Solution Manual Heat And Mass Transfer Cengel 5th Edition Chapter 3 Guide

The heat transfer from the not insulated pipe is given by:

$I=\sqrt{\frac{\dot{Q}}{R}}$

The Nusselt number can be calculated by: The heat transfer from the not insulated pipe

$\dot{Q}=10 \times \pi \times 0.004 \times 2 \times (80-20)=8.377W$

Solution:

Assuming $h=10W/m^{2}K$,

$\dot{Q}=\frac{423-293}{\frac{1}{2\pi \times 0.1 \times 5}ln(\frac{0.06}{0.04})}=19.1W$ The heat transfer from the not insulated pipe

$Nu_{D}=0.26 \times (6.14 \times 10^{6})^{0.6} \times (7.56)^{0.35}=2152.5$