CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

Porous Media modeling

Register Blogs Community New Posts Updated Threads Search

Like Tree11Likes

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 28, 2010, 16:56
Default Porous Media modeling
  #1
New Member
 
Rupak
Join Date: Aug 2010
Location: Rochester, NY
Posts: 6
Rep Power: 16
rupakbanerjee is on a distinguished road
How do i define a region to be porous?

I was working with the tutorial part 8, 'modelling flow through a porous media'. The only thing i did not understand is whether the region has to be defined as being porous while it is modelled in Gambit, or do i just create a meshed volume and define it as porous when i import it to Fluent.

I can only proceed once i know how to create the porous media.

thanks for the help
Takue likes this.
rupakbanerjee is offline   Reply With Quote

Old   August 31, 2010, 18:15
Default
  #2
New Member
 
symon
Join Date: Jul 2009
Posts: 1
Rep Power: 0
s25011 is on a distinguished road
I built the region as fluid in gambit and then define it as porous in the boundary conditions!

Quote:
Originally Posted by rupakbanerjee View Post
How do i define a region to be porous?

I was working with the tutorial part 8, 'modelling flow through a porous media'. The only thing i did not understand is whether the region has to be defined as being porous while it is modelled in Gambit, or do i just create a meshed volume and define it as porous when i import it to Fluent.

I can only proceed once i know how to create the porous media.

thanks for the help
s25011 is offline   Reply With Quote

Old   August 31, 2010, 18:34
Default
  #3
New Member
 
Rupak
Join Date: Aug 2010
Location: Rochester, NY
Posts: 6
Rep Power: 16
rupakbanerjee is on a distinguished road
when you say you defined it as porous boundary condition, do you mean using the porous jump as the boundary conditio?
rupakbanerjee is offline   Reply With Quote

Old   September 4, 2010, 05:39
Default
  #4
New Member
 
Join Date: Jul 2010
Posts: 22
Rep Power: 16
Mansureh is on a distinguished road
Quote:
Originally Posted by rupakbanerjee View Post
when you say you defined it as porous boundary condition, do you mean using the porous jump as the boundary conditio?

hi
If you want to model flow in a porous medium in fluent, you should specify the zone as fluid zone in gambit, and then in "cell zone conditions" dialog box, enable porous zone check box , and specify related parameters such as porosity.
good luck
6863523 and ali_reza like this.
Mansureh is offline   Reply With Quote

Old   November 18, 2010, 03:16
Default
  #5
oky
New Member
 
Oky Andytya
Join Date: Nov 2010
Posts: 26
Rep Power: 16
oky is on a distinguished road
As i know the parameter in porous zone is inertial and viscous resistance.
How to define it?
Is there any formula or something?

Would you like give an example.

Thank you. Danke.
oky is offline   Reply With Quote

Old   November 18, 2010, 16:30
Default
  #6
New Member
 
Rok Sibanc
Join Date: Sep 2009
Posts: 9
Rep Power: 17
snow is on a distinguished road
http://www.cfd-online.com/Wiki/Fluen...e_drop_data.3F
chaitanyaarige and BlnPhoenix like this.
snow is offline   Reply With Quote

Old   November 22, 2010, 23:49
Question
  #7
oky
New Member
 
Oky Andytya
Join Date: Nov 2010
Posts: 26
Rep Power: 16
oky is on a distinguished road
My porous media is a cell zone

I did't use porous-jump, may be any formulation or something ?
oky is offline   Reply With Quote

Old   November 23, 2010, 07:11
Default
  #8
New Member
 
Rok Sibanc
Join Date: Sep 2009
Posts: 9
Rep Power: 17
snow is on a distinguished road
Yes but for the porous zone (cells) has two parameters (viscous resistance and inertial resistance) that you have to specify. And you determine these two from the pressure drop vs velocity profile using the equations at the link.
snow is offline   Reply With Quote

Old   December 2, 2010, 07:17
Wink
  #9
New Member
 
Nelly
Join Date: Oct 2010
Posts: 5
Rep Power: 16
nelly is on a distinguished road
Quote:
Originally Posted by oky View Post
As i know the parameter in porous zone is inertial and viscous resistance.
How to define it?
Is there any formula or something?

Would you like give an example.

Thank you. Danke.
Hi Oky, did you get to find the parameters?

If not, here is the explanation.

