Question

The moisture in hot, humid, stagnant air surrounding a cold-water pipeline continually diffuses to the cold surface where it condenses. The condensed water forms a liquid film around the pipe, and then continuously drops off the pipe to the ground below. At a distance of 10 cm from the surface of the pipe, the moisture content of the air is constant. Close to the pipe, the moisture content of the air approaches the vapor pressure of water evaluated at the temperature of the pipe

What is the simplest differential form of Fick's flux equation for water vapor, NA?

Answer 1

Answer:

The simplest differential form of Fick's flux equation for water vapor is

$\frac{1}{r} \frac{d}{dr} (rN_{rA} )=0$

Explanation:

Fick's law has to do with the density of the particles is proportional to their concentration gradient. For this question some assumptions will be taken into account:

-The pipe is considered to be very long and diffusion only occurs in the r direction.

-The reaction is not homogeneous, therefore RA = 0

-The concentration of the component A is constant

-No mixing, only diffusion

Due to the complexity of the terms used in solving the Fick equation, the solution is found in the attached file.