How to get volume fraction from mass fraction fields?

mactone · October 3, 2022, 02:09

Dear Former & Paraviewer,

I have case results of CO、CO2、H2O、H2、CH4、N2、O2 (species mass fraction distribution). How can I post-process it into volume fraction?

In Fluent, I can choose plotting using mass fraction or volume fraction. How can I do it in paraview? By using some kind of function to regulate them?

Thank you.

Krapf · October 3, 2022, 05:05

I don't know of any ready-made function in OpenFOAM that converts mass fractions to volume fractions. But if you have access to the density $\rho_i$ of species

, you can use the calculator filter in ParaView:

$\varphi_i = \frac{w_i/\rho_i}{\sum_{z=1}^Z {(w_z/\rho_z)}}$

$\varphi$ - volume fraction
- mass fraction
$\rho$ - density

October 3, 2022, 02:09	How to get volume fraction from mass fraction fields?	#1
mactone Member mactone hsieh Join Date: Apr 2012 Location: Taiwan Posts: 31 Blog Entries: 1 Rep Power: 15	Dear Former & Paraviewer, I have case results of CO、CO2、H2O、H2、CH4、N2、O2 (species mass fraction distribution). How can I post-process it into volume fraction? In Fluent, I can choose plotting using mass fraction or volume fraction. How can I do it in paraview? By using some kind of function to regulate them? Thank you.

October 3, 2022, 05:05		#2
Krapf Senior Member Join Date: Oct 2017 Posts: 140 Rep Power: 10	I don't know of any ready-made function in OpenFOAM that converts mass fractions to volume fractions. But if you have access to the density $\rho_i$ of species , you can use the calculator filter in ParaView: $\varphi_i = \frac{w_i/\rho_i}{\sum_{z=1}^Z {(w_z/\rho_z)}}$ $\varphi$ - volume fraction - mass fraction $\rho$ - density jherb and mactone like this.

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