|
[Sponsors] |
November 21, 2012, 14:24 |
Eulerian–Eulerian coupled with VOF
|
#1 |
Senior Member
Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 162
Rep Power: 14 |
Hi Dear friends,
How do Coupled Eulerian–Eulerian homogeneous multiphase Model with a VOF method in fluent? (Eulerian–Eulerian homogeneous multiphase Models to calculate the flow field and VOF to determine shape of the free surface) TNX |
|
November 22, 2012, 03:24 |
|
#2 |
Senior Member
Rick
Join Date: Oct 2010
Posts: 1,016
Rep Power: 27 |
Hi,
as I know you can only choose one multiphase model, eulerian multiphase or vof model. Daniele |
|
November 22, 2012, 03:35 |
|
#3 |
Senior Member
Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 162
Rep Power: 14 |
||
November 22, 2012, 03:50 |
|
#4 | |
Senior Member
Rick
Join Date: Oct 2010
Posts: 1,016
Rep Power: 27 |
Quote:
However I never used the vof model to study the free surface: my "top" boundary condition was a simmetry condition in all simulations. Post a sketch of what you want to do (domain, dimensions) and add some more details on fluids you want to mix. Daniele |
||
November 22, 2012, 04:17 |
|
#5 | |
Senior Member
Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 162
Rep Power: 14 |
Quote:
Last edited by jamalf64; November 22, 2012 at 07:27. |
||
November 22, 2012, 05:14 |
|
#6 | |
Senior Member
Rick
Join Date: Oct 2010
Posts: 1,016
Rep Power: 27 |
Quote:
If you can't have a converged solution or your results are not accurate you have to switch to unsteady simulation (implicit formulation, less accurate then the explicit, but more stable); the time step will be dependent on the rotational speed of your impeller (the solution has to converge in max 40 iterations, if it doesn't reduce the time step). As a first try I use a time step "time to complete one revolution/8". For unsteady simulation you can use either mrf or sliding mesh approches: sliding mesh is more accurate, but it is more more expensive in therm of computational time. Since you have not baffles, mrf should give good results. Try to setup in fluent your problem, then report back if you have problems. Daniele |
||
November 22, 2012, 05:20 |
|
#7 | |
Senior Member
Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 162
Rep Power: 14 |
Quote:
|
||
November 22, 2012, 14:51 |
stirred tank
|
#8 |
Senior Member
Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 162
Rep Power: 14 |
dear friend,
I attached a file about my broblem. if possible for you, please help me. thank you so much Last edited by jamalf64; November 22, 2012 at 17:18. |
|
November 22, 2012, 15:57 |
|
#9 | |
Senior Member
Rick
Join Date: Oct 2010
Posts: 1,016
Rep Power: 27 |
Quote:
please elaborate more "System must be stable after a period of time, but is not and results are wrong". Why "impeller" is stationary?it should be rotating as shaft and fluid rotor.. Maybe also a pressure outlet for the top is more indicated instead of simmetry. If possibile upload somewhere cas/dat files, if not possible post some contour picture of phases. Daniele |
||
November 22, 2012, 16:22 |
|
#10 |
Senior Member
Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 162
Rep Power: 14 |
System should be stable after a period of time, but did not stable and it seems that results are wrong
Why "impeller" is stationary? Because tutorial of fluent(stirred tank) like this. I set top of tank as pressure inlet (like tutorial of fluent) but results dont change. Last edited by jamalf64; November 22, 2012 at 17:39. |
|
November 22, 2012, 16:26 |
|
#11 |
Senior Member
Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 162
Rep Power: 14 |
It is not possible to send case/dat files because their sizes is large (20MB).
forgive me |
|
November 23, 2012, 04:11 |
|
#12 |
Senior Member
Rick
Join Date: Oct 2010
Posts: 1,016
Rep Power: 27 |
Are you sure you obtained a converged solution?
what are the values of residuals? Can you create a vertical plane and post a contour of velocity magnitude? Then, in fluent create 2 planes, below and above the impeller, then monitor the area weight velocity magnitude: the values must not change in each iteration; if the values are changing yet when the next iteration starts you have not a converged solution. (Refer to the tank tutorial to monitor velocity magnitude values) Shaft and impeller have to rotate: you can set the shaft to rotate with absolute rotational velocity and the impeller to rotate with 0 relative rotational velocity (in respect to the rotor fluid rotational velocity). Daniele |
|
November 23, 2012, 04:30 |
|
#13 | |
Senior Member
Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 162
Rep Power: 14 |
Quote:
|
||
May 23, 2016, 09:08 |
|
#14 |
New Member
Devarajan K
Join Date: May 2016
Location: Warangal, Telengana
Posts: 3
Rep Power: 10 |
I am also working in the multiphase simulation of stirred tanks. In these images of volume fraction, impeller zone is black. How you had done this? In my case, impeller and baffle regions are also coming in the phases after patching
|
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
problem about VOF and species couple | Cloud | FLUENT | 0 | June 15, 2012 02:23 |
the initialization of the coupled level set method and vof model in FLUENT 13.0 | dutliang | FLUENT | 3 | December 13, 2011 22:28 |
DPM model coupled with VOF | Doug | FLUENT | 0 | March 1, 2005 17:37 |
Difficult BCs about Freesurface Simulation by VOF | Yongguang Cheng | FLUENT | 0 | September 19, 2003 08:39 |
Coupled 1D/3D STAR-CD Training | CD adapco Group Marketing | Siemens | 1 | November 13, 2002 16:48 |