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

Slurry flow question

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

Like Tree1Likes
  • 1 Post By ghorrocks

Reply
 
LinkBack Thread Tools Display Modes
Old   March 19, 2014, 02:42
Default Slurry flow question
  #1
New Member
 
Ivan
Join Date: Mar 2014
Posts: 11
Rep Power: 3
iorozco86 is on a distinguished road
Hi guys, im actually doing solid - liquid simulations and in slurry transport the solid phase goes to the bottom of the channel and form a "solid bed", in transient analysis this bed propagates trough the pipe in function of time and im trying to calculate its velocity, obviously I could do this plotting the concentration at different times and positions, but im trying to do an expression to calculate its velocity, so what I did is to do a line that cross from inlet to out let an positioning it inside the bed, and the parameter that its going to be changing in time and position is the volumetric fraction of solids, ANY IDEA OF HOW I CAN TRACK THIS VF THROUGH THE LINE AND THEN PUT IT IN FUCTION OF TIME AND DISTANCE?

thanks
iorozco86 is offline   Reply With Quote

Old   March 19, 2014, 06:55
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,931
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
If your slurry model is done by particle tracking then just use the particle tracks.

If your slurry model is done by a eularian model (I presume with an inhomogenous model) then on the line you drew have a look at the velocity of the solids volume fraction.
iorozco86 likes this.
ghorrocks is offline   Reply With Quote

Old   March 19, 2014, 12:07
Default thanks for replie
  #3
New Member
 
Ivan
Join Date: Mar 2014
Posts: 11
Rep Power: 3
iorozco86 is on a distinguished road
ill try that, but the line is inside the solid bed, but this solid bed is static, it propagates in the sense that it doesn't move but a portion of new static bed is added, so I really don't know the velocity will help, that's what I want to track it by the concentration of solids, thanks =)
iorozco86 is offline   Reply With Quote

Old   March 19, 2014, 17:39
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,931
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Can you show an image of what you are modelling and the parameter you wish to track?
ghorrocks is offline   Reply With Quote

Old   March 28, 2014, 18:59
Default hi for your reply
  #5
New Member
 
Ivan
Join Date: Mar 2014
Posts: 11
Rep Power: 3
iorozco86 is on a distinguished road
i want to track the velocity of propagation of the solid bed that is covering part of the anular space. As you see in the picture. it goes from the inlet to the out let. i cant track it by the solid velocity cuz in this bed is 0 (red zone occupied in the anular space). So what i imagine i can do is to track how some parts of the pipe have 1 of Volume Fraction. So i imagine i can do a line with points, and track how much of this points have 1 of VF, then compare with time how much points more does it have 1 VF and calculate the velocity, but im not so sure how to do this.
iorozco86 is offline   Reply With Quote

Old   March 29, 2014, 06:00
Default
  #6
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,931
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
The image did not get posted.

If the solids volume fraction moves as lumps then here is some ideas:
* Draw a planar object at the central plane. On this plane draw volume fraction. You should see the lumps travel along this plane.
* Draw an isosurface of voluem fraction =0.5 or some other intermediate value. Then you can view the lumps travelling along.
* If you want to be more objective then place a plane across the flow (Or use the inlet and/or outlet) and do a massflow integral of volume fraction over the plane. That will give the mass of solids passing through the plane in that time step. Export this as a csv file and you can integrate it in excel/matlab/python/whatever to get the mass flow over time.
ghorrocks is offline   Reply With Quote

Old   March 29, 2014, 14:35
Default thanks again bro!
  #7
New Member
 
Ivan
Join Date: Mar 2014
Posts: 11
Rep Power: 3
iorozco86 is on a distinguished road
here is the image! good ideas ill try that!, the problema for the mass flow trough a plane is that, when the solid bed reach the plane, it doesnt move any more, so it doesnt flow =s.
Attached Images
File Type: png Sin título.png (59.7 KB, 10 views)
iorozco86 is offline   Reply With Quote

Old   March 30, 2014, 05:34
Default
  #8
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,931
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Is this real? If yes then the CFD is accurately predicting what happens. If this does not happen then your model is inaccurate and have a look at the FAQs for some tips on that. In this case I but the key issue is the solid drag model and packing model. These are complex things to get right.

Which reminds me - what drag model and packing model are you using? Even better, please post the CCL of your simulation.
ghorrocks is offline   Reply With Quote

Reply

Tags
cel, cfx, function, multi phase

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
Simple question about pipe flow husker Main CFD Forum 1 February 29, 2012 04:40
Yes-No question about poiseuille flow amin144 OpenFOAM 8 January 10, 2012 07:10
VERY SIMPLE question from people works on unsteady flow amin144 Main CFD Forum 9 December 9, 2011 05:18
Question about Couette Flow Tiger Main CFD Forum 1 March 24, 2006 00:16
Question about flow in ducted fan in another duct Jane FLUENT 0 June 21, 2004 13:57


All times are GMT -4. The time now is 10:42.