CN116499692A - Wind tunnel flow velocity real-time measurement method and device - Google Patents
Wind tunnel flow velocity real-time measurement method and device Download PDFInfo
- Publication number
- CN116499692A CN116499692A CN202211505841.9A CN202211505841A CN116499692A CN 116499692 A CN116499692 A CN 116499692A CN 202211505841 A CN202211505841 A CN 202211505841A CN 116499692 A CN116499692 A CN 116499692A
- Authority
- CN
- China
- Prior art keywords
- pressure
- temperature
- total
- flow velocity
- wind tunnel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000691 measurement method Methods 0.000 title claims description 14
- 239000000523 sample Substances 0.000 claims abstract description 64
- 238000012937 correction Methods 0.000 claims abstract description 33
- 238000005259 measurement Methods 0.000 claims abstract description 33
- 238000001914 filtration Methods 0.000 claims abstract description 27
- 238000000034 method Methods 0.000 claims abstract description 27
- 238000004364 calculation method Methods 0.000 claims abstract description 23
- 230000003068 static effect Effects 0.000 claims description 27
- 238000012360 testing method Methods 0.000 claims description 18
- 230000000087 stabilizing effect Effects 0.000 claims description 8
- 238000009530 blood pressure measurement Methods 0.000 claims description 7
- 238000009529 body temperature measurement Methods 0.000 claims description 7
- 238000013461 design Methods 0.000 claims description 2
- 238000012216 screening Methods 0.000 claims description 2
- 210000003437 trachea Anatomy 0.000 claims description 2
- 238000009423 ventilation Methods 0.000 claims description 2
- 241001391944 Commicarpus scandens Species 0.000 abstract 1
- 238000009434 installation Methods 0.000 abstract 1
- 230000035939 shock Effects 0.000 abstract 1
- 238000011161 development Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011088 calibration curve Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000000700 radioactive tracer Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
- G01M9/06—Measuring arrangements specially adapted for aerodynamic testing
- G01M9/062—Wind tunnel balances; Holding devices combined with measuring arrangements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
- G01M9/08—Aerodynamic models
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Aerodynamic Tests, Hydrodynamic Tests, Wind Tunnels, And Water Tanks (AREA)
Abstract
The invention discloses a method and a device for measuring the flow velocity of a wind tunnel in real time, and belongs to the field of measurement and calibration of the flow velocity of gas. The method comprises the steps of sensor module calibration, probe connection, probe installation, signal filtering, speed calculation and speed correction. The device comprises a sensing module, a control main board, a module power supply, a case, a display screen, a pressure probe and a total temperature probe. In the aspect of selecting the sensitive element, the probe is adopted as the sensitive part, so that the problem that the supersonic velocity cannot be measured due to the fact that the sensitive element is fragile and easy to break is avoided, and meanwhile, the ultrasonic velocity sensor has no special requirement on the environment and is convenient to use; in the aspect of a measuring method, the flow velocity is rapidly calculated based on an aerodynamic function equation and an iteration method, and the problem that the velocity cannot be directly calculated in real time due to complex parameter relation caused by the existence of shock waves in the supersonic airflow in engineering application is solved. The invention can improve the flow velocity real-time measurement precision, can trace the source upwards, and is used as a flow velocity standard for calibrating various probes and anemometers.
Description
Technical Field
The invention belongs to the field of gas flow velocity measurement and calibration, and relates to a method and a device for measuring the flow velocity of a wind tunnel in real time.
Background
Wind tunnels are an indispensable component in the development of aircrafts, play an important role in aerospace engineering, and along with the development of industrial aerodynamics, the wind tunnels are indispensable in the fields of transportation, house construction, wind energy utilization and the like, and in various wind tunnel tests, the airflow speed of a wind tunnel flow field is required to be accurately measured; meanwhile, the wind tunnel can also be used as a flow velocity calibration device to calibrate various probes and anemometers by matching with a main standard.
Currently, the instruments used for wind tunnel flow velocity measurement mainly comprise a pitot tube flow velocity meter, a hot wire flow velocity meter, a laser Doppler velocimeter and the like, and the instruments can also be used as a flow velocity standard. The Pitot tube flowmeter is based on Bernoulli equation principle, utilizes a micro differential pressure meter to carry out speed calculation, and has a limited range due to the measurement principle, wherein the speed measurement range is only 70m/s at most; the hot wire type flow velocity measuring instrument can measure 300m/s at the highest, but the sensitive element of the hot wire probe is very thin and fragile and is often easily blown off; the laser Doppler velocimeter can measure the velocity of supersonic airflow, but the use is not very convenient because the light path is complex and tracer particles need to be scattered.
Disclosure of Invention
In order to overcome the technical defects, the main purpose of the invention is to provide a method and a device for measuring the flow velocity of a wind tunnel in real time, which are used for rapidly solving the flow velocity of the wind tunnel based on an aerodynamic function equation, and simultaneously have the functions of calibration, filtering, real-time acquisition and display, self calibration and the like, can accurately measure the subsonic velocity, transonic velocity and supersonic wind tunnel airflow velocity, and can trace upwards to serve as a flow velocity standard for calibrating various probes and anemometers.
The invention aims at realizing the following technical scheme:
the invention discloses a wind tunnel flow velocity measurement method, which comprises the following steps:
the pressure and temperature sensing modules are calibrated, each measuring range pressure module is sequentially connected with a pressure standard device, standard pressure is given by the pressure standard device according to preset pressure values P1, P2, … and Pn, measured values P1', P2', … and Pn ' of each pressure module are recorded, pressure correction values delta P1, delta P2, …, delta Pn and pressure correction curves are obtained, and the interpolation algorithm is utilized to obtain pressure correction values in the whole measuring range, so that the pressure calibration is completed; the temperature sensing module is connected with a temperature standard device, standard temperature is given by the temperature standard device according to preset temperature values T1, T2, … and Tn, measured values T1', T2', … and Tn ' of the temperature sensing module are recorded, temperature correction values delta T1, delta T2, … and delta Tn and a temperature correction curve are obtained, and the temperature correction value in the whole range is obtained by utilizing an interpolation algorithm, so that temperature calibration is completed.
And the probe is connected with a selected pressure probe and is connected with a pressure sensing module of a corresponding range for measuring the pressure of the airflow. Two total pressure probes are used for measuring supersonic speed air flow, a total static pressure probe is used for measuring subsonic speed air flow, a total temperature probe is selected and connected to a temperature sensing module, and the total temperature of the air flow is measured.
And when the subsonic air flow is measured, the total static pressure probe is arranged in the subsonic wind tunnel test section core area, and the temperature probe is arranged in the wind tunnel stabilizing section.
Filtering pressure and temperature measurement signals, adopting a parallel line filtering method, setting a threshold value according to constraint conditions, screening the validity of measurement data, filtering measurement values which do not meet the constraint conditions, removing coarse errors, and ensuring the reality and effectiveness of the data; the constraint conditions comprise a pressure measurement module, a temperature measurement module precision requirement and a test result.
Calculating the speed, namely calculating the airflow velocity v by using pressure and temperature measured values;
and correcting the velocity, namely correcting the calculated airflow velocity v by using the Doppler laser velocimeter LDV as a standard, and obtaining a correction coefficient by comparing the LDV standard value and the calculated value under each flow velocity to obtain a corrected flow velocity value.
The wind tunnel flow velocity measurement method disclosed by the invention further comprises the following steps of tracing upwards according to the corrected flow velocity value, and using the corrected flow velocity value as a flow velocity standard for calibrating various probes and anemometers.
