Aerodynamic parameter system test method

Abstract

The invention relates to the technical field of aerodynamic testing, and discloses an aerodynamic parameter system testing method which comprises the following steps: testing a temperature, humidity and wind speed simulation system; checking a sunlight simulation system; checking the rain and snow simulation system; a multi-channel temperature measuring device is used for testing an aerodynamic parameter system and testing temperature uniformity of a nozzle and other reference surfaces, and a platinum resistance thermometer is used as a sensor. When the number of measurement channels is smaller than the number of uniformity inspection points, a movable support can be adopted, inspection can be conducted at different inspection points, the maximum allowable error of a measurement standard system is + / -0.2 DEG C, and the inspection requirement can be met; a positioning support needs to be installed on a standard total radiometer, the adjusting accuracy of the support needs to meet the requirement of the total radiometer for the installation levelness, and the adjustable horizontal distance range and the adjustable vertical distance range of the support need to meet the requirement of sunlight system inspection.

Description

Technical Field

[0001] The present invention relates to the technical field of aerodynamic testing, and in particular to an aerodynamic parameter system testing method. Background Art

[0002] With the vigorous development of the automotive industry, automotive R&D and testing work has increased dramatically. Since automotive environmental wind tunnels can accurately simulate the extreme environment required for automotive testing in any season and weather, they have received more and more attention. The automotive environmental wind tunnel is mainly composed of multiple subsystems such as the fan system, chassis dynamometer system, sunlight simulation system, vehicle data acquisition system and distributed control system. Therefore, during the automotive environmental wind tunnel test, the control of each wind tunnel subsystem is an important part of the automotive environmental wind tunnel.

[0003] In the prior art, during the automobile aerodynamic inspection process, it is impossible to simultaneously inspect the temperature, humidity, wind speed simulation system, sunshine simulation system, rain and snow simulation system, and aerodynamic parameter system, resulting in a large amount of space and steps required for aerodynamic parameter inspection, making the inspection efficiency low. In view of this, we propose an aerodynamic parameter system inspection method. Summary of the invention

[0004] The purpose of the present invention is to provide an aerodynamic parameter system inspection method to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for testing an aerodynamic parameter system, the method comprising the following steps:

[0006] S1. Inspection of temperature, humidity and wind speed simulation system;

[0007] S2. Inspection of the sunshine simulation system. For the inspection of irradiance intensity, the standard pyranometer needs to be installed at the inspection reference point, the sunshine simulation lamp stand is adjusted to the designed height, and the simulation system is adjusted to output the irradiance intensities commonly used in large, medium and small wind tunnels. After the irradiance intensity enters the stable stage for 15 minutes, a total of n sampling data of the irradiance intensity data are recorded, and each data is numbered as Ei. The sampling frequency is 0.1-1Hz, and the sampling time is greater than 20min.

[0008] S3. Inspection of rain and snow simulation system;

[0009] S4. Inspection of aerodynamic parameter system;

[0010] S41, airflow angle test;

[0011] S42, axial static pressure gradient.

[0012] Optionally, S1 includes: when testing the range, measurement accuracy, control stability, stabilization time and conversion rate of temperature and humidity, the inspection standard sensor is arranged at the temperature and humidity control parameter inspection reference point; when testing the range, measurement accuracy, control stability, stabilization time and conversion rate of wind speed, the inspection standard sensor is arranged at the nozzle inspection reference point; when testing the uniformity of nozzle temperature, humidity and wind speed, the inspection point should be arranged on the nozzle uniformity inspection reference plane; after arranging the temperature, humidity and wind speed sensors, set the temperature, humidity and wind speed simulation system of the automotive environmental wind tunnel test room to the inspection point, start running, and start recording the temperature, humidity and wind speed of each measuring point after reaching a stable state, and determine the sampling frequency and sampling time according to the equipment operating status and inspection requirements.