The formula is
Dp/L= [(viscosity/alpha)*velocity]+ [C2*1/2*density*velocity^2]
(dp/l =viscousr resistance + inertial resistance)

and


plot dp/l vs velocity in excel. The pressure drop can be obtained from cfd.

The values for velocity can be arbitrarily chosen say for ex. 0 to 20 m/s (even more if you want more points)

Plot Dp/L vs velocity based on above formula and examine the curve how it looks like. If it is a straight line then use only dp/l=viscous resistance.
If it is a quadratic equation use (dp/l =viscousr resistance + inertial resistance). Find K and C2 with these curves.

Hope this helps .

cheers
Nelly
chaitanyaarige, Andriy70 and Takue like this.
nelly is offline   Reply With Quote

Old   December 20, 2010, 04:01
Default
  #10
oky
New Member
 
Oky Andytya
Join Date: Nov 2010
Posts: 26
Rep Power: 16
oky is on a distinguished road
How to calculate the diameter particle [Dp] if i use Ergun or Blake-Kozeny equation to define inertial resisitance and porosity? [see ANSYS Fluent 6.3 User's Guide - 7.19.6]

Blake-Kozeny Equation:
P/L={150*mu*(1-e)^2}/{Dp^2*e^3}*V$

where:
P/L : Pressura drop
mu : viscosity
e : void fraction
Dp : Perticle diameter
V$ : Velocity unlimited

Thank you !
Regrads
OKY
oky is offline   Reply With Quote

Old   December 20, 2010, 05:25
Default
  #11
New Member
 
Nelly
Join Date: Oct 2010
Posts: 5
Rep Power: 16
nelly is on a distinguished road
Quote:
Originally Posted by oky View Post
How to calculate the diameter particle [Dp] if i use Ergun or Blake-Kozeny equation to define inertial resisitance and porosity? [see ANSYS Fluent 6.3 User's Guide - 7.19.6]

Blake-Kozeny Equation:
P/L={150*mu*(1-e)^2}/{Dp^2*e^3}*V$

where:
P/L : Pressura drop
mu : viscosity
e : void fraction
Dp : Perticle diameter
V$ : Velocity unlimited

Thank you !
Regrads
OKY
Hi This is the reply given by Mr. Jayaprakash in a previous thread discussion,

The Ergun equation assumes that the bed is filled with uniform sized and shaped particles. The sphericity parameter is used as a conversion factor for non-spherical particles (comparing the surface-volume ratio of those particles to an equivalent spherical particle).

Of course, for fully spherical particle, the sphericity = 1.

Sphericity = (6/Dp)/(Sp/Vp)

Dp = Diameter of the particle
Sp = Surface area of the particle
Vp = Volume of the particle

For 'not so crazy' shapes, like sand particles, you can use sphericity around 0.8 - 0.9.

Complete list of sphericity values can be found in "Perry's Chemical Engineers Handbook", or "Unit Operations of Chemical Engineering by McCage, Smith and Harriot" or similar books
Andriy70 likes this.
nelly is offline   Reply With Quote

Old   December 21, 2010, 21:56
Default
  #12
oky
New Member
 
Oky Andytya
Join Date: Nov 2010
Posts: 26
Rep Power: 16
oky is on a distinguished road
How to calculate the heat transfer in porous media [for conduction and convection heat transfer]?

Thank you,
Regrads
OKY
oky is offline   Reply With Quote

Old   February 1, 2011, 21:53
Default
  #13
oky
New Member
 
Oky Andytya
Join Date: Nov 2010
Posts: 26
Rep Power: 16
oky is on a distinguished road
Hi everyone,

I'm trying simulation porous media in rectangular channel, but the result isn't suitable with any research.

So, would you help me. I wish someone can check my simulation and give some reports if there is something wrong.

Thank you for your help.
Please send your e-mail, than i will send you my works to to your email.
my e-mail: oky.andytya.net@gmail.com

Regrads,
OKY Andytya P

note:
I use ANSYS Fluent 6.3 [CFD]
oky is offline   Reply With Quote

Old   May 20, 2011, 04:42
Default
  #14
New Member
 
M. A.
Join Date: Jul 2010
Posts: 27
Rep Power: 16
motahar is on a distinguished road
Hi friends,
I'm simulating a tube with water flow.
The tube encounters boiling near the wall.
I intend to calculate 'void fraction versus enthalpy' along the channel.
Can you help me how to calculate void fraction?

