{"id":299,"date":"2023-09-28T17:32:58","date_gmt":"2023-09-28T20:32:58","guid":{"rendered":"https:\/\/utfpr.curitiba.br\/lassip\/?p=299"},"modified":"2023-09-28T21:24:09","modified_gmt":"2023-09-29T00:24:09","slug":"mullet","status":"publish","type":"post","link":"https:\/\/utfpr.curitiba.br\/lassip\/2023\/09\/28\/mullet\/","title":{"rendered":"Noninvasive multiphase level measurement with an ultrasonic probe"},"content":{"rendered":"\n

Q:<\/strong> Is it possible to measure levels in multiphase (water+oil) tanks using an ultrasonic probe? Plus, noninvasively?<\/strong><\/p>\n\n\n\n

With this question in mind, we visited our colleagues at UTFPR’s Multiphase Flow Research Center (NUEM)<\/a> and performed some experiments. And the answer is: YES!<\/strong><\/p>\n\n\n\n

Prof. Eduardo N. dos Santos<\/a> kindly granted us some time at their separation tank, where some very interesting research has been conducted on oil-water separation methods. We counted on the help of, among others, former LASSIP member Everton Trento Jr., who currently works at NUEM.<\/p>\n\n\n\n

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Separation tank at NUEM<\/figcaption><\/figure>\n\n\n\n

The tank was partially filled with water and oil. An 3.5MHz ultrasonic probe (transducer) was coupled to the bottom of the tank using glycerine as coupling liquid and connected to an OmniScan MX2 inspection system.<\/p>\n\n\n\n

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(a) Complete setup; (b) Detail of the hatch of the tank, where the water and oil phases are distinguishable; (c) Transducer coupled to the bottom of the tank.<\/figcaption><\/figure>\n\n\n\n

The method is quite simple: the MX2 system repeatedly emits ultrasonic pulses to the tank. The pulses cross the steel wall of the tank and start to travel through the water. On the water-oil interface, part of the acoustic energy will be reflected back and captured by the transducer, which acts as both emitter and receiver. Another part of the acoustic energy will travel through the oil and hit the oil-air interface, where it will be reflected back and travel all the way back to the transducer. The Times of Flights (TOF) of these two pulses are proportional to the levels of water and oil.<\/p>\n\n\n\n

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The transducer emits an ultrasonic pulse inside the tank. (a) Part of the acoustic energy is reflected on the water-oil interface. (b) Other part is reflected on the oil-gas interface. <\/figcaption><\/figure>\n\n\n\n

We tracked the two TOFs on the screen of the MX2 system. Since the level of oil used in the experiment was quite low, the two pulses were close to each other in time. The Figure below shows the screen of the MX2 system. The voltage trace shows the acoustic pressure measured by the transducer after the last pulse was emitted. The lower graph shows the same information, but the voltages are represented in a color scale. A small history of the last traces is also shown, where each line represents a different trace.<\/p>\n\n\n\n

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Detail of the screen of the OmniScan MX2 system<\/figcaption><\/figure>\n\n\n\n

The video below shows a small time lapse. Note that the history shows the two pulses shifting to the left as the level of water drops.<\/p>\n\n\n\n

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