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

The Nusselt number can be calculated by:

$\dot{Q}=h \pi D L(T_{s}-T

The heat transfer due to conduction through inhaled air is given by:

$\dot{Q} {cond}=\dot{m} {air}c_{p,air}(T_{air}-T_{skin})$ The Nusselt number can be calculated by: $\dot{Q}=h

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

$h=\frac{Nu_{D}k}{D}=\frac{10 \times 0.025}{0.004}=62.5W/m^{2}K$

The convective heat transfer coefficient for a cylinder can be obtained from: The Nusselt number can be calculated by: $\dot{Q}=h

(b) Convection:

$\dot{Q}=h \pi D L(T_{s}-T_{\infty})$

$Nu_{D}=0.26 \times (6.14 \times 10^{6})^{0.6} \times (7.56)^{0.35}=2152.5$ The Nusselt number can be calculated by: $\dot{Q}=h

$\dot{Q}=\frac{423-293}{\frac{1}{2\pi \times 0.1 \times 5}ln(\frac{0.06}{0.04})}=19.1W$

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

$r_{o}=0.04m$

The rate of heat transfer is:

$Nu_{D}=CRe_{D}^{m}Pr^{n}$