[0013] Optionally, S1 further includes: during the measurement accuracy test, the wind tunnel parameters should be in a stable stage, the temperature, humidity, wind speed standard and the wind tunnel measurement system record data simultaneously, and the arithmetic mean is calculated as follows:

[0014]

[0015] The maximum allowable error is the difference between the two and is calculated as follows:

[0016] e=PV wt,avg -PV std,avg

[0017] When checking control stability, the wind tunnel parameters should be checked after setting the control target value and when they are in a stable stage. The maximum and minimum values ​​of the measured values ​​within the sampling time are taken, and the upper and lower deviation data are calculated as follows:

[0018] ΔPV upper =PV max -PV set

[0019] ΔPV lower =PV min -PV set

[0020] Where, PV max is the maximum value of the wind tunnel parameter measurement; PV min is the minimum value of the wind tunnel parameter measurement; ΔPV upper ΔPV is the upper deviation of the wind tunnel parameter measurement value; lower is the lower deviation of the wind tunnel parameter measurement value; PV set is the set value of the wind tunnel parameter, i.e., the control target value;

[0021] When testing the conversion rate, the initial state should be in a stable stage; the process from setting the conversion difference or target value of the parameter to the first reaching of the target value is the parameter conversion process; the conversion rate of the parameter conversion process is calculated as follows:

[0022]

[0023] Where RampRate is the parameter conversion rate; PV target PV is the target value for parameter conversion. ini is the measured value of the wind tunnel parameter at the initial stable stage when setting the conversion difference or target value; t ramp It is the time from the start of parameter conversion to the first time the wind tunnel parameter reaches the set target value;

[0024] When testing the uniformity of temperature, humidity and wind speed, the system should be in a stable stage and sampled for a period of time according to the design requirements. The sampling time should not be less than 10 minutes. During the sampling time, the arithmetic mean of the measurement sampling set of each measuring point, such as number i, with a total of n sampling values ​​during the sampling time, is taken as the representative value of the measuring point and is calculated as follows:

[0025]

[0026] The arithmetic mean of all measurement point sets, measurement point number j, a total of m measurement locations, is calculated as follows:

[0027]

[0028] The maximum value of all measurement point sets, measurement point number j, and a total of m measurement locations is calculated as follows:

[0029] PV max =max(PV j.avg )

[0030] The minimum value of all measurement point sets, measurement point number j, and a total of m measurement locations is calculated as follows:

[0031] PV min =min(PV j.avg )

[0032] When the uniformity is measured using the maximum deviation, it is calculated as follows:

[0033] The upper deviation is: ΔPV upper =PV max -PV avg

[0034] The lower deviation is: ΔPV lower =PV min -PV avg

[0035] When the uniformity is measured using standard deviation, it is calculated as follows:

[0036] Optionally, the S3 further includes:

[0037] S31, adjust the flow rate of the working medium of the inspection circuit to the inspection point in sequence, and read the indications of the standard flow meter and the flow rate of the rain and snow simulation system at the same time after the flow rate stabilizes, wherein the accumulated value for 10 minutes is used;

[0038] S32. For the test of precipitation, a collector is proposed to be used, and the working time of the collector is recorded by a stopwatch or other time recording tool;

[0039] S33. Assume that the inlet area of ​​the rain and snow collector is A, in m2; the collection time is t, in h; the mass increase of the collector is m, in g; then the experimental precipitation P is calculated as follows:

[0040] The unit is g / (m 2 h);

[0041] The unit is mm / h.

[0042] Optionally, the S41 further includes:

[0043] Use an inclinometer and a total station to confirm the horizontal and vertical deflection angles of the measuring instrument, and use an airflow angle measuring instrument or an airflow relative measuring instrument to measure the local airflow deflection angle;

[0044] When a five-hole probe is used, a semi-opposite or non-opposite measurement method is usually used for measurement.

[0045] Optionally, the S42 further includes:

[0046] Use an axial detection tube or a single-tube mobile measuring device to measure the static pressure distribution along the center line of the test section, and use a pressure transmitter to measure the static pressure at the reference point. The static pressure coefficient of each measuring point is calculated according to the following formula:

[0047] Where: ε0 is the correction coefficient of each static pressure hole or single tube of the detection tube; q is the dynamic pressure of the reference point of the test section, Pa;

[0048] Draw C p ~X curve; calculate the axial static pressure gradient of the model area according to the following formula;

[0049]

[0050] Where: X i is the distance from the i-th measuring point to the entrance of the test section, m; C piis the pressure coefficient of the i-th measuring point; m is the number of measuring points.

[0051] Compared with the prior art, the present invention provides an aerodynamic parameter system inspection method, which has the following beneficial effects:

[0052] 1. The aerodynamic parameter system inspection method, the nozzle and other reference surface temperature uniformity inspection is planned to use a multi-channel temperature measurement device, and the sensor is planned to use a platinum resistance thermometer. When the number of measurement channels is less than the number of uniformity inspection points, a movable bracket can be used to inspect at different inspection points. The maximum allowable error of the measurement standard system is ±0.2℃, and it can meet the inspection requirements; the standard pyranometer needs to be installed with a positioning bracket, and the bracket adjustment accuracy should meet the pyranometer's requirements for installation level. The bracket's adjustable horizontal distance range and vertical distance range should meet the requirements of the sunshine system inspection.

[0053] 2. The aerodynamic parameter system inspection method, when inspecting the test precipitation, can be fixed at a designated position of a specific inspection reference surface at the nozzle or below the nozzle, the rain and snow simulation and wind simulation system should be in a stable working state. When inspecting the uniformity of precipitation, the set precipitation is based on the design requirements. Snowfall density can be measured by volume measurement and weight weighing method. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a schematic diagram of the process of the present invention;

[0055] Figure 2 It is a schematic diagram of the arrangement structure of the measuring points at the nozzle of the present invention;

[0056] Figure 3 This is a schematic diagram of the test connection structure of the water flow meter of the present invention;

[0057] Figure 4 A schematic diagram of the structure of the water flow meter inspection connection of the present invention. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] like Figure 1-Figure 4 As shown, the present invention provides a technical solution: an aerodynamic parameter system inspection method, comprising the following steps:

[0060] S1. Inspection of temperature, humidity and wind speed simulation system;

[0061] Temperature, humidity and wind speed inspection points can select commonly used temperature, humidity and wind speed values ​​according to needs;

[0062] The checkpoint data used in this embodiment are as follows:

[0063] Serial number Temperature(℃) Humidity (%RH) Wind speed (km / h) 1 -20 / 40 2 0 / 80 3 38 30，50 40，120

[0064] When testing the range, measurement accuracy, control stability, stabilization time, and conversion rate of temperature and humidity, the standard sensor for testing is arranged at the reference point for testing the temperature and humidity control parameters. The installation of the temperature and humidity sensor needs to take into account the influence of the solar simulator. To ensure the accuracy of the measurement, for areas affected by solar radiation, it is necessary to add radiation shielding measures for the sensor.

[0065] When testing the wind speed range, measurement accuracy, control stability, stabilization time, and conversion rate, the standard sensor for testing is arranged at the nozzle test reference point. The reference point can be positioned using specially designed tooling or tools.

[0066] When inspecting the uniformity of nozzle temperature, humidity and wind speed, the inspection points should be arranged on the nozzle uniformity inspection reference surface. The measurement points are arranged in a chessboard pattern. If there is no regulation on the number of measurement points, the measurement points can be arranged in a 5×5 pattern or with a spacing of no more than 50 cm. Figure 2 shown.

[0067] After arranging the temperature, humidity and wind speed sensors, set the temperature, humidity and wind speed simulation system of the automotive environmental wind tunnel test room to the inspection point, start the operation, and start recording the temperature, humidity and wind speed of each measurement point after reaching a stable state. Determine the sampling frequency and sampling time according to the equipment operation status and inspection requirements; if there is no regulation, the sampling frequency data is as follows:

[0068] Serial number project Sampling frequency 1 temperature 1Hz 2 Relative humidity 1Hz 3 Wind speed 10Hz

[0069] When checking the measurement accuracy, the wind tunnel parameters should be in a stable stage. The temperature, humidity, wind speed standard (as an approximate true value) and the wind tunnel measurement system should record data at the same time, and the arithmetic mean value should be calculated as follows:

[0070]

[0071] The maximum allowable error is the difference between the two and is calculated as follows:

[0072] e=PV wt,avg -PV std,avg (3)

[0073] When checking control stability, the wind tunnel parameters should be checked after setting the control target value and when they are in a stable stage. Take the maximum and minimum values ​​of the measured values ​​within the sampling time, and calculate the upper and lower deviation data as follows:

[0074] ΔPV upper =PV max -PV set (4)

[0075] ΔPV lower =PV min -PV set (5)

[0076] Where, PV max is the maximum value of the wind tunnel parameter measurement; PV min is the minimum value of the wind tunnel parameter measurement; ΔPV upper ΔPV is the upper deviation of the wind tunnel parameter measurement value; lower is the lower deviation of the wind tunnel parameter measurement value; PV set is the set value of the wind tunnel parameter, that is, the control target value.

