CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

Problem with fluidized bed simulation using TwoPhaseEulerFoam

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 11, 2008, 06:08
Default Dear FOAMers, I try to get
  #1
New Member
 
Matthias Schreiber
Join Date: Mar 2009
Location: Cottbus, Germany
Posts: 4
Rep Power: 17
matthias_schreiber is on a distinguished road
Dear FOAMers,

I try to get familiar with the twoPhaseEulerFoam-Solver in order to do bubbling fluidized bed simulations in the future. Therefore I started with the tutorial "bed2", but ran into various problems:

a) After some timesteps alpha becomes larger than the setting for alpha_max, finally leading to a blown-up alpha-equation.

Last output:

DILUPBiCG: Solving for alpha, Initial residual = 0.00204016, Final residual = 6.59748e-11, No Iterations 4
Dispersed phase volume fraction = 0.275033 Min(alpha) = -3.08343e-18 Max(alpha) = 0.854645
DILUPBiCG: Solving for alpha, Initial residual = 9.44561e-05, Final residual = 3.20813e-12, No Iterations 4
Dispersed phase volume fraction = 0.275033 Min(alpha) = -3.08222e-18 Max(alpha) = 0.854609
GAMG: Solving for p, Initial residual = 0.00263152, Final residual = 6.91613e-09, No Iterations 27
time step continuity errors : sum local = 2.04471e-09, global = 2.39621e-10, cumulative = 3.95656e-07
DILUPBiCG: Solving for alpha, Initial residual = 0.00101853, Final residual = 5.98548e-11, No Iterations 4
Dispersed phase volume fraction = 0.275033 Min(alpha) = -3.08317e-18 Max(alpha) = 0.854606
DILUPBiCG: Solving for alpha, Initial residual = 8.03968e-05, Final residual = 3.01421e-11, No Iterations 167
Dispersed phase volume fraction = -5.04093 Min(alpha) = -25360.6 Max(alpha) = 8585.28
1 additional process aborted (not shown)

b) The bed expansion is not uniform and looks like a funnel.

Picture:

c) There are "fallen vortices" of high theta values on the side walls of the freeboard.

Picture:

Does anybody has some hints or best-practice guidelines for this kind of simulation with OF?
Many Thanks in advance.

Matthias
matthias_schreiber is offline   Reply With Quote

Old   June 11, 2008, 12:28
Default Servus Matthias, there are
  #2
Member
 
lord_kossity's Avatar
 
Andreas Dietz
Join Date: Mar 2009
Location: Munich
Posts: 79
Rep Power: 17
lord_kossity is on a distinguished road
Servus Matthias,

there are several threads about twoPhaseEulerFoam.

http://www.cfd-online.com/OpenFOAM_D...es/1/6470.html

http://www.cfd-online.com/OpenFOAM_D...es/1/1019.html

First one is quite general about the parameters in this solver

Second one is more about the issue of convergence problems regarding overpacking.

Regards,
Andreas
lord_kossity is offline   Reply With Quote

Old   June 11, 2008, 12:44
Default Hello Andreas, before posti
  #3
New Member
 
Matthias Schreiber
Join Date: Mar 2009
Location: Cottbus, Germany
Posts: 4
Rep Power: 17
matthias_schreiber is on a distinguished road
Hello Andreas,

before posting I searched for related threads and also consulted the ones you mentioned already. Unfortunately I still have problems to set up a converging simulation.

Regards,
Matthias
matthias_schreiber is offline   Reply With Quote

Old   June 11, 2008, 13:49
Default Hello Matthias, tomorrow I
  #4
Member
 
lord_kossity's Avatar
 
Andreas Dietz
Join Date: Mar 2009
Location: Munich
Posts: 79
Rep Power: 17
lord_kossity is on a distinguished road
Hello Matthias,

tomorrow I could send you one of my cases if you are then still intersted in them and provide me your email.
lord_kossity is offline   Reply With Quote

Old   June 12, 2008, 04:37
Default Hello Andreas, this would b
  #5
New Member
 
Matthias Schreiber
Join Date: Mar 2009
Location: Cottbus, Germany
Posts: 4
Rep Power: 17
matthias_schreiber is on a distinguished road
Hello Andreas,

this would be very nice. Please use this email address:

matthias.schreiber_at_tu-cottbus.de

Thanks a lot!

Matthias
matthias_schreiber is offline   Reply With Quote

Old   June 12, 2008, 07:49
Default Unfortunately Andreas' case wa
  #6
New Member
 
Matthias Schreiber
Join Date: Mar 2009
Location: Cottbus, Germany
Posts: 4
Rep Power: 17
matthias_schreiber is on a distinguished road
Unfortunately Andreas' case was a bubble column and no fluidzed bed simulation.
So, are there some FOAMers with experience in using kinetic theory for gas-solid fluidzed beds?

Regards,
Matthias
matthias_schreiber is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
fluidized bed simulation hosseini CFX 1 July 28, 2010 15:45
Fluidized Bed Simulation Siaw Khur CFX 9 July 28, 2010 15:43
Fluidized bed simulation Siaw Khur CFX 3 July 28, 2010 15:42
Fluidized Bed Simulation dyxu OpenFOAM Running, Solving & CFD 1 August 4, 2007 22:50


All times are GMT -4. The time now is 06:50.