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

mixture mass continuity v.s. volumetric mixture continuity in pressure equation

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 9, 2011, 09:14
Default mixture mass continuity v.s. volumetric mixture continuity in pressure equation
  #1
Member
 
Kai
Join Date: May 2010
Location: Shanghai
Posts: 61
Blog Entries: 1
Rep Power: 15
kaifu is on a distinguished road
Hi Foamers,

In two phase flow solves (like bubbleFoam and twoPhaseEulerFoam), the pressure is constructed by linearly combination of phase continuity eqn. (see page 112, Rusche phd thesis). There are two kinds of combination: mixture mass continuity and volumetric mixture continuity. In adiabatic case (like water and air), the volumetric mixture continuity is adopted because "the lighter phase is poorly conserved when the mixture mass continuity equation is used". However if we consider the subcooled nucleate boiling, since there is a phase change, we have to use the mixture mass continuity equation instead. And then the solver doesnt work. I have my own developed solver for adiabatic case (which starts from solver twoPhaseEulerFoam) which adopts the volumetric mixture continuity eqn ant it works well. However if I only change the volumetric mixture continuity eqn into mixture mass continuity eqn and nothing else is changed including the test case(2D adiabatic upward bubbly flow, refer to http://www.cfd-online.com/Forums/ope...ated-wall.html), the velocity of both phase diverged. I can see the max velocity is initially generated in vicinity of inlet. It moves from inlet to outlet, and keeps increasing during simulation. And that is a big problem. Anybody could give me suggestions or hint? I am quite sure there is a way to handle this problem since nucleate boiling model is already implemented in fluent and star-cd... Thanks very much.

// Kai
kaifu is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
IcoFoam parallel woes msrinath80 OpenFOAM Running, Solving & CFD 9 July 22, 2007 03:58
Could anybody help me see this error and give help liugx212 OpenFOAM Running, Solving & CFD 3 January 4, 2006 19:07
continuity equation for the mixture mateus Main CFD Forum 0 May 2, 2003 04:59
Gas pressure question Dan Moskal Main CFD Forum 0 October 24, 2002 23:02
non linear continuity equation S.Venkat Main CFD Forum 0 May 30, 2000 08:43


All times are GMT -4. The time now is 00:21.