[0077] When testing the conversion rate, the initial state should be in the stable stage. The process from setting the conversion difference or target value of the parameter to the first reaching of the target value is the parameter conversion process. The conversion rate of the parameter conversion process is calculated as follows:

[0078]

[0079] Where RampRate is the parameter conversion rate; PV target PV is the target value for parameter conversion. ini is the measured value of the wind tunnel parameter at the initial stable stage when setting the conversion difference or target value; t ramp It is the time from the start of parameter conversion to the time when the wind tunnel parameter reaches the set target value for the first time.

[0080] When testing the uniformity of temperature, humidity and wind speed, the system should be in a stable stage and sampled for a period of time according to the design requirements. The sampling time should not be less than 10 minutes. During the sampling time, the arithmetic mean of the measurement sampling set of each measuring point (such as number i, a total of n sampling values ​​during the sampling time) is taken as the representative value of the measuring point and is calculated as follows:

[0081]

[0082] The arithmetic mean of all measurement point sets (measurement point number j, a total of m measurement locations) is calculated as follows:

[0083]

[0084] The maximum value of all measurement point sets (measurement point number j, a total of m measurement locations) is calculated as follows:

[0085] PV max =max(PV j.avg ) (9)

[0086] The minimum value of all measurement point sets (measurement point number j, a total of m measurement locations) is calculated as follows:

[0087] PV min =min(PV j.avg ) (10)

[0088] When the uniformity is measured using the maximum deviation, it is calculated as follows:

[0089] The upper deviation is: ΔPV upper =PV max -PV avg (11)

[0090] The lower deviation is: ΔPV lower =PV min -PV avg (twenty two) When the uniformity is measured using standard deviation, it is calculated as follows:

[0091]

[0092] S2. Inspection of sunlight simulation system;

[0093] For the inspection of irradiance intensity, it is necessary to install a standard global radiation meter at the inspection reference point, adjust the sunlight simulation lamp stand to the designed height, and adjust the simulation system to output the irradiance intensities commonly used in large, medium and small wind tunnels. After the irradiance intensity enters the stable stage for 15 minutes, record a total of n sampling data of the irradiance intensity. The single data is numbered Ei, the sampling frequency is 0.1~1Hz, and the sampling time is greater than 20min.

[0094] The irradiation intensity is the arithmetic mean of the sampling data when the regulation system has the same output:

[0095]

[0096] The control stability of irradiation intensity is measured by upper and lower limit deviations, and the calculation formula is as follows:

[0097] The upper deviation is: ΔE upper =E max -E avg (45)

[0098] The lower deviation is: ΔE lower =E min -Eavg (56)

[0099] When checking the uniformity of irradiation, the irradiation intensity setting value is based on the design requirements, and the lower limit, middle point and upper limit of the irradiation intensity are taken as the inspection points.

[0100] The inspection points for irradiation uniformity are arranged within the effective irradiation surface defined by the design. The spacing is based on the design requirements. If there is no specification, a rectangular chessboard with a spacing of no more than 0.5m is preferably used. A standard total radiation intensity table is used to measure the irradiation intensity of each point on the chessboard, which has a total of m measurement points and a single measurement point numbered Ej.

[0101] The irradiance at a single measuring point is expressed as its time average value, and the calculation formula is as follows:

[0102]

[0103] When uniformity is expressed as maximum deviation, it is calculated as follows:

[0104] The upper deviation is: ΔE upper =E max -E avg (78)

[0105] The lower deviation is: ΔE lower =E min -E avg (89)

[0106] When uniformity is expressed as standard deviation, it is calculated as follows:

[0107]

[0108] The area that can meet the irradiation uniformity requirement is taken as the effective irradiation area.

[0109] S3. Inspection of rain and snow simulation system;

[0110] Online inspection of flow meter:

[0111] choose Figure 3 or Figure 4 Connect the standard flow meter and the flow meter to be tested in series, and fully exhaust the air in the pipeline.

[0112] The flow meter to be tested is connected in series to the test circuit. Figure 3 As shown; the standard flow meter is connected in series to the working circuit as shown Figure 4 shown.