I'm in an emergency condition.
Waiting for your comments!!!

Thanks Everybody
motahar is offline   Reply With Quote

Old   May 25, 2011, 00:04
Default
  #15
oky
New Member
 
Oky Andytya
Join Date: Nov 2010
Posts: 26
Rep Power: 16
oky is on a distinguished road
Hi,

I want ask, how to get the value of convection coefficien [h] from Fluent directly ?

Thank you, regrads

OKY
oky is offline   Reply With Quote

Old   March 18, 2012, 15:11
Default Porous Jump
  #16
New Member
 
Akim Faisal
Join Date: Jan 2012
Posts: 18
Rep Power: 14
Akim679 is on a distinguished road
Hi,

I am having problems with specifying the boundary condition of a bottom wall of a 3D rectangular channel as a "porous jump" . In GAMBIT I select Boundary type as "Porous Jump" however, when I import my mesh in FLUENT I receive an error stating that: "Cannot change porous to porous-jump because
there is only one adjacent cell thread". I am not sure what that means, can anyone please help me with this case. Any suggestion is appreciated.

Thanks,
Akim
Akim679 is offline   Reply With Quote

Old   September 8, 2012, 16:53
Default
  #17
Senior Member
 
zaynah K.
Join Date: Jun 2012
Location: Mauritius
Posts: 138
Rep Power: 14
zaynah04 is on a distinguished road
hi

had you been able to simulate your flow through porous??
if so please contact me..

zaynah
zaynah04 is offline   Reply With Quote

Old   March 6, 2013, 10:01
Default
  #18
New Member
 
Join Date: Mar 2013
Posts: 8
Rep Power: 13
Leram is on a distinguished road
Quote:
Originally Posted by Akim679 View Post
Hi,

I am having problems with specifying the boundary condition of a bottom wall of a 3D rectangular channel as a "porous jump" . In GAMBIT I select Boundary type as "Porous Jump" however, when I import my mesh in FLUENT I receive an error stating that: "Cannot change porous to porous-jump because
there is only one adjacent cell thread". I am not sure what that means, can anyone please help me with this case. Any suggestion is appreciated.

Thanks,
Akim
Hi Akim,

I am modelling a tube through which mixture of air and water passes and there is an air permeable membrane around the internal wall of the tube which is permeable to air only. I should model this as VOF in Fluent.

First, I need to set this wall boundary as Porous Jump in Gambit. I did the following steps in Gambit and when importing the mesh into Fluent, I got the same Error Message as you got: "Cannot change porous to porous-jump because there is only one adjacent cell thread".

1) created a cylinder as volume
2) meshed it
3) set the boundaries as inflow, outflow, and porous jump (for the volume)
4) set the fluid zone
5) export the mesh to Fluent

I was wondering if you could get rid of this Error Messsage and how?

Or if any body else can help me model this case, it is much appriciated!

Thanks,
Leram
Leram is offline   Reply With Quote

Old   May 15, 2013, 11:36
Default
  #19
New Member
 
hadi
Join Date: Apr 2013
Posts: 16
Rep Power: 13
hadi.iraji is on a distinguished road
http://aerojet.engr.ucdavis.edu/fluenthelp/tutfiles/
hadi.iraji is offline   Reply With Quote

Old   August 21, 2013, 17:17
Default Porous media modeling
  #20
New Member
 
i man
Join Date: Feb 2013
Posts: 10
Rep Power: 13
chocolater is on a distinguished road
What is the most suitable software to simulat a porous media(some thing like flow past a fabric) and pressure drops?
CFX or Fluent?

Mohammed Alomari likes this.
chocolater is offline   Reply With Quote

Reply

Tags
gambit, porous


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
modeling the fluid flow in porous media by Fluent Mohsen Nazari FLUENT 5 April 26, 2019 05:45
Modeling heat transfer through a porous media harimighty FLUENT 3 July 23, 2016 06:11
Discrete phase modeling on porous media magnounibo FLUENT 0 April 9, 2009 09:18
Modeling thin perforated plates as porous media Mike FLUENT 0 August 21, 2007 05:16
porous media: Fluent or Star-CD? Igor Main CFD Forum 0 December 5, 2002 16:16


All times are GMT -4. The time now is 07:01.