APPLICATION OF AIR TORQUE POSITION DAMPERS FOR AIRFLOW MEASUREMENT

The subject of the paper is a damper, which is referred to as ATP (Air Torque Position) based on its mode of operation. The ATP damper indirectly measures air velocity by assessing the torque applied to the blades and their position. The airflow rate is determined by multiplying the air velocity with the cross-sectional area of the damper. Previous research on the accuracy of measurement and validity of mathematical model of the ATP damper has been analyzed for the entire range of blade angle of attack (0° – 90°). The difference between the measured and the modeled velocity was ±10% of the measured velocity. This way of analysis is more appropriate for the ATP damper as a measuring control device, where, in addition to airflow measurement, the damper also plays a role in regulating the airflow rate. In this work, the accuracy of air velocity and validity of mathematical model of the ATP damper was analyzed for a fixed value of the blade angle of attack. The reason for this is that, in practice, an ATP damper would be used for airflow measurement with a single set value of the blade angle of attack. Within this research the damper with two flat blades has been analyzed, where one blade is a measuring blade, while the other blade is in a fixed position. The following two cases were analyzed: with straight duct sections both upstream and downstream of the damper and with a straight duct section upstream of the damper. For the first case for certain damper blade angles of attacks (20o, 40o, 80o and 90o), the difference between the measured and the modeled velocity was within ±2% of the measured velocity. This data analysis approach shows promise for the application of ATP dampers in airflow measurement in the future.