[0113] Adjust the working medium flow of the inspection circuit to the inspection point in sequence. After the flow stabilizes, read the indications of the standard flow meter and the rain and snow simulation system flow at the same time, using the 10-minute cumulative value.

[0114] For the inspection of experimental precipitation, a collector is proposed to be used, and the working time of the collector is recorded by a stopwatch or other time recording tools.

[0115] Assume that the inlet area of ​​the rain and snow collector is A, in m2. The collection time is t, in h, and the mass increase of the collector is m, in g. Then the experimental precipitation P is calculated as follows:

[0116]

[0117] S4. Inspection of aerodynamic parameter system;

[0118] S41, airflow angle test;

[0119] Use an inclinometer and a total station to confirm the horizontal and vertical deflection angles of the measuring instrument, and use an airflow angle measuring instrument or an airflow relative measuring instrument (five-hole probe or seven-hole probe) to measure the local airflow deflection angle.

[0120] When using a five-hole probe, a semi-opposite or non-opposite measurement method is usually used for measurement. For example, the relative airflow angle can be obtained based on the probe's differential pressure coefficient and angle corresponding chart; thereby further obtaining the airflow pitch angle Δα and the airflow yaw angle Δβ; or the probe can be mounted upright and reversed on the measurement bracket, and the measurement angle can be changed within a certain range, thereby obtaining two sets of corresponding data of the differential pressure coefficient and the measurement angle when mounted upright and reversed, and further obtaining Δα and Δβ through the two sets of data.

[0121] S42, axial static pressure gradient;

[0122] Use an axial detection tube or a single-tube mobile measuring device to measure the static pressure distribution along the center line of the test section, and use a pressure transmitter to measure the static pressure at the reference point. The static pressure coefficient of each measuring point is calculated according to the following formula:

[0123]

[0124] Where: ε0 is the correction coefficient of each static pressure hole or single tube of the detection tube; q is the dynamic pressure of the reference point of the test section, Pa.

[0125] Draw C p ~X curve. The axial static pressure gradient of the model area (or a certain section thereof) is calculated according to the following formula.

[0126]

[0127] Where: X i is the distance from the i-th measuring point to the entrance of the test section, m; C pi is the pressure coefficient of the i-th measuring point; m is the number of measuring points.

[0129] The above generally describes the present invention in detail, but it is obvious to a person skilled in the art that some modifications or improvements can be made to the present invention. Therefore, modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A method for checking an aerodynamic parameter system, characterized in that: The method comprises the following steps: S1. Inspection of temperature, humidity and wind speed simulation system; S2. Inspection of the sunshine simulation system. For the inspection of irradiance intensity, the standard pyranometer needs to be installed at the inspection reference point, the sunshine simulation lamp stand is adjusted to the designed height, and the simulation system is adjusted to output the irradiance intensities commonly used in large, medium and small wind tunnels. After the irradiance intensity enters the stable stage for 15 minutes, a total of n sampling data of the irradiance intensity data are recorded, and each data is numbered as Ei. The sampling frequency is 0.1-1Hz, and the sampling time is greater than 20min. S3. Inspection of rain and snow simulation system; S4. Inspection of aerodynamic parameter system; S41, airflow angle test; S42, axial static pressure gradient.

2. The aerodynamic parameter system inspection method according to claim 1, characterized in that: The S1 includes: When testing the temperature and humidity range, measurement accuracy, control stability, stabilization time and conversion rate, the inspection standard sensors are arranged at the temperature and humidity control parameter inspection reference points; when testing the wind speed range, measurement accuracy, control stability, stabilization time and conversion rate, the inspection standard sensors are arranged at the nozzle inspection reference points; when testing the nozzle temperature, humidity and wind speed uniformity, the inspection point should be arranged on the nozzle uniformity inspection reference plane; after arranging the temperature, humidity and wind speed sensors, set the temperature, humidity and wind speed simulation system of the automotive environmental wind tunnel test room to the inspection point, start running, and start recording the temperature, humidity and wind speed of each measuring point after reaching a stable state, and determine the sampling frequency and sampling time according to the equipment operating conditions and inspection requirements.

