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

How to create a tank which partially filled with fluid?

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

Like Tree2Likes

Reply
 
LinkBack Thread Tools Display Modes
Old   February 2, 2013, 12:39
Default
  #21
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,097
Rep Power: 16
RodriguezFatz will become famous soon enough
At the inlet, did you set the volume fraction of feed to "1" and all others to 0?
Otherwise you will pipe phase 1 as default in, which might be different to feed...
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   February 3, 2013, 05:12
Default
  #22
Senior Member
 
SSL
Join Date: Oct 2012
Posts: 227
Rep Power: 5
msaeedsadeghi is on a distinguished road
As I said before, you can use patch to set initial volume fraction of each phase. or use UDF.
msaeedsadeghi is offline   Reply With Quote

Old   February 3, 2013, 08:52
Default
  #23
New Member
 
Join Date: Jan 2013
Posts: 21
Rep Power: 4
ORYON is on a distinguished road
I did set the volume fraction of feed by 1, but same problem occur too.
ORYON is offline   Reply With Quote

Old   February 4, 2013, 05:54
Default
  #24
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,097
Rep Power: 16
RodriguezFatz will become famous soon enough
Quote:
Originally Posted by msaeedsadeghi View Post
As I said before, you can use patch to set initial volume fraction of each phase. or use UDF.
I don't see how that helps here. He does not seem to have a problem with initial values, but with his settings. The pictures at t=0 look like they should...

Quote:
Originally Posted by ORYON View Post
I did set the volume fraction of feed by 1, but same problem occur too.
Some setting is wrong. Which multiphase model do you use? Please post values / settings you changed in Fluent?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   February 4, 2013, 10:13
Default
  #25
New Member
 
Join Date: Jan 2013
Posts: 21
Rep Power: 4
ORYON is on a distinguished road
here is the setting part 1
Attached Images
File Type: jpg setting1.jpg (58.1 KB, 11 views)
File Type: jpg setting2-Pressure outlet.jpg (64.8 KB, 13 views)
File Type: jpg setting2-velocityinlet.jpg (62.4 KB, 12 views)
File Type: jpg setting3-solution method.jpg (57.5 KB, 10 views)
File Type: jpg setting4-solution control.jpg (16.8 KB, 9 views)
ORYON is offline   Reply With Quote

Old   February 4, 2013, 10:15
Default
  #26
New Member
 
Join Date: Jan 2013
Posts: 21
Rep Power: 4
ORYON is on a distinguished road
here is the setting part2
Thanks
Attached Images
File Type: jpg setting5-solution initialization.jpg (50.5 KB, 8 views)
File Type: jpg setting6-patch.jpg (43.4 KB, 11 views)
File Type: jpg Setting7-run calculation.jpg (54.6 KB, 13 views)
ORYON is offline   Reply With Quote

Old   February 4, 2013, 10:37
Default
  #27
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,097
Rep Power: 16
RodriguezFatz will become famous soon enough
Hi,

1)
Are you sure about your time step size?
With 20m/s at the velocity inlet and dt=60s the fluid will move 1200m each timestep! I am afraid that these settings can't converge... Can you show your residual history?

2)
Why don't you set the velocity normal to the surface at the velocity inet, but instead you use a direction vector?

EDIT: I just realized that you did some curious things in your calculation settings... Do you know, what all these values mean? Timestep, Number of Iterations, ...
ORYON likes this.
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   February 5, 2013, 19:24
Talking
  #28
New Member
 
Kolela Lela
Join Date: Aug 2012
Posts: 9
Rep Power: 4
Koromajor is on a distinguished road
CFD codes are not like Word, Excel or Powerpoint that you can learn to use on your own and it will be fine. When it comes to CFD, you really need to understand what you are doing (your model, fluid dynamics, numerical methods, etc...). And obviously you are lacking a bit of background.
Koromajor is offline   Reply With Quote

Old   February 6, 2013, 04:53
Default
  #29
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,097
Rep Power: 16
RodriguezFatz will become famous soon enough
Quote:
Originally Posted by Koromajor View Post
CFD codes are not like Word, Excel or Powerpoint that you can learn to use on your own and it will be fine.
Yes you can!
ghost82 likes this.
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   February 6, 2013, 06:52
Default
  #30
New Member
 
Join Date: Jan 2013
Posts: 21
Rep Power: 4
ORYON is on a distinguished road
This is the first time I'm contact with CFd, I still fresh with it and still got a big room for improvement. I'll spend more to time on it.
Btw, in order to maintain filling rate at 20m/s, what time step and interaction I should use?
ORYON is offline   Reply With Quote

Old   February 6, 2013, 07:52
Default
  #31
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,097
Rep Power: 16
RodriguezFatz will become famous soon enough
I would: Estimate how far I want to travel the feed during one timestep. Let's say 0.5m.
Now, your time step has to be 0.5m / 20m/s = 0.025s.
Then, you set the number of iterations per timestep to 1. This can't work. Since the set of equations is nonlinear, you have to iterate each time step for convergence. I would set the number of iterations to 25 and see how the residuals behave.

