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-   -   twoPhaseEulerFoam and transport properties (http://www.cfd-online.com/Forums/openfoam/65091-twophaseeulerfoam-transport-properties.html)

 Sebk June 3, 2009 10:43

twoPhaseEulerFoam and transport properties

Hi all,

I have some questions about transport properties with twoPhaseEulerFoam solver.

1) I don't understand what is the signification of d. Is is the diameter of the discrete phase ? But this is meaningless for the continuous...

2) Is Nu necessary for the discrete phase when we use granular theory ?

Best regards,

Sébastien

 villet June 7, 2009 16:41

Hi Sébastien,

I have asked the same questions from myself in the past. In "twoPhaseEulerFoam" the parameter "d" is the diameter of the phase (particles or bubbles) and required for each phase even though not used in all cases. As you may be familiar, diameter appears in drag models.

In "interfacialProperties" dictionary you define the drag phase which is e.g. the dispersed particle phase in gas-particle flows. However, in some cases (like in liquid-gas mixtures) a phase may be considered dispersed or continuous depending on the region in the flow. Then it's reasonable to use a blended (or symmetric) drag model. In that case the diameter of the continuous phase is used in the calculation. An example of that is the "bubbleColumn" tutorial.

About your second question. If you use granular theory for dispersed particle phase, viscosity is calculated using one of the models provided in OpenFOAM. Still you need to give a value for "nu" because it's required building the phase objects in the solver.

Hope this helps,
Ville

Quote:
 Originally Posted by Sebk (Post 218133) 1) I don't understand what is the signification of d. Is is the diameter of the discrete phase ? But this is meaningless for the continuous... 2) Is Nu necessary for the discrete phase when we use granular theory ?

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