# Porous Media

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 July 11, 2011, 09:45 Porous Media #1 New Member   Shriram Join Date: Jul 2011 Posts: 2 Rep Power: 0 Hello, I am trying to model a porous medium with transient fluid flow through a circular duct of length 0.4m . The fluid is air at 1000K and 1 m/s and the porous medium is made up of Alumina pellets of dia 5mm. I have selected the alumina as a dispersed solid while air is a continuous fluid. Porosity setting is at 0.4, I calculated quadratic resistance loss using the equation provided in the help file with a prior knowledge of dp from a rough analytical calculation, I am not sure if this method is the correct approach to find quadratic resistance. Under fluid models, heat transfer is checked with total energy setting and turbulence is also specified using k-epsilon model. My prob: Given the conductivity of alumina as almost 1000 times that of air, I believe the time taken for the thermal wave to propagate through the medium would be at a slow rate say 1mm/s, however my solution seems to indicate a steady temperature distribution with in 2 sec into the simulation. I would apperciate if anyone could provide some insight on whether this approach is correct or if i have missed something crucial. Thank you. Shriram

 July 11, 2011, 19:14 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 14,195 Rep Power: 109 Doesn't this suggest the thermal inertia of the pellets is not being taken into account properly? Do the pellets move? If not then this could also be modelled single phase with the pallets modelled by a porous medium with heat transfer. This would be a much simpler model and hopefully has all the necessary physics.

 July 11, 2011, 19:14 #3 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 14,195 Rep Power: 109 Doesn't this suggest the thermal inertia of the pellets is not being taken into account properly? Do the pellets move? If not then this could also be modelled single phase with the pallets modelled by a porous medium with heat transfer. This would be a much simpler model and hopefully has all the necessary physics.

July 12, 2011, 09:31
#4
New Member

Shriram
Join Date: Jul 2011
Posts: 2
Rep Power: 0
Quote:
 Originally Posted by ghorrocks Doesn't this suggest the thermal inertia of the pellets is not being taken into account properly? Do the pellets move? If not then this could also be modelled single phase with the pallets modelled by a porous medium with heat transfer. This would be a much simpler model and hopefully has all the necessary physics.
Hi ghorrocks,

Exactly you are correct, the thermal inertia doesn't seem to be taken into account. Do you have any idea how to incorporate it? Also what I learnt from previous posts, the solid phase heat transfer is not accounted in the porous model it seems.

The pellets do not move, they are just randomly arranged.

Thank you.

Shriram

 July 12, 2011, 18:53 #5 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 14,195 Rep Power: 109 OK, in that case definitely use a single phase model flowing through a porous medium. In V13 I think you can couple the temperature of the porous medium to the flow. I think this is exactly what you are looking for.

 Tags heat transfer, porous media, transient flow

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Bernard Van FLUENT 29 January 26, 2017 05:09 VT_Bromley FLUENT 5 March 23, 2011 11:38 PK FLUENT 0 February 16, 2007 12:12 Azman FLUENT 0 July 31, 2006 11:11 Igor Main CFD Forum 0 December 5, 2002 16:16

All times are GMT -4. The time now is 11:40.

 Contact Us - CFD Online - Privacy Statement - Top