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hildeew2 (Electrical) (OP)
15 Mar 12 11:09
Hey all,

I am trying to determine the heat flow into the insulation of an electrical cable with insulation from a heat source touching it at one point along its length. (Like a cylinder sitting on a hot slab) I am ignoring any convection at the moment.

I have the equation:

Q = (2pi*k*l*(T1-T2))/(ln(r1/r2))

But i believe this is for a temperature source surrounding the entire circumference and not just at a point.

Please let me know if I am wrong about the equation and if not what equation i can use to solve for the heat flow into the cable insulation.

Thanks.
vpl (Nuclear)
15 Mar 12 12:13
Is this a school assignment?

Patricia Lougheed

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hildeew2 (Electrical) (OP)
15 Mar 12 12:59
No.

It's a calculation to support the experimentally proven fact that conductors running single phased in metallic conduit will melt the insulation.

I left this out to try and keep my question simple as to not create a side discussion about the experiment itself, which will surely now happen.

Thanks for your input.
MintJulep (Mechanical)
16 Mar 12 16:51
The simple one-dimensional equation you have is not going to get you where you need to be.

You would appear to have at least two-dimensional heat transfer, with internal heat generation.

Probably not safe to ignore convection either.

Start with a clear statement of the problem.

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