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fluidistic
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Homework Statement
A rod with length [tex]L[/tex] and section [tex]A[/tex] has its extremities in contact with 2 springs of heat whose temperatures are [tex]T_A[/tex] and [tex]T_B[/tex] such that [tex]T_A>T_B[/tex]. The rod is an environment where the temperature is worth [tex]T_0[/tex] (constantly).
a)Determine the function [tex]T(x)[/tex] that describes the temperature of the rod in the steady state, for the case in which the rod is covered by a insulating material.
b)Calculate the value of [tex]\vec q[/tex] in the 2 extremities of the rod.
c)Determine [tex]T'(x)[/tex] while in steady state, that describes the temperature of the rod if we remove the insulating material and supposing that [tex]T_0=T_B[/tex].
d)What is the value of [tex]\vec q[/tex] in each of the extremities in this new situation?
e)Calculate the flux by unit of time that is emitted by the surface of the rod.
Homework Equations
None but the thermal conductivity coefficient is worth [tex]h[/tex]. (conductivity between the rod and the environment).
The conduction coefficient is [tex]K[/tex] and the perimeter of the rod is [tex]P[/tex].
The Attempt at a Solution
a)In the steady state, [tex]T(x)=ax+b[/tex].
I've found out that [tex]T(x)= \left ( \frac{T_A-T_B}{L}\right ) x+T_A [/tex]. At least it satisfies the initial conditions.
b)[tex]\vec q =-KA \frac{\partial T}{\partial x}=-\frac{KA}{L}(T_B-T_A)[/tex]. I'm sure I made an error here. It seems that the q vector is constant in all the rod, sounds like possible though... I'm unsure I must say. If it wasn't constant then the temperature would change.
c)Heat from the rod will be transferred to the environment at a rate [tex]\frac{dQ}{dt}=\bold q = hA(T_0-T)[/tex] where [tex]T[/tex] is the temperature of the rod.
I'm a bit lost here. Should I replace [tex]T[/tex] by the [tex]T(x)[/tex] I've found in part a) ?
Once I get help on this, I'll look for the rest. Thank you in advance.