If you put something hot into a liquid, you have to worry about forming a film of vapor that keeps the liquid from touching the hot thing, and radically reduces the heat transfer. It's all tied up with the turbulence in the liquid, the surface tension of the liquid, etc.
Boiling is a really good way to move heat: the heat of vaporization is huge, for a small temperature change, compared to just the liquid's specific heat. But, it's more complex to design. It's used in very high power solid state electronics and in high power vacuum tubes, as well. The key is that the boiling point of the liquid has to be close to the desired operating temperature of the parts being cooled. Various Freons work well. Look up Leidenfrost effect (why LN2 droplets skitter around, or water on a hot pancake griddle).. It's also related to why you can walk across burning coals in bare feet. (the true test of belief in Physics) James Lux, P.E. Task Manager, SOMD Software Defined Radios Flight Communications Systems Section Jet Propulsion Laboratory 4800 Oak Grove Drive, Mail Stop 161-213 Pasadena, CA, 91109 +1(818)354-2075 phone +1(818)393-6875 fax From: Jonathan Aquilina [mailto:eagles051...@gmail.com] Sent: Wednesday, April 07, 2010 7:59 AM To: Lux, Jim (337C) Cc: Hearns, John; beowulf@beowulf.org Subject: Re: [Beowulf] 96 cores in silent and small enclosure filming in what sense with the heat though i thought that the heat would prevent the oil from congealing?
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