CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   Nanofluid Modeling at Microchannel Heat-Sink (http://www.cfd-online.com/Forums/fluent/102833-nanofluid-modeling-microchannel-heat-sink.html)

mech-engineer June 4, 2012 05:46

Nanofluid Modeling at Microchannel Heat-Sink
 
Hi every all
Pls tell me is it possible to simulate nanofluid as Eulerian two-phase flow in microchannel in FLUENT?
I'm working with CFX to model above mentioned problem,but I can't gain correct solution specially for heat transfer equations of two phases,namely dispersed solids and continuous fluid.Do you have appropriate way to overcome this problem in software or I should choice another way?

Amir June 4, 2012 08:07

Dear Behzad,

Why didn't you use UDS (scalar transport) instead of multi-phase modelling?!

Bests,

mech-engineer June 4, 2012 11:26

Hi Amir
I had never used this option (UDS).Pls explain more about it and tell me how it can be applied to my modeling?Can I obtain a good solution via UDS for nanofluid flow in microchannel?Also tell me,did you never simulate nanoscale flow in FLUENT to assure me about obtaining a reasonable solution in this software?

Amir June 4, 2012 11:47

Quote:

Originally Posted by mech-engineer (Post 364667)
I had never used this option (UDS).Pls explain more about it and tell me how it can be applied to my modeling?

UDS is an auxiliary scalar equation used to evaluate secondary phase concentration:
\frac{\partial}{\partial t} \rho C + \nabla . (\rho U C) = \nabla . (\rho D \nabla C) + sources
It's common to use this capability in nano fluid simulations.
Quote:

Originally Posted by mech-engineer (Post 364667)
Can I obtain a good solution via UDS for nanofluid flow in microchannel?Also tell me,did you never simulate nanoscale flow in FLUENT to assure me about obtaining a reasonable solution in this software?

Off course you can. It can properly model convection and diffusion mechanism and you'll probably need additional UDFs for correcting other properties.

Bests,

mech-engineer June 4, 2012 11:57

You said,probably need to correct other properties.Which properties are your meaning?Can I use conservation equations at default form for nanofluid or it is necessary to correct them?How I can apply Cunningham slip correction factor on the drag coefficient to ensure no-slip condition for flow around a sphere nanoparticle?

Amir June 4, 2012 12:10

Quote:

Originally Posted by mech-engineer (Post 364671)
You said,probably need to correct other properties.Which properties are your meaning?Can I use conservation equations at default form for nanofluid or it is necessary to correct them?How I can apply Cunningham slip correction factor on the drag coefficient to ensure no-slip condition for flow around a sphere nanoparticle?

Dear Behzad,

This equation has a conservative form and we are talking about Eulerian approach not lagrangian so we don't have Cunningham factor explicitly; i.e, we implicitly model nano particles, we model their effects; otherwise if you insist on using Lagrangian approach (DPM models) you'll face few bugs in modelling brownian motion. Regarding additional UDFs; they're needed to correct fluid viscosity and density and so on ....

Bests,

shenyan June 12, 2014 03:32

Quote:

Originally Posted by mech-engineer (Post 364600)
Hi every all
Pls tell me is it possible to simulate nanofluid as Eulerian two-phase flow in microchannel in FLUENT?
I'm working with CFX to model above mentioned problem,but I can't gain correct solution specially for heat transfer equations of two phases,namely dispersed solids and continuous fluid.Do you have appropriate way to overcome this problem in software or I should choice another way?

hello sir
yes you can use fluent and upper version of it(ansys) to model a two-phase flow easily.you can fallow this manner
Define>>models>>multiphase>> then you can choose your model,there are 3models (mixture,wet vapor(i think) & eulerian).


All times are GMT -4. The time now is 06:41.