# Difficult to model using vof

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 July 5, 2013, 14:41 Difficult to model using vof #1 New Member   elahe65 Join Date: Jul 2013 Posts: 1 Rep Power: 0 I will be very grateful if you could answer my question, I want to a two-phase model using vof, including water and air. Do I need to define the two-volume in gambit or in Fluent need to do this? For example, 0.15 m air and 0.2 m water in the canals, where should I enter these values? how about the volume fraction According to these values?

July 5, 2013, 18:49
#2
Senior Member

Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 124
Rep Power: 4
Quote:
 Originally Posted by elahe65 I will be very grateful if you could answer my question, I want to a two-phase model using vof, including water and air. Do I need to define the two-volume in gambit or in Fluent need to do this? For example, 0.15 m air and 0.2 m water in the canals, where should I enter these values? how about the volume fraction According to these values?
You dont need to define two volumes in gambit.
after initialization in fluent you must patch second phase.
step by step: 1- define air as primary phase 2- define water as secondary phase 3- initialize 4- adapt/region/define range of x,y,z for patch secondary phase/mark 5- solve/initialize/patch(phase:water/variable:volume fraction/register to patch:marked zone in step 4/ click patch) 6- iterate

Jamal

 July 6, 2013, 00:49 #3 Senior Member   Saeed Join Date: Jan 2013 Posts: 177 Rep Power: 4 I am doing this subject but when i am using open channel flow boundary and patch the water, after a few iterate, the water height is good but after more iteration water is going up and Occupies whole the model. I think the problem is due to initialize option. Every time i choose compute from all zones, this problem occurs and Every time i enter x velocity, just a little water enter from inlet and flowing to downstream( there is no flow, back of that water) please help Last edited by flow_CH; July 17, 2013 at 06:57.

July 6, 2013, 03:38
#4
Senior Member

Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 124
Rep Power: 4
Quote:
 Originally Posted by flow_CH I am doing this subject but when i am using open channel flow boundary and patch the water, after a few iterate, the water height is good but after more iteration water is going up and Occupies whole the model. I think the problem is due to initialize option. Every time i choose compute from all zones, this problem occurs and Every time i enter x velocity, just a little water enter from inlet and flowing to downstream( there is no flow, back of that water) see attached image please help
you must wait until solution be converged. this way(your method) is wrong to judge.

 July 6, 2013, 05:30 #5 Senior Member   Saeed Join Date: Jan 2013 Posts: 177 Rep Power: 4 which case? the first that water Occupies whole the model or about two images?

 March 14, 2014, 12:36 #6 Member   Join Date: Jan 2014 Location: Turkey Posts: 36 Rep Power: 3 Hello dear friends, I try to simulate melting process using VOF model. Pcm is solid phase initialy. Upper part of the solid there is air. They do not mix eachother. Natural convection is active. My primary phase air, secondary phase is pcm (phase change material). I have some questions to be sure about my model. First, I do not define interface between air and pcm. Mean, There are 3 cell zone: air, fin ,pcm but I do not create name selection for this interface in meshing. Is it ok? Initial condition of Wholesystem temperature is 293K, but air temp is 300K. how to set air temp ? For cell zone condition, all cell zone (air, pcm, fin ) show mixture. Also for example, if I change pcm to phase2, all of cell zone change to phase 2 Only for secondary phase (pcm), I patch within fluent by adapt-region-mark then patch. Ok? Value of volume fraction should be 1 or 0 while patching?? I am confused. Initialy pcm is solid. For initial values phase-2 volume fraction is 0. Ok? I did some iteration for a short time to check model. For results, in graphics-countors I can not see total temperature for phase 1 and 2 only entalphy values I see for phase1 and 2. Also countors of solidification/melting it shows only mixture. Mixture show what? Any interaction should I use like surface tension etc. Thanks for your help.

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post A8anato_psofimi FLUENT 2 November 10, 2009 15:42 wanghong FLUENT 3 March 13, 2006 10:57 yan FLUENT 3 December 16, 2005 02:17 Yongguang Cheng FLUENT 0 September 19, 2003 07:39

All times are GMT -4. The time now is 08:46.

 Contact Us - CFD Online - Top