A method for automatic calibration of a five-hole probe in a wind tunnel

Abstract

The application discloses a wind tunnel five-hole probe automatic calibration method, and relates to the field of wind tunnel tests. The method realizes automatic calibration of multiple working conditions through cooperation of a probe angle adjusting mechanism, a control unit and a measuring unit. The method can safely and efficiently realize the automatic calibration test function of the wind tunnel five-hole probe, reduces the operation amount of test personnel, reduces the number of probe test posts, avoids the safety hidden danger caused by human operation, significantly improves the operation economy of the wind tunnel five-hole probe calibration test, and greatly reduces the consumption of water, electricity and other resources in the test process.

Description

Technical Field

[0001] This invention relates to the field of wind tunnel testing, and more specifically, to an automated calibration method for a five-hole probe in a wind tunnel. Background Technology

[0002] A five-hole wind tunnel probe is an aerodynamic probe used to measure three-dimensional flow field parameters. It can be used to obtain information such as airflow velocity, airflow direction, total pressure, and static pressure in a three-dimensional flow field. It is widely used in wind tunnels for testing airflow deflection angle. Each pressure gauge hole of the five-hole wind tunnel probe has different mechanical characteristics due to manufacturing factors, and the aerodynamic characteristics of each hole vary depending on the airflow conditions. To ensure the quality of test data, each five-hole wind tunnel probe must undergo rigorous wind tunnel calibration. During calibration tests, each probe needs to be calibrated under different angle conditions with varying pressures, temperatures, and velocity flow fields to improve calibration accuracy. Typically, the number of calibration points ranges from hundreds to thousands, resulting in a very large workload and consequently, significant energy and human resource consumption during wind tunnel operation. Therefore, improving the efficiency and economic efficiency of five-hole wind tunnel probe calibration is a crucial problem that must be solved. Summary of the Invention

[0003] To address the aforementioned shortcomings, this invention provides an automated calibration method for a five-hole probe in a wind tunnel, which can safely and efficiently achieve automated calibration testing of the five-hole probe in a wind tunnel.

[0004] To achieve the above-mentioned objectives, this invention provides an automated calibration method for a five-hole probe in a wind tunnel, the method comprising:

[0005] Step 1: With the wind tunnel stationary, install the five-hole probe of the wind tunnel onto the clamping device of the probe angle adjustment mechanism, and connect the pressure pipe of the five-hole probe of the wind tunnel to the pressure sensor or pressure scanning valve of the measurement system.

[0006] Step 2: Adjust the installation position of the wind tunnel five-hole probe so that the distance between the head of the wind tunnel five-hole probe and the probe origin positioning pin is within the preset range during the rotation of the wind tunnel five-hole probe;

[0007] Step 3: Adjust the probe angle adjustment mechanism to ensure that the initial positions of the α and β angles of the five-hole probe in the wind tunnel are both at the standard zero position; this ensures the accuracy of the probe calibration data. Adjusting the initial probe position to the standard zero position ensures that the initial probe direction is consistent with the airflow direction in the test section, which remains constant. Measuring data by changing the probe angle involves measuring the pressure value of the probe relative to different airflow directions. If the initial probe position is not at zero, subsequent calibration data will contain significant errors.

[0008] Step 4: Based on the wind tunnel five-hole probe calibration requirements, and using the target flow field parameters input from the control unit and the target parameters of the probe angle adjustment mechanism, generate the working condition information for the wind tunnel five-hole probe calibration.

[0009] Step 5: Input the initial operating condition sequence number based on the control unit;

[0010] Step 6: Based on the current operating condition number, the control unit reads the corresponding operating condition parameters from the operating condition information and sends the operating condition parameters to the corresponding control modules.

[0011] Step 7: Based on the operating parameters, the control unit controls the corresponding control module to realize closed-loop control of the flow field parameters and angle control of the probe angle adjustment mechanism;

[0012] Step 8: The control unit determines whether the flow field parameters and the angle of the five-hole probe in the wind tunnel have met the standards; if they have, proceed to step 9; if they have not, continue to step 7.

