Phase change UDF

rampal · November 19, 2015, 09:03

Hi friends,
I'm doing 2D simulation of "pulsating heat pipe" in fluent. For phase change I'm using UDF which is written below. When Interpreting this UDF, mass source term is not coming in "CEll zone condition" dialogue box. Can anyone help me? Please see this UDF and notify if there is any error. My UDf is:

#include "udf.h"
#include "sg_mphase.h"
#define T_SAT 308
#define LAT_HT 2418.5394e3
DEFINE_SOURCE(vap_src,cell,pri_th,dS,eqn)
{
Thread *mix_th, *sec_th;
real m_dot_v;
mix_th = THREAD_SUPER_THREAD(pri_th);
sec_th = THREAD_SUB_THREAD(mix_th,1);
/*m_dot_v=0.0;*/
if(C_T(cell, mix_th) >= T_SAT)
{
m_dot_v = 0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;

dS[eqn] = 0.0;
}

if(C_T(cell, mix_th) <= T_SAT)
{
m_dot_v = -0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*fabs(T_SAT - C_T(cell,pri_th))/T_SAT;
dS[eqn] = -0.1*C_R(cell, pri_th)*fabs(C_T(cell, pri_th) - T_SAT)/T_SAT;
}
return m_dot_v;
}

DEFINE_SOURCE(liq_src, cell, sec_th, dS, eqn)
{
Thread * mix_th, *pri_th;
real m_dot_l;
mix_th = THREAD_SUPER_THREAD(sec_th);
pri_th = THREAD_SUB_THREAD(mix_th, 0);
/*m_dot_l=0.0;*/
if(C_T(cell, mix_th) >= T_SAT)
{
m_dot_l = -0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;
dS[eqn] = -0.1*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;
}
if(C_T(cell, mix_th) <= T_SAT)
{
m_dot_l = 0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*fabs(T_SAT - C_T(cell,pri_th))/T_SAT;
dS[eqn] =0.0;
}

return m_dot_l;
}

DEFINE_SOURCE(enrg_src, cell, mix_th, dS, eqn)
{
Thread *pri_th, *sec_th;
real m_dot;
pri_th = THREAD_SUB_THREAD(mix_th, 0);
sec_th = THREAD_SUB_THREAD(mix_th, 1);
if(C_T(cell, mix_th) >= T_SAT)
{
m_dot = -0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;
dS[eqn] = -0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*LAT_HT/T_SAT;
}

if(C_T(cell, mix_th) <= T_SAT)
{
m_dot = 0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*fabs(T_SAT - C_T(cell,pri_th))/T_SAT;
dS[eqn] = 0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*LAT_HT/T_SAT;
}
return LAT_HT*m_dot;
}

I'm so confuse that what I should do. I'll be very very thankful for your valuable help.

shahid nadeem · December 15, 2015, 04:33

Did you got the results bro. And how can i change this to 3D case. Thank you

Quote:

Originally Posted by rampal

Hi friends,
I'm doing 2D simulation of "pulsating heat pipe" in fluent. For phase change I'm using UDF which is written below. When Interpreting this UDF, mass source term is not coming in "CEll zone condition" dialogue box. Can anyone help me? Please see this UDF and notify if there is any error. My UDf is:

#include "udf.h"
#include "sg_mphase.h"
#define T_SAT 308
#define LAT_HT 2418.5394e3
DEFINE_SOURCE(vap_src,cell,pri_th,dS,eqn)
{
Thread *mix_th, *sec_th;
real m_dot_v;
mix_th = THREAD_SUPER_THREAD(pri_th);
sec_th = THREAD_SUB_THREAD(mix_th,1);
/*m_dot_v=0.0;*/
if(C_T(cell, mix_th) >= T_SAT)
{
m_dot_v = 0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;

dS[eqn] = 0.0;
}

if(C_T(cell, mix_th) <= T_SAT)
{
m_dot_v = -0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*fabs(T_SAT - C_T(cell,pri_th))/T_SAT;
dS[eqn] = -0.1*C_R(cell, pri_th)*fabs(C_T(cell, pri_th) - T_SAT)/T_SAT;
}
return m_dot_v;
}

DEFINE_SOURCE(liq_src, cell, sec_th, dS, eqn)
{
Thread * mix_th, *pri_th;
real m_dot_l;
mix_th = THREAD_SUPER_THREAD(sec_th);
pri_th = THREAD_SUB_THREAD(mix_th, 0);
/*m_dot_l=0.0;*/
if(C_T(cell, mix_th) >= T_SAT)
{
m_dot_l = -0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;
dS[eqn] = -0.1*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;
}
if(C_T(cell, mix_th) <= T_SAT)
{
m_dot_l = 0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*fabs(T_SAT - C_T(cell,pri_th))/T_SAT;
dS[eqn] =0.0;
}

return m_dot_l;
}

DEFINE_SOURCE(enrg_src, cell, mix_th, dS, eqn)
{
Thread *pri_th, *sec_th;
real m_dot;
pri_th = THREAD_SUB_THREAD(mix_th, 0);
sec_th = THREAD_SUB_THREAD(mix_th, 1);
if(C_T(cell, mix_th) >= T_SAT)
{
m_dot = -0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;
dS[eqn] = -0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*LAT_HT/T_SAT;
}

if(C_T(cell, mix_th) <= T_SAT)
{
m_dot = 0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*fabs(T_SAT - C_T(cell,pri_th))/T_SAT;
dS[eqn] = 0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*LAT_HT/T_SAT;
}
return LAT_HT*m_dot;
}

