CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   OpenFOAM Running, Solving & CFD (http://www.cfd-online.com/Forums/openfoam-solving/)
-   -   Slurry (sand water) flow in twoPhaseEulerFlow possible? (http://www.cfd-online.com/Forums/openfoam-solving/93697-slurry-sand-water-flow-twophaseeulerflow-possible.html)

jochemvandenbosch October 24, 2011 08:14

Slurry (sand water) flow in twoPhaseEulerFlow possible?
 
Hi everybody,

As a part of my MSc. thesis I am trying to model a slurry flow (sand/water) in OpenFOAM (for different geometries). I heard that i could best use the twoPhaseEulerFlow solver for this problem, however I have found only examples regarded pneumatic conveying in combination for this solver.
Can this solver also be used for a liquid/solid interface. Some specifics of my research are:
Turbulent flow (Re>>2300)
Pipe flow
Sand (2600kg/m^3), water mixture
Concentrations ranging from 10 to 40%
Medium fine sand, d50 approximately 300-600 micrometer

I am particularly interested in the pressure drop allong the length of the pipe. Is the twoPhaseEulerFlow the right solver to use and do you think I would have to adjust this solver. If it is not the one to use, which one should I use.

Thanks so much in advance!!!

Best regards!

alberto October 26, 2011 11:27

Yes, it should work. The code might present some instability if particles pack. Please, search the forum for discussions on the topic.

jochemvandenbosch October 27, 2011 03:21

Hi Alberto. Thanks for your response. I did some research (mostly on this forum) and for now I've decided to go with settlingFoam instead of twoPhaseEulerFoam, since the first is based on the drift-flux model, which I already have some experience with (is taught by my university). Also packing might occur (not sure). settlingFoam seems more appropiate for this task (although it doesn't provide means to simulate a sliding bed...).
Do you know of any thesis' that use settlingFoam to simulate slurry flow.

Thanks in advance & best regards,

alberto October 27, 2011 14:26

OK. Just keep in mind that the algebraic slip model (mixture model) is valid for relatively low particle concentrations and it might have limitations on the Stokes number.

BTW, I am working on slurry flow with my (heavily) modified version of twoPhaseEuler, and it is working fairly well.

jochemvandenbosch October 31, 2011 05:25

Hi Alberto, thanks for your tips. About the mixture model for low concentration, my professor (Cees van Rhee) used this model in het PhD thesis (on the sedimentation process in a trailing suction hopper dredger) succesfully for concentrations up to 40% (sand in water). What are your thoughts about this (what do you consider a high concentration?)?

Best regards,

ps. what kind of slurry flow are you working on, sand/water? And open-channel flow or pipeflow?

alberto October 31, 2011 11:46

Hi Jochem,

as long as the hypotheses behind the model are satisfied, you can use it. Remember that the mixture model is derived making quite strong assumptions:

- Local equilibrium among the phases, which limits the validity to low Stokes numbers

- Mixture hypothesis, which limits the property ratio of the phases

When it comes to fluid-particle flows, the mixture model is suggested in case the particle loading is "low". How low depends on the flow conditions, but since you do not consider particle-particle interactions, I would say ~10%. You find applications with much higher concentrations, however. There are doubts on the validity of the model under those conditions however.

I deal with slurry flow in ducts (high St number).

Best,


All times are GMT -4. The time now is 07:28.