[0013] Step 9: The control unit sends the current flow field parameters and the angle data of the five-hole probe in the wind tunnel to the measurement unit;

[0014] Step 10: The measurement unit begins data acquisition based on the received data, and stores the data after acquisition is completed;

[0015] Step 11: The control unit determines whether the current operating condition number is the last operating condition number. If yes, proceed to step 13; otherwise, increment the current operating condition number by 1 and return to step 6. The measurement unit determines whether the current operating condition information is the last operating condition for the same flow field target parameter. If yes, proceed to step 12; otherwise, do not perform any action.

[0016] Step 12: The measurement unit plots the characteristic curves of the five-hole probe in the wind tunnel based on the stored data;

[0017] Step 13: The control unit executes a shutdown action to bring the wind tunnel to a silent state.

[0018] The principle of this invention is as follows: Based on the functional requirements of the wind tunnel five-hole probe calibration test and the traditional test procedure, an automated calibration method for the wind tunnel five-hole probe is designed. Simultaneously, a control unit and a measurement unit are designed based on this method. These units call upon various hardware devices in the wind tunnel to achieve automated probe calibration. The traditional wind tunnel five-hole probe calibration test procedure is as follows: 1. Manually input the target flow field parameters; 2. The control program controls the wind tunnel to the target parameters; 3. Manually input the target parameters for the probe angle adjustment mechanism; 4. The control program controls the probe to the target angle; 5. Manually operate the measurement system to start data acquisition; 6. After data acquisition, manually process the data to obtain the probe characteristic curve. Compared to the traditional method, this invention can automate all the above steps without requiring manual operation.

[0019] Preferably, step 2 specifically includes: placing the probe origin positioning pin at the center of the wind tunnel five-hole probe head, controlling the probe angle adjustment mechanism to move within the full range of angles α and β, observing and measuring whether the distance between the center of the wind tunnel five-hole probe head and the probe origin positioning pin is always within a preset range; if not, adjusting the installation length and installation angle of the wind tunnel five-hole probe.

[0020] Preferably, step 3 specifically includes:

[0021] Place the inclinometer on the top of the five-hole probe in the wind tunnel, observe the inclinometer's inclination value, and control the probe angle adjustment mechanism to move in the α direction to make the inclinometer's inclination value 0. The inclinometer, as a standard instrument, can measure the actual value in the probe α direction and measure whether the probe angle is at the standard zero position. If not, it needs to be adjusted to the zero position.

[0022] The reflector is placed on the side wall of the test section, and the first angle of the side wall is measured using a collimator. The angle of the side wall serves as the reference for the probe angle β. The angle of the collimator is fixed relative to the test section. Then, the reflector is placed on the side of the five-hole probe in the wind tunnel, and the collimator angle is observed. The probe angle adjustment mechanism is then controlled to move in the β direction so that the collimator angle is displayed as the first angle. The collimator can measure the actual value in the probe direction b. In order to adjust the probe in the β direction to be consistent with the direction of the test section side wall, the direction of the test section side wall is consistent with the airflow direction.

[0023] In the current state, the α and β angles of the probe angle adjustment mechanism are set to zero. The purpose of setting it to zero in the current state is as follows: the angle values ​​of the probe angle adjustment mechanism are absolute values. Initially, when both the α and β angles of the probe angle adjustment mechanism are 0, the probe may not be at the zero position in the wind tunnel airflow direction. Therefore, it is necessary to measure using an inclinometer and collimator. If there is a deviation, the angle of the probe angle adjustment mechanism needs to be adjusted. After adjustment, the α and β angles of the probe angle adjustment mechanism are no longer 0. In order to ensure that the probe angle adjustment mechanism, the probe, and the airflow direction are consistent (to ensure that the probe changes by the same number of degrees as the adjustment mechanism), the current values ​​of the α and β angles of the probe angle adjustment mechanism are considered to be zero, i.e., a zeroing operation is performed.

[0024] Preferably, step 4 specifically includes:

[0025] Input several calibration parameters on the control unit. Each calibration parameter includes: target parameters of the flow field and target parameters of the probe angle adjustment mechanism. Target parameters of the flow field include: wind tunnel wind speed, total wind tunnel pressure, and total wind tunnel temperature. Target parameters of the probe angle adjustment mechanism include: α-angle motion range, number of α-angle motion points, α-angle motion speed, β-angle motion range, number of β-angle motion points, and β-angle motion speed.

