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leila.a June 21, 2011 00:47

fluent
 
hi....
my project is about modeling in thermosyphon with nano fluid.
how can I define udf for nano fluid?

alighaffari June 21, 2011 00:57

I think it won't be necessary to use UDF. You can directly define nanoparticles diameter in DPM model or other multiphase models.

Amir June 21, 2011 10:29

Quote:

Originally Posted by leila.a (Post 312819)
hi....
my project is about modeling in thermosyphon with nano fluid.
how can I define udf for nano fluid?

Hi,
You have to use UDS instead. obviously, you may need writing UDF in order of including special terms in UDS equation such as source terms.

Quote:

Originally Posted by alighaffari (Post 312821)
I think it won't be necessary to use UDF. You can directly define nanoparticles diameter in DPM model or other multiphase models.

Hi,

DPM is not a good suggestion for nano-fluid modelling because of its restrictions and bugs in small particles.

fshak92 December 29, 2012 20:03

Quote:

Originally Posted by Amir (Post 312917)
Hi,
You have to use UDS instead. obviously, you may need writing UDF in order of including special terms in UDS equation such as source terms.

Dear Amir,

I'd like to model a combination of ethylen glycol and silver nanoparticles .(the combination lies on a solid plate and then heats)

The viscosity of ethylen is in order of 1 cP but the combination of that should become about 70 cP.

Would you please give me a little explanation about using UDS regarding my problem?

thank you in advance.

Amir December 30, 2012 09:32

Quote:

Originally Posted by omid88 (Post 399418)
Dear Amir,

I'd like to model a combination of ethylen glycol and silver nanoparticles .(the combination lies on a solid plate and then heats)

The viscosity of ethylen is in order of 1 cP but the combination of that should become about 70 cP.

Would you please give me a little explanation about using UDS regarding my problem?

thank you in advance.

Hi Omid,

Sure; UDS is an additional scalar transport equation, you can use this capability of FLUENT to model the concentration of nano particles. In your case, the main media would be ethylen glycol and the UDS can be performed in order to model the concentration of silver particles. You have to bear in mind that in this procedure, you'll need extra UDFs defining the physical properties; e.g., viscosity, density, thermal conductivity and so on; obviously, these properties are functions of silver concentration. Hope that'd help.
Do not hesitate to ask if it's not clear or more elaborations are required.

Bests,


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