|
[Sponsors] |
January 25, 2016, 05:31 |
Problem with porous media
|
#1 |
New Member
Lisa
Join Date: Dec 2015
Posts: 8
Rep Power: 10 |
Hello foamers,
I have a Problem with my porousSimpleFoam case. In the attached Picture you can see a cylinder located in a box. I want to generate a flow through the box. The cylinder has a porosity i defined in porosity properties. My Problem is that OpenFoam seems to ignore my porous media because there is no velocity in the cylinder (i can see that when i do a plot over line for the velocity in paraView) The box and the cylinder are two different meshes. I generated both with snappyHexMesh and merged them into one case for my simulations with porousSimpleFoam.. Do you think there could be a Problem? Thanks! |
|
January 31, 2016, 13:51 |
|
#2 |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 10,974
Blog Entries: 45
Rep Power: 128 |
Quick answer: If you only merged the two meshes, then they are technically considered by OpenFOAM has being two completely independent regions, even if they are overlapped over each other.
You will need to use one of the following solutions:
__________________
|
|
February 1, 2016, 03:56 |
|
#3 |
New Member
Lisa
Join Date: Dec 2015
Posts: 8
Rep Power: 10 |
Thank you very much for your quick answer!
I tried the stitchMesh Utility but i get the following error: --> FOAM FATAL ERROR: Points on patch sides do not match to within tolerance 5.39231e-06 OpenFOAM thinks the meshes don't complement each other, am i right? Where can i Change the tolerance of stitchMesh? I can't find something about that... For better understanding my case: My box and my cylinder were first overlapping each other( like in my Picture above) But for using stitchMesh i meshed my box without the volume of my cylinder and meshed my cylinder seperatly so that i can put both meshes together with mergeMeshes. I did that so that i get two patches i can put together. What am i doing wrong? my boundary after merging: zylinder // patch from box without volume of cylinder { type patch; nFaces 8880; startFace 870467; } porosity //patch from cylinder merged into box { type patch; nFaces 19802; startFace 879347; } Last edited by Lisl; February 2, 2016 at 04:56. |
|
February 3, 2016, 03:31 |
|
#4 |
New Member
Lisa
Join Date: Dec 2015
Posts: 8
Rep Power: 10 |
I found a toleranceDict and changed some values (made the tolerances larger)
But the error is still there. I executed stitchMesh with stitchMesh -perfect -toleranceDict (nameDict) masterPatch slavePatch Here are the entries for my toleranceDict: pointMergeTol 0.3; edgeMergeTol 0.0201; nFacesPerSlaveEdge 5; edgeFaceEscapeLimit 10; integralAdjTol 0.8; edgeMasterCatchFraction 0.4; edgeCoPlanarTol 0.8; edgeEndCutoffTol 0.0001; What am I doing wrong? Can please someone give me a hint?? Thanks! |
|
February 21, 2016, 14:32 |
|
#5 |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 10,974
Blog Entries: 45
Rep Power: 128 |
Quick answer: Sorry for the late reply, but without access to the case, there isn't much I can do.
Nonetheless, I did look into similar cases several months ago and they are all documented here: http://www.cfd-online.com/Forums/ope...mesh-used.html - please study the content of that thread! If after reading it all you still can figure it out, please provide access to your case, even if it has to be through a DropBox or Google Drive link provided via private message.
__________________
|
|
February 18, 2018, 03:42 |
|
#6 | |
Member
Ramana
Join Date: Jul 2017
Location: India
Posts: 58
Rep Power: 8 |
Quote:
I am doing case similar to the one specified above. my goal is to simulate "Incompressible Flow and heat transfer from a heated(const.Temp Tw) porous cylinder to flowing wind( temp. Tf). The computational domain appended as below Code:
cfd domain.png and I did the following steps for simulation. Solver modification Code:
Case simulation Code:
Code:
Flow and heat transfer parameters considered Re 40 Darcy no (Da ): 10e-2 porosity value: 0.993 Pr :0.71 Nusselt number through Paraview in following steps Code:
Cd and "Nu" values are not matching with the literature values.i am clueless what went wrong in my case setup i am struck i need help to proceed further. case,solver and literature is enclosed for your advise. https://www.dropbox.com/sh/16iu1o6mn...z4l_ApTia?dl=0 Last edited by svramana; March 20, 2018 at 01:09. |
||
March 7, 2018, 15:36 |
|
#7 |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 10,974
Blog Entries: 45
Rep Power: 128 |
Quick answer: I don't have enough time to look into this myself, but please check the cases and reports that are available here: http://www.tfd.chalmers.se/~hani/kurser/OS_CFD/ - I believe that there are at least a examples there on heat sources and porosity sources.
__________________
|
|
March 20, 2018, 01:27 |
Heat transfer from PorousZone
|
#8 | |
Member
Ramana
Join Date: Jul 2017
Location: India
Posts: 58
Rep Power: 8 |
Quote:
i have gone through the link ,unfortunately i did not find any clue regarding porous heat transfer related case. Flow is incompressible Re=40,Pr=0.7 Code:
My problem here is to simulate heat transfer between fluid at say 283K and porous zone at 343k. The flow is modeled as single domain and porous zone is defined here as flow resistance(Darcy -Forchheimer model) by adding addional sink term to N-S equations
Ramana |
||
March 20, 2018, 10:49 |
Porous heat transfer model
|
#9 |
Senior Member
Lasse Brams Vinther
Join Date: Oct 2015
Posts: 112
Rep Power: 10 |
Hello Ramana,
I have developed a solver that handles heat transfer between porous media and surrounding fluid in a single domain approach with solver determined Nusselts number, Reynolds number and heat transfer coefficient. The sovler is attached in the following link: https://www.dropbox.com/s/affha5r5ht...am.tar.gz?dl=0 You may be able to use some the code, the relevant part for you is in the reactor region of the solver, with EEqn and TcEqn being the fluid and porous media solvers. I would implement the same approach in your solver and assign the epsilon to be 1 for the entire domain except in the porous region, with the issue being the implementation of the external heat transfer from the outer surface to the porous absent domain. I'll attach an example when I get to my home computer but the above link should be sufficient for an approach of your own. Note its for openFOAM V4. Note I have not immensely tested it and I have some issues exist with the AoV scale vs the heat transfer coefficient unit in the solver, but I'm looking into it. |
|
March 21, 2018, 00:52 |
|
#10 | |
Member
Ramana
Join Date: Jul 2017
Location: India
Posts: 58
Rep Power: 8 |
Quote:
i wanna submit my thesis this month end ,i don't want to try new solver at this point .i have done some modifications and developed a solver for my case. The only problem being the heat transfer between fixed temperature porous zone and fluid.i will be glad if you can help me in this The solver and test case can be found here https://www.dropbox.com/s/l9nzgqjwc2...er.tar.gz?dl=0 Regards, Ramana |
||
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
mass transfer through porous media | Ahmed Khattab | OpenFOAM Running, Solving & CFD | 1 | October 16, 2015 03:44 |
Pressure drag problem in porous media with interFoam | skp | OpenFOAM Running, Solving & CFD | 8 | May 27, 2015 08:10 |
Porous media solving problem | mulfal | OpenFOAM Running, Solving & CFD | 2 | June 23, 2010 05:31 |
species mass source in porous media ? | PK | FLUENT | 0 | February 16, 2007 11:12 |
Testing the integrity of POROUS media and por jump | Azman | FLUENT | 0 | July 31, 2006 11:11 |