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

Complex multiphase melting problem

Register Blogs Community New Posts Updated Threads Search

Like Tree9Likes
  • 1 Post By leff
  • 1 Post By Redpoko
  • 1 Post By leff
  • 1 Post By leff
  • 1 Post By ghorrocks
  • 1 Post By Redpoko
  • 1 Post By ghorrocks
  • 2 Post By baserinia

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 22, 2011, 10:41
Angry Complex multiphase melting problem
  #1
New Member
 
Join Date: Apr 2011
Posts: 8
Rep Power: 15
leff is on a distinguished road
Hi,

The problem i'm dealing with involves the pouring of molten steel into enclosure which contains an aluminum block.
I would like to simulate the melt process of the aluminum block by the molten steel. In such case, it becomes a 3 liquids problem (molten steel, molten aluminum and air).
Is ANSYS CFX capable of performing such calculations?

I would appreciate your help a lot!!

Thanks
shahid nadeem likes this.
leff is offline   Reply With Quote

Old   May 22, 2011, 20:54
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,854
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
Yes, but you will have to do a lot of development in melting models. This sort of stuff is not built in. CFX support might have some examples of melting to get you started, but expect to do a lot of model development before it is accurate.
ghorrocks is offline   Reply With Quote

Old   May 23, 2011, 05:20
Default
  #3
New Member
 
Y.Z
Join Date: Mar 2009
Location: Stuttgart
Posts: 8
Rep Power: 17
Redpoko is on a distinguished road
Send a message via MSN to Redpoko
Quote:
Originally Posted by ghorrocks View Post
Yes, but you will have to do a lot of development in melting models. This sort of stuff is not built in. CFX support might have some examples of melting to get you started, but expect to do a lot of model development before it is accurate.
hi ghorrocks, How good could CFX deal with another relative simple case -- pouring of molten steel into a pool and part of the steel are solidified on the bottom of the pool?
shahid nadeem likes this.
Redpoko is offline   Reply With Quote

Old   May 23, 2011, 11:12
Default
  #4
New Member
 
Join Date: Apr 2011
Posts: 8
Rep Power: 15
leff is on a distinguished road
Hi Redpoko,

The case you presented seems to be much simpler than mine. Would you like to model the pouring process also or is it enough to start from a filled pool?
For the first case, it would be a 2-phase problem (mine is 3). Try google for commercial casting problems. Several codes such as FLOW3D, MAGMA, etc. are designed especially for casting problem.
In the second case, it would be a simple 1 phase problem, which I don't think is an issue.
shahid nadeem likes this.
leff is offline   Reply With Quote

Old   May 23, 2011, 11:21
Default
  #5
New Member
 
Join Date: Apr 2011
Posts: 8
Rep Power: 15
leff is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
Yes, but you will have to do a lot of development in melting models. This sort of stuff is not built in. CFX support might have some examples of melting to get you started, but expect to do a lot of model development before it is accurate.

ghorrocks! Thanks for the reply!
Could you please extend your reply on which models I would have to develop(in CFX programing language, right?) ?

As a first step I was thinking to model to the molten steel and air as liquids only. The Aluminum would be a solid, and I'm interested in obtaining the heating of it, without becoming liquid nor absorbing latent heat.
Would it still require development of melting models?

Thanks again!
shahid nadeem likes this.
leff is offline   Reply With Quote

Old   May 23, 2011, 19:57
Default
  #6
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,854
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
Quote:
As a first step I was thinking to model to the molten steel and air as liquids only. The Aluminum would be a solid, and I'm interested in obtaining the heating of it, without becoming liquid nor absorbing latent heat.
That is a much simpler model as there is no phase change. This can be done with the models already in CFX I suspect.

The tricky bit will be the phase change of the aluminium melting. That will require development.
shahid nadeem likes this.
ghorrocks is offline   Reply With Quote

Old   May 24, 2011, 16:27
Default
  #7
New Member
 
Y.Z
Join Date: Mar 2009
Location: Stuttgart
Posts: 8
Rep Power: 17
Redpoko is on a distinguished road
Send a message via MSN to Redpoko
Quote:
Originally Posted by leff View Post
Hi Redpoko,

The case you presented seems to be much simpler than mine. Would you like to model the pouring process also or is it enough to start from a filled pool?
For the first case, it would be a 2-phase problem (mine is 3). Try google for commercial casting problems. Several codes such as FLOW3D, MAGMA, etc. are designed especially for casting problem.
In the second case, it would be a simple 1 phase problem, which I don't think is an issue.
hi Leff, my case is to simulate the solidification process from a filled pool. sounds not that difficult, right? Actually I've even simplified the model to such a simplest 2D case that the top side is adiabatic BC, and the bottom side is solid-liquid interface, which needs to be set as isothermal BC (mushy zone ignored). Inside pool is the liquid material. SST k-w has been used here.