Further, the speed calculation method is as follows:
step 1: calculating the Mach number Ma of the air flow;
the supersonic airflow calculates Mach number according to the relation between the front and back parameters of the laser, and the calculation model is as follows:
-total wavefront pressure, pa, measured by a steady-stage total pressure probe;
-total pressure after the test, pa, measured by a test section total pressure probe;
ma—gas flow mach number;
k-specific heat ratio, 1.4 for air;
and (3) making:
wherein a is a constant, and a is more than 0 and less than 1;
carry (2) into (1):
the following results were obtained by reducing the formula (3):
order the
The Mach number is solved by adopting the following iterative method:
1) Taking the initial point x 0 And x 1 Maximum iteration number N and iteration accuracy epsilon, setting i=1;
2) Calculation of
3) If |x i+1 -x i |<Epsilon, stopping the operation;
4) Stopping calculation if i=n; otherwise set i=i+1, go 2).
The subsonic airflow calculates the Mach number according to the aerodynamic function τ (Ma) formula, and the calculation model is as follows:
p * -total pressure of the measuring points, measured by a total static pressure probe, pa;
p is the static pressure of the measuring point, and is measured by a total static pressure probe and Pa;
k-specific heat ratio, 1.4 for air;
step 2: calculating the static air temperature, obtaining the static air temperature according to the Mach number calculated in the step 1 of the total air temperature, and calculating the model as follows:
T * -total temperature of the air flow, K, measured by a total temperature sensor;
t-air flow static temperature, K;
step 3: calculating the airflow velocity v:
r-gas constant, 287.06 for air, J/(kg.K).
The invention also discloses a wind tunnel flow velocity real-time measurement device which is used for realizing the wind tunnel flow velocity real-time measurement method. The wind tunnel flow velocity real-time measuring device comprises:
the sensing module comprises a pressure sensing module and a temperature sensing module, and different measuring range modules are configured according to the measurement parameter requirements;
the control main board is used for realizing the calculation process of the whole measurement method and realizing the functions of calibration, filtering and self calibration;
the module power supply is used for supplying power to the measuring device;
the sensing module, the control main board and the module power supply are fixed in the case;
the display screen is a touch integrated display screen and is used for displaying parameters, wherein the parameters comprise wind speed, mach number and temperature obtained through collection and calculation; the system is also provided with operation option keys, wherein the operation option keys comprise calibration, filtering, acquisition, storage and self calibration;
the pressure probe is used for collecting the total static pressure of the wind tunnel airflow, is connected with the pressure sensing module through the board passing air pipe socket, and the pressure sensing module transmits the airflow pressure value to the control main board;
the total temperature probe is used for collecting the total temperature of the wind tunnel airflow and is connected with the temperature sensing module through the temperature signal input interface, and the temperature sensing module transmits the resistance value of the probe into a temperature signal and transmits the temperature signal to the control main board.
Preferably, the calibration function has a pressure and temperature sensing module calibration function;
preferably, the filtering function adopts a parallel line filtering method and has the function of compatible self-defined filtering algorithm, and is configured according to specific conditions;
preferably, the self-calibration function is used for realizing speed correction, and writing the LDV standard value and the device measured value under each flow rate into the device system to obtain a correction coefficient;
the power switch is installed to the machine case front panel, and the rear panel is fixed with board trachea socket, temperature signal input interface, USB interface, net gape, socket, and machine case internally mounted reason line frame is convenient for inside the wiring, and the design ventilation hole of machine case left and right sides, internally mounted radiator fan.
The beneficial effects are that:
1. the wind tunnel flow velocity measurement method solves the problem that the supersonic speed air flow parameter relationship is complex and the velocity cannot be directly calculated in real time by adopting the aerodynamic function and the iterative algorithm, and can realize the wind tunnel flow velocity online real-time measurement compared with the prior measurement and calculation method.
2. According to the wind tunnel flow velocity measurement method disclosed by the invention, the calibration of pressure, temperature and speed parameters is realized through the calibration of the sensing module and the speed correction, the calibrated parameters can be traced to the highest national standard, the accuracy and the reliability of the test result are ensured, and the flow velocity online real-time measurement precision is improved.
