CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > CFX

Heat transfer within Porous Media

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   March 26, 2006, 21:41
Default Heat transfer within Porous Media
Posts: n/a
Is that possible to accout for both flow and heat transfer in porous media? I have checked the ANSYS CFX manual and found that the energy equation only take the consideration of fluid (section: ANSYS CFX-Solver, Release 10.0: Theory | Basic Solver Capability Theory | Flow in Porous Media | ). I wonder how can I add the heat transfer from solid framework to fluid flow under the assumption of either thermal equilibrium or non thermal equilibrium.
  Reply With Quote

Old   March 26, 2006, 23:55
Default Re: Heat transfer within Porous Media
Posts: n/a
Dear Twiti,

If you want to do the thermal equilibrium approximation, that is T_solid = T_fluid, you can "fake" the thermal conductivity within the porous domain as

K = (K_fluid * Volume Porosity + K_solid * (1-Volume Porosity)) / Volume Porosity..

That should work..

For the non-thermal equilibrium, the workaround is more elaborate (via additional variables), and you should contact your CFX help desk for details..

Good luck, Opaque..

  Reply With Quote

Old   March 27, 2006, 02:24
Default Re: Heat transfer within Porous Media
Eugeny Pavlov
Posts: n/a
Yes, this is problem of CFX. I ask my frend in Moskow, and they reply to my -"It is impossible, becouse no contact access to nodal value of function". In STAR-CD this is possible.

Sorry for my english Russia, Syberia, Krasnoyarsk
  Reply With Quote

Old   March 27, 2006, 10:08
Default Re: Heat transfer within Porous Media
Posts: n/a
Dear Eugeny,

If your friend is interested in solving a similar problem as Twiti, and has ANSYS CFX 10.0 already, sugggest to contact the CFX help desk.. Help desk can give them a note describing how to solve this issue using Additional Variables.. Requires a bit of a variable substitution for the equations to introduce the solid properties in a fluid equation..

It has been done for steady and transient problems.. You just need to know what the ANSYS CFX solver is doing, to workaround the current limitations.. There is no need to access internal data..

Good luck, Opaque
  Reply With Quote

Old   March 28, 2006, 15:23
Default Re: Heat transfer within Porous Media
Posts: n/a
the solution is "Diffusive Transport Model" This equation does not compute the convective part. So the quantity is only transported by diffusion and will stay in place.

that's the way I've done:

Add some additional variable(unspecified): cpSolid rhoSolid VSolid ASolid mSolid TSolid kSolid

and AV specific: HSolid

In Fluid Model you can define the values for individual AV eg. (all algrebaic eq): cpSolid=500[W/(m^2*K)] rhoSolid=200[kg/m^3] VSolid=0.1*Volume of Finite Volumes ASolid=200[m^2/m^3]*Volume of Finite Volumes mSolid=VSolid*rhoSolid TSolid=HSolid/(mSolid*cpSolid) cpSolid=1000[J/(kg*K)]

and HSolid as Transport Equation. Kinematic Diffusity is the thermal diffusivity. But as you just want to have it in your subdomain you should define: 2e-4[m^2/s]*Subdomain, so outside the subdomain it is 0.0.

You can't define Diffusive Transport in Pre, so define normal transport and edit the def-file later.

the sources in your subdomain are: for the fluid kSolid*ASolid*(TSolid-Temperature)/Volume of Finite Volumes for the solid kSolid*ASolid*(Temperature-TSolid)* Density

If you expect great gradients it is good to define source coefficients.

that's it. bye martin
  Reply With Quote

Old   March 28, 2006, 15:38
Default Re: Heat transfer within Porous Media
Posts: n/a
Dear Martin,

Thanks for the hints, but this applies to the porous domain approximation via Fluid Domain plus a SubDomain.. I think that Twiti wants to use the Porous Domain as in 10.0 (this is a new feature)..

Your approximation does not account for the fact that the solid matrix has a different volume than the fluid part.. Here , the solid and fluid are within the same porous domain. However, the idea is very similar but you must include the Volume Porosity in your terms..

Twiti, you can also pick it up from here.. Good luck, Opaque
  Reply With Quote

Old   November 7, 2015, 10:29
New Member
jogendra pal
Join Date: Oct 2015
Posts: 7
Rep Power: 4
JOGENDRA PAL is on a distinguished road
dear all.. i am facing same problem. can u please tell me how to simulate convection effect of fluid in porous media
JOGENDRA PAL is offline   Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
heat transfer to porous media... club68512 FLOW-3D 5 November 4, 2010 00:20
Conjugate heat transfer problem with porous media piko Siemens 1 April 17, 2009 15:41
heat transfer with porous media gokul FLUENT 0 February 24, 2009 14:43
heat transfer in porous media Miko Siemens 5 May 24, 2007 05:12
REG POROUS MEDIA HEAT TRANSFER Rashmi Venkat FLUENT 6 June 1, 2006 05:13

All times are GMT -4. The time now is 04:05.