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multiphase flow with moving interface combined with diffusion

Martijn van Dongen
I'm working on a simulation of two droplets in air coalescing into one combined droplet in which I want to follow in time the mass transport of a species C in one droplet into the coalesced droplet. The species has to remain into the droplet phase and not diffuse into the air.

I'm using the Laminar two-phase flow (phase field) to describe the coalescing of the two droplets in air with a time dependent simulation. This part of the model is working quite well both in 2d and 3d.
Combining this model in the same study with the transport in diluted species (convection & diffusion) physics to describe the mass transport of an species C with start concentration C0 from the single one droplet into the combined coalesced droplet I run into problems.
The main problem is that the species C does not remain in droplet phase but also diffuses into the surrounding air.

In my opinion, I somehow have to use the phase field variable phipf with value=-1 to track the moving liquid-air interface to prevent the transport of the species from the droplet to the air.

Does anybody have any suggestions?

1 Reply Last Post Nov 16, 2012, 8:36 AM EST
Nagi Elabbasi Certified Consultant
Posted: 5 years ago Nov 16, 2012, 8:36 AM EST
You can make the transport diffusion coefficient a function of the phase field variable. With a low diffusion in air the species is more likely to stay in the droplets.

Nagi Elabbasi
Veryst Engineering
You can make the transport diffusion coefficient a function of the phase field variable. With a low diffusion in air the species is more likely to stay in the droplets. Nagi Elabbasi Veryst Engineering

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