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Heat transfer problem - conduction in a cylinder

  • Thread starter ana111790
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Homework Statement


The following cylinder has a temperature inside Ti and temperature outside To. Using the general equation for heat conduction in a cylinder, write the temperature distribution equation as a function of the radius T(r). What is the temperature midway at r=a? (Take the heat conductivity = k, and length of cylinder is L).
Assume no convection and constant temperature across the length of the cylinder.

[PLAIN]http://img40.imageshack.us/img40/7344/radiusproblem.jpg [Broken]

Homework Equations



Fourier's Law in cylindrical coordinates: q''= -k (dT/dr)

The Attempt at a Solution


Boundary conditions:
r=ri, T=Ti
r=ro, T=To

So integrating Fourier's equation with these boundary points I get:
To-Ti= -roq'' ln(ro/ri)

I think this gives the temperature difference though, not the distribution and I also have the q'' (flux term) still in the equation as an unknown. How would I find the temperature distribution and T(r=a)?
 
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Answers and Replies

  • #2
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Steady-state, no heat generation for cylinder: d/dr(r*dT/dr)=0

integrate twice with respect to r: T(r)=C_1*ln(r)+C_2
 

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