Chapter 2, Problem 2.49P

Two-dimensional, steady-state conduction occurs in a hollow cylindrical solid of thermal conductivity $k=16\text{W/m}\cdot \text{K,}$ outer radius $r_o=1\text{m}$ and overall length $2z_o=5\text{m,}$ where the origin of the coordinate system is located at the midpoint of the center line. The inner surface of the cylinder is insulated, and the temperature distribution within the cylinder has the form $T\left(r,z\right)=a+b{r}^2+c\ln r+d{z}^2,$ where $a=-20°\text{C,}b=150°{\text{C/m}}^2,c=-12°\text{C,}d=-300°{\text{C/m}}^{\text{2}}$ and r and z are in meters.

1. Determine the inner radius $r_i$ of the cylinder.
2. Obtain an expression for the volumetric rate of heat generation, $\stackrel{.}{q}\left({\text{W/m}}^3\right).$ Determine the axial distribution of the heat flux at the outer surface, $q_r^{"}\left(r_o,z\right).$ What is the heat rate at the outer surface? Is it into or out of the cylinder?
3. Determine the radial distribution of the heat flux at the end faces of the cylinder, $q_r^{"}\left(z,+z_o\right)$ and $q_r^{"}\left(r,-z_o\right).$ What are the corresponding heat rates? Are they into or out of the cylinder?
4. Verify that your results are consistent with an over-all energy balance on the cylinder.