field

[0001] The invention belongs to the technical field of wind tunnel tests, and in particular relates to a continuous force measurement wind tunnel test method based on a differential pressure scanning valve. Background Art

[0002] A wind tunnel is a pipe-shaped test device used to simulate the flow of gas around an aircraft or object. It generates and controls airflow artificially to simulate the flow of gas around an aircraft model, measure the effect of airflow on the model, and observe physical phenomena. Wind tunnels are generally powered by compressors (fans) or air tanks, and establish stable airflow conditions by real-time measurement of the total pressure in the stable section in front of the test section and the static pressure of the test section, and real-time control and adjustment of the compressor speed or the opening of the air tank valve.

[0003] Wind tunnel pressure test is a very important wind tunnel test project in aircraft design. The pressure data acquisition system used in wind tunnel pressure test generally adopts differential pressure scanning valve, which can measure multi-channel pressure data at the same time. The pressure scanning system connects several pressure scanning valve blocks, and each valve block contains several channels. At present, the test can measure the pressure data of thousands of channel pressure measurement points at the same time according to the size of the test model. During the test, the differential pressure scanning valve generally connects and measures the reference pressure end pressure through one channel. The pressure value measured in other channels is the actual pressure at each channel minus the reference end pressure. The differential pressure scanning valve can effectively avoid data errors caused by the change of the zero point of the scanning valve. In addition, the measured pressure data needs to be dimensionless, which helps to improve the versatility of the test data, simplify the model, reduce the number of parameters, improve the accuracy, and facilitate theoretical analysis.

[0004] Generally, during a wind tunnel test, the total pressure in the wind tunnel needs to be adjusted appropriately to meet the requirements of different test types. At present, the total pressure adjustment range of the wind tunnel test section in China is basically between 0.015MPa and 0.4MPa. This places higher requirements on the range of pressure measuring equipment (such as pressure scanning valve) in pressure measurement tests, and the accuracy of the measuring equipment is closely related to the range. An excessively large measurement range will greatly affect the pressure measurement accuracy within a small range.

[0005] There are generally two methods for current wind tunnel pressure testing. The first is to connect the reference end of the differential pressure scanning valve to the stable atmospheric environment outside the wind tunnel, and measure the pressure value of the atmospheric environment in real time. The second is to provide a stable reference pressure for the pressure scanning valve through a pressure controller in the wind tunnel or directly connect the reference pressure end to a stable pressure vessel, which also requires real-time recording and measurement of the pressure in the pressure controller or pressure vessel. The pressure range measured by the pressure scanning valve of the first type is basically determined to be the atmospheric pressure plus the scanning valve range, and the pressure measurement range is limited. For tests with higher total pressure conditions, it is necessary to replace the large-range pressure scanning valve equipment, and at the same time, it is necessary to install an atmospheric pressure gauge at the reference pressure extraction position to synchronously measure the atmospheric pressure value; the pressure scanning valve of the second type can adjust the reference pressure end pressure value according to the test requirements to achieve the pressure measurement range of the pressure scanning valve, but it is necessary to adjust the reference end pressure in real time according to the wind tunnel flow field conditions to ensure that the pressure scanning valve range always meets the requirements. For the method of controlling the reference pressure by the pressure controller, there are extremely high requirements on the stability and reliability of the pressure controller and its output reference pressure pipeline. Once the pressure controller fails, it is very easy to cause the pressure scanning valves used in all tests to exceed the range and be damaged. For adjusting the reference pressure through a stable pressure vessel, it takes time to adjust the pressure in the pressure vessel, which will have a great impact on the efficiency of the wind tunnel test. Finally, both of the above methods require real-time measurement and recording of the reference pressure value output by the atmospheric pressure gauge or pressure controller while the pressure scanning valve is collecting data. The atmospheric pressure gauge or pressure controller or the measuring equipment for measuring the pressure of the pressure vessel used introduces measurement equipment errors to the pressure measured by the pressure scanning valve, affecting the accuracy of the test data. Summary of the invention