[0026] The control unit automatically generates operating condition information data based on the input calibration parameters and stores it in the operating condition information table. The operating condition information table includes several operating condition information arrays arranged in sequence. Each operating condition information array includes: wind tunnel wind speed, wind tunnel total pressure, wind tunnel total temperature, α angle, α angle velocity, β angle, and β angle velocity.

[0027] Preferably, step 6 specifically includes:

[0028] The control unit reads the corresponding wind tunnel wind speed, wind tunnel total pressure, wind tunnel total temperature, α angle, α angle velocity, β angle and β angle velocity from the operating condition information array according to the operating condition sequence number;

[0029] The wind tunnel wind speed is sent to the wind speed closed-loop module, the wind tunnel total pressure is sent to the total pressure closed-loop module, the wind tunnel total temperature is sent to the total temperature closed-loop module, and the α angle, α angle motion velocity, β angle and β angle motion velocity are sent to the probe angle adjustment mechanism control module.

[0030] Preferably, step 7 specifically includes:

[0031] The control unit controls the wind speed closed-loop module to achieve closed-loop control of the wind tunnel wind speed;

[0032] The control unit controls the total pressure closed-loop module to achieve closed-loop control of the wind tunnel's total pressure;

[0033] The control unit controls the total temperature closed-loop module to achieve closed-loop control of the wind tunnel's total temperature;

[0034] The control unit controls the probe angle adjustment mechanism control module to achieve angle control of α and β angles.

[0035] Preferably, the control unit determines whether the flow field parameters and the angle of the five-hole probe in the wind tunnel have met the standards, specifically including:

[0036] The control unit collects several data points of wind speed, total pressure, and total temperature at a set rate, and then calculates whether the difference between the collected data and the target value is lower than the corresponding error compliance requirements. The control unit also determines whether the actual values ​​of the α and β angles of the probe angle adjustment mechanism are lower than the target values ​​and the corresponding error compliance requirements.

[0037] Preferably, step 10 specifically includes:

[0038] The measurement unit determines whether the current wind tunnel wind speed, wind tunnel total pressure, and wind tunnel total temperature are the latest flow field parameters; if so, it clears the data storage array and graphic data in the measurement unit; that is, if it is the first time the flow field parameters are received, they are the latest, or if the flow field parameters received later are inconsistent with the previous flow field parameters, they are also the latest.

[0039] Collect several pressure data points on the five-hole probe pressure holes of the wind tunnel at a set rate, and calculate the average pressure data of each pressure hole.

[0040] Calculate the first probe angle coefficient K under the current working condition. α Second probe angle coefficient K β ;

[0041] The wind tunnel wind speed, total wind tunnel pressure, static wind tunnel pressure, total wind tunnel temperature, α angle of the probe angle adjustment mechanism, β angle of the probe angle adjustment mechanism, pressure data, and K are included. α and K β All are stored in the data storage array.

[0042] Preferably, the wind tunnel five-hole probe has five pressure holes, and the average pressure data of the five pressure holes are P1, P2, P3, P4 and P5, respectively.

[0043] K α and K β The calculation methods are as follows:

[0044] K α =(P3-P1) / (2×P2-P1-P3);

[0045] K β =(P5-P4) / (2×P2-P4-P5).

[0046] Preferably, the characteristic curve of the five-hole probe in the wind tunnel is plotted as follows: for each angle α, K...α As the x-axis, with K β Plot a set of curves on the ordinate; then for each β angle, use K... β As the x-axis, with K α Plot a set of curves on the vertical axis to obtain the probe characteristic curve.

[0047] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0048] This method can safely and efficiently realize the automated calibration test function of the five-hole probe in the wind tunnel, reduce the workload of test personnel, reduce the number of positions for probe testing, and avoid the safety hazards caused by human operation. At the same time, it significantly improves the operational economy of the five-hole probe calibration test in the wind tunnel and greatly reduces the consumption of resources such as water and electricity during the test process. Attached Figure Description

[0049] The accompanying drawings, which are provided to further illustrate embodiments of the invention and constitute a part of this invention, are not intended to limit the scope of the invention.

