CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Pre-Processing

Temperature dependent properties

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 13, 2015, 06:05
Default Temperature dependent properties
  #1
New Member
 
Luuk Buijs
Join Date: Mar 2015
Posts: 19
Rep Power: 9
lcbuijs is on a distinguished road
Dear FOAMers,

I'm trying to implement temperature dependent fluid properties (density, viscosity, heat capacity, etc.) in my simulation using the thermophysicalProperties dictionary in buoyantPimpleFoam. My simulation concerns natural convection of water in a cubical cavity heated from below (a Rayleigh-Benard cell). I'm thinking that including the properties as polynomials might be the best way to do this, seeing as the temperature differences are not very large.

I've looked through the forums and found some similar threads, but these are mainly concerned with more advanced functionality of the dictionary. I'm simply having trouble finding out where to start, mainly because I'm completely new to the use of this dictionary itself. In short my question is as follows: what is the correct/most suitable way to set up this dictionary for my case?

Any help is greatly appreciated! Best regards,
Luuk
lcbuijs is offline   Reply With Quote

Old   March 13, 2015, 07:39
Default
  #2
Senior Member
 
Bernhard Linseisen
Join Date: May 2010
Location: Heilbronn
Posts: 183
Blog Entries: 1
Rep Power: 14
Linse is on a distinguished road
I would suggest to use the code already implemented. ;-)

If you check within the reactingFoam-tutorials for example, you will find several cases where heat capacity et al. are computed based on temperature. It depends on the constant->thermophysicalProperties->thermoType .
If there is an entry "janaf" for thermo, the heat capacity will be computed based on a polynomial of grade 5 depending on temperature.

Certainly you will find other temperature-dependent properties as well. Some might not be implemented to your liking, but I guess the janaf-stuff is a good entry-point for implementing your own definitions if needed.
In addition you will find a lot of interesting code within $FOAM_SRC/thermophysicalModels that might help a lot...
Linse is offline   Reply With Quote

Old   March 16, 2015, 04:49
Default
  #3
New Member
 
Luuk Buijs
Join Date: Mar 2015
Posts: 19
Rep Power: 9
lcbuijs is on a distinguished road
Dear Linse,

Thank you very much for your reply. I will look into the tutorials that I can find for this dictionary. Just a small additional question though. Can you tell me what would be the correct/most suitable entries for type and equationOfState in my case? I'm sure I can figure out the rest by myself, but this would narrow down the options significantly and be a nice starting point.

Thanks again and best regards,
Luuk
lcbuijs is offline   Reply With Quote

Old   June 22, 2015, 10:22
Default
  #4
New Member
 
Join Date: Jun 2015
Posts: 2
Rep Power: 0
ali.lajevardi is on a distinguished road
Quote:
Originally Posted by Linse View Post
I would suggest to use the code already implemented. ;-)

If you check within the reactingFoam-tutorials for example, you will find several cases where heat capacity et al. are computed based on temperature. It depends on the constant->thermophysicalProperties->thermoType .
If there is an entry "janaf" for thermo, the heat capacity will be computed based on a polynomial of grade 5 depending on temperature.

Certainly you will find other temperature-dependent properties as well. Some might not be implemented to your liking, but I guess the janaf-stuff is a good entry-point for implementing your own definitions if needed.
In addition you will find a lot of interesting code within $FOAM_SRC/thermophysicalModels that might help a lot...
please tell me ,address that note clear ( it means: $FOAM_SRC/thermophysicalModels) - thanks
ali.lajevardi is offline   Reply With Quote

Old   June 26, 2015, 19:28
Default
  #5
Senior Member
 
Bernhard Linseisen
Join Date: May 2010
Location: Heilbronn
Posts: 183
Blog Entries: 1
Rep Power: 14
Linse is on a distinguished road
Dear Luuk,

I am sorry for that late reply upon your question. Probably you have found good settings for your case already. But for what it is worth:
If you do not know which settings are available, using a banana is a great help with many of OpenFOAM's capabilities. If at the place of one setting in the dictionary you put "banana" (or any other rubbish word) instead of a valid value, OF will tell you the acceptable entries. Most of the time these already will enable you to make a reasonable choice.

Looking at your case, I probably would have chosen the "perfectGas" settings, as in OF-nomenclature this is identical to what is often referred to as ideal gas. If you need to use a polynomial heat capacity approach or if a constant value is acceptable, depends on the gases, the temperature range, your accuracy requirements...

@Ali: I am sorry, but I do not understand your question...
$FOAM_SRC/thermophysicalModels should point to a directory where one finds plenty of different models and source code files related to treatment of thermophysical properties.

Cheers,
Bernhard
Linse 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
melting problem: looking for appropriate solvers som OpenFOAM Running, Solving & CFD 326 December 7, 2021 08:09
UDF for Temperature Dependent Energy Source er.mkumar Fluent UDF and Scheme Programming 8 September 17, 2018 14:14
Temperature dependent propertys and finalIteration in chtMultiRegionFoam waiter120 OpenFOAM 0 February 20, 2013 05:22
temperature dependent heat flux rohinibc Fluent UDF and Scheme Programming 0 December 11, 2012 08:45
Two-Phase Buoyant Flow Issue Miguel Baritto CFX 4 August 31, 2006 12:02


All times are GMT -4. The time now is 21:42.