抄録
Ultrasonic pulsed Doppler method (UDM) can obtain velocity profile on the ultrasonic beam path. By integrating the velocity profile over the pipe, flow-rate can be derived with high accuracy. In order to measure higher velocity by using feedback method, the larger measurement volume is required. With increasing of the measurement volume, it has been reported that the measurement accuracy near-wall region becomes low. In order to improve the measurement accuracy, multi-wave ultrasonic method which employs two ultrasonic sensors with basic frequency of 2 & 8 MHz is proposed. The velocity distribution was accurately obtained over the pipe by combining velocity distributions at 8 MHz for the near-wall region and 2 MHz for the region far from the transducer. Furthermore, the accuracy of the flow-rate was also improved with the proposed method.
