A real-time measurement method and device for wind tunnel flow velocity

Abstract

The present invention discloses a method and device for real-time measurement of wind tunnel flow velocity, which belongs to the field of gas flow velocity measurement and calibration. The method of the present invention includes the steps of sensor module calibration, probe connection, probe installation, signal filtering, velocity calculation, and velocity correction. The device of the present invention includes a sensor module, a control mainboard, a module power supply, a chassis, a display screen, a pressure probe, and a total temperature probe. In terms of the selection of sensitive elements, the present invention adopts a probe as the sensing part to avoid the problem that the supersonic flow velocity cannot be measured due to the fragility of the sensitive elements. At the same time, it has no special requirements for the environment and is easy to use. In terms of the measurement method, the flow velocity is quickly solved based on the aerodynamic function equation and the iterative method, which solves the problem that the supersonic airflow in engineering applications cannot directly solve the velocity in real time due to the existence of shock waves and the complex parameter relationship. The present invention can improve the accuracy of real-time flow velocity measurement and can trace back to the source. It can be used as a flow velocity standard for calibration of various probes and anemometers.

Description

Technical Field

[0001] The invention belongs to the field of gas flow rate measurement and calibration, and relates to a real-time wind tunnel flow rate measurement method and device. Background Art

[0002] Wind tunnels are an indispensable component in aircraft development. They not only play an important role in aerospace engineering, but with the development of industrial aerodynamics, they are even more indispensable in transportation, building construction, wind energy utilization and other fields. In various wind tunnel tests, it is necessary to accurately measure the airflow velocity in the wind tunnel flow field; at the same time, wind tunnels can also be used as flow velocity calibration devices, and cooperate with the main standard to calibrate various probes and anemometers.

[0003] Currently, instruments used for wind tunnel velocity measurement primarily include pitot tube velocities, hot-wire flowmeters, and laser Doppler velocities. These instruments can also serve as velocity standards. Pitot tube velocities are based on the Bernoulli equation and utilize a micro-differential pressure gauge to calculate velocity. However, due to the limitations of this principle, their measurement range is limited to only 70 m / s. Hot-wire velocities can measure speeds up to 300 m / s, but the hot-wire probe's sensitive element is very thin and fragile, and is often easily blown off. Laser Doppler velocities can measure supersonic airflow velocities, but their complex optical path and the need to disperse tracer particles make them inconvenient to use. Summary of the Invention

[0004] In order to overcome the above-mentioned technical deficiencies, the main purpose of the present invention is to provide a real-time wind tunnel flow velocity measurement method and device, which can quickly solve the wind tunnel flow velocity based on the aerodynamic function equation, and at the same time has the functions of calibration, filtering, real-time acquisition and display, self-calibration, etc., and can accurately measure subsonic, transonic and supersonic wind tunnel airflow velocities. At the same time, it can be traced back to the source and used as a flow velocity standard for the calibration of various probes and anemometers.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The present invention discloses a method for measuring wind tunnel flow velocity, comprising the following steps:

[0007] To calibrate the pressure and temperature sensing modules, connect each range pressure module to the pressure standard device in sequence. The pressure standard device will give the standard pressure according to the preset pressure values ​​P1, P2, …, Pn. Record the measured values ​​P1', P2', …, Pn' of each pressure module to obtain the pressure correction values ​​△P1, △P2, …, △Pn and the pressure correction curve. Use the interpolation algorithm to obtain the pressure correction value within the entire range to complete the pressure calibration. Connect the temperature sensing module to the temperature standard device. The temperature standard device will give the standard temperature according to the preset temperature values ​​T1, T2, …, Tn. Record the measured values ​​T1', T2', …, Tn' of the temperature sensing module to obtain the temperature correction values ​​△T1, △T2, …, △Tn and the temperature correction curve. Use the interpolation algorithm to obtain the temperature correction value within the entire range to complete the temperature calibration.