[0006] The problem to be solved by the present invention is that the reference pressure error measured by the reference pressure measuring device will be introduced into the test result, and a continuous force measurement wind tunnel test method based on a differential pressure scanning valve is proposed.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions: A continuous force measurement wind tunnel test method based on a differential pressure scanning valve comprises the following steps: S1. The aircraft test piece is installed in the wind tunnel test section to form an aircraft model; S2. The differential pressure scanning valve is installed in the aircraft model. The reference pressure channel and the last measurement channel of the differential pressure scanning valve are connected to the static pressure air pipeline of the wind tunnel station chamber to measure the pressure at the same position as the static pressure sensor of the wind tunnel. The other measurement channels are normally connected to the air pipeline of the pressure measuring holes on the surface of the aircraft model. S3. Calculate the range of the differential pressure scanning valve according to the wind tunnel test conditions; S4. Conduct wind tunnel tests and simultaneously collect pressures at pressure gauge holes on the surfaces of the aircraft model under different conditions, total pressure in the wind tunnel, and static pressure in the wind tunnel chamber; S5. Determine the validity of the test data, based on the differential pressure scanning valve range obtained in step S3, determine whether the difference between the static pressure of the wind tunnel chamber collected by the last channel of the differential pressure scanning valve and the static pressure of the wind tunnel chamber collected by the static pressure sensor of the wind tunnel satisfies the measurement accuracy; S6. Experimental data processing: processing the effective experimental data obtained in step S5 to calculate the wind tunnel flow field Mach number, wind tunnel flow field static pressure, and the aircraft model. The pressure of the pressure tap and pressure coefficient ; S7. According to the method of step S4 to step S6, complete all test runs of the aircraft model state and obtain the pressure coefficient used for load integration or calculation of atmospheric parameters.

[0008] Furthermore, in step S2, the reference pressure channel of the differential pressure scanning valve and the last measuring channel are connected to the static pressure gas pipeline of the wind tunnel station chamber using different pressure pipelines.

[0009] Furthermore, in step S3, the total pressure of the wind tunnel flow field is set according to the wind tunnel test conditions. Subtract the static pressure of the wind tunnel flow field The maximum value is the differential pressure scanning valve range , the expression is: ; in, Indicates k The total pressure of the wind tunnel flow field in the test is: Indicates k Static pressure of wind tunnel flow field during the test.

[0010] Furthermore, in step S5, the test data validity judgment formula is set to judge the difference between the wind tunnel static pressure collected by the last channel of the pressure scanning valve and the wind tunnel static pressure collected by the wind tunnel static pressure sensor. Satisfies the following formula, ; Wherein, K represents the measurement accuracy of the pressure scanning valve.

[0011] Furthermore, the specific implementation method of step S6 is to obtain the total wind tunnel pressure according to step S4. , Wind tunnel chamber static pressure , the aircraft model collected by the differential pressure scanning valve The pressure of the pressure tap , , and the Mach number of the wind tunnel flow field is obtained , wind tunnel flow field static pressure, aircraft model The pressure of the pressure tap and pressure coefficient ; Mach number of wind tunnel flow It is expressed as: ; ; in, is the reference pressure Mach number of the station chamber, for and The correction amount, The value is a constant, determined by flow field calibration in each test section of each wind tunnel; Wind tunnel flow field static pressure It is expressed as: ; Since the reference static pressure in the wind tunnel chamber It is expressed as: ; The pressure correction value of the static pressure value of the wind tunnel test section flow field and the static pressure value of the reference point in the room at different Mach numbers and total pressures in the flow field calibration is obtained. , expressed as: ; The value of is determined by the flow field calibration of each test section in each wind tunnel; For differential pressure scanning valve, the first The pressure of the pressure tap The pressure measured at the reference pressure end plus the pressure actually measured by the pressure scanning valve is specifically expressed as: ; in, It is the pressure value actually measured in each channel of the differential pressure scanning valve; Finally, the first The pressure measured by the pressure measuring hole is dimensionless, and the first Pressure coefficient of each pressure tap , expressed as: .

