CN102262166B - Wind-tunnel wind profiler and control method thereof - Google Patents

Abstract

The invention relates to a wind tunnel anemometer and its control method, comprising a data collection unit, a wireless data transmission unit and a control processing device, the data collection unit includes a plurality of hot film probes and a data acquisition card; the wireless data The transmission part includes a wireless sending device and a wireless receiving device, the hot film probe is connected to the data acquisition card, and the wind speed signal collected by the hot film probe is calibrated and converted into a voltage signal and sent to the data acquisition card. A/D converter, so that the data acquisition card completes the collection of the wind speed signal output by the hot film probe, and sends the wind speed data collected to the wireless sending device; the wireless sending device will The received wind speed data is sent to the wireless receiving device in a wireless manner, and the control processing device is connected with the wireless receiving device. It has the characteristics of simple structure, feasible performance, low cost, easy to carry and install, simple field connection, flexible and reliable use.

Description

Wind Tunnel Wind Velocity Profiler and Its Control Method

technical field

The invention relates to a wind tunnel wind speed profiler and a control method thereof, in particular to a wind tunnel wind speed profiler based on a hot film sensor and a wireless sensor network and a control method thereof.

Background technique

Soil wind erosion is the primary cause of land desertification and sandstorm disasters in arid, semi-arid and partially sub-humid areas, and is also one of the major environmental problems in many countries and regions in the world. Sand movement is as harmful as natural disasters such as floods, droughts and storms. It can bury farmland and pastures, destroy crops and blow away topsoil and seeds, seriously eroding the land on which human beings depend. At the same time, wind and sand movement can also hinder traffic, bury railways and highways, and endanger driving safety.

In my country, the Institute of Environment and Engineering in Cold and Arid Regions of the Chinese Academy of Sciences built the first large-scale indoor wind tunnel in 1967, and carried out simulation experiments on wind erosion movement, thus creating a new situation in the study of wind erosion movement in my country. The line meter and the sand collector simulate the natural wind in the wind tunnel to study the soil wind erosion.

At present, the commonly used anemometers for measuring wind speed are mechanical, differential pressure and hot wire. The mechanical anemometer mainly uses the wind cup and the impeller as the sensing element, and its response lags behind. In addition, the wear and stagnation caused by the movable elements in the wind and sand environment make the reliability of the instrument low and the error is large; the differential pressure anemometer The Pitot tube is equipped with a micro-pressure transmitter to output the signal. Due to the loss of air pressure along the connecting pipeline and the blockage of the Pitot tube caused by the wind and sand flow, the measurement accuracy of the wind speed is affected; the hot-wire anemometer is based on the thermal It is made by the principle of transfer. Since an electrically heated metal filament (generally a platinum wire with a diameter of 3-5 μm) is placed in the air flow during the measurement, it is easily polluted and damaged, which affects the heat transfer effect and reduces the temperature. measurement accuracy. In addition, the above-mentioned anemometers require a large number of line connections during data collection and transmission, and the lines are easily bent and broken during use, which affects the measurement accuracy on the one hand, and brings a lot of inconvenience to the test work on the other hand.

Fig. 1 shows a schematic structural diagram of an anemometer in the prior art. As shown in Figure 1, the wind speed measurement device in the prior art is composed of a pitot tube and a protective box. When measuring, the pitot tube is connected to a differential pressure transmitter, and the total pressure and static pressure signals received in the pitot tube are transmitted through the transmitter. The electrical signal is converted into a dynamic voltage electrical signal by a device. After conditioning (such as filtering and amplification), the electrical signal is input to the A/D converter for analog-to-digital conversion, and then the signal is collected by a microcomputer sampling system, and finally the data is processed by software.

The wind speed measuring device shown in Fig. 1 has the following defects: (1) The system uses a pitot tube and a long rubber tube as the main measuring elements, and the sensitivity and accuracy are poor. In a certain range of wind speed, the absolute value of air pressure measured by pitot tube is much smaller than the differential pressure value measured by static pressure difference. The measurement error of differential pressure sensor is certain, and the result will lead to relative error of velocity pressure measurement results. Therefore, the Pitot tube is only suitable for the measurement conditions with wind speed greater than 4m/s; and when working in the field, the pressure measuring hole of the wind speed sensor may be blocked by dust or sand in the air and lose the speed measurement function. In addition, when the rubber tube connecting the Pitot tube and the differential pressure transmitter is long, the rubber tube is easily bent and deformed, resulting in reduced measurement sensitivity. Moreover, due to the inertia of the measurement system, it takes a certain amount of time for the measurement medium and the measured medium to reach equilibrium, which causes a certain time delay for the pulsation change of the airflow. In the high-frequency pulsation airflow, the measurement result will be smaller than the actual value. (2) There are too many connections in the measuring device, and it is inconvenient to move the measuring point. When measuring wind speed in the field, the measuring point will move at any time, and the existing wind speed collection and data processing devices are connected together, which needs to be installed and disassembled when moving, which brings uncertainty to the accuracy and accuracy of the measurement results , and it is also inconvenient to use.

Contents of the invention

The object of the present invention is to provide a wind tunnel anemometer and its control method with simple structure, feasible performance, low cost, easy to carry and install, simple on-site connection, flexible and reliable use.

In order to solve the above technical problems, the present invention adopts the following technical solutions: a wind tunnel anemometer, characterized in that it includes a data acquisition unit, a wireless data transmission unit and a control processing device, and the data acquisition unit includes a plurality of hot film Probe and data acquisition card; the wireless data transmission part includes a wireless sending device and a wireless receiving device, the hot film probe is connected to the data acquisition card, and the wind speed signal collected by the hot film probe is converted into a voltage after calibration The signal is sent to the A/D converter in the data acquisition card, so that the data acquisition card completes the collection of the wind speed signal output by the hot film probe, and sends the wind speed data collected by it to the A wireless sending device; the wireless sending device sends the received wind speed data to the wireless receiving device in a wireless manner, and the control processing device is connected with the wireless receiving device to obtain the wind speed received by the wireless receiving device data, and analyze and process the acquired wind speed data.

Further, the wireless sending device sends out the received wind speed data in a time-division manner.

Further, each of the hot film probes is constructed as a sensor node, and further, preferably, the sensor nodes form a sensor network.

Further, the control processing device includes an interpolation calculation module, a data storage module and a result data analysis module.

Further, the interpolation operation module is used to convert the wind speed data in the form of current into corresponding wind speed values.

Further, the distribution of the hot film probes in the vertical direction satisfies a logarithmic relationship.

Further, the data collection unit and the wireless sending device are movable.

Further, the data acquisition part also includes a rotating device, the hot film probe is arranged on the rotating device, when the hot film probe is not in use, the hot film probe is rotated to a safe position through the rotating device, and the hot film probe is rotated to a safe position during use. , the hot film probe can be rotated to the working position only by rotating the rotating device.

The present invention also provides a control method of a wind tunnel anemometer, characterized in that: comprising the following steps:

(1) Read the setting parameters set by the user;

(2) Start the fan;

(3) controlling the rotation of the fan by means of frequency conversion so as to realize wind speed regulation;

(4) By checking whether the rotating speed of the fan is stable at a certain value, it is judged whether the wind speed in the wind tunnel has reached a stable state;

(5) If the steady state is reached, then carry out data collection and data processing, and display the wind speed and draw the wind profile; then further change the wind speed and continue to perform step (3);

(6) If the steady state is not reached, proceed to step (3).

The anemometer in the present invention adopts the integral hot-film anemometer, and its anti-vibration and anti-pollution ability is far higher than that of the traditional hot-wire anemometer, and has high long-term stability; in addition, it has multiple installation methods, The probe can be easily fixed at the measured airflow position; further, the wind speed profiler has the characteristics of high precision and good consistency, sensitive response to extremely low wind speed, and accurate measurement of air speed close to 0m/s, It can accurately measure the average speed, direction, pulsation speed and its frequency spectrum and temperature of the wind; finally, the hot film probe in the wind speed profiler can output a 4-20mA or 0-5V standard signal under the power supply of 24VDC, which The output signal has a linear relationship with the wind speed.

Description of drawings

Fig. 1 is a schematic structural diagram of an anemometer in the prior art.

Figure 2 is a schematic diagram of the wind speed measurement and control system based on wireless communication.

Figure 3 is a flow chart of wind speed measurement and control.

Detailed ways

The technical solution of the present invention will be described in detail below.

As shown in Figure 2, the wind tunnel wind speed profiler based on hot film sensor and wireless sensor network among the present invention comprises: data acquisition part, wireless data transmission part and control processing device 5, and described data acquisition part comprises a plurality of A hot film probe 1 and a data acquisition card 2; the wireless data transmission part includes a wireless sending device 3 and a wireless receiving device 4. Preferably, the hot film probe 1 is used to measure wind speed, the hot film probe 1 is connected to the data acquisition card 2, and the wind speed signal collected by the hot film probe 1 is calibrated and converted into a voltage signal and sent to the The A/D converter in the data acquisition card 2, so that the data acquisition card 2 completes the collection of the wind speed signal output by the hot film probe 1, and sends the wind speed data collected by it to the wireless Sending device 3; The wireless sending device 3 sends the wind speed data it receives to the wireless receiving device 4 in a wireless manner, preferably, the wireless sending device 3 sends the wind speed data it receives to External transmission; the control processing device 5 is connected with the wireless receiving device 4, so as to obtain the wind speed data received by the wireless receiving device 4, and analyze and process the obtained wind speed data.

