Application of Ultrasonic Time-Domain Correlation Method to Two Phase Flow Measurements
T. Hayashida1, H. Murakawa1, H. Kikura1, M. Aritomi1, and M. Mori2
1 Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, N1-13, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8550 Japan, Email: firstname.lastname@example.org
2 Tokyo Electric Power Company, 4-1, Egasaki-cho, Tsurumi-ku, Yokohama, 230-8510 Japan
Here, the authors focus on two-phase flow measurement using ultrasound. Previously, we developed a way to measure bubbly flow using UVP. By this method, we are able to separate liquid information from bubbles information to some degrees. However, when the bubble number density is low a problem occurs, because the effect of liquid information is strong under that condition. From this fact, we applied the ultrasound time domain correlation method (UTDC) to two-phase flow measurement. This method is our original technique to measure the velocity distribution. It is based on the cross- correlation between two consecutive echoes of ultrasonic pulses. With this method, we can separate liquid information from bubble information even when the bubble number density is low, because reflected signals depend on the size of reflectors and the frequency of ultrasound. In this study, the authors applied the UTDC methods to rectangular channel using a multi-wave ultrasonic transducer (TDX). The multi-wave TDX has two kinds of basic frequencies. One is 2MHz for the velocity of rising bubbles and the other is 8MHz for the liquid velocity. So, it enables us to measure the velocity of the liquid and that of bubbles at the same point and time.
Keywords Ultrasound, frequency, time domain, Two phase flow
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