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

gas-liquid 2 phase flow in microchannels using VoF

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 19, 2011, 04:53
Question gas-liquid 2 phase flow in microchannels using VoF
  #1
New Member
 
Join Date: Nov 2010
Posts: 12
Rep Power: 6
LyngHoo is on a distinguished road
Hi, everyone. I'm trying to use VoF model to simulate gas-liquid two-phase
flow in microchannels. firstly, I started with a 2-D simulation in a 500 micron
wide T-shape microchannel. Details are listed below,
# Segregated time dependent unsteady solver
# PRESTO! for pressure interpolation
# PISO for pressure-velocity coupling
# Second-Order Up-Wind scheme for momentum equation
# Geometry Reconstruction scheme for interface interpolation
# Implicit body force for body force formulation
# Courant Number 0.25 for volume fraction calculation
# d = 0.5 mm, gas and liquid inlet length is 3*d, respectively. Main channel is
15*d in length.
# U_L= U_G = 0.02 m/s
# surface tension of water is 0.072 N/m
# Contact angle 0
# Velocity inlets
# Pressure outlet ( 0 gauge pressure )
# No-slip wall condition

after that I tryed to reproduct one work of Qian et. al.( chem. eng. sci. 2006
) by simulating a ─┴───── shaped microchannel in 2-D domain. the channel
width, d, is aslo 0.5mm. And keep all the settings above unchanged, and
these seetings are uniform as Qian reported in his paper.
I can get the Taylor bubble flow pattern if the liquid goes in horizontally from
the left inlet, and gas geos into the channel vertically. But if I exchange the
two fluids, I got stratified flow pattern instead of Taylor flow. and refining grid
is not working. However, increasing surface tension by a factor of 1.5 works.
But according to Qian et. al.( chem. eng. sci. 2006 ), they got Taylor flow in
such ─┴───── shaped channel.
and I tried a Y-shaped channel with same configurations, and got stratified
flow. But when I incresing the surface tension of water (0.072 N/m) by a
factor of 1.2, Taylor flow can be obtained. So I wander why a lower serface
tension can get a correct flow pattern. In many literature, they can get
correct flow pattern with surface tension as low as approximately 0.02 N/m.
How could they done that. Did I do something wrong?

Last edited by LyngHoo; July 19, 2011 at 07:59.
LyngHoo is offline   Reply With Quote

Old   November 13, 2012, 20:01
Default reply to Lynghoo
  #2
New Member
 
Justin
Join Date: Nov 2012
Posts: 1
Rep Power: 0
zmh021810 is on a distinguished road
Well, I also saw that paper and recently I am going to do the same thing.

Well do you have the exact same setting comparing with Qian's paper? Because I know that the surface tension is very important to control the slung flow, you can only have slung flow when the surface tension is large enough.

Well, do you finish your simulaiton yet? I want to talk with you about this

field.for example, Qian's paper said both the inlets are fixed by uniform velocity distribution, do you also did it in the same way?

another problem is: do you use patch option in fluent?

Best wishes for you!

Justin
zmh021810 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
Convergence criteria of Solid liquid two phase flow. trystwithgaurav FLUENT 0 August 17, 2009 17:48
2 phase flow liquid flow solid particles sachin OpenFOAM Running, Solving & CFD 0 August 28, 2008 16:51
gas liquid flow Yuqing Feng CFX 0 May 4, 2004 21:26
Transient natural gas flow description Leila FLUENT 0 November 29, 2003 17:06
liquid and gas flow faouzi FLUENT 3 July 10, 2001 09:52


All times are GMT -4. The time now is 09:00.