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

Transient Simulation in ANSYS CFX

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

Reply
 
LinkBack Thread Tools Display Modes
Old   June 10, 2014, 14:23
Exclamation Transient Simulation in ANSYS CFX
  #1
New Member
 
Join Date: May 2014
Posts: 7
Rep Power: 4
tomide is on a distinguished road
please i am trying to simulate hydrate formation in a subsea pipeline system. i have tried to model the flow to the best of my ability but i am having issues with the transient time step flow setting.

i am trying to simulate a flow in a pipe such that the pressure is kept constant and the temperature is reduced gradually. please how to set the time step such that the temperature only changes after every complete run (meaning a molecule of the gas moves from the inlet to the outlet before the temperature changes).

thank you.
tomide is offline   Reply With Quote

Old   June 10, 2014, 19:09
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 12,832
Rep Power: 100
ghorrocks is a jewel in the roughghorrocks is a jewel in the roughghorrocks is a jewel in the rough
Your simlation sounds strange. If you are doing a transient model then your temperature should follow the temperature versus time curve. If you are doing a series of separate conditions a steady state simulation is a better way of doing it rather than a transient simulation.
ghorrocks is offline   Reply With Quote

Old   June 11, 2014, 19:00
Default
  #3
New Member
 
Join Date: May 2014
Posts: 7
Rep Power: 4
tomide is on a distinguished road
thank you very much.. i ran a steady state flow instead.
tomide is offline   Reply With Quote

Old   June 16, 2014, 15:36
Default
  #4
New Member
 
Damith
Join Date: May 2013
Posts: 3
Rep Power: 5
shooter is on a distinguished road
Hi,

I'm very interested in this area. Can you please describe the simulation setup for hydrate formation. are you using UDF??

Thanks!!
shooter is offline   Reply With Quote

Old   June 16, 2014, 20:30
Default please help
  #5
New Member
 
Join Date: May 2014
Posts: 7
Rep Power: 4
tomide is on a distinguished road
i am trying to replicate a published experimental set up where hydrate was formed but i am using ansys cfx. right now i am having issues with the solver. keeps telling me error.

----------------------------------
Error in subroutine FNDVAR :
Error finding variable DENSAT_FL1
GETVAR originally called by subroutine cal_DIAM

+--------------------------------------------------------------------+
| Writing crash recovery file |
+--------------------------------------------------------------------+

Details of error:-
----------------
Error detected by routine MAKDIR
CDRNAM = cal_IPTC
CRESLT = OLD

Current Directory : /FLOW/SOLUTION/TSTEP5/CLOOP1/ZN1/VERTICES
tomide is offline   Reply With Quote

Old   June 16, 2014, 21:40
Default
  #6
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 12,832
Rep Power: 100
ghorrocks is a jewel in the roughghorrocks is a jewel in the roughghorrocks is a jewel in the rough
Have you defined all necessary material properties? I suspect you need to define some saturation conditions - maybe the density, and possibly linked to a bubble/nucleation diameter or something like that.
ghorrocks is offline   Reply With Quote

Old   June 17, 2014, 11:44
Default
  #7
New Member
 
Join Date: May 2014
Posts: 7
Rep Power: 4
tomide is on a distinguished road
@glenn yes i have specified all the material properties needed. i am trying to use the droplet phase change for one of the fluid but i noticed that if i changed the fluid to a dispersed fluid and input a mean diameter the solver doesnt give any error but the problem is that i want to use the droplet phase change cause i want a nucleation to occur in the pipeline. please help me if you can. thanks
tomide is offline   Reply With Quote

Reply

Tags
cfx 14, hydrate, time stepping, time steps

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
Transient Simulation in ANSYS CFX ylm054 CFX 7 April 25, 2016 20:05
Fluid structure interaction jnattia Main CFD Forum 25 May 21, 2015 09:16
Resume Transient simulation HMR CFX 1 June 28, 2011 21:13
ANSYS to acquire CFX Fred FLUENT 0 February 18, 2003 22:04
ANSYS to acquire CFX Fred CD-adapco 0 February 18, 2003 22:03


All times are GMT -4. The time now is 17:25.