[0012] Beneficial effects of the present invention: The present invention discloses a continuous force measurement wind tunnel test method based on a differential pressure scanning valve, which greatly reduces the range requirement of the pressure scanning valve in the wind tunnel test by connecting the reference pressure end of the differential pressure scanning valve to the static pressure of the wind tunnel chamber, thereby solving the problem in the prior art that the pressure scanning valve has a limited range or has high reliability and risk while reducing the test efficiency.

[0013] The present invention discloses a continuous force measurement wind tunnel test method based on a differential pressure scanning valve. By connecting the static pressure of the resident chamber to the reference pressure end of the differential pressure scanning valve, the pressure data measured in the test is subtracted from the static pressure value of the resident chamber of the wind tunnel when being dimensionless, thereby eliminating the reference pressure of the differential pressure scanning valve and solving the problem in the prior art that the reference pressure error measured by the reference pressure measuring equipment will be introduced into the test results.

[0014] The present invention discloses a continuous force measurement wind tunnel test method based on a differential pressure scanning valve. The pressure data measured by the differential pressure scanning valve is basically symmetrically distributed along the static pressure of the flow field. The present invention fully utilizes the small-range linear segment range near the scanning valve 0 value. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of a continuous force measurement wind tunnel test method based on a differential pressure scanning valve according to the present invention; Figure 2 Comparison of the pressure scanning valve ranges for two reference pressure methods; Figure 3 It is the pressure coefficient distribution diagram of a typical airfoil section of the method of the present invention. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the specific embodiments described are only part of the embodiments of the present invention, rather than all of the specific embodiments. The components of the specific embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations, and the present invention can also have other embodiments.

[0017] Therefore, the following detailed description of the specific embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected specific embodiments of the present invention. Based on the specific embodiments of the present invention, all other specific embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0018] In order to further understand the content, features and effects of the present invention, the following specific implementation methods are given as examples, and the attached Figure 1 -Attached Figure 3 The detailed instructions are as follows:

[0019] Embodiment 1: A continuous force measurement wind tunnel test method based on a differential pressure scanning valve comprises the following steps: S1. The aircraft test piece is installed in the wind tunnel test section to form an aircraft model; S2. The differential pressure scanning valve is installed in the aircraft model. The reference pressure channel and the last measurement channel of the differential pressure scanning valve are connected to the static pressure air pipeline of the wind tunnel station chamber to measure the pressure at the same position as the static pressure sensor of the wind tunnel. The other measurement channels are normally connected to the air pipeline of the pressure measuring holes on the surface of the aircraft model. Furthermore, in step S2, the reference pressure channel of the differential pressure scanning valve and the last measuring channel are connected to the static pressure gas pipeline of the wind tunnel station chamber using different pressure pipelines; the internal pressures of the two channels are not connected; Specifically, the differential pressure scanning valve can be replaced by a pressure measuring device having the same function as the pressure scanning valve; S3. Calculate the range of the differential pressure scanning valve according to the wind tunnel test conditions; Furthermore, in step S3, the total pressure of the wind tunnel flow field is set according to the wind tunnel test conditions. Subtract the static pressure of the wind tunnel flow field The maximum value is the differential pressure scanning valve range , the expression is: ; in, Indicates k The total pressure of the wind tunnel flow field in the test is: Indicates k The static pressure of the wind tunnel flow field during the test; Furthermore, unlike the reference pressure end which uses atmospheric pressure as a reference, the required pressure scanning valve range when using atmospheric pressure as a reference is ,in Indicates the atmospheric pressure value, generally about 0.1MPa.

[0020] Compared with using the atmospheric environment as the reference pressure, using the static pressure of the wind tunnel test section as the reference pressure can greatly reduce the requirements for the range of the pressure scanning valve during high total pressure testing. Correspondingly, the absolute error of the pressure scanning valve is proportional to the range.

