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I Thermal Resistance to Centerline

  1. Dec 30, 2017 #1

    Given an infinitely long cylinder with a specified surface heat flux,

    the thermal resistance of an annular region is given by,

    R_th = ln(r_out / r_in) / (2 pi L k).

    When I'm calculating the thermal resistance to the centerline, r_in = 0.

    Does that mean there is infinite thermal resistance?
  2. jcsd
  3. Dec 30, 2017 #2


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    2017 Award

    Staff: Mentor

    “Yes”. A finite heat flow to a single line is unphysical.
  4. Dec 30, 2017 #3
    The resistance is infinite and, to have a finite rate of radial heat flow, you would need to have an ideal line heat source at r=0, featuring an infinite temperature gradient at r=0 and an infinite temperature.
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