[0050] Figure 1 This is a flowchart illustrating an automated calibration method for a five-hole probe in a wind tunnel according to the present invention. Detailed Implementation

[0051] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other.

[0052] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0053] Example 1;

[0054] Please refer to Figure 1 This invention provides an automated calibration method for a five-hole probe in a wind tunnel. This method utilizes the following devices, equipment, units, or software during its execution, which are described and explained in the embodiments of this invention:

[0055] Power system: Used to provide power to the wind tunnel and adjust the wind speed of the wind tunnel, including motors, frequency converters and PLC equipment, etc., which are existing systems and will not be described in detail in this embodiment of the invention.

[0056] Pressure regulating system: used to adjust the air pressure in the wind tunnel, such as the total pressure, including: pressure pipelines (air intake, air supply, exhaust and vacuum), vacuum unit, pressure regulating valves (air intake, air supply, exhaust and vacuum), PLC equipment, etc.; the pressure pipelines are connected and cooperate with the corresponding vacuum unit and pressure regulating valves to form the pressure regulating system, which is an existing system and will not be described in detail in this embodiment of the invention.

[0057] Temperature control system: used to adjust the overall temperature of the wind tunnel, including wind tunnel heat exchangers, heaters, refrigeration units and PLC equipment, etc.; as an existing system, the embodiments of the present invention will not be described in detail.

[0058] The probe angle adjustment mechanism is used to adjust the angle of the probe and includes: an α-angle motion mechanism, a β-angle motion mechanism, a probe clamping device, a motor, an encoder, a driver, a PLC device, etc. For reference, see CN119984733A. As it is an existing mechanism, the embodiments of the present invention will not be described in detail.

[0059] Measurement system: used to measure pressure, including pressure sensors or pressure scanning valves;

[0060] The control unit includes functional modules such as a wind speed closed-loop module, a total pressure closed-loop module, a total temperature closed-loop module, an adjustment mechanism control module, a probe automated process control module, and a communication module. These modules are used for closed-loop control of the wind tunnel's wind speed, total pressure, and total temperature flow field parameters, positioning control of the adjustment mechanism's α and β angles, and data interaction with the measurement system.

[0061] The measurement unit is used to collect data from pressure sensors or pressure scanning valves. At the same time, it processes the collected data to obtain the angle coefficient and velocity coefficient of the five-hole probe, and plots the characteristic curves and velocity characteristic curves of the five-hole probe.

[0062] The following section uses a five-hole wind tunnel probe as an example to provide a detailed explanation of this method:

[0063] Step 1: With the wind tunnel stationary, install the five-hole probe on the clamping device of the probe angle adjustment mechanism, and connect the five pressure tubes of the five-hole probe to the pressure sensor or pressure scanning valve of the measurement system.

[0064] Step 2: Adjust the probe installation position so that the probe head remains at the same origin during rotation. Specific method: Place the probe origin positioning pin at the center of the probe head. Control the probe angle adjustment mechanism to move across the entire range of angles α and β. Observe and measure whether the distance between the center of the probe head and the probe origin positioning pin is always within 1mm. If not, adjust the probe's installation length and angle. Flow field parameters at different locations in a wind tunnel test section are often different; the optimal parameters are usually found near the center of the test section. After the wind tunnel is built, it is typically necessary to calibrate and measure the flow field parameters at that location, including wind speed, total pressure, total temperature, and airflow deflection angle. The wind speed, total pressure, and total temperature parameters measured after the wind tunnel is in operation also refer to the flow field parameters at that location. Therefore, during probe calibration, the probe head must remain near the center of the wind tunnel test section throughout the entire angle change process. Only then will the flow field parameters at the probe head be consistent with the parameters measured by the wind tunnel. Ultimately, only then will the calibrated data be accurate.

