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Science

Sound Increases the Efficiency of Boiling 96

Posted by timothy
from the centerfold-for-the-journal-of-boiling-research dept.
hessian writes "Scientists at the Georgia Institute of Technology achieved a 17-percent increase in boiling efficiency by using an acoustic field to enhance heat transfer. The acoustic field does this by efficiently removing vapor bubbles from the heated surface and suppressing the formation of an insulating vapor film."
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Sound Increases the Efficiency of Boiling

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  • by aaronb1138 (2035478) on Friday May 25, 2012 @11:57PM (#40117799)

    The amount of efficiency increase might be novel, or the input energy to remove the bubbles might be, but using an "acoustic field" is nothing new in industry. Lots of industrial systems use some form of vibrator to decrease bubble to surface adhesion for increased fluid heating speed and thus, efficiency. They also frequently use such systems to reduce surface foaming, especially in conjunction with vacuum systems to prevent fluid foaming or excess dissolved bubbles / gases.

    • by TheLink (130905) on Saturday May 26, 2012 @12:34AM (#40118007) Journal
      Just curious, how much more efficient is this compared to using microwaves? I think with microwaves it doesn't matter that much that there are bubbles - the waves will heat the next available spot - no contact needed.

      Can't always use microwaves though e.g. liquid is not suitable, or it's not convenient.
      • by jo_ham (604554)

        It entirely depends on the dielectric properties of the liquid you're heating, the shape of the vessel, the material it's made from and the wavelength of the microwaves - even water can be difficult to heat in the "right" (or wrong as it would be) circumstances.

    • Anyone using this in industrial refrigeration?

      I can't help but think of deliberately running a fancoil unit with an unbalanced fan so it vibrates the evaporator coil.

      Or, possibly mounting piezoelectric "shakers" to the evaporator tubes and deliberately manufacturing them to resonate.

      Thanks, Hessian, for bringing this up. Anything I can do to increase efficiency in refrigeration is of great interest to me.

      There are a lot of unpublished tricks I have come across that significantly increase refrig
      • You might check out Rex Research [rexresearch.com] for odd (and usually, but not always, wrong) ideas on heating and cooling (among other things).

        There are many, many cranks and perpetual-motion machines on this site. There are also some workable devices mixed in. The former are sometimes entertaining and the latter are often fascinating. The ones which I can't tell if they're brilliant or just cranks are my favorites.
        Some relevant bits, (no guarantees, but less flaky than most):
        Heat / Cold [section]
        Appropriate / Low Technol

        • by anubi (640541)
          Thanks, Sav!

          I'll bookmark this one... that's an interesting link!

          You are right... every cutting edge technology has its share of cranks - what makes it really bad is quite a few cranks use credentials from respected institutions to lend credibility to their scam.

          What'cha think about this one?

          http://www.terawatt.com/ [terawatt.com]
    • by billstewart (78916) on Saturday May 26, 2012 @03:04AM (#40118777) Journal

      Back in the 70s we used to use loud music to agitate the water in our bongs - it made them much more effective and, like, cosmic!

    • by Anonymous Coward

      Lots of industrial systems use some form of vibrator ... for increased ... efficiency.

      not just the industrial systems. i can think of one industry that uses various compact vibrators to reach certain goals faster and more efficiently than the standard process. it can also be used to reach those goals in quick succession. though using them for prolonged periods often leads to an eventual overall energy drain resulting in some extended downtime. so it's generally prudent to use them sparingly. it's an energy efficiency issue.

      • by greywire (78262)

        Lots of industrial systems use some form of vibrator ... for increased ... efficiency.

        not just the industrial systems. i can think of one industry that uses various compact vibrators to reach certain goals faster and more efficiently than the standard process. it can also be used to reach those goals in quick succession. though using them for prolonged periods often leads to an eventual overall energy drain resulting in some extended downtime. so it's generally prudent to use them sparingly. it's an energy efficiency issue.

        This has to be one of the best double entendre comments I have ever seen.

        Its so good I bet there are a lot of people who would only see the straightforward meaning. And for the rest of us, we can't read it with straight face.

