Chapter 8, Problem 8.26P

Engine oil flows through a $\text{25}-\text{mm}$ -diameter tube at a rate of $0.\text{5 kg}/\text{s}$ . The oil enters the tube at a temperature of $\text{25}°\text{C}$ , while the tube surface temperature is maintained at $\text{1}00°\text{C}$ .

(a) Determine the oil outlet temperature for a $\text{5}-\text{m}$ and for a $\text{1}00-\text{m}$ bug tube. For each case, compare the log mean temperature difference w the arithmetic mean temperature difference.

(b)For $5\le L\le 100$ m, compute and plot the average Nusselt number ${\overline{Nu}}_D$ and the oil outlet temperature as a function of L.