Anemometer measurement in exhaust
The ventilation port will perceive a relatively balanced distribution of airflow inside the duct: a high-speed zone is generated on the surface of the free ventilation port, while other areas are low-speed zones, and vortices are generated on the grid. According to different design methods of the grid, the airflow cross-section is relatively stable at a certain interval (about 20cm) in front of the grid. In this situation, it is common to use a large anemometer to stop measuring the diameter of the rotor. Due to the larger diameter, uneven flow velocity can be stopped uniformly and its uniformity value can be calculated over a larger range.
The anemometer uses a volumetric flow funnel to stop measuring at the suction port:
Even without the interference of grids at the exhaust point, the path of air activity has no direction and its airflow cross-section is extremely uneven. The reason is that there is a partial vacuum inside the pipeline, which extracts air in a funnel-shaped manner into the chamber. Even in areas where the extraction is very close, there is no position that meets the measurement conditions for stopping the measurement operation. If the grid measurement method with uniform value calculation function is used to stop the measurement, and the volumetric flow rate method is used to stop the measurement and confirm the volumetric flow rate, as long as the pipeline or funnel measurement method can provide repeatable measurement results. In this situation, measuring funnels of different sizes can meet the application requirements. The application measuring funnel can generate a fixed section that meets the flow velocity measurement conditions at a certain interval in front of the sheet valve. The center of the section is measured and fixed, the center of the section is measured and fixed, and the center of the section is measured and fixed. The measured value obtained from the flow velocity probe can be multiplied by the funnel coefficient to calculate the extracted volumetric flow rate. (such as funnel coefficient of 20)
Testing method for wind speed
Wind speed testing includes testing for uniform wind speed and testing for turbulent components (wind turbulence 1-150KHz, different from variations). The methods for testing uniform wind speed include thermal, ultrasonic, impeller, and skin testing
Thermal wind speed testing method
This method is to test the resistance change caused by the cooling of the sensor due to wind when it is powered on, and thus test the wind speed. Unable to obtain information on wind direction. In addition to being easy to carry and convenient to use, it has a high cost performance ratio and is widely adopted as a standardized product for anemometers. The elements of the thermal anemometer include platinum wire, thermocouple, and semiconductor, but our company uses platinum winding wire. The material of platinum wire is very stable materially. Therefore, it has advantages in long-term stability and temperature compensation.
