CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

reverse flow?

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

LinkBack Thread Tools Display Modes
Old   March 9, 2007, 13:57
Default reverse flow?
Posts: n/a
Hi, we have a system consisting on air and water inlets into a t-junction. The resultant biphasic mixture flows in a pipe into a cubic cavity with a pressure outlet b.c at the opposite face. Diameter of pipes is of the order of mm while side of the cube is 20cm. We're using mixture and k-epsilon models. With turbulence intensity around 1% and hydraulic diameter 1mm we've got convergence problems and error message about reverse flow at the outlet. Do you have any idea about where does the problem come from? Thank you.

  Reply With Quote

Old   March 9, 2007, 14:41
Default Re: reverse flow?
Posts: n/a
It is not an error. Reverse flow at the out may be due to high back pressure.
  Reply With Quote

Old   March 9, 2007, 18:11
Default Re: reverse flow?
Posts: n/a
I'm not sure I understand your geometry, but the backflow and the convergence issues may be the same issue. In my experience, the backflow is usually due to the boundary being too close (to the region of interest) and the backflow causes convergence issues. I would try moving the outflow further downstream.

  Reply With Quote

Old   March 11, 2007, 17:10
Default Re: reverse flow?
Posts: n/a
I would try to reduce turbulence intesnity. And wait for some time to converge. If not , I would again "initialize" the solution. If there is no other source if error, it should converge.
  Reply With Quote

Old   March 18, 2007, 15:46
Default Re: reverse flow?
Posts: n/a
with a mixture model being used, i suggest tht turbulence intensity is not realistic in this case. also flow from 1mm hydraulic dia (a micro channel)into a 20 cm cubic region??? i think ricard, u need to make sure of the dimensions u r using to model the flow
  Reply With Quote


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
Reverse Flow Bharati FLUENT 0 September 14, 2010 01:09
Flow simulation in reverse drum mixer Patel Chirag CFX 0 July 19, 2010 15:05
reverse flow alikami FLUENT 1 June 2, 2010 04:19
Reverse flow in the VOF model yan FLUENT 1 May 26, 2005 09:14
reverse flow Giovanni FLUENT 11 October 15, 2001 03:01

All times are GMT -4. The time now is 20:12.