A continuous force measurement wind tunnel test method based on a differential pressure pressure scanning valve

Abstract

A continuous force measurement wind tunnel testing method based on a differential pressure scanning valve belongs to the field of wind tunnel testing technology. To address the problem that reference pressure errors measured by reference pressure measuring equipment can introduce errors into the test results, this invention includes: installing a differential pressure scanning valve inside an aircraft model; connecting the reference pressure channel and the last measurement channel of the differential pressure scanning valve to the static pressure pipeline of the wind tunnel's stagnation chamber, measuring the pressure at the same location as the wind tunnel static pressure sensor; calculating the range of the differential pressure scanning valve; conducting wind tunnel tests, simultaneously collecting pressure data from pressure measuring holes on various surfaces of the aircraft model under different conditions, the total wind tunnel pressure, and the static pressure of the wind tunnel's stagnation chamber; judging whether the difference between the static pressure of the wind tunnel's stagnation chamber collected by the last channel of the differential pressure scanning valve and the static pressure of the wind tunnel's stagnation chamber collected by the wind tunnel static pressure sensor meets the measurement accuracy requirements based on the range of the differential pressure scanning valve; and processing the valid experimental data to calculate the coefficients of the pressure measuring holes in the wind tunnel flow field.

Description

Technical Field

[0001] This invention belongs to the field of wind tunnel testing technology, specifically relating to a continuous force measurement wind tunnel testing method based on a differential pressure scanning valve. Background Technology

[0002] A wind tunnel is a tubular testing device used to simulate the flow of gas around an aircraft or object. It artificially generates and controls airflow to simulate the gas flow around an aircraft model, measure the effects of the airflow on the model, and observe physical phenomena. Wind tunnels are typically powered by compressors (fans) or air tanks. Stable airflow conditions are established by real-time measurement of the total pressure in the stable section ahead of the test section and the static pressure of the test section, and by controlling and adjusting the compressor speed or the opening of the air tank valves.

[0003] Wind tunnel pressure testing is a crucial component of aircraft design. The pressure data acquisition system used in wind tunnel pressure testing typically employs a differential pressure scanning valve, capable of simultaneously measuring pressure data from multiple channels. The pressure scanning system connects to several pressure scanning valve blocks, each containing several channels. Currently, depending on the size of the test model, the system can simultaneously measure pressure data from thousands of pressure measurement points. During testing, the differential pressure scanning valve generally connects to and measures the reference pressure at one channel. The pressure values ​​measured at other channels are the actual pressure at each channel minus the reference pressure. The differential pressure scanning valve effectively avoids data errors caused by variations in the zero point of the scanning valve. Furthermore, the measured pressure data needs to be dimensionless, which helps improve the versatility of the test data, simplify the model, reduce the number of parameters, improve accuracy, and facilitate theoretical analysis.

[0004] During wind tunnel testing, the total pressure inside the wind tunnel needs to be adjusted appropriately to meet the requirements of different test types. Currently, the total pressure adjustment range of wind tunnel test sections in China is basically between 0.015MPa and 0.4MPa. This places higher demands on the range of pressure measuring equipment (such as pressure scanning valves) in pressure testing. The accuracy of the measuring equipment is closely related to its range; an excessively large measuring range will greatly affect the pressure measurement accuracy within a small range.

[0005] In current wind tunnel pressure testing, there are generally two methods. The first method is to connect the reference end of the differential pressure scanning valve to a stable atmospheric environment outside the wind tunnel and measure the atmospheric pressure value in real time. The second method is to provide a stable reference pressure to the pressure scanning valve through a pressure controller inside the wind tunnel or to directly connect the reference pressure end to a stable pressure vessel. Similarly, it is necessary to record and measure the pressure inside the pressure controller or pressure vessel in real time. The pressure measurement range of the first type of pressure scanning valve is basically determined to be atmospheric pressure plus the scanning valve range. The pressure measurement range is limited. For tests with high total pressure conditions, it is necessary to replace it with a large-range pressure scanning valve. At the same time, an atmospheric pressure gauge needs to be installed at the reference pressure extraction position to measure the atmospheric pressure value simultaneously. The second type of pressure scanning valve can adjust the reference pressure end pressure value according to the test requirements to achieve the pressure measurement range of the pressure scanning valve. However, 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 with a pressure controller, the stability and reliability of the pressure controller and its output reference pressure pipeline are required to a very high degree. Once the pressure controller fails, it is very easy to cause all pressure scanning valves used in the test to be damaged beyond their range. For adjusting the reference pressure through a stable pressure vessel, the adjustment of the pressure inside the pressure vessel takes time, which will have a significant impact on the efficiency of wind tunnel tests. 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 collects data. The atmospheric pressure gauge, pressure controller, or pressure measuring equipment used to measure the pressure of the pressure vessel introduces errors into the pressure measured by the pressure scanning valve, affecting the accuracy of the test data. Summary of the Invention