[0065] Step 3: Adjust the probe angle adjustment mechanism so that the initial positions of the α and β angles of the five-hole probe in the wind tunnel are both at the standard zero position. Specific method: Place the inclinometer on top of the probe and observe the inclinometer value. Then, control the probe angle adjustment mechanism to move in the α direction until the inclinometer displays 0. Place the reflector on the side wall of the test section and use a collimator to measure the first angle. Then, place the reflector on the side of the probe and observe the collimator angle. Next, adjust the probe angle adjustment mechanism to move in the β direction until the collimator angle displays the first angle. In this state, set the α and β angles of the probe angle adjustment mechanism to zero.

[0066] Step 4: Based on the wind tunnel five-hole probe calibration requirements, and using the target flow field parameters input from the control unit and the target parameters of the probe angle adjustment mechanism, generate the working condition information for the wind tunnel five-hole probe calibration.

[0067] Specific method: Input the single-cycle flow field target parameters (wind speed, total pressure, total temperature) and mechanism target parameters (α-angle motion range, α-angle motion points, α-angle motion speed, β-angle motion range, β-angle motion points, β-angle motion speed) into the control software, and click the "Generate Operating Information" button. The control software will automatically generate operating information data based on the above input parameters and store it in the operating information array (as shown in Table 1 below). According to the probe calibration requirements, input the single-cycle process target parameters and mechanism target parameters again, and continue to generate operating information data.

[0068] Table 1. Array of Operating Condition Information

[0069]

[0070] The data in Table 1 can be automatically generated based on the input parameters, which are: wind speed, total pressure, total temperature, α-angle range of motion, number of α-angle points of motion, α-angle speed of motion, β-angle range of motion, number of β-angle points of motion, and β-angle speed of motion.

[0071] The automatic generation method is as follows:

[0072] 1) Calculate the α-angle motion interval based on the α-angle motion range and the number of α-angle motion points. α-angle motion interval = (2 × α-angle motion range) / (number of α-angle motion points - 1);

[0073] The specific α angle value is calculated based on the α angle movement range, the number of α angle movement points, and the α angle movement interval. The α angle values ​​are: -α angle movement range; -α angle movement range + 1 × α angle movement interval; -α angle movement range + 2 × α angle movement interval; ...; -α angle movement range + (number of α angle movement points - 1) × α angle movement interval; the movement range is the angle of one side of the movement range. For example, if the movement range 'a' is 5, the generated movement range is actually a series of points between -5 and 5.

[0074] 2) Calculate the β-angle motion interval based on the β-angle motion range and the number of β-angle motion points. β-angle motion interval = (2 × β-angle motion range) / (number of β-angle motion points - 1);

[0075] 3) The specific β angle value is calculated based on the β angle movement range, the number of β angle movement points, and the β angle movement interval. The β angle values ​​are as follows: -β angle movement range; -β angle movement range + 1 × β angle movement interval; -β angle movement range + 2 × β angle movement interval; ...; -β angle movement range + (number of β angle movement points - 1) × β angle movement interval;

[0076] 4) Combine the α angle value and the β angle value to obtain (number of α angle movement points × number of β angle movement points) pieces of working condition information.

[0077] For example, if the input parameters are wind speed 100, total pressure 150, total temperature 10, α-angle motion range 2, α-angle motion points 5, α-angle motion speed 0.5, β-angle motion range 2, β-angle motion points 5, and β-angle motion speed 1, then the operating condition information entries 1-25 in Table 1 will be generated.

[0078] Step 5: Input the initial operating condition sequence number based on the control unit; specifically: after inputting the initial operating condition sequence number on the control software, start the probe automated process control module;

[0079] Step 6: Based on the current operating condition number, the control unit reads the corresponding operating condition parameters from the operating condition information and sends the operating condition parameters to the corresponding control modules.

[0080] Step 7: Based on the operating parameters, the control unit controls the corresponding control modules to achieve closed-loop control of the flow field parameters and angle control of the probe angle adjustment mechanism; specifically: Wind speed closed-loop module: Closed-loop control of wind tunnel wind speed is achieved by adjusting the motor speed using a PID algorithm. Total pressure closed-loop module: When the target total pressure is greater than atmospheric pressure, the opening degree of the valve on the booster pipe is preset, and the opening degree of the valve on the exhaust pipe is adjusted using a PID algorithm to achieve closed-loop control of the wind tunnel total pressure; when the target total pressure is less than atmospheric pressure, the opening degree of the valve on the vacuum pipe and the power of the vacuum unit are preset, and the opening degree of the valve on the make-up air pipe is adjusted using a PID algorithm to achieve closed-loop control of the wind tunnel total pressure; Total temperature closed-loop control: Closed-loop control of the wind tunnel total temperature is achieved by adjusting the heat exchanger outlet temperature of the temperature control system using a PID algorithm. Adjustment mechanism control module: Positioning control of the α and β angles is achieved by controlling the motor positions of the α and β angle motion mechanisms.

