CFD Online Logo CFD Online URL
Home > Forums > OpenFOAM

Volume fraction calculation

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   September 30, 2011, 08:48
Default Volume fraction calculation
New Member
Join Date: Sep 2011
Posts: 12
Rep Power: 8
eric weddle is on a distinguished road
Hello there.

I work with multiphasic simulations and I'm currently evaluating OpenFOAM to check the possibility of using it for the simulations I work with.

My doubt rests over how OpenFOAM ensures that the sum of all components' volume fractions are equal to one.

In the TwoPhaseEulerFoam solver, the component a volume fraction (alpha) is calculated by a transport equation and the volume fraction of the second phase, b, is simply (1-alpha).

But I'm more interested in simulations with three and more components.

In multiphaseInterFoam, I couldn't understand how they ensure that the sum of all the fractions are equal to one.
Could any of you explain it to me?

Actually, my goal is to have a code in which I would calculate the volume fractions through transport equations (with source terms) for all the phases and apply a constraint so that the summation of their values are always equal to 1. Any thoughts on this?

Thank you guys for your colaboration
eric weddle is offline   Reply With Quote

Old   October 5, 2011, 10:55
Senior Member
Kent Wardle
Join Date: Mar 2009
Location: Illinois, USA
Posts: 218
Rep Power: 14
kwardle is on a distinguished road
Good question. multiphaseInterFoam in fact does not quite ensure that the volume fractions sum to 1. If you take a look at the min, max values for any phase it is typically as much as a few percent over 1 (~1.05 -- can be worse on tet meshes). That said, I have been working with Henry Weller on a different multiphase solver which required him to write a multiphase implementation of his MULES solver which indeed can do just this--the sums are several orders of magnitude better and the overall volume fraction is well conserved. My guess is that you will see this out in new versions of multiphaseInterFoam soon. It may already be in 2.0.x, I am not sure, but I don't think so.
kwardle is offline   Reply With Quote


alpha, component, multiphase, volume fraction

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Volume fraction to mass fraction Torsaki CFX 9 February 21, 2015 11:46
interDyMFoam - change in volume fraction gopala OpenFOAM Running, Solving & CFD 0 April 27, 2009 10:46
On the damBreak4phaseFine cases paean OpenFOAM Running, Solving & CFD 0 November 14, 2008 22:14
fluent add additional zones for the mesh file SSL FLUENT 2 January 26, 2008 12:55
the Eulerian model and the lower volume fraction hx li FLUENT 2 October 27, 2005 06:17

All times are GMT -4. The time now is 09:17.