[0006] The problem this invention aims to solve is that the error in the reference pressure measured by the reference pressure measuring device will introduce experimental results. It proposes a continuous force measurement wind tunnel test method based on a differential pressure scanning valve.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A continuous force measurement wind tunnel test method based on a differential pressure scanning valve includes the following steps:

[0009] S1. The aircraft test component is installed in the wind tunnel test section to form an aircraft model;

[0010] S2. The differential pressure scanning valve is installed inside the aircraft model. The reference pressure channel and the last measurement channel of the differential pressure scanning valve are connected to the static pressure gas pipeline of the wind tunnel stagnation chamber, and measure the pressure at the same location as the wind tunnel static pressure sensor. Other measurement channels are normally connected to the pressure measuring hole gas pipeline on the surface of the aircraft model.

[0011] S3. Calculate the range of the differential pressure scanning valve based on the wind tunnel test conditions;

[0012] S4. Conduct wind tunnel tests and simultaneously collect data on the pressure at the pressure measurement holes on each surface of the aircraft model under different conditions, the total pressure of the wind tunnel, and the static pressure in the wind tunnel chamber.

[0013] S5. Determine the validity of the test data. Based on the range of the differential pressure scanning valve 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 wind tunnel static pressure sensor meets the measurement accuracy.

[0014] S6. Experimental Data Processing: Process the valid experimental data obtained in step S5 to calculate the Mach number of the wind tunnel flow field, the static pressure of the wind tunnel flow field, and the first-order displacement of the aircraft model. Pressure at each pressure test hole and pressure coefficient ;

[0015] S7. Following the methods in steps S4-S6, complete all test runs of the aircraft model state to obtain the pressure coefficients used for load integration or calculation of atmospheric parameters.

[0016] Furthermore, in step S2, the reference pressure channel of the differential pressure scanning valve and the last measurement channel are connected to the static pressure gas pipeline of the wind tunnel sump chamber using different pressure pipelines.

[0017] 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 range of the differential pressure scanning valve. The expression is:

[0018] ;

[0019] in, Indicates the first k The total pressure of the wind tunnel flow field in this test Indicates the first k The static pressure of the wind tunnel flow field in this test.

[0020] Furthermore, in step S5, the formula for judging the validity of the test data is set as the difference between the static pressure in the wind tunnel chamber collected by the last channel of the pressure scanning valve and the static pressure in the wind tunnel chamber collected by the wind tunnel static pressure sensor. Satisfy the following formula,

[0021] ;

[0022] Where K represents the measurement accuracy of the pressure scanning valve.

[0023] Furthermore, the specific implementation method of step S6 is as follows: based on the total wind tunnel pressure collected in step S4... wind tunnel static pressure chamber The differential pressure scanning valve collected data from the aircraft model. Pressure at each pressure test hole , The Mach number of the wind tunnel flow field was obtained. Wind tunnel flow field static pressure, aircraft model Pressure at each pressure test hole and pressure coefficient ;

[0024] Mach number of wind tunnel flow field Represented as:

[0025] ;

[0026] ;

[0027] in, For the reference pressure Mach number in the room, for and The correction amount, The value is a constant, determined by flow field calibration in each test section of each wind tunnel;

[0028] wind tunnel flow field static pressure Represented as:

[0029] ;

[0030] Due to the reference static pressure in the wind tunnel chamber Represented as:

[0031] ;

[0032] This yields the pressure correction between the static pressure values ​​of the wind tunnel test section and the static pressure values ​​at the stagnation chamber reference point for different Mach numbers and total pressures during the non-flow field calibration. , represented as:

[0033] ;

[0034] The values ​​are determined by flow field calibration of each test section in each wind tunnel;

[0035] For differential pressure scanning valves, the first pressure on the surface of the aircraft model... Pressure at each pressure test hole The pressure measured at the reference pressure end, plus the actual pressure measured by the pressure scanning valve, is expressed as follows:

[0036] ;

[0037] in, These are the actual pressure values ​​measured in each channel of the differential pressure scanning valve.

