A cup filled partially with water, air is flowing above the cup. The distance between the water surface and the top of the cup is initially $50cm.$

Water evaporates at $40C$ a system pressure of $101\mathrm{.}325$kPa, vapor pressure at the air$-$water interface is the saturation pressure of water at $40C,$ which is $12\mathrm{.}351$kPa, diffusion coefficient $D_{AB}=2\mathrm{.}8{10}^{-5}\frac{m^2}{s}.$

Assume steady state $1-$D diffusion, stagnant air inside, and dilute system.

Plot the concentration profile inside the device in Excel.

Plot flux of water vapor, NA in Excel.

Calculate NA and $cA$ at $z=30cm,$ in in Excel.

Repeat $1-3$ using Comsol and compare your results obtained from the analytical solution.