I'm so confuse that what I should do. I'll be very very thankful for your valuable help.

rampal · December 15, 2015, 23:19

I have not got any results till now, but I think there will be no change in udf for 3D case.

shahid nadeem · December 15, 2015, 23:33

Oh Thank you so much if i get results i ll inform you. Hope i get it

Thank you

Quote:

Originally Posted by rampal

I have not got any results till now, but I think there will be no change in udf for 3D case.

rampal · December 16, 2015, 02:02

Thanks Brother,
I'm also doing this problem. I have read UDF manual carefully. Now I'm trying to update UDf. I'll also inform you, if there is any up-gradations in results.
Thanks

MDSHUJAN · June 17, 2016, 08:56

Quote:

Originally Posted by rampal

Hi friends,
I'm doing 2D simulation of "pulsating heat pipe" in fluent. For phase change I'm using UDF which is written below. When Interpreting this UDF, mass source term is not coming in "CEll zone condition" dialogue box. Can anyone help me? Please see this UDF and notify if there is any error. My UDf is:

#include "udf.h"
#include "sg_mphase.h"
#define T_SAT 308
#define LAT_HT 2418.5394e3
DEFINE_SOURCE(vap_src,cell,pri_th,dS,eqn)
{
Thread *mix_th, *sec_th;
real m_dot_v;
mix_th = THREAD_SUPER_THREAD(pri_th);
sec_th = THREAD_SUB_THREAD(mix_th,1);
/*m_dot_v=0.0;*/
if(C_T(cell, mix_th) >= T_SAT)
{
m_dot_v = 0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;

dS[eqn] = 0.0;
}

if(C_T(cell, mix_th) <= T_SAT)
{
m_dot_v = -0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*fabs(T_SAT - C_T(cell,pri_th))/T_SAT;
dS[eqn] = -0.1*C_R(cell, pri_th)*fabs(C_T(cell, pri_th) - T_SAT)/T_SAT;
}
return m_dot_v;
}

DEFINE_SOURCE(liq_src, cell, sec_th, dS, eqn)
{
Thread * mix_th, *pri_th;
real m_dot_l;
mix_th = THREAD_SUPER_THREAD(sec_th);
pri_th = THREAD_SUB_THREAD(mix_th, 0);
/*m_dot_l=0.0;*/
if(C_T(cell, mix_th) >= T_SAT)
{
m_dot_l = -0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;
dS[eqn] = -0.1*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;
}
if(C_T(cell, mix_th) <= T_SAT)
{
m_dot_l = 0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*fabs(T_SAT - C_T(cell,pri_th))/T_SAT;
dS[eqn] =0.0;
}

return m_dot_l;
}

DEFINE_SOURCE(enrg_src, cell, mix_th, dS, eqn)
{
Thread *pri_th, *sec_th;
real m_dot;
pri_th = THREAD_SUB_THREAD(mix_th, 0);
sec_th = THREAD_SUB_THREAD(mix_th, 1);
if(C_T(cell, mix_th) >= T_SAT)
{
m_dot = -0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*fabs(C_T(cell, sec_th) - T_SAT)/T_SAT;
dS[eqn] = -0.1*C_VOF(cell, sec_th)*C_R(cell, sec_th)*LAT_HT/T_SAT;
}

if(C_T(cell, mix_th) <= T_SAT)
{
m_dot = 0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*fabs(T_SAT - C_T(cell,pri_th))/T_SAT;
dS[eqn] = 0.1*C_VOF(cell, pri_th)*C_R(cell, pri_th)*LAT_HT/T_SAT;
}
return LAT_HT*m_dot;
}

I'm so confuse that what I should do. I'll be very very thankful for your valuable help.

Hi. Did you make your udf work, and did you get condensation? Can you share your final udf wih me ?

zakizadeh · January 22, 2017, 02:10

Hi
I'm trying to simulate thermosyphon. But when the UDF read, and I want to run, the following error was printed!
please help

FLUENT received fatal signal (ACCESS_VIOLATION)
1. Note exact events leading to error.
2. Save case/data under new name.
3. Exit program and restart to continue.
4. Report error to your distributor.

my email: zakizadeh.ac@gmail.com

rampal · January 27, 2017, 23:00

Dear friends, currently I'm not working on this project. Perhaps my udf was working, but not coming realistic results. I want to complete this project, but unfortunately currently I'm not in research institution. This project requires commercial ANSYS software.