[0008] For probe connection, select a pressure probe and connect it to the pressure sensing module of the corresponding range to measure the airflow pressure. Use two total pressure probes for supersonic airflow and a total static pressure probe for subsonic airflow. Select a total temperature probe and connect it to the temperature sensing module to measure the total airflow temperature.

[0009] Probe installation: When measuring supersonic airflow, two total pressure probes are installed in the stable section and the core area of ​​the test section of the supersonic wind tunnel respectively. When measuring subsonic airflow, the total static pressure probe is installed in the core area of ​​the subsonic wind tunnel test section, and the temperature probe is installed in the stable section of the wind tunnel.

[0010] Pressure and temperature measurement signal filtering uses a parallel line filtering method. Based on the constraints, thresholds are set to identify the validity of the measurement data, and measurement values ​​that do not meet the constraints are filtered out, eliminating gross errors and ensuring the authenticity and validity of the data. The constraints include the accuracy requirements of the pressure measurement module and the temperature measurement module and the test results.

[0011] Velocity calculation, using pressure and temperature measurements to calculate the airflow velocity v;

[0012] Velocity correction uses the Doppler laser velocimeter LDV as a standard to correct the calculated airflow velocity v. The correction coefficient is obtained by comparing the LDV standard value and the calculated value at each flow rate to obtain the corrected flow velocity value.

[0013] The wind tunnel flow velocity measurement method disclosed in the present invention further includes the following steps: tracing back to the source based on the corrected flow velocity value and using it as a flow velocity standard for calibrating various probes and anemometers.

[0014] Furthermore, the speed calculation method is as follows:

[0015] Step 1: Calculate the airflow Mach number Ma;

[0016] Among them, the supersonic airflow calculates the Mach number based on the relationship between the parameters before and after the shock wave. The calculation model is as follows:

[0017]

[0018] ——Total pressure at the wavefront, measured by the total pressure probe in the stable section, Pa;

[0019] ——Total pressure after the wave, measured by the total pressure probe in the test section, Pa;

[0020] Ma——airflow Mach number;

[0021] k - specific heat ratio, which is 1.4 for air;

[0022] make:

[0023] Wherein, a is a constant, 0<a<1;

[0024] Substitute (2) into (1):

[0025]

[0026] Simplifying formula (3), we get the following results:

[0027]

[0028] make

[0029] The following iterative method is used to solve the Mach number:

[0030] 1) Take the initial points x0 and x1, the maximum number of iterations N and the iteration accuracy ε, and set i = 1;

[0031] 2) Calculation

[0032] 3) If |x i+1 -x i |<ε, then stop the operation;

[0033] 4) If i=N, stop the calculation; otherwise, set i=i+1 and go to 2).

[0034] The Mach number of subsonic airflow is calculated according to the aerodynamic function τ(Ma) formula. The calculation model is as follows:

[0035]

[0036] p * ——Total pressure at the measuring point, measured by the total static pressure probe, Pa;

[0037] p——static pressure at the measuring point, measured by the total static pressure probe, Pa;

[0038] k - specific heat ratio, which is 1.4 for air;

[0039] Step 2: Calculate the static temperature of the airflow. The static temperature of the airflow is obtained based on the total airflow temperature and the Mach number calculated in step 1. The calculation model is as follows:

[0040]

[0041] T * ——Total air flow temperature, measured by the total temperature sensor, K;

[0042] T——static temperature of air flow, K;

[0043] Step 3: Calculate the airflow velocity v:

[0044]

[0045] R is the gas constant, which is 287.06 for air, J / (kg·K).

[0046] The present invention also discloses a wind tunnel flow velocity real-time measurement device for implementing the wind tunnel flow velocity real-time measurement method. The wind tunnel flow velocity real-time measurement device comprises:

[0047] Sensing modules, including pressure and temperature sensing modules, can be configured with different range modules according to measurement parameter requirements;

[0048] Control mainboard, used to realize the entire measurement method calculation process as well as calibration, filtering, and self-calibration functions;

[0049] Module power supply, used to power the measuring device;

[0050] Chassis, sensor module, control mainboard, and module power supply are fixed in the chassis;

[0051] The display screen is a touch-integrated display screen for displaying parameters, including wind speed, Mach number, and temperature obtained through collection and calculation; and is provided with operation option buttons, including calibration, filtering, collection, storage, and self-calibration;

[0052] The pressure probe is used to collect the total static pressure of the wind tunnel airflow. It is connected to the pressure sensing module through the through-board air pipe socket. The pressure sensing module transmits the airflow pressure value to the control main board. The through-board air pipe socket makes the pressure sensing module interface perpendicular to the air pipe connection to avoid bending of the air pipe and facilitate disassembly.