3. In the existing wind tunnel flow velocity measuring device, a sensitive element of the device based on the bridge balance principle is fragile and cannot measure supersonic velocity, a light path of the device based on the optical principle is complex, trace particles need to be scattered, and distortion is easy to measure in a severe environment. The wind tunnel flow velocity real-time measuring device disclosed by the invention adopts the probe as the sensing part, has strong environmental adaptability, simultaneously avoids the problem that sensitive elements are easy to damage and cannot be measured, and has the measuring range covering subsonic and supersonic airflow speeds, thereby effectively expanding the wind tunnel flow velocity measuring range and ensuring the measuring precision of the device.
Drawings
FIG. 1 is a schematic diagram of a wind tunnel flow velocity real-time measurement device;
FIG. 2 is a schematic diagram of a display screen interface of a wind tunnel flow velocity real-time measurement device disclosed by the invention;
FIG. 3 is a calibration graph of a pressure and temperature sensing module of the wind tunnel flow velocity real-time measurement method disclosed by the invention.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings.
Example 1
The embodiment discloses a wind tunnel flow velocity measurement method, which comprises the following specific implementation steps:
the pressure and temperature sensing modules are calibrated, each measuring range pressure module is sequentially connected with a pressure standard device, standard pressure is given by the pressure standard device according to preset pressure values P1, P2, … and Pn, measured values P1', P2', … and Pn ' of each pressure module are recorded, pressure correction values delta P1, delta P2, …, delta Pn and pressure correction curves are obtained, and the interpolation algorithm is utilized to obtain pressure correction values in the whole measuring range, so that the pressure calibration is completed; connecting a temperature sensing module with a temperature standard device, giving standard temperature by the temperature standard device according to preset temperature values T1, T2, … and Tn, recording measured values T1', T2', … and Tn ' of the temperature sensing module, obtaining temperature correction values delta T1, delta T2, … and delta Tn and a temperature correction curve, obtaining temperature correction values in the whole range by utilizing an interpolation algorithm, and finishing temperature calibration;
the probe connection is used for selecting a pressure probe, connecting the pressure probe to a pressure sensing module with a corresponding measuring range, using two total pressure probes when measuring supersonic speed air flow, using a total static pressure probe when measuring subsonic speed air flow, selecting a total temperature probe, and connecting the total temperature probe to a temperature sensing module, wherein the total temperature sensing module is used for measuring the total temperature of the air flow;
and when the subsonic air flow is measured, the total static pressure probe is arranged in the subsonic wind tunnel test section core area, and the temperature probe is arranged in the wind tunnel stabilizing section.
Filtering pressure and temperature measurement signals, adopting a parallel line filtering method, setting a threshold value to discriminate the validity of measurement data according to constraint conditions such as the accuracy requirements of a pressure measurement module and a temperature measurement module, test results and the like, filtering measurement values which do not meet the constraint conditions, removing coarse errors, and ensuring the reality and effectiveness of the data;
calculating the speed, namely calculating the airflow velocity v by using pressure and temperature measured values;
and (3) correcting the velocity, namely correcting the calculated airflow velocity v by using a Doppler laser velocimeter (LDV) as a standard, and obtaining a correction coefficient by comparing the LDV standard value and the calculated value under each flow velocity, thereby finally obtaining a corrected flow velocity value.
The speed calculation method is as follows:
step 1: calculating the Mach number Ma of the air flow;
the supersonic airflow calculates Mach number according to the relation between the front and back parameters of the laser, and the calculation model is as follows:
-total wavefront pressure, pa, measured by a steady-stage total pressure probe;
-total pressure after the test, pa, measured by a test section total pressure probe;
ma—gas flow mach number;
k-specific heat ratio, 1.4 for air;
and (3) making:
carry (2) into (1):
the following results were obtained by reducing the formula (3):
order theThe Mach number is solved by adopting the following iterative method:
1) Taking the initial point x 0 And x 1 Maximum iteration number N and iteration accuracy epsilon, setting i=1;
2) Calculation of
3) If |x i+1 -x i |<Epsilon, stopping the operation;
4) Stopping calculation if i=n; otherwise set i=i+1, go 2).
