Air flows in a 4-cm-diameter wet pipe at 20ºC and 1 atm with an average velocity of 4 m/s...

Air flows in a 4-cm-diameter wet pipe at 20ºC and 1 atm with an average velocity of 4 m/s in order to dry the surface. The Nusselt number in this case can be determined from where Re = 10,550 and Pr = 0.731. Also, the diffusion coefficient of water vapor in air is 2.42×10-5 m2/s. Using the analogy between heat and mass transfer, the mass transfer coefficient inside the pipe for fully developed flow becomes

(a) 0.0918 m/s

(b) 0.0408 m/s

(c) 0.0366 m/s

(d) 0.0203 m/s

(e) 0.0022 m/s