Preferably, the hot-film probe 1 is a hot-film wind speed sensor, which includes a hot-film made of platinum, which is exposed in the air to be measured, and heated to a certain temperature (such as a constant temperature higher than the measured temperature). Measure the wind speed at a certain temperature, such as 200°C), and then control the current input to the hot film so that the heat generated by the current on the hot film is equivalent to the heat dissipation of the hot film in the wind, and the hot film maintains a constant temperature, then the value of the current is a function of wind speed.

Preferably, each of the hot film probes 1 is constructed as a sensor node, and further, preferably, the sensor nodes form a sensor network. Preferably, the sensor nodes are randomly scattered or deterministically deployed in the application environment, and a sensor network is formed through self-organization, and the sensor nodes respectively act as data acquisition nodes, data transfer nodes, and cluster heads in the sensor network according to algorithms, It can monitor, perceive and collect information (such as wind speed data) of various environments or monitoring objects in the network distribution area in real time, and transmit the information to the control processing device 5 for processing.

Preferably, the wind tunnel anemometer further includes a power supply device 6 for supplying power to the wireless sending device and the data acquisition unit. Preferably, the power supply device 6 is a storage battery.

Preferably, the wireless sending device 3 and the wireless receiving device 4 respectively have ZigBee wireless modules, and the wireless sending device 3 and the wireless receiving device 4 communicate using the ZigBee wireless communication protocol. Further, between the wireless sending device 3 and the data acquisition card 2, between the wireless receiving device 4 and the control processing device 5, a general industrial standard MODBUS bus interface is also equipped to realize the data acquisition card 2, control Serial data communication between the processing device 5 and its corresponding ZigBee wireless module, the MODBUS bus interface on the side of the wireless sending device 3 transmits the hot film current value to the ZigBee module of the wireless sending device 3, and the wireless sending device 3 The ZigBee module on one side of the receiving device 4 sends the received current value to the control processing device 5 through the MODBUS bus interface for processing. ZigBee wireless communication technology has the advantages and characteristics of long communication distance, strong anti-interference ability, flexible networking, reliable and stable performance, etc.; it can realize transparent transmission of data between devices between point-to-point, point-to-multipoint, and multipoint-to-multipoint. Since the relationship between the acquisition terminal (that is, the data acquisition card) and the acquisition node (that is, the hot film probe) is a point-to-multipoint communication relationship, and each acquisition node has basically the same structure and is within the wireless signal coverage of the acquisition terminal , are independent of each other, therefore, compared with the traditional wired system, it not only solves the complex field connection, but also is more flexible and reliable in application. Preferably, the MODBUS interface is an RS232 interface.

Preferably, the control processing device 5 includes an interpolation operation module, a data storage module and a result data analysis module; ) interface) to the control processing device 5 for processing, the control processing device 5 converts the wind speed data in the form of current into corresponding wind speed values through its built-in interpolation calculation module, and stores it in the control processing device 5 built in the data storage module, and then, the result data analysis module built in the control processing device 5 draws the wind speed contour line according to the wind speed value and analyzes the degree of turbulence. Preferably, the data storage module includes a database, preferably an ACCESS database. Due to the use of the database, it can meet the requirements of multi-channel real-time data collection, and can quickly play back and analyze historical data when the amount of data is large.

Preferably, the distribution of the hot film probes 1 in the vertical direction satisfies a logarithmic relationship, that is, they are arranged in logarithmic coordinates. For example, the height positions of the hot film probe 1 from the ground are respectively 2cm, 4cm, 8cm, 16cm, 32cm and 64cm.

Preferably, in order to achieve the goal that the stability and uniformity of the airflow will not change greatly when the airflow passes through the anemometer, the anemometer is designed as a slender body structure, and preferably, the windward side of the baffle is designed as a wedge-shaped structure , so that the wind speed profiler minimizes the disturbance and influence on the original flow field of the wind tunnel when collecting data in the wind tunnel flow field, so as to ensure that the collected data can truly reflect the flow field quality characteristics of the wind tunnel.