3. The aerodynamic parameter system inspection method according to claim 1, characterized in that: Said S1 further comprises: When checking the measurement accuracy, the wind tunnel parameters should be in a stable stage. The temperature, humidity, wind speed standard and wind tunnel measurement system should record data at the same time and calculate the arithmetic mean value as follows: The maximum allowable error is the difference between the two and is calculated as follows: and=PV wt,avg -PV std,avg When checking control stability, the wind tunnel parameters should be checked after setting the control target value and when they are in a stable stage. The maximum and minimum values ​​of the measured values ​​within the sampling time are taken, and the upper and lower deviation data are calculated as follows: ΔPV upper =PV max -PV set ΔPV lower =PV min -PV set In the formula, PV max is the maximum value of the wind tunnel parameter measurement; PV min is the minimum value of the wind tunnel parameter measurement; ΔPV upper ΔPV is the upper deviation of the wind tunnel parameter measurement value; lower is the lower deviation of the wind tunnel parameter measurement value; PV set is the set value of the wind tunnel parameter, i.e., the control target value; When testing the conversion rate, the initial state should be in a stable stage; the process from setting the conversion difference or target value of the parameter to the first reaching of the target value is the parameter conversion process; the conversion rate of the parameter conversion process is calculated as follows: Where RampRate is the parameter conversion rate; PV target PV is the target value for parameter conversion. ini is the measured value of the wind tunnel parameter at the initial stable stage when setting the conversion difference or target value; t ramp It is the time from the start of parameter conversion to the first time the wind tunnel parameter reaches the set target value; When testing the uniformity of temperature, humidity and wind speed, the system should be in a stable stage and sampled for a period of time according to the design requirements. The sampling time should not be less than 10 minutes. During the sampling time, the arithmetic mean of the measurement sampling set of each measuring point, such as number i, with a total of n sampling values ​​during the sampling time, is taken as the representative value of the measuring point and is calculated as follows: The arithmetic mean of all measurement point sets, measurement point number j, a total of m measurement locations, is calculated as follows: The maximum value of all measurement point sets, measurement point number j, and a total of m measurement locations is calculated as follows: PV max =max(PV j.avg ) The minimum value of all measurement point sets, measurement point number j, and a total of m measurement locations is calculated as follows: PV min =min(PV j.avg ) When the uniformity is measured using the maximum deviation, it is calculated as follows: The upper deviation is: ΔPV upper =PV max -PV avg The lower deviation is: ΔPV lower =PV min -PV avg When the uniformity is measured using standard deviation, it is calculated as follows:

4. The aerodynamic parameter system inspection method according to claim 1, characterized in that: The S3 further comprises: S31, adjust the flow rate of the working medium of the inspection circuit to the inspection point in sequence, and read the indications of the standard flow meter and the flow rate of the rain and snow simulation system at the same time after the flow rate stabilizes, wherein the accumulated value for 10 minutes is used; S32. For the test of precipitation, a collector is proposed to be used, and the working time of the collector is recorded by a stopwatch or other time recording tool; S33. Assume that the inlet area of ​​the rain and snow collector is A, in m2; the collection time is t, in h; the mass increase of the collector is m, in g; then the experimental precipitation P is calculated as follows: The unit is g / (m 2 h); The unit is mm / h.

5. The aerodynamic parameter system inspection method according to claim 1, characterized in that: The S41 further comprises: Use an inclinometer and a total station to confirm the horizontal and vertical deflection angles of the measuring instrument, and use an airflow angle measuring instrument or an airflow relative measuring instrument to measure the local airflow deflection angle; When a five-hole probe is used, a semi-opposite or non-opposite measurement method is usually used for measurement.

6. The aerodynamic parameter system inspection method according to claim 1, characterized in that: The S42 further comprises: Use an axial detection tube or a single-tube mobile measuring device to measure the static pressure distribution along the center line of the test section, and use a pressure transmitter to measure the static pressure at the reference point. The static pressure coefficient of each measuring point is calculated according to the following formula: Where: ε0 is the correction coefficient of each static pressure hole or single tube of the detection tube; q is the dynamic pressure of the reference point of the test section, Pa; Draw C p ~X curve; calculate the axial static pressure gradient of the model area according to the following formula; Where: X i is the distance from the i-th measuring point to the entrance of the test section, m; C pi is the pressure coefficient of the i-th measuring point; m is the number of measuring points.

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