[0021] S4. Conduct wind tunnel tests and simultaneously collect pressures at pressure gauge holes on the surfaces of the aircraft model under different conditions, total pressure in the wind tunnel, and static pressure in the wind tunnel chamber; Furthermore, the specific implementation method of step S4 includes the following steps: S4.1. According to the test requirements, the wind tunnel compressor speed is adjusted to achieve the required wind tunnel flow field Mach number in the wind tunnel test section where the aircraft model is installed. , total wind tunnel pressure ; S4.2. When the attitude angle of the aircraft model to be tested is in place and the flow field of the test section reaches a stable state, , is the Mach number of the wind tunnel flow field under stable conditions, To obtain the total wind tunnel pressure under stable conditions, the pressure scanning valve collects the pressure of the surface pressure measuring hole of the aircraft model after 3 seconds. At the same time, the wind tunnel total pressure sensor and the wind tunnel static pressure sensor collect the total wind tunnel pressure respectively. and wind tunnel static pressure .

[0022] S5. Determine the validity of the test data, based on the differential pressure scanning valve range obtained in step S3, determine whether the difference between the static pressure of the wind tunnel chamber collected by the last channel of the differential pressure scanning valve and the static pressure of the wind tunnel chamber collected by the static pressure sensor of the wind tunnel satisfies the measurement accuracy; Furthermore, in step S5, the test data validity judgment formula is set to judge the difference between the wind tunnel static pressure collected by the last channel of the pressure scanning valve and the wind tunnel static pressure collected by the wind tunnel static pressure sensor. Satisfies the following formula, ; Wherein, K represents the measurement accuracy of the pressure scanning valve; S6. Experimental data processing: processing the effective experimental data obtained in step S5 to calculate the wind tunnel flow field Mach number, wind tunnel flow field static pressure, and the aircraft model. The pressure of the pressure tap and pressure coefficient ; The specific implementation method of step S6 is to use the wind tunnel total pressure collected in step S4 , Wind tunnel chamber static pressure , the aircraft model collected by the differential pressure scanning valve The pressure of the pressure tap , , and the Mach number of the wind tunnel flow field is obtained , wind tunnel flow field static pressure, aircraft model The pressure of the pressure tap and pressure coefficient ; Mach number of wind tunnel flow It is expressed as: ; ; in, is the reference pressure Mach number of the station chamber, for and The correction amount, The value is a constant, determined by flow field calibration in each test section of each wind tunnel; Wind tunnel flow static pressure It is expressed as: ; Since the reference static pressure in the wind tunnel chamber It is expressed as: ; The pressure correction value of the static pressure value of the wind tunnel test section flow field and the static pressure value of the reference point in the room at different Mach numbers and total pressures in the flow field calibration is obtained. , expressed as: ; The value of is determined by the flow field calibration of each test section in each wind tunnel; For differential pressure scanning valve, the first The pressure of the pressure tap The pressure measured at the reference pressure end plus the pressure actually measured by the pressure scanning valve is specifically expressed as: ; in, It is the pressure value actually measured in each channel of the differential pressure scanning valve; Finally, the surface of the aircraft model The pressure measured by the pressure measuring hole is dimensionless, and the first Pressure coefficient of each pressure tap , expressed as: .

[0023] Through the above formula, the dimensionless pressure coefficient of the pressure measuring hole on the surface of the aircraft model is It is related to the pressure actually measured in the scanning valve measurement channel, the dynamic pressure of the wind tunnel flow field, and the pressure correction amount obtained by flow field calibration, and has nothing to do with the pressure at the reference pressure end of the pressure scanning valve.

[0024] S7. According to the method of step S4 to step S6, complete all test runs of the aircraft model state and obtain the pressure coefficient used for load integration or calculation of atmospheric parameters.

