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-   -   Volume fraction to mass fraction (http://www.cfd-online.com/Forums/cfx/19098-volume-fraction-mass-fraction.html)

 Torsaki July 30, 2002 23:44

Volume fraction to mass fraction

hi, all friend I have the value of volume fraction in my result and i want to change the volume fraction to mass fraction or concentration. How i do?

Torsaki

 Robin July 31, 2002 10:37

Re: Volume fraction to mass fraction

Hi Torsaki,

Look to the units for the answer...

To get the mass fraction, multiply by the density ratio of the two materials:

((m^3)_1/(m^3)_2)*(kg/m^3)_1/(kg/m^3)_2=(kg_1/kg_2)

You can use a similar method to convert to concentration.

Robin

 New User August 6, 2002 00:36

Re: Volume fraction to mass fraction

Hi all,
If i have volume fraction and i want to cover to concentrition how can i do?Thanknew user

 hamza August 13, 2002 16:01

Solution Method in CFX 5.5.1

hi any one,

I want to know as soon as possible what the Alogarethim solution method use in the CFX 5.5.1 is it SIMPLE method or another method?

 Robin August 14, 2002 08:56

Re: Solution Method in CFX 5.5.1

Hi Hamza,

Simply put, CFX-5 uses a coupled multigrid approach whereby the hydrodynamic equations (u,v,w,p) are solved simultaneously in a single matrix at each timestep.

For a more thorough explanation, see http://www.cfd-online.com/Forum/cfx_...e.cgi?read=934, or contact CFX.

Regards, Robin

 msohail December 25, 2010 01:35

mass fraction to (%vol/vol)

HI all
I am totally lost in the conversion .I need to convert mass fraction to (vol/vol)%. I ahve two gases 0.316 of FReon and 0.684 of Nitrogen.

 ghorrocks December 25, 2010 05:12

You use the gas densities to convert mass fraction to volume fraction, as described above.

 mitchOlson August 19, 2011 11:23

It looks like I was having the same problem to convert from mass fraction to volume fraction. Here is the formula:

vf1=1/(1+(rho1/rho2)*(1/wf1-1))
vf2=1/(1+(rho2/rho1)*(1/wf2-1))

where, vf1=phase 1 volume fraction
vf2=phase 2 volume fraction
wf1=phase 1 mass fraction
wf2=phase 2 mass fraction
rho1=phase 1 density
rho2=phase 2 density

PS. To double check you correctly entered the formula check that vf1 + vf2 = 1

 msohail August 21, 2011 00:40