Application of ultrasonic doppler method for bubbly flow measurement using two ultrasonic frequencies

In this paper, a new technique for multi-phase flow measurement is proposed. This technique is based upon an ultrasonic Doppler method (UDM). Using different sizes of ultrasonic transducers (TDXs) for the UDM measurement, the measured data apparently differ. With a change in the measurement volume, the velocity PDF significantly changes. Applying this method for multi-phase flow, several types of particles whose sizes are considerably different can be obtained for each velocity distributions. To obtain each velocity at the same time and at the same position, a new Multi-wave TDX is developed. Using the Multi-wave TDX, this method was utilized for the measurement of bubbly flow in vertical pipe. To confirm the accuracy of each velocity distribution, the velocity PDFs were calculated. The results clarified that this method has high applicability.