The subsonic airflow calculates the Mach number according to the aerodynamic function τ (Ma) formula, and the calculation model is as follows:
p * -total pressure of the measuring points, measured by a total static pressure probe, pa;
p is the static pressure of the measuring point, and is measured by a total static pressure probe and Pa;
k-specific heat ratio, 1.4 for air;
step 2: calculating the static air temperature, obtaining the static air temperature according to the Mach number calculated in the step 1 of the total air temperature, and calculating the model as follows:
T * -total temperature of the air flow, K, measured by a total temperature sensor;
t-air flow static temperature, K;
step 3: calculating the airflow velocity v:
r-gas constant, 287.06 for air, J/(kg.K).
Example 2
Based on the implementation principle of embodiment 1, the embodiment discloses a wind tunnel flow velocity real-time measurement device, which is used for realizing the wind tunnel flow velocity real-time measurement method. As shown in fig. 1, the wind tunnel flow velocity real-time measurement device mainly comprises a case 1, a temperature sensing module 2, a pressure sensing module 3, a control main board 4, a module power supply 5, a display screen 6, a total temperature probe 7 and a pressure probe 8, wherein the case has the following external dimensions: the wide range is 462.2mm, the height is 191.8mm, the depth is 356mm, and the functions of calibration, filtering, real-time acquisition and display, self calibration and the like are achieved.
The temperature transmitting module 2, the pressure sensing module 3, the control main board 4 and the module power supply 5 are fixed in the case, and the display screen 6 is arranged on the front panel of the case 1. The temperature transmitting module 2 is input by Pt100, outputs RS485, has a sampling rate of 20Hz, a measuring range (0-300) DEG C and an accuracy of 0.1 percent, and is provided with 24V direct current by a module power supply 5; the pressure sensing module 3 is a digital pressure meter, one measuring range (0-300) kPa, one measuring range (0-200) kPa, one measuring range (0-120) kPa, an output signal RS485, the precision is 0.05 level, and the module power supply 5 supplies direct current (12-24) V.
The power switch 11 is arranged on the front panel of the case 1, the board passing air pipe socket 12, the temperature signal input interface 13, the USB interface 14, the net mouth 15 and the socket 16 are fixed on the rear panel, the wire arranging frame is arranged in the case 1, the internal wiring is convenient, the vent holes are arranged on the left side and the right side of the case 1, and the cooling fan 17 is arranged in the case;
the display screen 6 is a touch integrated display screen, can display parameters such as wind speed, mach number, temperature and the like obtained through collection and calculation, and simultaneously has operational option keys such as calibration, filtering, collection, storage, self calibration and the like, as shown in figure 2;
the calibration function can realize the calibration of the pressure and temperature sensing module; the filtering function adopts a parallel line filtering method, and meanwhile, the system can write in a self-defined filtering algorithm and is configured according to specific conditions; the self-calibration function can realize speed correction, and the LDV standard value and the device measured value under each flow rate are written into the device system to obtain a correction coefficient;
the total temperature probe 7 is used for collecting the total temperature of wind tunnel airflow, pt100 is selected and connected with the temperature transmitting module 2 through the temperature signal input interface 13, and the temperature transmitting module 2 transmits the probe resistance value into a temperature signal and transmits the temperature signal into the control main board;
the pressure probe 8 is used for collecting total static pressure of wind tunnel airflow, is connected with the pressure sensing module 3 through the board passing air pipe socket 12, the pressure sensing module 3 transmits the airflow pressure value into the control main board, the board passing air pipe socket 12 enables the pressure sensing module interface to be vertically connected with the corresponding air pipe, bending of the air pipe is avoided, and meanwhile the air pipe is convenient to detach.
Specific example 1: based on the measuring methods and devices of the embodiments 1 and 2, taking a certain supersonic wind tunnel (the maximum total incoming flow pressure is 0.25MPa, and the maximum operation Mach number is 2.2) as an example, the specific practice of measuring the supersonic airflow velocity by using the invention is shown.
The device pressure sensing module and the temperature sensing module are calibrated, and a calibration curve is shown in fig. 3.
