HW 2 - p 3.28 - Evaporation of a Water Film on a Flat Plate - 5 pts
Air at 1 atm flows at 2 m/s across the surface of a 2-in.-long surface that is covered with a thin film of water. If the air and water are maintained at 25oC, and the diffusivity of water in air at these conditions is 0.25cm2/s, estimate the mass flux for the evaporation of water at the middle of the surface assuming laminar boundary-layer flow. Is this assumption reasonable?
posted by Dr. B at 2:24 PM
2 Comments:
It is correct to use xB,lm in this problem. I did not because I assumed the solution was dilute. This is not correct. When you use xB,lm, you should get NA = 2.07 x 10^-6 mol/cm^2-s.
I will accept either method, but the RIGHT thing to do is to use xB,LM
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