Wind speed testing methods and classification of anemometers
Test method for wind speed
Wind speed (velocity) testing includes testing of average wind speed and testing of turbulence components (turbulence of wind at 1-150KHz, different from fluctuations). A thermal anemometer tests the average wind speed. There are methods for testing average wind speed, such as thermal, ultrasonic, impeller, and skin drag tube. However, among these methods, the * * anemometer utilizes the principle of heat dissipation. Below, we will explain the methods for measuring these wind speeds.
1、 Thermal anemometer
This method tests the resistance change generated by the sensor cooling due to wind when it is in the energized state, thereby testing the wind speed. Unable to obtain information on wind direction.
In addition to being easy to carry and convenient, it has a high cost performance ratio and is widely adopted as a standard product for anemometers.
The elements of thermal anemometers include platinum wires, thermocouples, and semiconductors,
2、 Ultrasonic type
This method tests the transmission time of ultrasound waves at a certain distance, and the arrival time is delayed due to the influence of wind, thereby testing the wind speed.
When it is to the third power, the wind direction can be known.
The sensor section is relatively large, and turbulence may occur around the testing section, resulting in irregular flow. The use is limited.
Low popularity.
3、 Impeller type
This method applies the principle of a windmill and tests the speed of the wind by measuring the number of revolutions of the impeller.
Used for meteorological observation, etc.
The principle is relatively simple and the price is cheap, but the testing accuracy is low, so it is not suitable for testing low wind speed and small wind speed changes.
Low popularity.
4、 Leather drag tube type
There are small holes on the front of the flow surface that form a right angle to it, and inside there are thin tubes that extract pressure from each hole. By testing its pressure difference (the former being full pressure and the latter being static pressure), the wind speed can be determined.
The principle is relatively simple and the price is cheap, but it must be set at a right angle to the flow surface, otherwise correct testing cannot be conducted. Not suitable for general use.
It is not used as an anemometer, but as a wind speed correction for high-speed areas.
