DECREASING OF VOLUME FLOW-RATE MEASUREMENT ERROR IN MODIFIED AVERAGING IMPACT TUBES
S. Walus
Abstract:
The criteria for classification of averaging impact tubes are introduced (the art of measuring of reference pressure, the construction of the primary device, the number of ports and their displacement, the way of taking of total pressure) and some technical solutions are presented. Mathematical model of averaging impact tube is introduced and the correction factor is derivated. This factor takes into account the fact, that the output signal from differential pressure transducer is proportional to the average of dynamic pressures (velocities in second power) but the flow-rate is proportional to the average of velocities. Author introduced proposal of independent pressures measurement and calculating velocities in front of these ports in purpose of estimating of velocity distribution and than calculating flow-rate analytically.
