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-   -   Help: CFX for granular flow (http://www.cfd-online.com/Forums/cfx/19064-help-cfx-granular-flow.html)

Dejun Jing July 12, 2002 16:26

Help: CFX for granular flow
 
Hi,

I will use CFX to simulate the flow behavior of fine powders that flow out of a hopper. I hope to prescribe the constitutive relations of solid phase through a kinetic theory approach.

We have both V4.4 and V5.5 versions of CFX, and now I only installed Version 5.5. However, I can not find where to input the parameters of kinetic theory. From its mannual (which is only for V5.0), it seems that the kinetic theory has not been incorporated, and the constitutive is based on empirical approach.

So, how can I incorporate the kinetic theory into my CFX 5.5 simulation? Shall I use CEL or fortran subroutines to add additional equation?

We also have V4.4 version. In this version, can kinetic theory be implemented directly? If so, I will uninstall V5.5 and install V4.4.

Thank you very much for your help.

Dejun Jing

Tommaso July 15, 2002 12:24

Re: Help: CFX for granular flow
 
Hi Dejun , I'm using V 4.4 to study granular flow , in this version kinetic theory is just implemented by a model proposed by Van Wachem et al. (1998).You can use it in the section >>PHASE DESCRIPTION , recalling some parameters as mean diameter , restitution coefficient , ... . Anyway it's possible to implement some additional equations using the subroutines USRBF and USRSRC , but before I thin it's better to test the model proposed by CFX.

Bye

Tommaso

Dejun Jing July 15, 2002 15:23

Re: Help: CFX for granular flow
 
Hi,Tommaso,

Thank you very much for your reply. Because I have installed and I am using the version of 5.5, I prefer use this 'latest' version.

In 5.5 version, can the kinetic theory for granular flow be implemented directly as in Version 4.4? Do I need to use CEL to add additional equation for granular temperature? Can CEL realize all the functions that cab ne realized by FORTRAN subroutines?

However, if the V5.5 is really less convenient than V4.4 with respect to implementing kinetic theory, I will turn to V4.4.

-Dejun

Tommaso July 16, 2002 04:45

Re: Help: CFX for granular flow
 
Hi Dejun, I haven't a great experience in CFX 5.5,because I have installed only version 4.4. Reading something about new features implemented in CFX V5.5,I noted the most powerful way to build a model by CEL and so I think it's possible to use it instead of USER FORTRAN subroutines. You can read the manual' section KEYWORD to see if there is KINETIC THEORY model under >>PHASE DESCRIPTION. Anyway you could ask to AEA the source code of the granular flow model present in V4.4,and so implement it in new version : sometimes it's possible to obtain some results in this way. If you cannot be able to obtain anything , the only solution is to return to V4.4. Bye and tell me about the CFX's developments,I'm really interested in it.

Tommaso


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