[0053] The total temperature probe is used to collect the total temperature of the wind tunnel airflow. It is connected to the temperature sensing module through the temperature signal input interface. The temperature sensing module converts the probe resistance into a temperature signal and transmits it to the control mainboard.

[0054] Preferably, the calibration function has the function of calibrating the pressure and temperature sensor modules;

[0055] Preferably, the filtering function adopts a parallel line filtering method and has a compatible custom filtering algorithm function, which is configured according to specific circumstances;

[0056] Preferably, the self-calibration function is used to achieve velocity correction, writing the LDV standard value and the device measurement value at each flow rate into the device system to obtain a correction coefficient;

[0057] The front panel of the chassis is equipped with a power switch, and the rear panel is fixed with a through-board air pipe socket, a temperature signal input interface, a USB interface, a network port, and a socket. A cable management rack is installed inside the chassis to facilitate internal wiring. Ventilation holes are designed on the left and right sides of the chassis, and a cooling fan is installed inside.

[0058] Beneficial effects:

[0059] 1. The present invention discloses a method for measuring wind tunnel flow velocity. By adopting aerodynamic functions and iterative algorithms, the present invention solves the problem that the supersonic airflow parameter relationship is complex and the velocity cannot be directly calculated in real time. Compared with the currently used method of measuring first and then calculating, the present invention can realize online real-time measurement of wind tunnel flow velocity.

[0060] 2. The present invention discloses a wind tunnel flow velocity measurement method, which realizes the calibration of pressure, temperature and velocity parameters through sensor module calibration and velocity correction. The calibrated parameters can be traced back to the highest national standards, ensuring the accuracy and reliability of the test results, thereby improving the accuracy of online real-time flow velocity measurement.

[0061] 3. Existing wind tunnel flow velocity measurement devices, such as those based on the bridge balance principle, suffer from fragile sensitive elements and are unable to measure supersonic flow velocities. Devices based on optical principles have complex optical paths and require the dissemination of tracer particles, which can easily cause measurement distortion in harsh environments. The present invention discloses a real-time wind tunnel flow velocity measurement device that uses a probe as the sensing element, offering strong environmental adaptability while avoiding the problem of fragile sensitive elements preventing measurement. The device's measurement range covers subsonic and supersonic airflow velocities, effectively expanding the wind tunnel flow velocity measurement range and ensuring the device's measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is a schematic diagram of the composition of a wind tunnel flow velocity real-time measurement device disclosed in the present invention;

[0063] Figure 2 This is a schematic diagram of a display screen interface of a wind tunnel flow velocity real-time measurement device disclosed in the present invention;

[0064] Figure 3 This is a calibration curve diagram of a pressure and temperature sensor module of a real-time wind tunnel flow velocity measurement method disclosed by the present invention. DETAILED DESCRIPTION

[0065] The present invention is described in detail below with reference to the accompanying drawings.

[0066] Example 1

[0067] This embodiment discloses a method for measuring wind tunnel flow velocity, and the specific implementation steps are as follows:

[0068] To calibrate the pressure and temperature sensing modules, connect each range pressure module to the pressure standard device in sequence. The pressure standard device will give the standard pressure according to the preset pressure values ​​P1, P2, ..., Pn. Record the measured values ​​P1', P2', ..., Pn' of each pressure module to obtain the pressure correction values ​​△P1, △P2, ..., △Pn and the pressure correction curve. Use the interpolation algorithm to obtain the pressure correction value within the entire range to complete the pressure calibration. Connect the temperature sensing module to the temperature standard device. The temperature standard device will give the standard temperature according to the preset temperature values ​​T1, T2, ..., Tn. Record the measured values ​​T1', T2', ..., Tn' of the temperature sensing module to obtain the temperature correction values ​​△T1, △T2, ..., △Tn and the temperature correction curve. Use the interpolation algorithm to obtain the temperature correction value within the entire range to complete the temperature calibration.

