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jaiminthejack
Posts: 5
Registered: ‎10-22-2012
Accepted Solution

how to handle two fluid in one model

312 Views, 6 Replies
10-25-2012 10:10 AM

Basically i want try on counterflow heat exchanger.

 

by void i create 1 volume for 1 fluid say-water 

 

but how to create other ex.like gas,air?

 

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wildej
Posts: 972
Registered: ‎08-25-2011

Re: how to handle two fluid in one model

10-26-2012 02:22 AM in reply to: jaiminthejack

You can use the same approach. Build Surfaces and Fill Void.

 

A better method is to add solid cylinders, extruded in CAD (3x dia inlet and 5x dia outlet), leaving the 2 internal sections hollow but sealed.

When you launch, CFD will automatically fill them for you.

 

The advantage of this is reduced work in CFD and also the extensions will ensure you have well developed flow before the fluid enters the model and prevents recirculation over the outlet Boundary Conditions.



Jon Wilde
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Member
jaiminthejack
Posts: 5
Registered: ‎10-22-2012

Re: how to handle two fluid in one model

10-26-2012 02:32 AM in reply to: wildej

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Member
jaiminthejack
Posts: 5
Registered: ‎10-22-2012

Re: how to handle two fluid in one model

10-26-2012 02:42 AM in reply to: wildej
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wildej
Posts: 972
Registered: ‎08-25-2011

Re: how to handle two fluid in one model

10-26-2012 03:03 AM in reply to: jaiminthejack

Looks like that should work, does it not?

 

Also, you may wish to consider running a 1/2 model to speed up the process, using a Slip/Symmetry BC along the cut-plane.



Jon Wilde
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Member
jaiminthejack
Posts: 5
Registered: ‎10-22-2012

Re: how to handle two fluid in one model

10-26-2012 10:11 AM in reply to: wildej

will u demonstrate it?

 

still m learining this software

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apolo.vanderberg
Posts: 307
Registered: ‎08-31-2011

Re: how to handle two fluid in one model

10-26-2012 11:17 AM in reply to: jaiminthejack

You should be able to do the full model yourself pretty easily.

With the Void Fill tool you would seal all four openings (Red Arrows)

Whether you get 1 or 2 fluid volumes will depend on the cad model. If your baffles are sealed (Orange Arrows)

then you should get 2 volumes, otherwise it will be treated as 1 continuos fluid domain.

HX.jpg

 

 

The aspect Jon mentioned for Half-Symmetry is very useul as it will reduce the overall model and computational resources.

To do that you would have to do an extrude-cut to get 1/2 the model (similar to the sliced view you have here).

Then you would mate an additional large flat plate to the "cut" side. This will help seal the openings length-wise.

This flat plate will get suppressed in the meshing dialog and not be part of the simulation

You will then build your Inlet and Outlet caps to seal the domain and have your interior fluid volumes generated.

Slip/Symm boundary conditions will be assigned to all Fluid faces that are on the Symmetry plane.

 

If you are just starting out, it may be worthwhile starting with fewer pipes (length-wise) so that you can get comfortable with the workflow and running and you can always add the complexity back in.

Apolo

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