In the first stage of a paper drying process, a cylinder of diameter 0.15 m is covered by moisture-soaked paper. The temperature of the paper is maintained at 70°C by imbedded electrical heaters. Dry air at a velocity of 10 m/s and temperature of 20°C flows over the cylinder.

(a) Calculate the required electrical power and the evaporation rate per unit length of the cylinder, q' and n'A, respectively.

(b) Generate plots of q' and n as a function of the dry air velocity for 5 < V < 20 m/s and for paper temperatures of 65, 70, and 75°C.