[0069] Probe connection: select the pressure probe and connect it to the pressure sensing module of the corresponding range to measure the airflow pressure. Use two total pressure probes when measuring supersonic airflow, and use the total static pressure probe when measuring subsonic airflow. Select the total temperature probe and connect it to the temperature sensing module to measure the total temperature of the airflow.

[0070] Probe installation: When measuring supersonic airflow, two total pressure probes are installed in the stable section and the core area of ​​the test section of the supersonic wind tunnel respectively. When measuring subsonic airflow, the total static pressure probe is installed in the core area of ​​the subsonic wind tunnel test section, and the temperature probe is installed in the stable section of the wind tunnel.

[0071] Pressure and temperature measurement signal filtering uses a parallel line filtering method. Based on the accuracy requirements of the pressure and temperature measurement modules and the constraints of test results, a threshold is set to identify the validity of the measurement data, and measurement values ​​that do not meet the constraints are filtered out to eliminate gross errors and ensure the authenticity and validity of the data.

[0072] Velocity calculation, using pressure and temperature measurements to calculate the airflow velocity v;

[0073] Velocity correction uses the Doppler laser velocimeter (LDV) as a standard to correct the calculated airflow velocity v. The correction coefficient is obtained by comparing the LDV standard value with the calculated value at each flow rate, and finally the corrected flow velocity value is obtained.

[0074] The speed is calculated as follows:

[0075] Step 1: Calculate the airflow Mach number Ma;

[0076] Among them, the supersonic airflow calculates the Mach number based on the relationship between the parameters before and after the shock wave. The calculation model is as follows:

[0077]

[0078] ——Total pressure at the wavefront, measured by the total pressure probe in the stable section, Pa;

[0079] ——Total pressure after the wave, measured by the total pressure probe in the test section, Pa;

[0080] Ma——airflow Mach number;

[0081] k - specific heat ratio, which is 1.4 for air;

[0082] make: Substitute (2) into (1):

[0083]

[0084] Simplifying formula (3), we get the following results:

[0085]

[0086] make The following iterative method is used to solve the Mach number:

[0087] 1) Take the initial points x0 and x1, the maximum number of iterations N and the iteration accuracy ε, and set i = 1;

[0088] 2) Calculation

[0089] 3) If |x i+1 -x i |<ε, then stop the operation;

[0090] 4) If i=N, stop the calculation; otherwise, set i=i+1 and go to 2).

[0091] The Mach number of subsonic airflow is calculated according to the aerodynamic function τ(Ma) formula. The calculation model is as follows:

[0092]

[0093] p * ——Total pressure at the measuring point, measured by the total static pressure probe, Pa;

[0094] p——static pressure at the measuring point, measured by the total static pressure probe, Pa;

[0095] k - specific heat ratio, which is 1.4 for air;

[0096] Step 2: Calculate the static temperature of the airflow. The static temperature of the airflow is obtained based on the total airflow temperature and the Mach number calculated in step 1. The calculation model is as follows:

[0097]

[0098] T * ——Total air flow temperature, measured by the total temperature sensor, K;

[0099] T——static temperature of air flow, K;

[0100] Step 3: Calculate the airflow velocity v:

[0101]

[0102] R is the gas constant, which is 287.06 for air, J / (kg·K).

