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Old   April 16, 2014, 11:47
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shenyan
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Originally Posted by ghorrocks View Post
Then I suspect you have defined the nanoparticles as a continuous phase and that does not sound correct.

Can you describe what you are modelling and why you are sure you need a two-phase eularian model for it? For most nanoparticle flow there is no slip of the nanoparticles relative to the continuous fluid, and this means a multiphase model is not appropriate.
well, briefly i want to model a nanofluid behavior in single-phase & two-phase models,then compare them with experimental data, i'm not sure that eulerian model is a suitable choose to modelling, but to this comparison i need to this modelling & defintion.
please tell me this sir
thank you
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Old   April 16, 2014, 18:35
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What are the nanoparticles? What do they do to the flow? What is the flow? What do you want to compare?
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Old   April 17, 2014, 01:44
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What are the nanoparticles? What do they do to the flow? What is the flow? What do you want to compare?
this modelling is one part of my thesis,i can't explain it detail, i just want to know that do you know how define nanoparticle's viscisity in eulerian model or no,i be thankful you if tell me...
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Old   May 30, 2014, 02:00
Default Eulerian-Langrangian method in nanofluids heat transfer enhancement
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MOHAMAD KAMAL HILMI
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Hi,

I would like to ask is it possible to model a nanofluids heat transfer using the Eulerian-Langragian method?
Fyi, I'm trying to study the particle behaviors such as particle collision and particle sticking and their effects on the overall heat transfer in nanofluids.
Thanks!

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Kamal
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Old   May 30, 2014, 02:08
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I should write an FAQ on this....

CFX has no nanofluid models. The multiphase model in CFX is a MICRO scale model. It assumes that the lagrangian phase is affected by things like inter-phase slip, particle density and particle mass - these are all micro scale physics. In nano scales things like Brownian motion, surface chemistry, and molecular polarity are important.

So if inter-phase slip, particle density, mass and similar properties are important in your case then you can use CFX's multiphase model.

If you require Brownian motion, surface chemistry, molecular polarity and all these types of nano scale physics then you have to develop the model yourself inside CFX or use some other software.

Particle collision and sticking on the nano scale sounds like Van Der Waal forces to me, along with molecular polarity/ionic stuff. CFX does not have these models, and adding them is not easy (or they would already be in there).
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Old   May 30, 2014, 02:15
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Originally Posted by ghorrocks View Post
I should write an FAQ on this....

CFX has no nanofluid models. The multiphase model in CFX is a MICRO scale model. It assumes that the lagrangian phase is affected by things like inter-phase slip, particle density and particle mass - these are all micro scale physics. In nano scales things like Brownian motion, surface chemistry, and molecular polarity are important.

So if inter-phase slip, particle density, mass and similar properties are important in your case then you can use CFX's multiphase model.

If you require Brownian motion, surface chemistry, molecular polarity and all these types of nano scale physics then you have to develop the model yourself inside CFX or use some other software.

Particle collision and sticking on the nano scale sounds like Van Der Waal forces to me, along with molecular polarity/ionic stuff. CFX does not have these models, and adding them is not easy (or they would already be in there).
Thank you for the reply. Yes, my study will be interested in all those nano-scales physics (Brownian etc). I will implement the use of UDF in Fluent for this purpose. Is there any recent research that have used this type of approach?
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Old   May 30, 2014, 02:24
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If you are using Fluent then try the Fluent forums.

Fluent has more models available and is more adaptable so you can add your own models. Thsi is probably going to be easier in Fluent than CFX.
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Old   May 30, 2014, 02:39
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Originally Posted by ghorrocks View Post
If you are using Fluent then try the Fluent forums.

Fluent has more models available and is more adaptable so you can add your own models. Thsi is probably going to be easier in Fluent than CFX.
Oh, so sorry haven't realized that this is CFX forum. I will try to ask around in Fluent forum. Again, thank you.
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Old   June 27, 2014, 03:21
Post Nanofluid particle diameter
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Can anyone please tell me how to set the size of nanofluid particle in Fluent?

Thank you in advance.
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Old   June 27, 2014, 06:18
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Have you read any of the posts in this thread? If you have a question about Fluent then try the Fluent forum.
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Old   June 27, 2014, 06:32
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Sorry, my bad...
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Old   October 20, 2014, 12:50
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Thanks for the reply, I'm modelling 2D flow natural convection in a square enclosure utilizing nanofluid in the presence of gravity, the hot and cold walls are 310 and 285 K respectively, the upper and lower walls are adiabatic, the nanofluid is Al2O3 -water based fluid , I'm trying to model the effective thermal conductivity and viscosity and density using mathematical models proposed by recent researchers , the properties will be modeled using UDF as a source code written in C, my question which model should I use? I've heard that some people used the two phase mixture model for modelling the nanofluid, this is an example:
http://www.sciencedirect.com/science...5193313001759#
and another clear example of using two phase mixture model:
http://www.sciencedirect.com/science...0072913001920#
I hope I could explain my case so waiting for explanation and how to use the UDF to model the properties? is the UDF used for both primary and secondary phase or only for the primary phase (water in this case), I've tried both but the contour for temperature looked that no temperature change along the body.
Regards
Hello Saleh
I am trying to model this case (encolsure filled with naofluid)
could you suggest me a tutorial please
Regards
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