On the Accuracy Evaluation of Ultrasonic Doppler Flowmeter

The accuracy evaluation of a pipe flowmeter using ultrasonic velocity profiler is investigated theoretically and experimentally. The error depends basically on the data points on discretized velocity profile, but it decreases rapidly with increasing the data points. It can be reduced, relative to the theoretical velocity profile, below 1% with about 100 data points. The error arising from averaging the instantaneous flow rate increases with the fluctuation amplitude in the loop and decreases with its frequency and total measurement time. A procedure to determine the total averaging time is proposed.