Hi, anyone has experience with this kind of simulations in fluent?

I'm simulating a liquid-gas system in which particles are released in the liquid only.

I've made some simulations but would like to ask a few questions for which I'm concerned.

Particularly if somebody knows a criteria on how fine the mesh must be and how big must be the length of path for the particle trajectories calculation.

Thanks for any help.

Newbie

HI, Whats your particle size ? Is your mesh size smaller than particle size while you are trying to track the free surface? Are you considering the properties of the surface of the particles ??!!

DC

thanks for your answer,

The particle size is 8 micras that is smaller than the smallest mesh element. I'm not considering the properties of the surface of the particles.

Hope this clarifies my question.

Thanks again.

Hi New1 How big is your domain ? Are doing 3d? To track 1 mm bubble (2d), I used 20 cells in 1 mm. The results looked sensible, however didn't validate though. DC

Hi, its a 2D simulation, my domain is about 2x1 milimeters. I'm using much finer mesh than yours, but I don't know if I'm doing Ok. When I use a smaller integration step for the particles tracking trajectories looks Ok. But I still have doubts and the fluent manual is not too clear.

Thanks for any comment

new1

Hi

Sorry for disturbing, but I did not know that the size of the cells must be larger than the size of particles!

For DPM modelling, what is usually the standard for the size of cells in comparison to the size of the particles?

I'm tracking something at is 1e-4m, the length of my cell is only 0.1m... I could not increase the size further, since the memory space it will take up will be so much larger.

Julie; That's one of my doubts, sorry for not be able to help.

Maybe someone with better skills and experience can help.

Regards.

New1

[fivep]

How about checking the values of y plus?
Though, what flow model do you use for the continuum phase?

[azna]

Hi ,

I am using VOF-DPM approach to model air bubbles into the lake, I'm getting higher terminal velocity than using eulerian approach, I specified air velocity in the boundary condition ( Inlet Velocity) and also in the DPM part.
I was wondering can somebody help me on this ? ( is there any similar papaer or tutorial for this case?

Thanks a lot