Solution Manual Heat And Mass Transfer Cengel 5th Edition Chapter 3 Apr 2026

A 2-m-diameter and 4-m-long horizontal cylinder is maintained at a uniform temperature of 80°C. Water flows across the cylinder at 15°C with a velocity of 3.5 m/s. Determine the rate of heat transfer.

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

$Nu_{D}=hD/k$

$r_{o}=0.04m$

The convective heat transfer coefficient for a cylinder can be obtained from:

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

$\dot{Q}=\frac{T_{s}-T_{\infty}}{\frac{1}{2\pi kL}ln(\frac{r_{o}+t}{r_{o}})}$

Assuming $k=50W/mK$ for the wire material,

Alternatively, the rate of heat transfer from the wire can also be calculated by: