engineering recuitment AAI JE Technical Mock Test 2020-21 Heat Transfer Conduction Heat Conduction Through Hollow and Composite Cylinders
Consider a long cylindrical tube of inner and outer radii, ri and ro, respectively, length, L and thermal conductivity, k. its inner and outer surfaces are maintained at Ti and To respectively (Ti > To) . Assuming one-dimensional steady-state heat conduction in the radial direction, the thermal resistance in the wall of the tube is
1
\(\frac{1}{{2\pi kL}}\ln \left( {\frac{{{r_i}}}{{{r_o}}}} \right)\)
2
\(\frac{L}{{2\pi {r_i}k}}\)
3
\(\frac{1}{{2\pi kL}}\ln \left( {\frac{{{r_o}}}{{{r_i}}}} \right)\)
4
\(\frac{1}{{4\pi kL}}\ln \left( {\frac{{{r_o}}}{{{r_i}}}} \right)\)