You could do 10 time steps with these settings and post a picture of the residuals here. Good luck!
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   February 6, 2013, 11:32
Default
  #32
New Member
 
Join Date: Jan 2013
Posts: 21
Rep Power: 4
ORYON is on a distinguished road
here is the residual result by using time step of 0.05, Number of timestep=10, and interations/time step=25.
Attached Images
File Type: jpg TS0.05.jpg (43.1 KB, 15 views)
ORYON is offline   Reply With Quote

Old   February 6, 2013, 11:35
Default
  #33
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,097
Rep Power: 16
RodriguezFatz will become famous soon enough
This looks bad...
How did you initialize your domain?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   February 6, 2013, 11:51
Default
  #34
New Member
 
Join Date: Jan 2013
Posts: 21
Rep Power: 4
ORYON is on a distinguished road
How you differentiate between good and bad residual from the graph?
Sorry, I can't understand your question.. Can u further explain to me?
ORYON is offline   Reply With Quote

Old   February 6, 2013, 11:55
Default
  #35
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,097
Rep Power: 16
RodriguezFatz will become famous soon enough
It looks like some of the residuals nearly don't change at all during these iterations. This should not happen.

What do you use for initialization? There is a button "initialize" at "Solution->Solution Initialization->" Do you use "hybrid"? I would go for "standard" and set every text box to zero. Then, hit "Initialize".

Can you post a picture of your mesh?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   February 6, 2013, 12:30
Default
  #36
New Member
 
Join Date: Jan 2013
Posts: 21
Rep Power: 4
ORYON is on a distinguished road
i set all the value as 0 except the temperature=113.
Attached Images
File Type: jpg img1.jpg (95.5 KB, 13 views)
File Type: jpg img2.jpg (92.6 KB, 11 views)
File Type: jpg img3.jpg (63.5 KB, 11 views)
ORYON is offline   Reply With Quote

Old   February 6, 2013, 14:35
Default
  #37
New Member
 
Kolela Lela
Join Date: Aug 2012
Posts: 9
Rep Power: 4
Koromajor is on a distinguished road
Quote:
Originally Posted by RodriguezFatz View Post
Yes you can!
Yes you can, except that you'll spend your time on forums to find clues. When it comes to complex cases, you'll be completely lost and won't be able to tell if your results make sense especially if you do not have validation data.

I still believe that to get the most out of CFD, you need to study it. Everyone can tick boxes but understanding what you are doing is different story.
Koromajor is offline   Reply With Quote

Old   February 6, 2013, 14:39
Default
  #38
New Member
 
Kolela Lela
Join Date: Aug 2012
Posts: 9
Rep Power: 4
Koromajor is on a distinguished road
Quote:
Originally Posted by ORYON View Post
i set all the value as 0 except the temperature=113.
Send me your case file and I'll tell you what you are doing wrong
Koromajor is offline   Reply With Quote

Old   February 7, 2013, 05:13
Default
  #39
New Member
 
Join Date: Jan 2013
Posts: 21
Rep Power: 4
ORYON is on a distinguished road
Quote:
Originally Posted by Koromajor View Post
Send me your case file and I'll tell you what you are doing wrong
Can you give me your personal email?
ORYON is offline   Reply With Quote

Old   February 11, 2013, 03:55
Default
  #40
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,097
Rep Power: 16
RodriguezFatz will become famous soon enough
Quote:
Originally Posted by ORYON View Post
Can you give me your personal email?
Now, what was the problem?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Reply

Tags
multiphase mixture, partially filled tank, stratification

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
partially filled tank, evaporation at liq-vap. prasanth FLUENT 5 July 24, 2013 17:12
How to create multiple solid fluid domain? Mishar FLUENT 0 January 25, 2005 04:05
Meshing a Sphere Ajay FLUENT 9 March 29, 2004 09:14
injection of fuel into tank filled with fuel mujahid FLUENT 1 February 19, 2004 07:36
Terrible Mistake In Fluid Dynamics History Abhi Main CFD Forum 12 July 8, 2002 09:11


All times are GMT -4. The time now is 21:03.