However, during the iteration the energy imbalance is always 100%. Finally simulation is terminated by fatal errors after 3000 steps. I am still working on it to figure out what's wrong with it. If you have any ideas, i am very glad to be informed.
shahid nadeem likes this.
Redpoko is offline   Reply With Quote

Old   May 24, 2011, 20:27
Default
  #8
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,854
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
Quote:
my case is to simulate the solidification process from a filled pool. sounds not that difficult, right?
Anything which involves phase change is complex and CFX does not have much built in for solidification. If there is no phase change then CFX should be able to handle it far better. If you are doing casting modelling I would consider casting software, such as the ones leff quoted, and there are many others (thermcast etc)
shahid nadeem likes this.
ghorrocks is offline   Reply With Quote

Old   May 28, 2011, 22:03
Default
  #9
New Member
 
A.R. Baserinia
Join Date: Jan 2010
Location: Canada
Posts: 24
Rep Power: 16
baserinia is on a distinguished road
Quote:
Originally Posted by Redpoko View Post
hi Leff, my case is to simulate the solidification process from a filled pool. sounds not that difficult, right?
I have some experience with casting/solidification modeling in CFX. I agree with ghorrokcs; CFX has no built-in feature for solidification. However, you can model your problem with a little bit of work.

To model the evolution of latent heat, you have two options:
1- Define two different materials for the liquid and solid phases of aluminum. Make sure that the difference between the reference enthalpies of solid and liquid phases at the melting temperature is equal to latent heat of fusion.
2- Take the derivative of the enthalpy curve of your material to obtain the c_p curve, which must have a peak at the melting temperature. Use it as the specific heat of your material.

To model the solid phase, you have to add a dominant source term in momentum equation to overwrite the CFX calculated velocity field. You can also use a high value for the viscosity of the solid phase.
leff and shahid nadeem like this.
baserinia is offline   Reply With Quote

Old   March 17, 2014, 04:04
Smile AL and Si casting
  #10
Member
 
Nazim
Join Date: Oct 2013
Posts: 93
Rep Power: 13
shahid nadeem is on a distinguished road
My Dear Friends i want to simulate a problem where in have to casting for al and si liquids in a single jar with rotating. i want to find the volume of aluminium and silica after getting solidified. silica is 15% and al is 85%.
Please help me
shahid nadeem is offline   Reply With Quote

Old   March 17, 2014, 04:44
Default
  #11
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,854
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
Sounds like you need casting simulation software, not a general CFD code like CFX. CFX does not have models to do what you want to do.
ghorrocks is offline   Reply With Quote

Old   March 18, 2014, 01:35
Default
  #12
Member
 
Nazim
Join Date: Oct 2013
Posts: 93
Rep Power: 13
shahid nadeem is on a distinguished road
no dudue i feel we can do it in FLUENT but exactly how i dont know
shahid nadeem is offline   Reply With Quote

Old   March 18, 2014, 17:46
Default
  #13
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,854
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
You can do it in CFX as well but you are going to have the develop a lot of models to get it to work. If you are not experienced in CFD development then I recommend you use software specifically written to model casting, such as http://www.transvalor.com/en/cmspages/thercast.6.html or https://www.esi-group.com/software-s...turing/casting
ghorrocks is offline   Reply With Quote

Reply

Tags
flow, free surface, melt, vof


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
Gambit - Mesh Problem for a complex 3D geometry Nelson FLUENT 3 May 28, 2012 07:57
melting problem bk Siemens 3 November 8, 2005 17:15
Problem of B.C. in Eulerian multiphase model Derek Jing FLUENT 0 May 12, 2002 12:52
MELTING PROBLEM Przemek FLUENT 1 April 17, 2002 04:22
CF4 - need advice on setting up multiphase problem Brett Towler CFX 2 August 18, 2000 17:38


All times are GMT -4. The time now is 22:00.