TABLE 1 measurement range (0-120) kPa pressure module calibration
Table 2 measuring range (0-200) kPa pressure module calibration
Table 3 measuring range (0-300) kPa pressure module calibration
Table 4 measuring range (0-300) deg.C temperature module calibration
| Temperature/. Degree.C | Temperature correction value/. Degree.C | Extended uncertainty U/°c 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 |
As shown in figure 1, two total pressure probes 8 are selected and respectively connected to a device (0-300) kPa range interface and a device (0-200) kPa range interface, a total temperature probe 7 is selected and connected to a temperature signal input port, the two total pressure probes are respectively arranged in a supersonic wind tunnel stabilizing section and a core area of a test section, the total temperature probes are arranged in the wind tunnel stabilizing section, a parallel line filtering method is adopted for pressure and temperature measurement signals, the threshold value is set to be 1%, and coarse errors are eliminated.
Starting the wind tunnel to about Mach number 2.2, collecting total pressure and total temperature signals, calculating Mach number by using the iterative algorithm in the embodiment 1, further calculating to obtain a speed value by formulas (6) - (7), and finally obtaining a correction value by a preset speed correction coefficient, wherein the correction coefficient is obtained by comparing an LDV standard value with a calculated value under each flow rate before use. The results within 5s of the measurement procedure were selected as follows:
table 5 measurement result parameters
| Total pressure/KPa of test section | Total pressure/KPa of stabilizing section | Total pressure of test section/total pressure of stabilizing 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 |
Uncertainty assessment was performed on the above measurement results, and the results are shown in the following table:
table 6 device measurement uncertainty assessment
The flow velocity measuring process shows that when the supersonic velocity air flow velocity of 700m/s is measured, the expansion uncertainty of the device is less than 0.5%, the expansion uncertainty of the current subsonic velocity standard is 0.6%, and the supersonic velocity air flow measuring difficulty is greater than that of the subsonic velocity air flow, so that the flow velocity measuring process can effectively improve the reliability of flow velocity measurement while realizing online measurement.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Claims (8)
1. A wind tunnel flow velocity measuring method is characterized in that: comprises the following steps of the method,
the pressure and temperature sensing modules are calibrated, each measuring range pressure module is sequentially connected with a pressure standard device, standard pressure is given by the pressure standard device according to preset pressure values P1, P2, … and Pn, measured values P1', P2', … and Pn ' of each pressure module are recorded, pressure correction values delta P1, delta P2, …, delta Pn and pressure correction curves are obtained, and the interpolation algorithm is utilized to obtain pressure correction values in the whole measuring range, so that the pressure calibration is completed; connecting a temperature sensing module with a temperature standard device, giving standard temperature by the temperature standard device according to preset temperature values T1, T2, … and Tn, recording measured values T1', T2', … and Tn ' of the temperature sensing module, obtaining temperature correction values delta T1, delta T2, … and delta Tn and a temperature correction curve, obtaining temperature correction values in the whole range by utilizing an interpolation algorithm, and finishing temperature calibration;
the probe is connected with a pressure probe, is connected to a pressure sensing module of a corresponding range and is used for measuring the pressure of the air flow; two total pressure probes are used for measuring supersonic speed air flow, a total static pressure probe is used for measuring subsonic speed air flow, a total temperature probe is selected and connected to a temperature sensing module, and the total temperature of the air flow is measured;
the probe is installed, when supersonic speed air flow is measured, two total pressure probes are respectively installed in the supersonic speed wind tunnel stabilizing section and the core area of the test section, when subsonic speed air flow is measured, the total static pressure probes are installed in the core area of the subsonic speed wind tunnel test section, and the temperature probes are installed in the wind tunnel stabilizing section;
filtering pressure and temperature measurement signals, adopting a parallel line filtering method, setting a threshold value according to constraint conditions, screening the validity of measurement data, filtering measurement values which do not meet the constraint conditions, removing coarse errors, and ensuring the reality and effectiveness of the data; the constraint conditions comprise a pressure measurement module, a temperature measurement module precision requirement and a test result;
calculating the speed, namely calculating the airflow velocity v by using pressure and temperature measured values;
and correcting the velocity, namely correcting the calculated airflow velocity v by using the Doppler laser velocimeter LDV as a standard, and obtaining a correction coefficient by comparing the LDV standard value and the calculated value under each flow velocity to obtain a corrected flow velocity value.
