Development of an air velocity and flow measurement system by using a novel circular disc

Abstract

In this paper, development of a sensor using a circular disc for air velocity measurement based on the drag force equation is proposed. The air velocity measurement sensor is basically designed with a load cell in order to determine the drag force. The circular disc is used for creating a drag force, and by using load cell, the drag force that acts on the circular disc is measured. As the circular disc's drag coefficient can be considered constant at Reynolds numbers between 103 and 106, it can be possible to obtain the explicit equation of drag force. The remaining components of drag force equation are obtained by measurement. The proposed air velocity measurement sensor is characterized by wind tunnel measurements. All measurements were performed in an ISO/IEC 17025 accredited calibration laboratory – the Wind Tunnel of Turkish State Meteorological Service. The characterization measurements were performed at air velocities between 1 m/s and 20 m/s. The correction factors were calculated and a calibration curve for the proposed air velocity measurement sensor was obtained. The calibration curve's linearity was higher than 0.99 and a comparison the results from a Micromanometer with Pitot-Tube shows that for the designed working range, the sensor has an acceptable performance for time-averaged air velocity measurements according to the requirements of the World Meteorological Organization.