Chapter 8, Problem 8.25P

Engine oil is heated by flowing through a circular tube of diameter $D=\text{ 5}0\text{ mm}$ and length $L=\text{ 25 m}$ and whose surface is maintained at $\text{15}0°\text{C}$ .

(a) If the flow rate and inlet temperature of the oil are $0.\text{5 kg}/\text{s}$ and $\text{2}0°\text{C}$ , what is the outlet temperature $T_{m,o}$ ? What is the total heat transfer rate q for the tube? For flow ranges in the range $0.5\le m\le 2.0\text{kg/s}$ , compute and plot the Variations of $T_{m,o}$ and q with m. For what flow rate(s) are q and $T_{m,o}$ maximized? Explain your results.