2 Phases with same parameters, any diffusion?

-Kai- · January 14, 2020, 08:25

Hi!

I’m struggling with what seems to be a pretty basic problem. I’m simulating a wash out kinetic in a fluidic device, I want to see how phase 1 is replaced by new injected phase 2. Both have the same physics, both of liquid water at the same temperature. My question is now if there is any diffusion? Or did I basically switched those off because I used for both phases the same properties?

Kind regards
Kai

vinerm · January 28, 2020, 09:47

Hi

That depends on the model used. if both the fluids belong to same phase as multiple species or components, then by default there is a diffusion coefficient applied. You may set it to very small value. If both fluids are treated as separate phases, then there is no diffusion by default since that would require mass transfer in the phase interaction.

January 14, 2020, 08:25	2 Phases with same parameters, any diffusion?	#1
-Kai- New Member Join Date: Feb 2016 Posts: 2 Rep Power: 0	Hi! I’m struggling with what seems to be a pretty basic problem. I’m simulating a wash out kinetic in a fluidic device, I want to see how phase 1 is replaced by new injected phase 2. Both have the same physics, both of liquid water at the same temperature. My question is now if there is any diffusion? Or did I basically switched those off because I used for both phases the same properties? Kind regards Kai

January 28, 2020, 09:47	Model dependent	#2
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 35	Hi That depends on the model used. if both the fluids belong to same phase as multiple species or components, then by default there is a diffusion coefficient applied. You may set it to very small value. If both fluids are treated as separate phases, then there is no diffusion by default since that would require mass transfer in the phase interaction. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

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