Hydrocyclone simulation and catalogue size problem
 

Hello guys,
This is my firts time on this forum and i hope to find out a anwser for my problem.
I'm simulating a hydrocyclone for sand separation in the pulp and paper industry.
I have face some difficulties so far. In summary my biggest problem is the insufficient catalogue size.
I see that other guys has been solved this problem adding a catalogue size parameter but I already tried it several times without success.
See the mensage below:

------------------------------------------------------+
| *** INSUFFICIENT CATALOGUE SIZE *** |
| *** INSUFFICIENT CATALOGUE SIZE *** |
| |
| |
| ACTION REQUIRED : Increase the file catalogue size. |
| ACTION REQUIRED : Increase the file catalogue size. |
| |
| |
| If the situation persists please contact the CFX Customer Helpline |
| If the situation persists please contact the CFX Customer Helpline |
| giving the following details:- |
| giving the following details:- |
| Current catalogue size : 51820 |
| Current catalogue size : 51820 |
+--------------------------------------------------------------------+
+--------------------------------------------------------------------+



Details of error:-
Details of error:-
----------------
----------------
Error detected by routine MAKDAT
Error detected by routine MAKDAT
CDANAM = KELPF CDTYPE = INTR ISIZE = 98
CDANAM = KELPF CDTYPE = INTR ISIZE = 98
CRESLT = FCAT
CRESLT = FCAT


Current Directory : /INTERP/NEW/MESH/TSTEP0/CLOOP0/ZN1/FCS2478
Current Directory : /INTERP/NEW/MESH/TSTEP0/CLOOP0/ZN1/FCS2478
WARNING: CFXSTP, Regression check error.

My desktop has the following configuration:
Windows® 7 Home Premium 64-Bit

3ª Generation Intel® Processor Core™ i7-3770 (3.4GHz up to 3.9GHz com Turbo Boost 2.0, 8 Threads, 8Mb Cache)


Memory 12GB, Dual Channel DDR3, 1600MHz (2x2Gb + 2x4Gb)
HD 2TB, SATA 3Gb/s (7200 RPM)
Vídeo NVIDIA® GeForce® GT 640 de 1GB DDR5, 128-bit

Please, someone can help me on this issue?

br,

Alexandre David

This thread has some tips:
http://www.cfd-online.com/Forums/cfx...e-problem.html

You can also increase catalog size with the advanced options on the launcher or with a command line argument.

But if it keeps moaning about catalog size then you have a problem with your setup. Usually this is caused by complex GGI interfaces or geometry and often is linked to bad meshing.

Ghorrocks,

The meshing is showing the mensag "Warning: Hard points are not supported and may be ignored for 3D pre-inflation, please check your model carefully. Project>Model 6/10/2012 12:09:15 AM.
I have 2518586 nodes and 13477652 elements.
This sand separator has a perforated insert with 3900 holes and it makes the simulation very heavy
See picture of mesh and setup if you have time.
Could you explain how to proceed with this command line argument?
I also tried adding the override catalogue size on the CFX-Pre using the global inicialization but it doesn't work as well.
Based on this information "Current catalogue size : 51820" how much I should increase the catalogue size? 150x?

Thank you in advance per your attention and help.
br,
Alexandre David
Brazil

Looks like your problem is in the complex mesh. If you are using catalog sizes of 150x then something is seriously wrong and will not be recovered simply by increasing it further.

I would consider replacing the perforated insert which you have directly modelled with a interface with an equivalent resistance, and possibly a directionality component for the particles.

If you want to directly model the insert like this you are going to have to make the mesh in the insert a little finer, and the mesh elsewhere finer as well. Of course this means the simulation will get even bigger :), but hey, that's CFD for you.

'Complex GGI / Catalogue issues'
 

Hi Glen,

I know this is an old thread but I was hoping you might elaborate on the 'complex GGI' aspect of the need for high catalogue size. I have a simulation with a single 'interface' defined for every place (over 150 discrete regions) where 2 different domains come into contact with each other. Would making separate GGI interfaces for each of these discrete contact regions improve the CFX performance? In other words, since my single GGI includes lots of contact regions, am I forcing CFX to search all of those contact regions for intersections with each element (N^2 computational effort). In this case would my simulation be more efficient if I set up 150 seperate interfaces, each of which only including 1 side of a single discrete interface?

Thanks

I do not know. I do not know the details of how GGI interfaces work and do their intersection search.

I can only suggest you try it and see how it goes.

[Q] Mass conservation in CFBC
 

There are 3 particles in circulation fluidized bed cogeneration problem. Ash and limestone will go outlet but sand will be circulated in the domain. How does CFX solver satisfy mass conservation? Of course a part of sand also go outside through outlet. But I guess sand will be acuumulated in the domain during the calculation. Does the solver try to satisfy mass conservation automatically?

Yes, the solver tries to conserve mass. The results are rubbish without mass conservation.

This is all basic stuff covered in any CFD textbook or the CFX documentation.

I'm working on trying it out now but it is a large (140M node) model so making changes is slow. I will post an update if dividing my complex GGI up into a greater number of smaller GGIs makes a significant improvement