|
[Sponsors] |
February 19, 2009, 15:10 |
Cp (Specific heat) UDF. When/what version???
|
#1 |
Guest
Posts: n/a
|
I've seen release notes saying UDF's can be used for specific heat. I compiled and loaded a DEFINE_PROPERTY UDF in 12.0.7, but when I select "user defined" for specific heat, a dialog pops up saying no UDFs have been loaded. What gives? Is this not fully functional yet or am I doing something wrong? Thanks!
|
|
February 21, 2009, 04:38 |
Re: Cp (Specific heat) UDF. When/what version???
|
#2 |
Guest
Posts: n/a
|
your UDF was not either loaded or you forgot to put return Cp; to your UDF
|
|
February 23, 2009, 16:32 |
Re: Cp (Specific heat) UDF. When/what version???
|
#3 |
Guest
Posts: n/a
|
Thanks for responding. Any other possibilities? I've done both.
To check my UDF, I wanted know if a DEFINE_PROPERTY had been loaded. So, I selected user-defined for the density and my UDF is there. However, doing the same with Cp gives a pop-up saying "No user-defined functions have been loaded". So, my thinking is that the Cp UDF functionality has not been completed as of version 12.0.7. |
|
February 23, 2009, 16:51 |
Use DEFINE_SPECIFIC_HEAT, not DEFINE_PROPERTY
|
#4 |
Guest
Posts: n/a
|
The udf.h file contains the define. Here it is:
#define DEFINE_SPECIFIC_HEAT(name, T, Tref, h, yi) real name(real T, real Tref, real *h, real *yi) So, write a UDF so as the one below... #include "udf.h" /* UDF that computes Cp for diatomic oxygen, O_2 */ DEFINE_SPECIFIC_HEAT(cell_cp_o2, T, Tref, h, yi) { real Cp; /* define your version of Cp here... */ return Cp; } |
|
February 25, 2009, 13:02 |
Re: in addition to defining Cp, the code must
|
#5 |
Guest
Posts: n/a
|
define the enthalpy for the specie (real *h) as the integral from Tref to T of the defined/returned Cp. The mass fractions, (real *yi) are given in the specie order as defined for the material.
! If the enthalpy is not defined, calculations requiring the energy equation will not work. |
|
January 10, 2013, 20:25 |
About the equation for h in the UDF for Cp
|
#6 | |
Member
Abhijeet Shrawage
Join Date: Feb 2012
Posts: 31
Rep Power: 14 |
Quote:
I have been trying to to what you said for a while but I seem to be having a problem with the way FLuent is calculating enthalpy. The integration i have done is correct for the polynomial for Cp (T) but Fluent is pulling a Tref value which causes my h to go negative. Can you give me any advice regarding this? Thanks |
||
May 3, 2013, 09:09 |
udf-cp
|
#7 | |
New Member
wang hui
Join Date: May 2013
Posts: 2
Rep Power: 0 |
Quote:
|
||
May 3, 2013, 09:17 |
udf-cp
|
#8 | |
New Member
wang hui
Join Date: May 2013
Posts: 2
Rep Power: 0 |
Quote:
and i also want to know how to get the "T",because there is not any position parameter among (T, Tref, h, yi).....very thanks |
||
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Specific heat in STAR-CD | Andrew | Siemens | 3 | September 3, 2009 23:33 |
specific heat and mean specific heat | Duan J Q | Siemens | 2 | November 20, 2007 06:59 |
specific heat | grzesiek | FLUENT | 2 | February 16, 2006 11:18 |
Specific heat | Andrea | CFX | 1 | May 30, 2004 01:55 |
specific heat in UDF | gino | FLUENT | 3 | November 22, 2001 23:16 |