[0025] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0026] Although the present application has been described above with reference to specific embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the various features in the specific embodiments disclosed in the present application may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A continuous force measurement wind tunnel test method based on a differential pressure scanning valve, characterized in that: The steps include: S1. The aircraft test piece is installed in the wind tunnel test section to form an aircraft model; S2. The differential pressure scanning valve is installed in the aircraft model. The reference pressure channel and the last measurement channel of the differential pressure scanning valve are connected to the static pressure air pipeline of the wind tunnel station chamber to measure the pressure at the same position as the static pressure sensor of the wind tunnel. The other measurement channels are normally connected to the air pipeline of the pressure measuring holes on the surface of the aircraft model. S3. Calculate the range of the differential pressure scanning valve according to the wind tunnel test conditions; S4. Conduct wind tunnel tests and simultaneously collect pressures at pressure gauge holes on the surfaces of the aircraft model under different conditions, total pressure in the wind tunnel, and static pressure in the wind tunnel chamber; S5. Determine the validity of the test data, based on the differential pressure scanning valve range obtained in step S3, determine whether the difference between the static pressure of the wind tunnel chamber collected by the last channel of the differential pressure scanning valve and the static pressure of the wind tunnel chamber collected by the static pressure sensor of the wind tunnel satisfies the measurement accuracy; S6. Experimental data processing: processing the effective experimental data obtained in step S5 to calculate the wind tunnel flow field Mach number, wind tunnel flow field static pressure, and the aircraft model. The pressure of the pressure tap and pressure coefficient ; S7. According to the method of step S4 to step S6, complete all test runs of the aircraft model state and obtain the pressure coefficient used for load integration or calculation of atmospheric parameters.

2. A continuous force measurement wind tunnel test method based on a differential pressure scanning valve according to claim 1, characterized in that: In step S2, the reference pressure channel of the differential pressure scanning valve and the last measuring channel are connected to the static pressure gas pipeline of the wind tunnel station chamber using different pressure pipelines.

3. A continuous force measurement wind tunnel test method based on a differential pressure scanning valve according to claim 2, characterized in that: In step S3, the total pressure of the wind tunnel flow field is set according to the wind tunnel test conditions. Subtract the static pressure of the wind tunnel flow field The maximum value is the differential pressure scanning valve range , the expression is: ； in, Indicates k The total pressure of the wind tunnel flow field in the test is: Indicates k Static pressure of wind tunnel flow field during the test.

4. A continuous force measurement wind tunnel test method based on a differential pressure scanning valve according to claim 3, characterized in that: In step S5, the test data validity judgment formula is set to judge the difference between the static pressure of the wind tunnel chamber collected by the last channel of the pressure scanning valve and the static pressure of the wind tunnel chamber collected by the wind tunnel static pressure sensor. Satisfies the following formula, ； Wherein, K represents the measurement accuracy of the pressure scanning valve.

5. A continuous force measurement wind tunnel test method based on a differential pressure scanning valve according to claim 4, characterized in that: The specific implementation method of step S6 is to use the wind tunnel total pressure collected in step S4 , Wind tunnel chamber static pressure , the aircraft model collected by the differential pressure scanning valve The pressure of the pressure tap , , and the Mach number of the wind tunnel flow field is obtained , wind tunnel flow field static pressure, aircraft model The pressure of the pressure tap and pressure coefficient ; Mach number of wind tunnel flow It is expressed as: ； ； in, is the reference pressure Mach number of the stationary chamber, for and The correction amount, The value is a constant, determined by flow field calibration in each test section of each wind tunnel; Wind tunnel flow field static pressure It is expressed as: ； Since the reference static pressure in the wind tunnel chamber It is expressed as: ； The pressure correction value of the static pressure value of the wind tunnel test section flow field and the static pressure value of the reference point in the room at different Mach numbers and total pressures in the flow field calibration is obtained. , expressed as: ； The value of is determined by the flow field calibration of each test section in each wind tunnel; For differential pressure scanning valve, the first The pressure of the pressure tap The pressure measured at the reference pressure end plus the pressure actually measured by the pressure scanning valve is specifically expressed as: ； in, It is the pressure value actually measured in each channel of the differential pressure scanning valve; Finally, the surface of the aircraft model The pressure measured by the pressure measuring hole is dimensionless, and the first Pressure coefficient of each pressure tap , expressed as: 。

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