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

UDF mass flow rate

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 16, 2007, 10:27
Default UDF mass flow rate
  #1
Juan
Guest
 
Posts: n/a
Hi, I'm new in fluent and i have a big project to make for university. I need to make a UDF in fluent which gives me the mass flow rate of a fluid that travels through a plane. I know you can do this with "report" and then surface integrals. But there are several flows passing through the plane. One major flow, and some secondary flows (which are in the opposite directions). So i have a criteria on which i can base which flows i want. But how do you turn this into an UDF. I've been reading through the manual, but up untill now, haven't found anything that would suit this problem. I think it's a very basic UDF, but for a newbie it's quite difficult . Any help would be welcome!
  Reply With Quote

Old   December 18, 2007, 08:13
Default Re: UDF mass flow rate
  #2
Greg
Guest
 
Posts: n/a
Hi,

you could iterate through all the faces of the plane and add the products of face_velocity*density*face_area only of those faces where the face_velocity is positive (or negative, depends on your problem).

You can get the face_area with BOUNDARY_FACE_GEOMETRY macro. You will find help in UDF manual how to get values at faces and how to iterate through faces.

Regards,

Greg

  Reply With Quote

Old   December 22, 2007, 10:29
Default Re: UDF mass flow rate
  #3
Juan
Guest
 
Posts: n/a
Thanks for this reply. I've been trying to write the UDF with the help of the manual, but there isn't much explanation in the manual about the basic functions. Could somebody have a look at my code and give some suggestions or tell me where i can find a list of the basic functions used with some explanation. This is my code so far

#include "udf.h"

DEFINE_ON_DEMAND(massflow_hor) { Thread *t; cell_t c; face_t f; real sum_massflow=0., A;

begin_f_loop(f,t) if(C_U(c,t)>0){

sum_massflow += C_U(c,t) * C_R(c,t) * F_AREA(A,f,t);

} end_f_loop(f,t) printf("the massflow is: %g",sum_massflow); }

Could somebody give me some suggestions, how i can compute the massflow through a plane that i want. E.G. that i can give an input which plane i want this function to work in. Also the AREA function gives an error, the A is defined wrongly.

thanks for your help.

  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
mass flow rate not conserved in turbomachine, interface defined wrong? wildli FLUENT 3 September 15, 2022 13:19
Mass flow rate: calculation v/s computation beguxa FLUENT 5 December 2, 2018 22:02
UDF to measure Mass Flow Rate a.lynchy Fluent UDF and Scheme Programming 31 October 4, 2018 15:10
Mass Flow Rate student87 CFX 4 January 2, 2010 05:45
mass flow rate entering and exiting a cell samir bensaid FLUENT 0 July 4, 2007 06:37


All times are GMT -4. The time now is 13:31.