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-   -   UDF for transient pressure inlet, mass flow check at nozzle exit and volumetric heat (http://www.cfd-online.com/Forums/fluent/91617-udf-transient-pressure-inlet-mass-flow-check-nozzle-exit-volumetric-heat.html)

kokoory August 17, 2011 02:07

UDF for transient pressure inlet, mass flow check at nozzle exit and volumetric heat
 
1 Attachment(s)
hello, guys.

I have a problem to apply udf to my model.
the problem is analysizing very small nozzle.
However, I have no idea to code and apply udf.

first, I used a pressure inlet to vary a total pressure from 0 to 10Mpa using udf.
It's good to check and analysis the nozzle. But, in addition, I have to apply checking a mass flow rate at nozzle exit. after checking the mass flow rate, I should apply a volumetric heat addition as per mass flow rate( mass flow rate * mdot Q).

here is the question.

1. I hooked the below code, however, I think it is not working. I wanna do change the pressure from 2Mpa to 10Mpa and check the mass flow rate at the exit simultaneously.
plz help me.. :(

Please see the attach

#include "udf.h"

face_t f;
cell_t c;

DEFINE_EXECUTE_AT_END(mass)
{
Domain *d;

real flow=0;
real p=0;

Thread *t;


d = Get_Domain(1);
t= Lookup_Thread(d, 7);

begin_f_loop(f,t)
{
flow+=F_FLUX(f,t);
}
end_f_loop(f,t)
p = C_P(c,t);
printf("MASS Flow Rate: %g\n",flow);
}

DEFINE_PROFILE(pre, t, i)
{
real pressure_mag;
real cu_tim;
//face_t f;
cu_tim = CURRENT_TIME;

if((cu_tim>=0)&&(cu_tim<10))
{
pressure_mag=202650+101325*cu_tim;
}

else
{
pressure_mag=1013250;
}

begin_f_loop(f,t)
{
F_PROFILE(f,t,i) = pressure_mag;
}
end_f_loop(f,t)
}


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