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Filling an "empty" space

Posted Oct 19, 2012, 6:40 p.m. EDT Fluid & Heat, Heat Transfer & Phase Change, Geometry Version 4.3a 6 Replies

Geoff Hodgson
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Hello, I'm new to Comsol and a novice at SW2012

It seems in order to model fluid flow through a heat exchanger, the volume filled with fluid (helium in this case) must be included in the model as a "solid", so that the inlet and outlet boundary conditions can be defined. Is this the case, and is there an easy way to create a part that "fills" the void? I have an existing SW2012 model of the HX.

Thanks,
Geoff
6 Replies Last Post Oct 22, 2012, 3:30 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Oct 20, 2012, 6:34 a.m. EDT
Hi

i beleive you must tell us which physics you are using, if it's solid heat exchange (only He conduction) or with fluid flow (mass and heat transport). Because for me an inlet in a physics solid case isnt really inline with my understanding ;)

--
Good luck
Ivar
Hi i beleive you must tell us which physics you are using, if it's solid heat exchange (only He conduction) or with fluid flow (mass and heat transport). Because for me an inlet in a physics solid case isnt really inline with my understanding ;) -- Good luck Ivar
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago Oct 20, 2012, 8:18 p.m. EDT
One way to model the gas volume is to create a block to represent that volume and subtract from it the heat exchanger geometry. You should not model that space as a “solid”. There is heat transfer in fluids capability which, as Ivar described, can handle convection as well as conduction through the gas.

Nagi Elabbasi
Veryst Engineering
One way to model the gas volume is to create a block to represent that volume and subtract from it the heat exchanger geometry. You should not model that space as a “solid”. There is heat transfer in fluids capability which, as Ivar described, can handle convection as well as conduction through the gas. Nagi Elabbasi Veryst Engineering
Geoff Hodgson
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Posted: 1 decade ago Oct 22, 2012, 11:57 a.m. EDT
Hello Ivar,

I'm using turbulent flow, fluid heat exchange and solid heat exchange models. In some operating conditions it is sub-atmospheric, so i have to use the transitional rarefied flow model.

Thanks,
Geoff


Hi

i beleive you must tell us which physics you are using, if it's solid heat exchange (only He conduction) or with fluid flow (mass and heat transport). Because for me an inlet in a physics solid case isnt really inline with my understanding ;)

--
Good luck
Ivar
Hello Ivar, I'm using turbulent flow, fluid heat exchange and solid heat exchange models. In some operating conditions it is sub-atmospheric, so i have to use the transitional rarefied flow model. Thanks, Geoff [QUOTE] Hi i beleive you must tell us which physics you are using, if it's solid heat exchange (only He conduction) or with fluid flow (mass and heat transport). Because for me an inlet in a physics solid case isnt really inline with my understanding ;) -- Good luck Ivar [/QUOTE]
Geoff Hodgson
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Posted: 1 decade ago Oct 22, 2012, 12:15 p.m. EDT
Good Morning Nagi,

Yes, I think I will need to use some kind of subtraction function to define the space. I realize that is it will not be a solid, but a 3D space filled with gas, but I think Solidworks thinks everything is a solid (hence the name!). The void to be filled is made more difficult because of internal turbulence inducers, I'll let you know how it goes.

Thank you for the help,
Geoff


One way to model the gas volume is to create a block to represent that volume and subtract from it the heat exchanger geometry. You should not model that space as a “solid”. There is heat transfer in fluids capability which, as Ivar described, can handle convection as well as conduction through the gas.

Nagi Elabbasi
Veryst Engineering


Good Morning Nagi, Yes, I think I will need to use some kind of subtraction function to define the space. I realize that is it will not be a solid, but a 3D space filled with gas, but I think Solidworks thinks everything is a solid (hence the name!). The void to be filled is made more difficult because of internal turbulence inducers, I'll let you know how it goes. Thank you for the help, Geoff [QUOTE] One way to model the gas volume is to create a block to represent that volume and subtract from it the heat exchanger geometry. You should not model that space as a “solid”. There is heat transfer in fluids capability which, as Ivar described, can handle convection as well as conduction through the gas. Nagi Elabbasi Veryst Engineering [/QUOTE]
Jeff Hiller COMSOL Employee

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Posted: 1 decade ago Oct 22, 2012, 12:47 p.m. EDT
The CAD Import Module provides an automated capability to turn the inside of a hollow object into an object of its own: the "Cap Faces" capability. This feature was introduced at version 4.2: see www.comsol.com/products/4.2/ and look for "Cap Faces".
The CAD Import Module provides an automated capability to turn the inside of a hollow object into an object of its own: the "Cap Faces" capability. This feature was introduced at version 4.2: see http://www.comsol.com/products/4.2/ and look for "Cap Faces".
Geoff Hodgson
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Posted: 1 decade ago Oct 22, 2012, 3:30 p.m. EDT
Thank You, Jean-Francois

I'll give that a try, that's exactly how I hope the program would work!

Geoff
Thank You, Jean-Francois I'll give that a try, that's exactly how I hope the program would work! Geoff

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