[0081] Step 8: The control unit determines whether the flow field parameters and the angle of the five-hole probe of the wind tunnel have met the standards; if they have, proceed to step 9; if they have not, continue to step 7. Specific method: The control software collects 50 points of wind speed, total pressure, and total temperature at a rate of 10 points per second, and then calculates whether the difference between the collected data and the target value is lower than the error compliance requirement; the control software determines whether the actual values ​​of the adjustment mechanism's α angle and β angle are lower than the target value than the error compliance requirement.

[0082] Step 9: The control unit sends the current flow field parameters and the angle data of the five-hole probe of the wind tunnel to the measurement unit; specifically, the control unit sends the current wind speed, total pressure, total temperature, α angle, and β angle data values ​​to the measurement unit, and at the same time, sends a start acquisition command.

[0083] Step 10: The measurement unit begins data acquisition based on the received data and stores the data after acquisition. Specific method: After receiving the start acquisition command, the measurement unit first determines whether the current wind speed, total pressure, and total temperature are the latest flow field parameters. If so, it clears the data storage arrays and graphs in the measurement software. Then, it begins acquiring pressure data P1, P2, P3, P4, and P5 at a rate of 10Hz from the five pressure holes of the probe, acquiring 100 points for each pressure data point. The average value of the five pressure data points is then calculated, and the first probe angle coefficient K under the current operating condition is calculated using the following formula. α Second probe angle coefficient K β After the calculations are completed, the wind speed, total pressure P0, total temperature, angle α, angle β, P1, P2, P3, P4, P5, and K will be included. α K β Store it in the data storage array.

[0084] K α =(P3-P1) / (2×P2-P1-P3);

[0085] K β =(P5-P4) / (2×P2-P4-P5);

[0086] In this process, the five-hole probe in the wind tunnel collects probe pressure data after undergoing multiple α and β angle changes under a certain flow field parameter. The probe angle coefficient K is then calculated. α K β Then, the probe characteristic curve under the current flow field parameters can be plotted, i.e., K. α K β A diagram showing the relationship between angles α and β.

[0087] After calibration, when the probe is used in other wind tunnels for airflow deflection tests, only the pressure values ​​of the five pressure holes at the probe tip need to be measured, and then K can be calculated using the above formula. α K β Then, according to K α K β Find the corresponding α angle and β angle in the probe characteristic curve of the corresponding flow field parameters. These α angle and β angle are the current airflow deflection angle of the wind tunnel.

[0088] Step 11: The control unit determines whether the current operating condition number is the last operating condition number. If yes, proceed to step 13; otherwise, increment the current operating condition number by 1 and return to step 6. The measurement unit determines whether the current operating condition information is the last operating condition for the same flow field target parameter (i.e., the input parameters are wind speed 100, total pressure 150, total temperature 10, α angle movement range 2, α angle movement point count 5, α angle movement speed 0.5, β angle movement range 2, β angle movement point count 5, β angle movement speed 1. This will generate operating condition information entries 1-25 in the table. The operating condition information corresponding to the same flow field target parameter (wind speed 100, total pressure 150, total temperature 10) consists of these 25 entries. The wind speed, total pressure, and total temperature are the same in these 25 entries, only the probe angle is different). If yes, proceed to step 12; otherwise, do not perform any action.

[0089] Step 12: The measurement unit plots the characteristic curve of the five-hole probe in the wind tunnel based on the stored data; specifically, the measurement unit plots the characteristic curve of the five-hole probe based on the data in the data storage array. Simultaneously, the data in the data storage array and the characteristic curve of the five-hole probe are stored on the computer. For each α angle, K... α As the x-axis, with K β Plot a set of curves on the ordinate; then for each β angle, use K... β As the x-axis, with K α Plot a set of curves on the vertical axis to obtain the probe characteristic curve.

