CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT > Fluent Multiphase

NETL III Fluidization Curve

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

Like Tree1Likes
  • 1 Post By Micael

LinkBack Thread Tools Search this Thread Display Modes
Old   August 14, 2018, 03:55
Default NETL III Fluidization Curve
New Member
Mario B.
Join Date: Feb 2018
Posts: 11
Rep Power: 8
blerli_91 is on a distinguished road
Hello People,

rigth now i try to simulate the NETL-Challenge III (small fluidized beds with particle distributions). The task is to obtain the fluidization curve and compare it with experimental data.
The thing is now, I am getting quite reasonable results for the pressure drop above the minimal fluidization velocity. It works quite fine with DDPM-KTGF and Euler Granular Model and also with different drag models and approaches for the particle distribution.

However when I try to simulate the section below the minimum fluidization velocity my results are very, very bad. My pressure dop is far to high, also I am not able to recreate the tendecy of the pressure drop in that section.
I already tried a lot different models (bulit in Models like DDPM, Euler Granular, Euler Granular Packed bed), drag models (Wen Yu, Gidaspow, Syamlal Obrien), Granular Viscosity (Gidaspow and Syamlal Obrien) and particle distrbution approaches (Constant Sauter mean diameter, Full distribution with Rosin Rammler) as well as models and values for frictional viscosity and coefficient of restitution. Also tried a bit varying the initial volume fraction in the bed.
But still I am getting somehow around the same wrong results for the calculation.
Maybe someone has an idea or already experience about that challenge? I am quite out of ideas right now... also I am still quite a beginner with Fluent and Multiphase

PS.: Also the task is to try to simulate the pressure drop with the Fluent built in Models... Found some Papers which are using UDF´s for the Drag Models...

Thank you
blerli_91 is offline   Reply With Quote

Old   August 17, 2018, 16:39
Senior Member
Join Date: Mar 2009
Location: Canada
Posts: 156
Rep Power: 18
Micael is on a distinguished road
Forget DDPM-KTGF for fixed bed, it's not valid.

For Euler-Euler (Two-Fluid-Model) it can work in fixed bed regime. Take care though of the frictional viscosity. Have you tried Shaeffer for Frictional viscosity in combinaison with Johnson-et-al Frictional pressure?
blerli_91 likes this.
Micael is offline   Reply With Quote

Old   August 20, 2018, 04:22
New Member
Mario B.
Join Date: Feb 2018
Posts: 11
Rep Power: 8
blerli_91 is on a distinguished road
Hi Micael,

yeah i already gave up with KTGF for it.

I also managed to get some better results for it with Euler Granular Packed Bed options (just in case someone else has troubles with it.: it is necessary to fix all the velocities of the solids inside the cell conditions dialog - for ALL zones not just in the packed bed zone, then it should work)

my results are still not that good but at least i got the linear dependency of pressure drop by gas velocity. so i will also try your suggested combination of schaeffer and johnson - thank you for that

(i just tried schaeffer without johnson). Also the results are getting a bit better with more detailled resolution of the particle distribution. But I did it just by adding additional phases...and the computational effort is increasing rapidly of course for that variant.

Is there maybe an "easy" way to create particle distribution for one solid phase for Euler Granular (I guess it will be possible with UDF´s - just don´t have any experience with UDF´s so I cant estimate how much effort it will be to implement it ...)
blerli_91 is offline   Reply With Quote


challenge, fluidization, fluidized bed, netl iii, pressure drop

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
[ICEM] Problems with coedge curves and surfaces tommymoose ANSYS Meshing & Geometry 6 December 1, 2020 11:12
[Gmsh] Vertex numbering is dense KateEisenhower OpenFOAM Meshing & Mesh Conversion 7 August 3, 2015 10:49
meshing of a compound volume in GMSH shawn3531 OpenFOAM 4 March 12, 2015 10:45
block-structured mesh for t-junction Robert@cfd ANSYS Meshing & Geometry 20 November 11, 2011 04:59
CFX4.3 -build analysis form Chie Min CFX 5 July 12, 2001 23:19

All times are GMT -4. The time now is 06:53.