CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

Melting and Solidification enthalpyporosity technique

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 11, 2007, 11:38
Default Hi all, I am trying to crea
  #1
New Member
 
Zaki Saldi
Join Date: Mar 2009
Posts: 18
Rep Power: 8
zakifoam is on a distinguished road
Hi all,

I am trying to create an openfoam module to simulate phase changes (i.e. melting & solidification) using enthalpy-porosity technique (following Brent et al, 1988), that allows the use of fixed mesh. Basically, the module originates from icoFoam, added with energy equation (in terms of temperature), buoyancy term in momentum equation, and extra source terms in both momentum & energy equation to account for the phase change.

My temperature equation looks like the following:

volScalarField dDHdt = fvc::ddt(DH);

{
fvScalarMatrix TEqn
(
fvm::ddt(T)
+ fvm::div(phi, T)
- fvm::laplacian(DT, T)
==
dDHdt/Cp
);

TEqn.solve();
}

where DH is the latent heat content of the cell, evaluated based on cell temperature. Assuming isothermal phase change, DH is zero if cell temperature is lower than melting point, or equals to latent heat of fusion if cell temperature is higher than melting point.

After running the melting simulation, I found out that the energy source term dDHdt/Cp is always zero throughout the computation. This makes me think that this term is still incorrectly handled in T equation above. I suppose, instead of explicitly specifying dDHdt, I should've put the time derivative of DH on the l.h.s implicitly along with T (referring to relevant thread here). But in this way, I still couldn't get any effect from the source term.

Has anyone ever tried to work on this problem? Any share of ideas & comments is welcome.

Thanks

zaki
zakifoam is offline   Reply With Quote

Old   July 11, 2007, 15:19
Default Hi Zaki, i assume you updat
  #2
Senior Member
 
Markus Hartinger
Join Date: Mar 2009
Posts: 102
Rep Power: 8
hartinger is on a distinguished road
Hi Zaki,

i assume you update DH before using fvc::ddt(DH), right? That happend to me once.

regards
markus
hartinger is offline   Reply With Quote

Old   July 11, 2007, 17:29
Default Hi Markus, Thanks for your
  #3
New Member
 
Zaki Saldi
Join Date: Mar 2009
Posts: 18
Rep Power: 8
zakifoam is on a distinguished road
Hi Markus,

Thanks for your response. Yes, I updated DH before using fvc::ddt(DH). This is carried out along with update of A for source term A*U in momentum equation that will force velocity to zero in solid cells.

Any suggestion for remedy?

regards,

zaki
zakifoam is offline   Reply With Quote

Old   July 12, 2007, 10:18
Default not really. just the usual, tr
  #4
Senior Member
 
Markus Hartinger
Join Date: Mar 2009
Posts: 102
Rep Power: 8
hartinger is on a distinguished road
not really. just the usual, trace back the calculation of DH and check what makes that zero or constant...
hartinger 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
How can I make the solid PCM to sink to the bottom as it melts? Lim FLUENT 6 December 22, 2014 03:29
melting and solidification mehdi Main CFD Forum 8 May 6, 2011 14:07
Solidification and melting with CFX Don CFX 0 December 1, 2008 12:30
Melting/solidification Andrea FLUENT 0 February 27, 2007 12:23
vof + solidification melting James FLUENT 0 November 29, 2002 11:56


All times are GMT -4. The time now is 04:21.