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cfd_user_pune October 26, 2018 05:44

Rate of evaporation | Hertz–Knudsen equation | Chloroform Evaporation
 
Dear All,

Before simulating evaporation process, I am trying to find theoretical rough estimation of amount of vapor generated/rate of evaporation (kg/s or kg/m^2/s) when 20 kg of chloroform is maintained in 0.75m(dia) 1.2m(height) tank at constant temperature of 50 degC. I may consider there is vent of very small diameter.

One of way doing it is Hertz–Knudsen equation (https://en.wikipedia.org/wiki/Hertz%E2%80%93Knudsen_equation[/url]). I got few doubts regarding this equation -
1)What are terms and their units in Hertz–Knudsen equation? Various litterateur has different forms of H-K equation to calculate evaporation.
2) I am getting some unrealistic answer when tried with dm/dt = Pv * sqrt ( m / (2*pi*R*T) ) Where Pv partial pressure of liq at 50 degC, m is molecular weight = 0.11938 kg/mol???(is unit correct) , R = 8.314 J / mol. K. I got answer as 36 kg/s which I thing is unrealistic.

Lastly, if one would try the CFD approach for this, what could be the model used, any tutorial will help more. If possible kindly guide on setting up model in fluent (quick step by step instructions).

Thank you.


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