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Heat transfer equation 1

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udirn1

udirn1

Electrical
Apr 17, 2009
23
Dear follow engineers.
I need your kind help.
I have a device which emits rf energy when touching the skin.
Because of this energy, the tissue heats up.
Now, there are 2 options:
1. If I place a non conductive lotion on the skin (high impedance), and then apply the rf energy, most of it will develop power on the layer beneath the skin, hence fat, as current prefers to flow through a lower impedance.this is like heating a resistor.and its dissipation time till cool down usually takes longer as its "locked" beneath the skin.
2. If I place a conductive lotion low impedance, most of the energy will be developed on the skin surface.however, since the upper skin tissue role is to evacuate heat much faster, I believe that the degradation rate would be faster than point 1.

My question, can someone help me with proving it mathematically using a heat transfer equation or else? It's been 30 years since college days....
Thanks
Udi
 
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RF probes tend to emit frequencies that excite certain molecules such as O-H bonds in fat; it's energy transfer, but not necessarily heat, at least, not in the vein of heat transfer equations.

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There is a 3rd option- don't touch your skin with the rf emitting device.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick
 
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A comment to IRstuff first reply "RF probes tend to emit frequencies that excite certain molecules..." being so wouldn't the molecules will generate heat due to the internal friction from their vibratory motion?
 
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I agree that there is a net heating, but it's not technically heat transfer, just as you would not claim that the powerlines are transferring heat to your heating system, particularly since heat transfer is typified by being conductive, convective, or radiative. One might argue that RF would be radiative, but since, as you rightly point out, it's more like a mechanical friction heating, it's not conventional radiative heating, so the conventional heat transfer equations are not applicable.

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I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
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I understand IRstuff position. So with regard to UDIRN1 question, I would entertain the idea that you'll have an increase in internal energy of the skin and of the flesh under the skin. UDIRN1 do some research on the biological effects of non ionizing radiation. Also many households have microwave ovens, so before these ovens were release to the public, there must have been an extensive amount of publications which could help your inquiries.
 
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I would actually suggest the OP research manufacturers of therapeutic and cosmetic RF systems, like:

Link RF is used as a cauterizing and tissue reduction technique for conditions like sleep apnea; I've had that done to myself, but to no avail [curse]

Link Link RF is known to cause repairable tissue damage that forces reconstitution of the collagen and other support tissues for firmer skin, etc. Different frequencies penetrate differently, and have differing results. No RF fat reduction, so far as I know, and there are already too many competitors in that arena anyway,

As alluded to by chicopee, there is a large swath of literature on both subjects.

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I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
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