| Co-Investigator(Kenkyū-buntansha) |
TAKEDA Yasushi Hokkaido University, Professor, 大学院・工学研究科, 教授 (90108481)
MORI Michitsugu The Tokyo Electric Power Company, Senior Researcher, 技術開発研究所, 主任研究員
ARITOMI Msanori Research Laboratory for Nuclear Reactors, Professor, 原子炉工学研究所, 教授 (60101002)
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| Research Abstract |
Pulse Ultrasonic Doppler method for accurate flow metering system has been developed. The principle of this method is based on the integration of instantaneous velocity profile over a pipe diameter so that it is expected to be able to eliminate installation problems such as entry length as well as to follow transient flow rate precisely. Therefore, in the present study, we report the results of multiline flow rate measurement employing this method. Flow metering principle by ultrasonic Doppler method in a circular pipe depends on the alignment of measuring lines. In most cases, metallic pipes are used at power plants. And some reflectors are needed to seed the water for now rate measurement using this method. Because clear water flows in the pipes at power plants. In this study, the comparison among several kinds of metallic pipes on the flow rate measurements have been investigated in a vertical pipe. Additionally, for reflectors ultrasonic cavitation bubbles were applied and the effe
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ct was compared with nylon powder, which used in the previous study. In this experiment, even for the metallic wall pipe, it is possible to measure the flow rate using multiline system with high accuracy. And for the ultrasonic reflector cavitation bubbles are achievable to be applied. As mentioned above, it is indicated that the present multiline flow metering system by using ultrasonic Doppler method has very high accuracy. And this method can be considered as a multipurpose system, because the flow rate can be measured under non-Ideal flow conditions such as non-developed flow or non-axisymmetric flow.
In the present study, a new velocity profile measurement technique using a ultrasound time-domain correlate ion method(UTDC) has been developed. The system is based on the cross-correlation between two consecutive echoes of ultrasonic pulses to detect the velocity. The UTDC has two advantages over the conventional ultrasound pulse Doppler method. First, the system has a better time resolution than the pulse Doppler method. Second, the system have no limitation in maximum measurable velocity, which is limited by Nyquist's sampling theorem. In this study, the velocity profile measurement using the UTDC is performed, and the velocity profiles measured by the UTDC method is good agreement with those results using the pulse Doppler method. Less
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