        Bravo.

    • I'm interested to know if this would increase the efficiency of a hydrogen generator, the ones that split water using positive and negative plates. I'm sure it's been tested at any rate, seems obvious that it would be worth testing when you read the summary.
  • by pinkj (521155) on Friday May 25, 2012 @11:57PM (#40117801)
    Sounds hot.
    • Re: (Score:3, Funny)

      by Anonymous Coward

      That's it; I'm taking away your pun license.

  • by Anonymous Coward

    Here's a paper from 2002 trying to quantize the effect in equations:

    http://doc.utwente.nl/43791/1/rectified.pdf

  • by Ukab the Great (87152) on Saturday May 26, 2012 @12:50AM (#40118105)

    But a heard pot boils real good.

  • by BlueStrat (756137) on Saturday May 26, 2012 @12:57AM (#40118141)

    There have been units around for years both for home use cleaning jewelry, etc, and for use in various industrial/manufacturing processes, including being used in electronics manufacturing, where I've seen them used to clean PCBs and other electronic assemblies & parts after they undergo a "dirty" manufacturing step like wave-solder, in order to remove all flux, dirt, and oils.

    They used a heated tank of solvent that was agitated by ultrasound transducers to greatly increase cleaning ability and decrease cleaning time. The first time I saw one like that was in the late 1970s. I worked in the government/military-related electronics and aerospace industry.

    Strat

    • In those units, the ultrasound is used to vibrate the dirt and shake it loose. The ones I know of (used in cleaning medical instruments) operate nowhere near the boiling point of the liquid.

      • by BlueStrat (756137)

        In those units, the ultrasound is used to vibrate the dirt and shake it loose. The ones I know of (used in cleaning medical instruments) operate nowhere near the boiling point of the liquid.

        Actually, you're correct as far as the units you mean, and I was wrong to include the home ultrasonic jewelry cleaners.

        The factory units I referred to, however, used boiling solvents. Of course, many solvents boil at lower temperatures than water. Some common solvents I saw used, like trichlorotriflouroethane, boil at quite low temperatures (118F, 47.7C for "Trich").

        The effect of the ultrasound on the boiling liquid was startling. With the ultrasound transducer(s) switched off, the solvent boiled in the nor

  • This reminds me... (Score:4, Interesting)

    by Roskolnikov (68772) on Saturday May 26, 2012 @12:58AM (#40118151)

    of the acoustic effects on disk arrays (and a Dtrace video that showed shouting having a detrimental effect on drive efficiency).

    wouldn't a pressurized vessel (cooker) have the same end result (in that vapor layer formation is prevented or retarded?)
    or as someone else mentioned, using microwaves to boil/heat faster?
    is the 17% efficiency gain taking into account the energy needed to blast the liquid with Eminem?

    the 'article' looks like a fluff piece and the comments say much the same, nothing to see here move along.

  • by mattr (78516) <mattr.telebody@com> on Saturday May 26, 2012 @02:27AM (#40118621) Homepage Journal

    I hesitate to ask what it sounds like when you stand next to a boiler being blasted with energetic sound waves.

  • So this means the watched pot only boils if it's listening to some kickin' tunes? Sweet.

  • Just blowing gently on the surface works just as well, and is probably much cheaper.
  • Helium has some strange properties. It has a negative JT coefficient for temperatures above about 50K. This means that when it is compressed it cools down instead of heating up.

    One of the most interesting is when it's a liquid it will boil until it gets to a transition temperature where it becomes a superfluid. Here the viscosity and heat transfer coefficient becomes near 0. So all boiling stops because any heat input is transferred to the molecules on the surface and they vaporize.

    http://www.youtube.com/wa [youtube.com]

  • was add energy more in, get more energy out.
  • I tried yelling "BOIL!!!" over and over at the pot I was using to boil an egg just now. Never happened. Wait... wasn't there also a study proving that a watched pot never boils?
  • This might have application in brewing....I wonder if this would have any effect on the emission of di-methyl sulfide.

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