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

UDS for Porous Media

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

Like Tree1Likes
  • 1 Post By piyushsharma0487

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 5, 2003, 20:13
Default UDS for Porous Media
  #1
cp
Guest
 
Posts: n/a
Hi All,

I am using UDF to model the solid temperature distribution in a heated porous media, through which cold air passes through. My domain is 8" long and the porous media is 1" thick and kept at 5" from the inlet. Currently, I have defined a UDS for solid temperature. It is by default applied throughout the domain, whereas the porous media is for only 1". How do I modify the UDS, which can be applied to only the specific section in the domain? What changes do I need to make in my UDF?

Any information on this would be helpful,

Thanks in advance,

Chendhil.
  Reply With Quote

Old   September 6, 2003, 03:16
Default Re: UDS for Porous Media
  #2
Greg Perkins
Guest
 
Posts: n/a
You'll have to be careful with this to make sure you are in fact modelling the two phases correctly.

My advice is to consider NOT using the porous media model for this situation but rather just use the standard gas phase and your UDS. To understand why, consider (for example) how you intend to model thermal conductivity in your "porous zone" and your "uds". You'll have to modify the normal conductivities to make adjustment for the fact that your porous zone is not really porous now just the gas phase etc. It can be done, but you'll have to work through that. I suggest you write down your equations exactly and then formulate whatever models you use to recover those equations exactly.

I've put some code for FLUENT 5.X a number of years ago (2000 I think) for doing the UDS stuff and interphase heat transfer in the udf code library and you may find it by searching the posts. That should give you a start, but the code needs some minor mods for FLUENT 6.x

Greg
  Reply With Quote

Old   September 6, 2003, 19:16
Default Re: UDS for Porous Media
  #3
cp
Guest
 
Posts: n/a
Thanks a lott Greg, for your valuable information.

I've got your code "udf_scalar_dos.c" from the repository and am looking into it. I will get back to you after understanding your implementation. I may have some questions. Hope you don't mind helping me out with this!!

Chendhil.
  Reply With Quote

Old   September 7, 2003, 20:10
Default Re: UDS for Porous Media - To Greg
  #4
cp
Guest
 
Posts: n/a
Hi

I looked at your code, "udf_scalar_dos.c". That was really an excellent code, well-written and with several self-explanations. Good! Now, I have a question: With reference to my posting on handling the porous media at a specified location in the domain, I think you have done it this way. Please correct me, if I am wrong.

1. You bypass all Fluent's in-built porous models and calculate the momentum source (based on the problem in hand)

2. Initialize the porosity in the actual porous region and set 1 in other places. I guess, this is where you handle the specific location of porous media in your domain.

3. Calculate the UDS solid diffusivity

4. Calculate solid-phase/fluid phase energy source terms with current porosity

5. Solve for Solid Temp, leaving ZETA intact

It would be helpful to me, if you explain any missing points. Thanks,

Chendhil.
  Reply With Quote

Old   September 7, 2003, 20:27
Default Re: UDS for Porous Media - To Greg
  #5
Greg Perkins
Guest
 
Posts: n/a
I don't have the code handy at the moment, but from memory that's sounds right.

Yes I don't use any internal FLUENT models. The only problem with this comes if you want to handle unsteady problems in which case the gas phase transient term will be incorrect by a factor of the porosity.

Zeta represents the bed/porous media porosity - I think its constant for this early version, but you can also solve a UDS for that so it changes with say reaction. These features are in my later codes and aren't in the basic one I posted.

Also, I think that basic code assumes a constant specific heat for the solid. In wish case I have divided it through the equation. For variable specific heat this needs to be modified.

Greg
  Reply With Quote

Old   September 8, 2003, 11:38
Default Re: UDS for Porous Media
  #6
cp
Guest
 
Posts: n/a
Thanks a lott for your information, Greg!!

Chendhil.
  Reply With Quote

Old   June 26, 2012, 14:44
Default
  #7
New Member
 
Piyush Sharma
Join Date: Mar 2012
Location: India, Uttar Pradesh
Posts: 6
Rep Power: 14
piyushsharma0487 is on a distinguished road
Hi,
I am also working on the porous media and need to solve it for solid temperature, it will be of great help if you could send me the "udf_scalar_dos.c", although i tried to find out but could not succeed in locating the file.

Thanks in Advance

Piyush Sharma
Demian16 likes this.
piyushsharma0487 is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
UDS porous media Nagendra FLUENT 12 August 17, 2022 14:30
Porous media setup issues in Fluent Bernard Van FLUENT 29 January 26, 2017 05:09
Including radiation when temperature is expressed as a UDS in porous media mj_no7 FLUENT 2 June 3, 2009 13:31
debug of a UDS about porous media! whiz FLUENT 0 February 16, 2009 10:41
Porous media convection UDS equations cp FLUENT 1 September 19, 2003 20:53


All times are GMT -4. The time now is 09:12.