Interphase Mass Transfer

[rfabdo]

Hi guys!

I've been working with some topics about mass transfer and there is a equation given by Bosnjakovic in his book "Technical thermodynamics" (1965) that describes Lewis Relation for Air-Vapor mixture. But he starts from this 2 equation:

1)

for Pd and Pg very close to 0

2)

for |Pd-Pg|>>0


How can i get the first and second equation?

I read some books and the most simmilar equation is for a Evaporation in a Column

m"= N" Mass transfer
Mw = molar mass
D = Mass diffusivity
Delta = Boundary layer lenght
R = Gas Constant
Tw = Water Temperature
Pg = Partial Vapor Pressure
Pg = Interphase Partial vapor pressure
C = Molar Concentration = Pi/RT
x = Mole fraction = Pi/Ptotal
Pi - Partial Pressure

 

[dvd]

The units are inconsistent between eqns. 1 & 2.

 

[rfabdo]

I think the second should have the atmospheric pressure multiplying all.