[Karu_p]

I am using mixture model in multiphase flow and species transport off. Is it correct or do I need to add species transport also? If I add species transport, which mixture template should I use?

I am trying to mix two fluids say ethanol and water just by diffusion. Any help is greatly appreciated.

Thanks in advance

[CFDYourself]

Hi Karu,
it depends on what you are trying to model.

if you are interested in mass-transfer/diffusion the easiest way to model this would be through species transport. So your whole domain would be one fluid 'mixture', of varying concentrations of water and alcohol (100% at each inlet). Changes in fluid properties such as density and viscosity could be set up to vary with concentration of the individual species components in the materials properties. IMO this would be the easiest way to set up the model and get started with running the simulations.

The 'mixture' model in contrast is usually used for simple two-phase simulations. The mixture model is like a Euler-Euler simulation, but both phases share a velocity field. I imagine this type of simulation could give you more info on mixing, but I imagine it taking more effort. I would ask the qn 'if the mixture model is for two-phase flow, and water and alchahol are miscible, is it appropraite?'.

[Karu_p]

Hi James

Thanks for the reply. FYI, I solved the problem as you explained it.But let me point that 'mixture' model is used for multicomponent systems not multiphase systems.

I used the species transport model and also mixture model to say that initially the channel filled with air. As the simulation proceeds, air would be replaced by the fluids from different inlets(pure liquids at the inlet) and mixing takes place by diffusion.

Do reply me if you are not clear.

[pmechz]

hi everybody
If I use the species transport model - can I use the mixture template with two liquids not gases?

[Hong M.H]

Originally Posted by Karu_p

Hi James

Thanks for the reply. FYI, I solved the problem as you explained it.But let me point that 'mixture' model is used for multicomponent systems not multiphase systems.

I used the species transport model and also mixture model to say that initially the channel filled with air. As the simulation proceeds, air would be replaced by the fluids from different inlets(pure liquids at the inlet) and mixing takes place by diffusion.

Do reply me if you are not clear.

Hi Mr. Karu_p, currently i m doing a roughly similar simulation as u mentioned in ur thread (mixing between water and ethanol in microchannel), but i m using simulating diffusion of dye and water in a mixing channel...

can u briefly explain to me how to u set the mixture model? how do u make the channel initially filled with air and make replace it by the fluids from different inlet?

Ur help are much appreciated...