2. A method of measuring a wind tunnel flow rate as claimed in claim 1, wherein: and the method further comprises the step of tracing upwards according to the corrected flow velocity value to serve as a flow velocity standard for calibrating various probes and anemometers.
3. A method of measuring the flow rate of a wind tunnel according to claim 1 or 2, wherein: the speed calculation method comprises the following steps:
step 1: calculating the Mach number Ma of the air flow;
the supersonic airflow calculates Mach number according to the relation between the front and back parameters of the laser, and the calculation model is as follows:
-total wavefront pressure, pa, measured by a steady-stage total pressure probe;
-total pressure after the test, pa, measured by a test section total pressure probe;
ma—gas flow mach number;
k-specific heat ratio, 1.4 for air;
and (3) making:
wherein a is a constant, and a is more than 0 and less than 1;
carry (2) into (1):
the following results were obtained by reducing the formula (3):
order the
The Mach number is solved by adopting the following iterative method:
1) Taking the initial point x 0 And x 1 Maximum iteration number N and iteration accuracy epsilon, setting i=1;
2) Calculation of
3) If |x i+1 -x i |<Epsilon, stopping the operation;
4) Stopping calculation if i=n; otherwise, setting i=i+1, turning to 2);
the subsonic airflow calculates the Mach number according to the aerodynamic function τ (Ma) formula, and the calculation model is as follows:
p * -total pressure of the measuring points, measured by a total static pressure probe, pa;
p is the static pressure of the measuring point, and is measured by a total static pressure probe and Pa;
k-specific heat ratio;
step 2: calculating the static air temperature, obtaining the static air temperature according to the Mach number calculated in the step 1 of the total air temperature, and calculating the model as follows:
T * -total temperature of the air flow, K, measured by a total temperature sensor;
t-air flow static temperature, K;
step 3: calculating the airflow velocity v:
r-gas constant.
4. A wind tunnel flow velocity real-time measurement device for realizing the wind tunnel flow velocity real-time measurement method as set forth in claim 3, wherein: comprising the steps of (a) a step of,
the sensing module comprises a pressure sensing module and a temperature sensing module, and different measuring range modules are configured according to the measurement parameter requirements;
the control main board is used for realizing the calculation process of the whole measurement method and realizing the functions of calibration, filtering and self calibration;
the module power supply is used for supplying power to the measuring device;
the sensing module, the control main board and the module power supply are fixed in the case;
the display screen is a touch integrated display screen and is used for displaying parameters, wherein the parameters comprise wind speed, mach number and temperature obtained through collection and calculation; the system is also provided with operation option keys, wherein the operation option keys comprise calibration, filtering, acquisition, storage and self calibration;
the pressure probe is used for collecting the total static pressure of the wind tunnel airflow, is connected with the pressure sensing module through the board passing air pipe socket, and the pressure sensing module transmits the airflow pressure value to the control main board;
the total temperature probe is used for collecting the total temperature of the wind tunnel airflow and is connected with the temperature sensing module through the temperature signal input interface, and the temperature sensing module transmits the resistance value of the probe into a temperature signal and transmits the temperature signal to the control main board.
5. The wind tunnel flow velocity real-time measurement device according to claim 4, wherein: the calibration function has the functions of calibrating the pressure and temperature sensing modules.
6. The wind tunnel flow velocity real-time measurement device according to claim 4, wherein: the filtering function adopts a parallel line filtering method, has the function of compatible self-defined filtering algorithm, and is configured according to specific conditions.
7. The wind tunnel flow velocity real-time measurement device according to claim 4, wherein: the self-calibration function is used for realizing speed correction, and writing the LDV standard value and the device measured value under each flow rate into the device system to obtain a correction coefficient.