[0090] Step 13: The control unit executes a shutdown action, adjusting the wind tunnel to a silent state. Specific methods: Exit the wind speed closed-loop module, reduce the motor speed to the lowest stable speed; adjust the wind tunnel total pressure closed-loop control to near atmospheric pressure; adjust the wind tunnel total temperature closed-loop control to near room temperature; adjust the α and β angles of the probe angle adjustment mechanism to zero.

[0091] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0092] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An automated calibration method for a five-hole probe in a wind tunnel, characterized in that, The method includes: Step 1: With the wind tunnel stationary, install the five-hole probe of the wind tunnel onto the clamping device of the probe angle adjustment mechanism, and connect the pressure pipe of the five-hole probe of the wind tunnel to the pressure sensor or pressure scanning valve of the measurement system. Step 2: Adjust the installation position of the wind tunnel five-hole probe so that the distance between the head of the wind tunnel five-hole probe and the probe origin positioning pin is within the preset range during the rotation of the wind tunnel five-hole probe; Step 3: Adjust the probe angle adjustment mechanism so that the initial positions of the α angle and β angle of the five-hole probe in the wind tunnel are both at the standard zero position; Step 4: Based on the wind tunnel five-hole probe calibration requirements, and using the target flow field parameters input from the control unit and the target parameters of the probe angle adjustment mechanism, generate the working condition information for the wind tunnel five-hole probe calibration. Step 5: Input the initial operating condition sequence number based on the control unit; Step 6: Based on the current operating condition number, the control unit reads the corresponding operating condition parameters from the operating condition information and sends the operating condition parameters to the corresponding control modules. Step 7: Based on the operating parameters, the control unit controls the corresponding control module to realize closed-loop control of the flow field parameters and angle control of the probe angle adjustment mechanism; Step 8: The control unit determines whether the flow field parameters and the angle of the five-hole probe in the wind tunnel have met the standards; if they have, proceed to step 9; if they have not, continue to step 7. Step 9: The control unit sends the current flow field parameters and the angle data of the five-hole probe in the wind tunnel to the measurement unit; Step 10: The measurement unit begins data acquisition based on the received data, and stores the data after acquisition is completed; Step 11: The control unit determines whether the current operating condition number is the last operating condition number. If yes, proceed to step 13; otherwise, increment the current operating condition number by 1 and return to step 6. The measurement unit determines whether the current operating condition information is the last operating condition for the same flow field target parameter. If yes, proceed to step 12; otherwise, do not perform any action. Step 12: The measurement unit plots the characteristic curves of the five-hole probe in the wind tunnel based on the stored data; Step 13: The control unit executes a shutdown action to bring the wind tunnel to a silent state.

2. The automated calibration method for a five-hole probe in a wind tunnel according to claim 1, characterized in that, Step 2 specifically includes: placing the probe origin positioning pin at the center of the wind tunnel five-hole probe head, controlling the probe angle adjustment mechanism to move within the full range of angles α and β, observing and measuring whether the distance between the center of the wind tunnel five-hole probe head and the probe origin positioning pin is always within the preset range; if not, adjusting the installation length and installation angle of the wind tunnel five-hole probe.

3. The automated calibration method for a five-hole probe in a wind tunnel according to claim 1, characterized in that, Step 3 specifically includes: Place the inclinometer on the top of the five-hole probe of the wind tunnel, observe the inclinometer's inclination value, and control the probe angle adjustment mechanism to move in the α direction so that the inclinometer's inclination value is 0. Place the reflector on the side wall of the test section, use a collimator to measure the first angle of the side wall, then place the reflector on the side of the five-hole probe of the wind tunnel, observe the collimator angle, and then control the probe angle adjustment mechanism to move in the β direction so that the collimator angle is displayed as the first angle. In the current state, set the α and β angles of the probe angle adjustment mechanism to zero.

4. The automated calibration method for a five-hole probe in a wind tunnel according to claim 1, characterized in that, Step 4 specifically includes: Input several calibration parameters on the control unit. Each calibration parameter includes: target parameters of the flow field and target parameters of the probe angle adjustment mechanism. Target parameters of the flow field include: wind tunnel wind speed, total wind tunnel pressure, and total wind tunnel temperature. Target parameters of the probe angle adjustment mechanism include: α-angle motion range, number of α-angle motion points, α-angle motion speed, β-angle motion range, number of β-angle motion points, and β-angle motion speed. The control unit automatically generates operating condition information data based on the input calibration parameters and stores it in the operating condition information table. The operating condition information table includes several operating condition information arrays arranged in sequence. Each operating condition information array includes: wind tunnel wind speed, wind tunnel total pressure, wind tunnel total temperature, α angle, α angle velocity, β angle, and β angle velocity.

5. The automated calibration method for a five-hole probe in a wind tunnel according to claim 4, characterized in that, Step 6 specifically includes: The control unit reads the corresponding wind tunnel wind speed, wind tunnel total pressure, wind tunnel total temperature, α angle, α angle velocity, β angle and β angle velocity from the operating condition information array according to the operating condition sequence number; The wind tunnel wind speed is sent to the wind speed closed-loop module, the wind tunnel total pressure is sent to the total pressure closed-loop module, the wind tunnel total temperature is sent to the total temperature closed-loop module, and the α angle, α angle motion velocity, β angle and β angle motion velocity are sent to the probe angle adjustment mechanism control module.

6. The automated calibration method for a five-hole probe in a wind tunnel according to claim 1, characterized in that, Step 7 specifically includes: The control unit controls the wind speed closed-loop module to achieve closed-loop control of the wind tunnel wind speed; The control unit controls the total pressure closed-loop module to achieve closed-loop control of the wind tunnel's total pressure; The control unit controls the total temperature closed-loop module to achieve closed-loop control of the wind tunnel's total temperature; The control unit controls the probe angle adjustment mechanism control module to achieve angle control of α and β angles.

7. The automated calibration method for a five-hole probe in a wind tunnel according to claim 1, characterized in that, The control unit determines whether the flow field parameters and the angle of the five-hole probe in the wind tunnel have met the standards, specifically including: The control unit collects several data points of wind speed, total pressure, and total temperature at a set rate, and then calculates whether the difference between the collected data and the target value is lower than the corresponding error compliance requirements. The control unit also determines whether the actual values ​​of the α and β angles of the probe angle adjustment mechanism are lower than the target values ​​and the corresponding error compliance requirements.

8. The automated calibration method for a five-hole probe in a wind tunnel according to claim 1, characterized in that, Step 10 specifically includes: The measurement unit determines whether the current wind tunnel wind speed, total wind tunnel pressure, and total wind tunnel temperature are the latest flow field parameters; if so, it clears the data storage array and graphic data in the measurement unit. Collect several pressure data points on the five-hole probe pressure holes of the wind tunnel at a set rate, and calculate the average pressure data of each pressure hole. Calculate the first probe angle coefficient K under the current working condition. α Second probe angle coefficient K β ; The wind tunnel wind speed, total wind tunnel pressure, static wind tunnel pressure, total wind tunnel temperature, α angle of the probe angle adjustment mechanism, β angle of the probe angle adjustment mechanism, pressure data, and K are included. α and K β All are stored in the data storage array.

9. The automated calibration method for a five-hole probe in a wind tunnel according to claim 8, characterized in that, The wind tunnel five-hole probe has five pressure holes, and the average pressure data of the five pressure holes are P1, P2, P3, P4 and P5, respectively. K α and K β The calculation methods are as follows: K α =(P3-P1) / (2×P2-P1-P3); K β =(P5-P4) / (2×P2-P4-P5)。 10. The automated calibration method for a five-hole probe in a wind tunnel according to claim 9, characterized in that, The characteristic curve of the five-hole probe in the wind tunnel is plotted as follows: for each angle α, K... α As the x-axis, with K β Plot a set of curves on the ordinate; then for each β angle, use K... β As the x-axis, with K α Plot a set of curves on the vertical axis to obtain the probe characteristic curve.

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