November 19, 2015, 09:03	Phase change UDF	#1
rampal Member Ram Kumar Pal Join Date: Apr 2015 Posts: 38 Rep Power: 11	Hi friends, I'm doing 2D simulation of "pulsating heat pipe" in fluent. For phase change I'm using UDF which is written below. When Interpreting this UDF, mass source term is not coming in "CEll zone condition" dialogue box. Can anyone help me? Please see this UDF and notify if there is any error. My UDf is: #include "udf.h" #include "sg_mphase.h" #define T_SAT 308 #define LAT_HT 2418.5394e3 DEFINE_SOURCE(vap_src,cell,pri_th,dS,eqn) { Thread mix_th, sec_th; real m_dot_v; mix_th = THREAD_SUPER_THREAD(pri_th); sec_th = THREAD_SUB_THREAD(mix_th,1); /m_dot_v=0.0;/ if(C_T(cell, mix_th) >= T_SAT) { m_dot_v = 0.1C_VOF(cell, sec_th)C_R(cell, sec_th)fabs(C_T(cell, sec_th) - T_SAT)/T_SAT; dS[eqn] = 0.0; } if(C_T(cell, mix_th) <= T_SAT) { m_dot_v = -0.1C_VOF(cell, pri_th)C_R(cell, pri_th)fabs(T_SAT - C_T(cell,pri_th))/T_SAT; dS[eqn] = -0.1C_R(cell, pri_th)fabs(C_T(cell, pri_th) - T_SAT)/T_SAT; } return m_dot_v; } DEFINE_SOURCE(liq_src, cell, sec_th, dS, eqn) { Thread * mix_th, pri_th; real m_dot_l; mix_th = THREAD_SUPER_THREAD(sec_th); pri_th = THREAD_SUB_THREAD(mix_th, 0); /m_dot_l=0.0;/ if(C_T(cell, mix_th) >= T_SAT) { m_dot_l = -0.1C_VOF(cell, sec_th)C_R(cell, sec_th)fabs(C_T(cell, sec_th) - T_SAT)/T_SAT; dS[eqn] = -0.1C_R(cell, sec_th)fabs(C_T(cell, sec_th) - T_SAT)/T_SAT; } if(C_T(cell, mix_th) <= T_SAT) { m_dot_l = 0.1C_VOF(cell, pri_th)C_R(cell, pri_th)fabs(T_SAT - C_T(cell,pri_th))/T_SAT; dS[eqn] =0.0; } return m_dot_l; } DEFINE_SOURCE(enrg_src, cell, mix_th, dS, eqn) { Thread pri_th, sec_th; real m_dot; pri_th = THREAD_SUB_THREAD(mix_th, 0); sec_th = THREAD_SUB_THREAD(mix_th, 1); if(C_T(cell, mix_th) >= T_SAT) { m_dot = -0.1C_VOF(cell, sec_th)C_R(cell, sec_th)fabs(C_T(cell, sec_th) - T_SAT)/T_SAT; dS[eqn] = -0.1C_VOF(cell, sec_th)C_R(cell, sec_th)LAT_HT/T_SAT; } if(C_T(cell, mix_th) <= T_SAT) { m_dot = 0.1C_VOF(cell, pri_th)C_R(cell, pri_th)fabs(T_SAT - C_T(cell,pri_th))/T_SAT; dS[eqn] = 0.1C_VOF(cell, pri_th)C_R(cell, pri_th)LAT_HT/T_SAT; } return LAT_HTm_dot; } I'm so confuse that what I should do. I'll be very very thankful for your valuable help.

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December 15, 2015, 23:19		#3
rampal Member Ram Kumar Pal Join Date: Apr 2015 Posts: 38 Rep Power: 11	I have not got any results till now, but I think there will be no change in udf for 3D case.

December 16, 2015, 02:02		#5
rampal Member Ram Kumar Pal Join Date: Apr 2015 Posts: 38 Rep Power: 11	Thanks Brother, I'm also doing this problem. I have read UDF manual carefully. Now I'm trying to update UDf. I'll also inform you, if there is any up-gradations in results. Thanks

January 22, 2017, 02:10		#7
zakizadeh New Member mehrdad Join Date: Oct 2015 Posts: 3 Rep Power: 10	Hi I'm trying to simulate thermosyphon. But when the UDF read, and I want to run, the following error was printed! please help FLUENT received fatal signal (ACCESS_VIOLATION) 1. Note exact events leading to error. 2. Save case/data under new name. 3. Exit program and restart to continue. 4. Report error to your distributor. my email: zakizadeh.ac@gmail.com

January 27, 2017, 23:00		#8
rampal Member Ram Kumar Pal Join Date: Apr 2015 Posts: 38 Rep Power: 11	Dear friends, currently I'm not working on this project. Perhaps my udf was working, but not coming realistic results. I want to complete this project, but unfortunately currently I'm not in research institution. This project requires commercial ANSYS software.