{"id":534,"date":"2022-10-08T09:27:47","date_gmt":"2022-10-08T00:27:47","guid":{"rendered":"https:\/\/lfc.media-creations.org\/?page_id=534"},"modified":"2022-12-07T15:06:41","modified_gmt":"2022-12-07T06:06:41","slug":"doc-page2-en","status":"publish","type":"page","link":"https:\/\/c-mng.cwh.hokudai.ac.jp\/lfc-me.eng\/Root\/research-project-en\/r-page-en\/doc-page2-en.html","title":{"rendered":"Ultrasonic measurement"},"content":{"rendered":"\n
We can understand the flow of a transparent fluid such as water that transmits visible light by the optical visualization. A lot of the fluids around us, however, are opaque fluids (e.g., liquid metal), transparent fluids turbid by containing many dispersions (e.g., emulsions), and liquids in opaque containers (e.g., pipeline). It is hard to perform the optical visualization to them. In such cases, the ultrasound possible to travel through optically opaque media is a useful tool for the measurement. Ultrasonic waves travel through a medium with a constant speed, and they are reflected and transmitted with a constant rate at the interface between substances. This reflected wave and transmitted wave contain information about the material, shape, and velocity of the substances, and it is possible obtain the information by analyzing their waveforms.<\/p>\n\n\n\n
Ultrasonic pulse echography is a familiar technology for us, which is known as echocardiography and ultrasonography in the hospital. But it is not generally used to measure flows in the industrial field. It makes the measurement be difficult due to a large difference in speeds of sound between medias in the flow, a high speed of the flow, and a high attenuation rate in the media. We have developed new echography techniques for monitoring multiphase flows. In the multiphase flow, ultrasonic waves reflect at the interface where the phase changes. By extracting and analyzing the waveform of this reflected wave, we can measure and monitor various information of the multiphase such as “liquid film thickness”, “distribution of distributed medias”, and “distribution size and concentration of mixtures”.<\/p>\n\n\n\n