Preferably, in order to meet the requirements of working in the field with strong wind and sand, and for the sealing of the structure of the data collection unit and the wireless sending device, the exterior of the structure is sealed with an iron sheet. Preferably, the thickness of the iron sheet is 0.5mm.

Preferably, the data acquisition unit and the wireless transmission device are movable, so they have the characteristics of easy portability, removable measurement points, anti-pollution and wide speed measurement range, and can meet the requirements of field work; further, because the hot film probe is easy to Therefore, in order to protect the hot film probe, the data acquisition part also includes a rotating device, the hot film probe is arranged on the rotating device, when the hot film probe is not in use, the hot film probe is made It is rotated to a safe position. When in use, the hot film probe can be rotated to the working position only by rotating the rotating device.

Preferably, as shown in Figure 3, the wind speed profiler adopts the following control algorithm, preferably, the control algorithm is set in the control processing device 5:

(1) Read the setting parameters set by the user;

(2) Start the fan;

(3) controlling the rotation of the fan by means of frequency conversion so as to realize wind speed regulation;

(4) By checking whether the rotating speed of the fan is stable at a certain value, it is judged whether the wind speed in the wind tunnel has reached a stable state;

(5) If the steady state is reached, then carry out data collection and data processing, and display the wind speed and draw the wind profile; then further change the wind speed and continue to perform step (3);

(6) If the steady state is not reached, proceed to step (3).

Preferably, it also includes the step of shutting down after the test is completed.

The control processing device in the wind speed profiler in the present invention adopts a modular structure design to facilitate expansion, debugging and modification. The wind speed data acquisition system is a multi-channel acquisition system to complete the synchronous acquisition of parameters such as wind speed and temperature.

The anemometer in the present invention adopts the integral hot-film anemometer, and its anti-vibration and anti-pollution ability is far higher than that of the traditional hot-wire anemometer, and has high long-term stability; in addition, it has multiple installation methods, The probe can be easily fixed at the measured airflow position; further, the wind speed profiler has the characteristics of high precision and good consistency, sensitive response to extremely low wind speed, and accurate measurement of air speed close to 0m/s, It can accurately measure the average speed, direction, pulsation speed and its frequency spectrum and temperature of the wind; finally, the hot film probe in the wind speed profiler can output a 4-20mA or 0-5V standard signal under the power supply of 24VDC, which The output signal has a linear relationship with the wind speed.

Claims (8)

1. a wind tunnel speed profiler is characterized in that: comprise data acquisition section, Wireless Data Transmission section and control treating apparatus, described data acquisition section comprises a plurality of hotting masks probes and data collecting card;

Described Wireless Data Transmission section comprises wireless transmission device and radio receiver, described hotting mask probe is connected with described data collecting card, the wind velocity signal that described hotting mask probe collects converts voltage signal to and delivers to the A/D converter in described data collecting card after calibration, thereby make described data collecting card complete the collection to the wind velocity signal of the output of described hotting mask probe, and the air speed data that it is collected send to described wireless transmission device;

The air speed data that described wireless transmission device receives it sends to described radio receiver wirelessly, described control treating apparatus is connected with radio receiver, thereby obtain the air speed data that described radio receiver receives, and the air speed data that it is got is analyzed and is processed ;

Described data acquisition section also comprises whirligig, described hotting mask probe is arranged on described whirligig, when not using described hotting mask probe, by described whirligig, described hotting mask probe is rotated to home, in use, only need the described whirligig of rotation, can be by the rotation of hotting mask probe to working position.

2. wind tunnel speed profiler as claimed in claim 1 is characterized in that: the air speed data that described wireless transmission device timesharing ground receives it outwards sends.

3. wind tunnel speed profiler as claimed in claim 1 is characterized in that: each described hotting mask probe is built as sensor node.

4. wind tunnel speed profiler as claimed in claim 1, it is characterized in that: described control treating apparatus comprises interpolation arithmetic module, data memory module and result data analysis module.

5. wind tunnel speed profiler as claimed in claim 4 is characterized in that: described interpolation arithmetic module is for converting the air speed data of current forms to corresponding air speed value.

6. wind tunnel speed profiler as described as claim 1-5 any one is characterized in that: the distribution of described hotting mask probe in the vertical direction meets logarithmic relationship.

7. wind tunnel speed profiler as described as claim 1-5 any one, it is characterized in that: described data acquisition section and wireless transmission device are movably.

8. wind tunnel speed profiler as claimed in claim 3, is characterized in that: described sensor node composition sensor network.

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