[0103] Example 2

[0104] Based on the implementation principle of Example 1, this embodiment discloses a wind tunnel flow velocity real-time measurement device for implementing the wind tunnel flow velocity real-time measurement method. Figure 1 As shown, the wind tunnel flow velocity real-time measurement device is mainly composed of a chassis 1, a temperature sensor module 2, a pressure sensor module 3, a control mainboard 4, a module power supply 5, a display screen 6, a total temperature probe 7, and a pressure probe 8. The chassis has an external dimension of: width 462.2mm × height 191.8mm × depth 356mm, and has functions such as calibration, filtering, real-time acquisition and display, and self-calibration.

[0105] The temperature transmitter module 2, pressure sensor module 3, control motherboard 4, and module power supply 5 are fixed in the chassis, and the display screen 6 is mounted on the front panel of chassis 1. The temperature transmitter module 2 uses a Pt100 input and RS485 output, with a sampling rate of 20Hz, a range of (0-300)°C, and an accuracy of 0.1%. The module power supply 5 provides 24V DC power. The pressure sensor module 3 uses a digital pressure gauge with a range of (0-300)kPa, a range of (0-200)kPa, and a range of (0-120)kPa. It outputs an RS485 signal with an accuracy of 0.05. The module power supply 5 provides a DC power supply of (12-24V).

[0106] The chassis 1 has a power switch 11 installed on the front panel, and a through-board air pipe socket 12, a temperature signal input interface 13, a USB interface 14, a network port 15, and a socket 16 are fixed on the rear panel. A cable management rack is installed inside the chassis 1 to facilitate internal wiring. Ventilation holes are designed on the left and right sides of the chassis 1, and a cooling fan 17 is installed inside.

[0107] The display screen 6 is a touch-integrated display screen that can display the wind speed, Mach number, temperature and other parameters collected and calculated, and has operation option buttons such as calibration, filtering, collection, storage, and self-calibration, as shown in the attached figure. Figure 2 As shown;

[0108] Among them, the calibration function can realize the calibration of pressure and temperature sensor modules; the filtering function adopts the parallel line filtering method, and the system can also write a custom filtering algorithm to configure it according to specific circumstances; the self-calibration function can realize speed correction, and the LDV standard value and the device measurement value at each flow rate are written into the device system to obtain the correction coefficient;

[0109] The total temperature probe 7 is used to collect the total temperature of the wind tunnel airflow. It uses Pt100 and is connected to the temperature transmitter module 2 through the temperature signal input interface 13. The temperature transmitter module 2 transmits the probe resistance value into a temperature signal and transmits it to the control mainboard.

[0110] The pressure probe 8 is used to collect the total static pressure of the wind tunnel airflow and is connected to the pressure sensing module 3 through the through-board air pipe socket 12. The pressure sensing module 3 transmits the airflow pressure value to the control main board. The through-board air pipe socket 12 enables the pressure sensing module interface to be vertically connected to the air pipe to avoid bending of the air pipe and facilitate disassembly.

[0111] Specific Example 1: Based on the measurement methods and devices of Examples 1 and 2, a supersonic wind tunnel (maximum inflow total pressure 0.25 MPa, maximum operating Mach number 2.2) is taken as an example to demonstrate the specific method of using the present invention to measure the supersonic airflow velocity.

[0112] Calibrate the pressure sensor module and temperature sensor module of the device. The calibration curve is shown in Figure 3 .

[0113] Table 1 Calibration of pressure module with range (0~120) kPa

[0114]

[0115] Table 2 Calibration of pressure module with range (0~200) kPa

[0116]

[0117]

[0118] Table 3 Calibration of pressure module with range (0-300) kPa

[0119]

[0120] Table 4 Range (0~300)℃ Temperature Module Calibration

[0121] Temperature / ℃ Temperature correction value / ℃ Expanded uncertainty U / ℃k=2 0 0.084 0.010 50 -0.042 0.010 100 -0.067 0.010 200 0.109 0.010 300 0.448 0.010

[0122] As attached Figure 1 As shown, two total pressure probes 8 are selected and connected to the (0-300) kPa range interface and the (0-200) kPa range interface of the device respectively. A total temperature probe 7 is selected and connected to the temperature signal input port. The two total pressure probes are respectively installed in the stable section and the core area of ​​the test section of the supersonic wind tunnel. The total temperature probe is installed in the stable section of the wind tunnel. The pressure and temperature measurement signals adopt the parallel line filtering method, and the threshold is set to 1% to eliminate gross errors.

[0123] The wind tunnel was opened to a Mach number of approximately 2.2, and total pressure and total temperature signals were collected. The Mach number was calculated using the iterative algorithm in Example 1. The velocity value was further calculated using formulas (6) to (7). Finally, a correction value was obtained using a preset velocity correction coefficient. The correction coefficient was obtained by comparing the LDV standard value with the calculated value at various flow rates before use. The results within 5 seconds of the measurement process are shown in the following table:

[0124] Table 5 Measurement results parameters

[0125] Total pressure of test section / KPa Total pressure in stable section / KPa Total pressure of test section / total pressure of stable section Mach number Total temperature / K Speed / (m / s) 177.83 277.49 0.64 2.17 506 703.39 179.21 275.97 0.65 2.15 506 700.03 178.60 276.88 0.65 2.15 506 700.03 179.14 276.37 0.65 2.15 506 700.03 178.37 276.92 0.64 2.17 506 703.39

[0126] The uncertainty of the above measurement results is evaluated, and the results are as follows:

[0127] Table 6 Evaluation of measurement uncertainty of the device

[0128]

[0129] The above process demonstrates the flow velocity measurement process of the present invention. When measuring a supersonic airflow velocity of 700 m / s, the expanded uncertainty of the device is less than 0.5%, while the current standard expanded uncertainty for subsonic flow velocity is 0.6%. Supersonic airflow measurement is more difficult than subsonic airflow. It can be seen that the present invention can effectively improve the reliability of flow velocity measurement while achieving online measurement.

[0130] The above specific description further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wind tunnel flow velocity measurement method, characterized by: The following steps are included: To calibrate the pressure and temperature sensing modules, connect each range pressure module to the pressure standard device in sequence. The pressure standard device will give the standard pressure according to the preset pressure values ​​P1, P2, ..., Pn. Record the measured values ​​P1', P2', ..., Pn' of each pressure module to obtain the pressure correction values ​​△P1, △P2, ..., △Pn and the pressure correction curve. Use the interpolation algorithm to obtain the pressure correction value within the entire range to complete the pressure calibration. Connect the temperature sensing module to the temperature standard device. The temperature standard device will give the standard temperature according to the preset temperature values ​​T1, T2, ..., Tn. Record the measured values ​​T1', T2', ..., Tn' of the temperature sensing module to obtain the temperature correction values ​​△T1, △T2, ..., △Tn and the temperature correction curve. Use the interpolation algorithm to obtain the temperature correction value within the entire range to complete the temperature calibration. Probe connection: select the pressure probe and connect it to the pressure sensing module of the corresponding range to measure the airflow pressure; use two total pressure probes when measuring supersonic airflow, and use the total static pressure probe when measuring subsonic airflow; select the total temperature probe and connect it to the temperature sensing module to measure the total temperature of the airflow; Probe installation: When measuring supersonic airflow, two total pressure probes are installed in the supersonic wind tunnel's stable section and the core area of ​​the test section respectively. When measuring subsonic airflow, the total static pressure probe is installed in the core area of ​​the subsonic wind tunnel's test section, and the temperature probe is installed in the wind tunnel's stable section. Pressure and temperature measurement signal filtering uses a parallel line filtering method. Based on the constraints, thresholds are set to identify the validity of the measurement data, and measurement values ​​that do not meet the constraints are filtered out to eliminate gross errors and ensure the authenticity and validity of the data. The constraints include the accuracy requirements of the pressure measurement module and the temperature measurement module and the test results. Velocity calculation, using pressure and temperature measurements to calculate the airflow velocity v; The speed calculation method is as follows: Step 1: Calculate the airflow Mach number Ma; Among them, the supersonic airflow calculates the Mach number based on the relationship between the parameters before and after the shock wave. The calculation model is as follows: ——Total pressure at the wavefront, measured by the total pressure probe in the stable section, Pa; ——Total pressure after the wave, measured by the total pressure probe in the test section, Pa; Ma——airflow Mach number; k - specific heat ratio, which is 1.4 for air; make: Wherein, a is a constant, 0<a<1; Substitute (2) into (1): Simplifying formula (3), we get the following results: make The following iterative method is used to solve the Mach number: 1) Take the initial points x0 and x1, the maximum number of iterations N and the iteration accuracy ε, and set i = 1; 2) Calculation 3) If |x i+1 -x i |<ε, then stop the operation; 4) If i = N, stop the calculation; otherwise, set i = i + 1 and go to 2); The Mach number of subsonic airflow is calculated according to the aerodynamic function τ(Ma) formula. The calculation model is as follows: p * ——Total pressure at the measuring point, measured by the total static pressure probe, Pa; p——static pressure at the measuring point, measured by the total static pressure probe, Pa; k——specific heat ratio; Step 2: Calculate the static temperature of the airflow. The static temperature of the airflow is obtained based on the total airflow temperature and the Mach number calculated in step 1. The calculation model is as follows: T * ——Total air flow temperature, measured by the total temperature sensor, K; T——static temperature of air flow, K; Step 3: Calculate the airflow velocity v: R——gas constant; Velocity correction uses the Doppler laser velocimeter LDV as a standard to correct the calculated airflow velocity v. The correction coefficient is obtained by comparing the LDV standard value and the calculated value at each flow rate to obtain the corrected flow velocity value.

2. A wind tunnel flow velocity measurement method according to claim 1, characterized in that: The method further includes the following steps: tracing back to the source based on the corrected flow velocity value and using it as a flow velocity standard for calibrating various probes and anemometers.

3. A wind tunnel flow velocity real-time measurement device, used to implement the wind tunnel flow velocity real-time measurement method according to claim 1 or 2, characterized in that: include, Sensing modules, including pressure and temperature sensing modules, can be configured with different range modules according to measurement parameter requirements; Control mainboard, used to realize the entire measurement method calculation process as well as calibration, filtering, and self-calibration functions; Module power supply, used to power the measuring device; Chassis, sensor module, control mainboard, and module power supply are fixed in the chassis; The display screen is a touch-integrated display screen for displaying parameters, including wind speed, Mach number, and temperature obtained through collection and calculation; and is provided with operation option buttons, including calibration, filtering, collection, storage, and self-calibration; The pressure probe is used to collect the total static pressure of the wind tunnel airflow. It is connected to the pressure sensing module through the through-board air pipe socket. The pressure sensing module transmits the airflow pressure value to the control main board. The through-board air pipe socket makes the pressure sensing module interface perpendicular to the air pipe connection to avoid bending of the air pipe and facilitate disassembly. The total temperature probe is used to collect the total temperature of the wind tunnel airflow. It is connected to the temperature sensing module through the temperature signal input interface. The temperature sensing module converts the probe resistance into a temperature signal and transmits it to the control mainboard.

4. A wind tunnel flow velocity real-time measurement device according to claim 3, characterized in that: The calibration function has the function of calibrating the pressure and temperature sensor modules.

5. The real-time wind tunnel flow velocity measurement device according to claim 3, characterized in that: The filtering function adopts a parallel line filtering method and is compatible with a custom filtering algorithm, which is configured according to specific circumstances.

6. The real-time wind tunnel flow velocity measurement device according to claim 3, characterized in that: The self-calibration function is used to achieve speed correction, and the LDV standard value and the device measurement value at each flow rate are written into the device system to obtain a correction coefficient.

7. The real-time wind tunnel flow velocity measurement device according to claim 3, characterized in that: The front panel of the chassis is equipped with a power switch, and the rear panel is fixed with a through-board air pipe socket, a temperature signal input interface, a USB interface, a network port, and a socket. A cable management rack is installed inside the chassis to facilitate internal wiring. Ventilation holes are designed on the left and right sides of the chassis, and a cooling fan is installed inside.

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