CFD Online URL
[Sponsors]
Home > Forums > FLUENT

Check for property conservation in a closed domain

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 27, 2011, 07:44
Default Check for property conservation in a closed domain
  #1
New Member
 
Gregory
Join Date: Mar 2011
Posts: 11
Rep Power: 5
Yr0gErG is on a distinguished road
How would you ensure property conservation in a closed domain?
For example if the entire domain is closed and only heat energy is coming in, is it safe to assume that properties like mass flow rate are always conserved?
Yr0gErG is offline   Reply With Quote

Old   March 27, 2011, 09:47
Default
  #2
New Member
 
mohsen
Join Date: Feb 2011
Posts: 13
Rep Power: 5
momech is on a distinguished road
hi.
if you work on 2D case,just enough to creat an arbitrary line in the domain so you can check the mass flow rate through it. (it should be almost zero[flow circulation!]){also it's better to use some lines at different positions}
And in 3D case creat planes...
good luck.
momech is offline   Reply With Quote

Old   March 27, 2011, 15:04
Default
  #3
New Member
 
Gregory
Join Date: Mar 2011
Posts: 11
Rep Power: 5
Yr0gErG is on a distinguished road
mins is a 3D case... is the default interior good enough?
Yr0gErG is offline   Reply With Quote

Old   March 28, 2011, 01:52
Default
  #4
New Member
 
Gregory
Join Date: Mar 2011
Posts: 11
Rep Power: 5
Yr0gErG is on a distinguished road
Hi, I tried the above mentioned suggestion, created two arbitrary planes within my domain and check for mass flow rate conservation. Is that correct? after about 200 iterations though, the mass flow rate started to oscillate quite largely. any advice?
Yr0gErG is offline   Reply With Quote

Old   March 28, 2011, 02:54
Default
  #5
New Member
 
mohsen
Join Date: Feb 2011
Posts: 13
Rep Power: 5
momech is on a distinguished road
Hi,as I mentioned before,it should come nearly zero{total mass flow rate through each plane}
you can:
alter your Turb. method, do further iterations to achieve the more accurate convergence,check the grid quality and....
momech is offline   Reply With Quote

Old   March 28, 2011, 05:52
Default
  #6
New Member
 
Gregory
Join Date: Mar 2011
Posts: 11
Rep Power: 5
Yr0gErG is on a distinguished road
ok i am using the incompressible ideal gas density for air and the RNG k-e turbulence model. the residuals and mass flow rate no longer oscillate. however, the mass flow rate is very slowly increasing with more iterations.
Yr0gErG is offline   Reply With Quote

Old   March 28, 2011, 06:15
Default
  #7
New Member
 
Gregory
Join Date: Mar 2011
Posts: 11
Rep Power: 5
Yr0gErG is on a distinguished road
Grid Check

Domain Extents:
x-coordinate: min (m) = -5.000000e-01, max (m) = 5.000000e-01
y-coordinate: min (m) = -5.000000e-01, max (m) = 5.000000e-01
z-coordinate: min (m) = -5.000000e-01, max (m) = 5.000000e-01
Volume statistics:
minimum volume (m3): 1.250000e-04
maximum volume (m3): 1.250000e-04
total volume (m3): 1.000000e+00
Face area statistics:
minimum face area (m2): 2.500000e-03
maximum face area (m2): 2.500000e-03
Checking number of nodes per cell.
Checking number of faces per cell.
Checking thread pointers.
Checking number of cells per face.
Checking face cells.
Checking bridge faces.
Checking right-handed cells.
Checking face handedness.
Checking face node order.
Checking element type consistency.
Checking boundary types:
Checking face pairs.
Checking periodic boundaries.
Checking node count.
Checking nosolve cell count.
Checking nosolve face count.
Checking face children.
Checking cell children.
Checking storage.
Done.
Yr0gErG is offline   Reply With Quote

Reply

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
air bubble is disappear increasing time using vof xujjun CFX 9 June 9, 2009 08:59
CFX Solver Memory Error mike CFX 1 March 19, 2008 09:22
CHT Problem - Domain Imbalance Parthipan CFX 5 September 11, 2007 11:13
rotating domain in rotating domain, different axis Robert Stringer CFX 3 December 4, 2006 08:04
Solver error message!!! IoSa CFX 1 September 14, 2006 05:48


All times are GMT -4. The time now is 15:31.