[0038] Finally, the first [unclear] on the surface of the aircraft model The pressure measured at each pressure gauge hole is dimensionless to obtain the first pressure of the aircraft model. Pressure coefficient of each pressure gauge hole , represented as:

[0039] .

[0040] The beneficial effects of this invention are:

[0041] The present invention discloses a continuous force measurement wind tunnel test method based on a differential pressure scanning valve. By connecting the reference pressure end of the differential pressure scanning valve to the static pressure of the wind tunnel chamber, the range requirement of the pressure scanning valve in the wind tunnel test is greatly reduced. This solves the problem of limited range or high reliability and risk of pressure scanning valves in the prior art, which also reduces test efficiency.

[0042] 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 stagnation 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 wind tunnel stagnation chamber when it is dimensionless, thus eliminating the reference pressure of the differential pressure scanning valve and solving the problem that the reference pressure error measured by the reference pressure measuring equipment in the prior art will introduce into the test results.

[0043] The present invention provides 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 makes full use of the small linear range near the 0 value of the scanning valve. Attached Figure Description

[0044] Figure 1 The flowchart is a continuous force measurement wind tunnel test method based on a differential pressure scanning valve as described in this invention.

[0045] Figure 2 Comparison of pressure scanning valve ranges for two reference pressure methods;

[0046] Figure 3 This is a typical airfoil profile pressure coefficient distribution diagram for the method of this invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described specific embodiments are merely a part of the embodiments of the invention, and not all of them. The components of the specific embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations, and the invention may also have other embodiments.

[0048] Therefore, the following detailed description of specific embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected specific embodiments of the invention. All other specific embodiments obtained by those skilled in the art based on these specific embodiments without inventive effort are within the scope of protection of this invention.

[0049] To further understand the invention's content, features, and effects, the following specific embodiments are provided, along with accompanying drawings. Figure 1 -Appendix Figure 3 Detailed explanation is as follows:

[0050] Example 1:

[0051] A continuous force measurement wind tunnel test method based on a differential pressure scanning valve includes the following steps:

[0052] S1. The aircraft test component is installed in the wind tunnel test section to form an aircraft model;

[0053] S2. The differential pressure scanning valve is installed inside the aircraft model. The reference pressure channel and the last measurement channel of the differential pressure scanning valve are connected to the static pressure gas pipeline of the wind tunnel stagnation chamber, and measure the pressure at the same location as the wind tunnel static pressure sensor. Other measurement channels are normally connected to the pressure measuring hole gas pipeline on the surface of the aircraft model.

[0054] Furthermore, in step S2, the reference pressure channel and the last measurement channel of the differential pressure scanning valve are connected to the static pressure gas pipeline of the wind tunnel sump chamber using different pressure pipelines; thus, the internal pressure of the two channels is not connected.

[0055] Specifically, the differential pressure scanning valve can be replaced with a pressure measuring device that has the same function as the pressure scanning valve;

[0056] S3. Calculate the range of the differential pressure scanning valve based on the wind tunnel test conditions;

[0057] 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 range of the differential pressure scanning valve. The expression is:

[0058] ;

[0059] in, Indicates the first k The total pressure of the wind tunnel flow field in this test Indicates the first k Static pressure of the wind tunnel flow field in this test;

[0060] Furthermore, unlike the reference pressure terminal which uses atmospheric pressure as a reference, the pressure scanning valve range required when using atmospheric pressure as a reference is... ,in This represents the atmospheric pressure value, which is typically around 0.1 MPa.

[0061] Compared to using atmospheric pressure as the reference pressure, using the static pressure of the wind tunnel test section as the reference pressure significantly reduces the requirements for the pressure scanning valve's range during high total pressure tests. Correspondingly, the absolute error of the pressure scanning valve is directly proportional to its range.

