CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens > STAR-CCM+

VOF bubble drift velocity

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 27, 2016, 19:35
Default VOF bubble drift velocity
  #1
New Member
 
Nicolas
Join Date: Jun 2009
Posts: 19
Rep Power: 16
niriosrat is on a distinguished road
The main purpose of the current simulations is to estimate the velocity at which a bubble of gas (known as Benjamin bubble) propagates along a liquid phase in a horizontal pipe considering a slug flow pattern. This velocity is known as the drift velocity and it is of interest to understand and predict its behavior under the variation of several parameters such as viscosity, density, surface tension (related with the Froud and viscosity dimensionless numbers) of the substance considered or diameter of the pipeline.


The predicted bubble drift velocity aggress with the experiments and literature data for water (0.001 Pa s) and oil viscosities up to 0.15 Pa s with an error up to 5%. When the viscosity increases at 0.3 Pa s the error increases around 30%. We are using STAR-CCM+ with VOF. Any suggestion on how to improve the results? We tried modified the sharpening factor, the angular factor and the Interface Momentum Dissipation (IMD), but with no luck. Any recommendation?
niriosrat is offline   Reply With Quote

Old   October 18, 2016, 09:01
Default
  #2
Member
 
Nils
Join Date: Nov 2015
Posts: 59
Rep Power: 10
Deranda is on a distinguished road
Hi

maybe you should work on your mesh and time-step.
The VoF Model needs a finde mesh at the interface of your 2 face flow.
And to avoid inadvertently surface convection, such as u have no sharp interface.
Another adjustment is to set the integral order to 2nd order in the solver settings
Deranda is offline   Reply With Quote

Reply

Tags
high viscosity, two-phase slug flow, vof

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
VOF Problem, Bubble must not rise CneSpaulding STAR-CCM+ 1 July 3, 2014 13:41
Coupled VOF and Multiphase Segregated Flow for a gas bubble problem?? EnronZhang STAR-CCM+ 1 December 19, 2013 08:41
Water subcooled boiling Attesz CFX 7 January 5, 2013 03:32
velocity of air Robert Main CFD Forum 4 January 22, 2007 18:42
VOF, liquid Velocity CFD MAN FLUENT 2 November 24, 2002 01:19


All times are GMT -4. The time now is 22:38.