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gfd43tg
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Homework Statement
From Fick's Law of Diffusion, ##N_{A}C_{B} - N_{B}C_{A} = -DC \frac {dC_{A}}{dz}##
Prove that Sh=2 for a volatile spherical droplet evaporating in a quiescent atmosphere. (Sherwood number for a sphere is given by ##Sh = \frac {k_{A}d}{D}##, where d = initial droplet diameter). At large distances from the sphere the concentration of the volatile component is zero. The saturated vapor pressure is negligibly small compared to the atmospheric pressure.
Homework Equations
The Attempt at a Solution
So I know ##P_{atm} \gg P^{*}##, and ##C_{A,\infty} = 0##. But how the heck can I use the equation to prove this relationship? I don't understand what the equation means. Is ##C_{B}## the concentration of air molecules in the spherical droplet? I would think the first term is just approximated as zero.