[0062] S4. Conduct wind tunnel tests and simultaneously collect data on the pressure at the pressure measurement holes on each surface of the aircraft model under different conditions, the total pressure of the wind tunnel, and the static pressure in the wind tunnel chamber.

[0063] Furthermore, the specific implementation method of step S4 includes the following steps:

[0064] S4.1. Based on the experimental requirements, the required Mach number of the wind tunnel flow field in the test section of the aircraft model installation area is set by adjusting the speed of the wind tunnel compressor. Wind tunnel total pressure ;

[0065] S4.2. When the attitude angle of the test aircraft model is in place and the flow field in the test section reaches a stable state, that is... , The Mach number of the wind tunnel flow field under steady conditions. To obtain the total wind tunnel pressure under stable conditions, the pressure scanning valve collects the pressure from the surface pressure measurement holes of the aircraft model after 3 seconds. Simultaneously, the total wind tunnel pressure sensor and the static wind tunnel pressure sensor collect the total wind tunnel pressure. Hefeng Tunnel Static Pressure .

[0066] S5. Determine the validity of the test data. Based on the range of the differential pressure scanning valve 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 wind tunnel static pressure sensor meets the measurement accuracy.

[0067] Furthermore, in step S5, the formula for judging the validity of the test data is set as the difference between the static pressure in the wind tunnel chamber collected by the last channel of the pressure scanning valve and the static pressure in the wind tunnel chamber collected by the wind tunnel static pressure sensor. Satisfy the following formula,

[0068] ;

[0069] Where K represents the measurement accuracy of the pressure scanning valve;

[0070] S6. Experimental Data Processing: Process the valid experimental data obtained in step S5 to calculate the Mach number of the wind tunnel flow field, the static pressure of the wind tunnel flow field, and the first-order displacement of the aircraft model. Pressure at each pressure test hole and pressure coefficient ;

[0071] The specific implementation method of step S6 is based on the total wind tunnel pressure collected in step S4. wind tunnel static pressure chamber The differential pressure scanning valve collected data from the aircraft model. Pressure at each pressure test hole , The Mach number of the wind tunnel flow field was obtained. Wind tunnel flow field static pressure, aircraft model Pressure at each pressure test hole and pressure coefficient ;

[0072] Mach number of wind tunnel flow field Represented as:

[0073] ;

[0074] ;

[0075] in, For the reference pressure Mach number in the room, for and The correction amount, The value is a constant, determined by flow field calibration in each test section of each wind tunnel;

[0076] wind tunnel flow field static pressure Represented as:

[0077] ;

[0078] Due to the reference static pressure in the wind tunnel chamber Represented as:

[0079] ;

[0080] This yields the pressure correction between the static pressure values ​​of the wind tunnel test section and the static pressure values ​​at the stagnation chamber reference point for different Mach numbers and total pressures during the non-flow field calibration. , represented as:

[0081] ;

[0082] The values ​​are determined by flow field calibration of each test section in each wind tunnel;

[0083] For differential pressure scanning valves, the first pressure on the surface of the aircraft model... Pressure at each pressure test hole The pressure measured at the reference pressure end, plus the actual pressure measured by the pressure scanning valve, is expressed as follows:

[0084] ;

[0085] in, These are the actual pressure values ​​measured in each channel of the differential pressure scanning valve.

[0086] Finally, the first [unclear] on the surface of the aircraft model The pressure measured at each pressure gauge hole is dimensionless to obtain the first pressure of the aircraft model. Pressure coefficient of each pressure gauge hole , represented as:

[0087] .

[0088] The dimensionless pressure coefficient of the pressure measuring hole on the surface of the aircraft model is obtained from the above formula. It is related to the actual pressure measured in the scanning valve's measurement channel and the dynamic pressure of the wind tunnel flow field, as well as the pressure correction amount obtained from the flow field calibration, but is not related to the pressure at the reference pressure end of the pressure scanning valve.

[0089] S7. Following the methods in steps S4-S6, complete all test runs of the aircraft model state to obtain the pressure coefficients used for load integration or calculation of atmospheric parameters.

