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

Mass Flow Rate Error

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 24, 2009, 17:04
Default Mass Flow Rate Error
  #1
New Member
 
Join Date: Nov 2009
Posts: 1
Rep Power: 0
jallison is on a distinguished road
Hi,

I have a pressure based, steady, wall bounded flow, with pressure inlet and outlet, where flow is driven by radial blades fixed to rotate in a fluid volume in a rotating frame. Inlet and outlet are both at ambient pressure. The walls are smooth, no-slip, with no-shear walls at the inlet and exit to give a calming length. Flow enters axially then is driven radially outward through a high aspect ratio channel. The program uses the SA turbulence model. When the walls bounding the channel are narrowly spaced, the mass flow rate matches experimental results. However, when the walls are widely spaced, the Fluent mass flow rate is about 30% less than the experimental mass flow rate. I believe the error is in the Fluent model, but despite checking monitors and residuals and allowing the models thousands of iterations to flatline, the mass flow rate is not coming out as expected.

I have attempted a laminar model which has the residuals stuck in a limit cycle before converging and k-omega which also seemed to display some sort of limit cycle, but was too computationally expensive anyway.

I have also attempted refining the mesh, with ~20 grid points between the wall and the rotating blade. This gives a mesh of 3M cells, and I can't afford any more.

Does anyone have any thoughts as to what could be causing this discrepancy?

Thanks, Jon
jallison is offline   Reply With Quote

Old   May 16, 2011, 16:22
Default Do u got solution?
  #2
New Member
 
Tanaji
Join Date: Sep 2010
Location: Texas Usa
Posts: 11
Rep Power: 16
tanaji is on a distinguished road
Send a message via Skype™ to tanaji
Hi Jallison,
I am also facing same problem of flow rate mismatch.

Let us know, if you have got the solution to fix this problem.

Thank you
tanaji is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
CFX turbo - Mass flow rate Vashishth Patel CFX 7 April 3, 2014 20:33
Compile problem ivanyao OpenFOAM Running, Solving & CFD 1 October 12, 2012 09:31
Problem with compile the setParabolicInlet ivanyao OpenFOAM Running, Solving & CFD 6 September 5, 2008 20:50
Compiling problems with hello worldC fw407 OpenFOAM Installation 21 January 6, 2008 17:38
mass flow rate error Masood FLUENT 0 May 22, 2005 00:32


All times are GMT -4. The time now is 15:53.