Ultrasound Injection

Discussion in 'Physics' started by joeyd999, Oct 6, 2017.

  1. joeyd999

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    Anyone got ultrasound experience here?

    I want to inject high power ultrasonic energy into a random mass with variable density and geometry by pressing a horn onto the surface (assume metal) of the mass (no glue or fasteners). I wish the energy to be distributed throughout the mass -- and there will be density changes along the way (high and low density liquids, gaseous volumes, metal connections). Tuning for resonance will not be possible.

    Question: Without any additional details, where are my pitfalls -- what problems can I expect?

    I know this is a broad question, and I can't give a lot of detail, but those with experience will understand what I am asking, I think.
     
  2. MrChips

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  3. joeyd999

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    I'm interested in directing the energy into and consuming it in liquid contained within the volume of the mass.

    Edit: I want to cavitate the liquid. But the geometry/size of the system and the location of the liquid will be pretty much random.
     
  4. Alec_t

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    I think one problem will be the horn, if you mean an air horn. There is a huge acoustic impedance mismatch between air and the assumed metal surface, so energy will be reflected rather than transferred through the surface. Or did you mean this kind of horn ?
     
  5. joeyd999

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  6. joeyd999

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    Also, are there safety issues with handling, say, 60W@40kHz of ultrasound energy? If human flesh comes in contact with the horn, will it cause injury? This is a new subject for me, BTW.
     
  7. wayneh

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    Yes, there are significant safety issues. I've used ultrasonic probes in the lab - probably less power than you're describing - and recall there were required safety protocols. But I also seem to recall that the danger diminished hugely with distance from the probe. Inverse square law, I suppose.

    I think the only way to get cavitation over a wide area and behind obstacles is to make a bath, like they use to clean jewelry. A point source horn can't cavitate around objects as far as I know.
     
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  8. joeyd999

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    Yup. I found this:

     
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  9. MrChips

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    Sorry, not my area of expertise.
    I am more into bone density measurements, EIT, imaging, and signal processing.
     
  10. RichardO

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    At this frequency and power I would worry about potential hearing damage as well.
     
  11. BR-549

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    Run down there to Cuba.....and see how they are doing it.
     
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  12. GopherT

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    Contact the guys from Mythbusters. They would still like to produce the “brown note”.
     
  13. Janis59

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    I have worked with 2kW 22...44 kHz magnetostrictor and 1500 kHz 60W piezostrictor. Last is temporary safe for touching, but first is not. Actually nothing may be sensed, but it is written in instruction that metal box doors must be closed without of gaps. Both are making cavitation in the water, thus count that for target power if cavitation is needed.
    First has AISI-306 actuator of about 10cm long and 8 mm thick, with pancake in the far end, with diameter of 15 mm and 4 mm thick. Second has reaction straight on the piezoceramics, which form the cup bottom of ca 36mm diam and 6mm thick. Both machines MUST be set into resonance, otherhow no cavitation.
     
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  14. joeyd999

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    And that is the answer I was looking for. Thanks.
     
  15. BR-549

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  16. joeyd999

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  17. BR-549

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    When they first said ultrasonic months ago......I was thinking >20k. I hear that sound on the video 24/7 for years now.
    The sound on the video is pretty close to my ear's ring. But was easy to discern.

    I thought they were damaged by sounds they could not hear.......and that was why they weren't sure the cause.

    Surely most people can hear that video.......and the change in volume.

    Does this mean one can take a high frequency but low power background tone 27/7 and drive people nuts?

    Like me?
     
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