[0090] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0091] Although this application has been described above with reference to specific embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of this application. In particular, as long as there is no structural conflict, the features in the specific embodiments disclosed in this application can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, this 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, Includes the following steps: S1. The aircraft test component is installed in the wind tunnel test section to form an aircraft model; S2. The differential pressure scanning valve is installed inside the aircraft model. The reference pressure channel and the last measurement channel of the differential pressure scanning valve are connected to the static pressure gas pipeline of the wind tunnel stagnation chamber, and measure the pressure at the same location as the wind tunnel static pressure sensor. Other measurement channels are normally connected to the pressure measuring hole gas pipeline on the surface of the aircraft model. S3. Calculate the range of the differential pressure scanning valve based on the wind tunnel test conditions; In step S3, based on the wind tunnel test conditions, the total pressure P0 of the wind tunnel flow field is set to be less than the static pressure P of the wind tunnel flow field. cp The maximum value is the range P of the differential pressure scanning valve. Range The expression is: P Range =MAX(P 0k -P cpk ) Among them, P 0k P represents the total pressure of the wind tunnel flow field in the k-th test. cpk This represents the static pressure of the wind tunnel flow field during the k-th test; S4. Conduct wind tunnel tests and simultaneously collect pressure data from pressure measurement holes on various surfaces of the aircraft model under different conditions, as well as the total wind tunnel pressure and the static pressure in the wind tunnel chamber. S5. Determine the validity of the test data. Based on the range of the differential pressure scanning valve 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 wind tunnel static pressure sensor meets the measurement accuracy. In step S5, the formula for judging the validity of the test data is set as the difference ΔP between the static pressure in the wind tunnel chamber collected by the last channel of the pressure scanning valve and the static pressure in the wind tunnel chamber collected by the wind tunnel static pressure sensor. ct Satisfy the following formula, △P ct ≤K*P Range Where K represents the measurement accuracy of the pressure scanning valve; S6. Experimental Data Processing: Process the valid experimental data obtained in step S5 to calculate the Mach number of the wind tunnel flow field, the static pressure of the wind tunnel flow field, and the pressure P at the i-th pressure measuring hole of the aircraft model. i and pressure coefficient C Pi ; S7. Following the methods in steps S4-S6, complete all test runs of the aircraft model state to obtain the pressure coefficients used for load integration or calculation of atmospheric parameters.

2. The 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 and the last measurement channel of the differential pressure scanning valve are connected to the static pressure gas pipeline of the wind tunnel sump chamber using different pressure pipelines.

3. The continuous force measurement wind tunnel test method based on a differential pressure scanning valve according to claim 2, characterized in that, The specific implementation method of step S6 is as follows: based on the total wind tunnel pressure P0 and the static pressure P in the wind tunnel chamber collected in step S4... ct The pressure P at the i-th pressure measuring port of the aircraft model, collected by the differential pressure scanning valve. i Given i = 1, 2, 3, ..., n, we obtain the Mach number M of the wind tunnel flow field. cp The static pressure in the wind tunnel flow field and the pressure P at the i-th pressure measuring hole of the aircraft model. i and pressure coefficient C Pi ; Mach number M in wind tunnel flow field cp Represented as: M cp =M ct +ΔM Among them, M ct Let M be the reference pressure Mach number for the stoichiometric chamber, and ΔM be M. ct With M cp The correction amount, ΔM, is a constant and is determined by the flow field calibration of each test section in each wind tunnel. wind tunnel flow field static pressure P cp Represented as: Due to the wind tunnel stabilization chamber reference static pressure P ct Represented as: This yields the pressure correction ΔP between the static pressure values ​​of the wind tunnel test section and the static pressure values ​​at the stagnation chamber reference point for different Mach numbers and total pressures during the non-flow field calibration. M , represented as: ΔP M =P cp -P ct ΔP M The values ​​are determined by flow field calibration of each test section in each wind tunnel; For a differential pressure scanning valve, the pressure P at the i-th pressure measuring hole on the surface of the aircraft model is... i The pressure measured at the reference pressure end, plus the actual pressure measured by the pressure scanning valve, is expressed as follows: P i =P ct +ΔP i Wherein, ΔP i These are the actual pressure values ​​measured in each channel of the differential pressure scanning valve. Finally, the pressure measured by the i-th pressure measuring hole on the surface of the aircraft model is dimensionless to obtain the pressure coefficient C of the i-th pressure measuring hole of the aircraft model. pi , represented as:

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