fluent
 

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.

Hi,

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

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,