8. The wind tunnel flow velocity real-time measurement device according to claim 4, wherein: the power switch is installed to the machine case front panel, and the rear panel is fixed with board trachea socket, temperature signal input interface, USB interface, net gape, socket, and machine case internally mounted reason line frame is convenient for inside the wiring, and the design ventilation hole of machine case left and right sides, internally mounted radiator fan.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211505841.9A CN116499692A (en) | 2022-11-28 | 2022-11-28 | Wind tunnel flow velocity real-time measurement method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211505841.9A CN116499692A (en) | 2022-11-28 | 2022-11-28 | Wind tunnel flow velocity real-time measurement method and device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116499692A true CN116499692A (en) | 2023-07-28 |
Family
ID=87317219
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211505841.9A Pending CN116499692A (en) | 2022-11-28 | 2022-11-28 | Wind tunnel flow velocity real-time measurement method and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116499692A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117949692A (en) * | 2024-03-27 | 2024-04-30 | 江西省气象探测中心 | Evaluation method and device for measurement uncertainty of photoelectric cup type anemometer |
-
2022
- 2022-11-28 CN CN202211505841.9A patent/CN116499692A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117949692A (en) * | 2024-03-27 | 2024-04-30 | 江西省气象探测中心 | Evaluation method and device for measurement uncertainty of photoelectric cup type anemometer |
| CN117949692B (en) * | 2024-03-27 | 2024-05-31 | 江西省气象探测中心 | Evaluation method and device for measurement uncertainty of photoelectric cup type anemometer |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104318107B (en) | A kind of high-precision atmosphere data acquisition methods of Trans-atmospheric flight aircraft | |
| CN104048808B (en) | A kind of kolmogorov sinai entropy probe | |
| CN103969022B (en) | A kind of hypersonic wind tunnel turbulivity indirect measurement method | |
| Gulitski et al. | Velocity and temperature derivatives in high-Reynolds-number turbulent flows in the atmospheric surface layer. Part 1. Facilities, methods and some general results | |
| CN204085645U (en) | With the gas flow standard device of self calibration structure | |
| CN104155473A (en) | Wind speed and wind direction sensing device | |
| CN212254182U (en) | Composite pressure-temperature probe | |
| CN116499692A (en) | Wind tunnel flow velocity real-time measurement method and device | |
| CN108195510A (en) | A kind of hot air wind tunnel calibration method of hot diaphragm type shear stress sensor | |
| CN111551215A (en) | Composite pressure-temperature probe and air flow velocity calculation method thereof | |
| CN110530597B (en) | Wind speed calibration system under low pressure | |
| CN114018349A (en) | Gas flow measuring device, measuring system and measuring method based on ultrasonic waves | |
| CN103308106B (en) | High-pressure inert gas fire extinguishing agent mass flowmeter | |
| CN112945500B (en) | Simulation measurement device and method for influence of transonic wind tunnel blocking degree | |
| CN104034378A (en) | Constant-current thermal gas mass flow meter and measuring method implemented by same | |
| CN111498141B (en) | Method and device for realizing real-time monitoring of airflow angle based on micro probe | |
| CN204679522U (en) | A kind of in large space to the device that air-flow velocity is measured | |
| CN109238738B (en) | Special vehicle cooling air volume testing device and method based on testability grating | |
| CN114046957B (en) | Three-dimensional shear layer correction method for open wind tunnel far-field noise measurement | |
| CN111307404B (en) | Device and method for testing internal flow field of jet fan | |
| Delhaye et al. | Enhanced performance of fast-response 3-hole wedge probes for transonic flows in axial turbomachinery | |
| CN110500203B (en) | High-speed free jet angle of attack measurement system of solid rocket ramjet based on weather vane | |
| CN112547294B (en) | Method for acquiring inlet air volume of medium-speed coal mill under thermal state | |
| CN203688579U (en) | Anemometer | |
| RU86751U1 (en) | MEASURING AERODYNAMIC INSTALLATION |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |