CFD Online Logo CFD Online URL
Home > Forums > OpenFOAM

a question about Massflow Calculation

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

LinkBack Thread Tools Display Modes
Old   January 28, 2011, 09:18
Default a question about Massflow Calculation
Join Date: May 2010
Location: munich
Posts: 44
Rep Power: 9
xck1986 is on a distinguished road
Hi Foamusers,

I have use rhoSimpleFoam to simulate a valve. Now I have a question about the massflow calculation.

In openfoam WIKI I have found a function:

type patchMassFlow;
functionObjectLibs ( "" );
verbose true;
patches ( inlet outlet );
factor 19.7363;

What I am not clear is the factor 19.7363. For My case I have use factor=1.
But the massflow results I get is 30% smaller than the results simulated by another CFD software StarCCM+.
In OpenFOAM WIKI, it said:

factor A
factor with which the results should be multiplied before being written to disk/terminal. Used to account for symmetries etc (not used by all function objects) Depending on the type of the functionObject in this library these entries are used:

So can anyone tell me what means here account for symmetries?
For my model I have use half of the CAD valve model to run the simulation, so I have a symmetryplane. Do I need to set this factor bigger than 1?

Thanks a lot!

Last edited by xck1986; January 29, 2011 at 15:19.
xck1986 is offline   Reply With Quote

Old   January 29, 2011, 13:47
Senior Member
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,240
Blog Entries: 1
Rep Power: 18
nimasam is on a distinguished road
hi chenkai
let me describe my point with an example.
u have an axiymetric mesh (consider a tube, you choose a section of it) as ur cross section is a portion of the main cross section, ur mass will be a portion of mass flow too! so i guess im not sure at ALL! the factor equals (tube cross section/ chosen cross section)
nimasam is offline   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
MRF and Heat transfer calculation Susan YU FLUENT 0 June 2, 2010 08:46
Defining output as input for second calculation mannobot FLUENT 1 June 2, 2010 04:20
calculate MASSFLOW for a component MAldaz CFX 1 November 7, 2007 12:41
re: Massflow reset in CFX 10 Wooster CFX 5 March 16, 2007 21:08
question K.L.Huang Siemens 1 March 29, 2000 04:57

All times are GMT -4. The time now is 20:57.