[Martin_Sz]

Hello
Anyome have idea how to model automatic heat curve in Fluent?
Problem description
I have solid steel shaft with diameter 0.1 m. Shaft is heated by hot gas inlet. Goal temperature of shaft is 500 C . Starting from 25 C. So I need to define automatic heating curve on inlet (only tempersture ) over time to optimal heating shaft to 500 C . Overheat can be 505C . I need control temperature on reference point on shaft over time .
Best regards

[Martin_Sz]

Anyone have any idea how to make function with if function which will be based on earlier iteration of temperature on reference point ???

[AlexanderZ]

so you need to vary inlet temperature depends on temperature of specific points, is it correct?

[Martin_Sz]

yes I need automatic control a temeporature on inlet based on refenece point temeprature on shaft.
For example I need have optimal heating curve to heat up shaft to 500 C but i dont want to overheat above 505 C. I can make head on curve for example in first minutes heating curve can be 700 C.
Best regards

[AlexanderZ]

you may use something like this

#include "udf.h"

cell_t cell;
Thread *thread;
real temp_criteria = 300.0;

DEFINE_ON_DEMAND(find_cell)
{
CX_Cell_Id cx_cell;
real NV_VEC(pt);
real c_centroid[ND_ND];
NV_D(pt, =, 0.5, 0.3, 0.2); //coordinate of your specified location,it must be in the domain coordinate range
CX_Start_ND_Point_Search();
cx_cell=*CX_Find_Cell_With_Point(pt);
CX_End_ND_Point_Search();
cell=RP_CELL(&cx_cell); //the right cell number
thread = RP_THREAD(&cx_cell); // the thread
C_CENTROID(c_centroid,cell,thread);
temp_criteria = C_T(cell,thread)
Message0("coordinate of the specified point: x=%g,y=%g,z=%g\n",pt[0],pt[1],pt[2]);
Message0("coordinate of the cell found: x=%g,y=%g,z=%g\n",c_centroid[0],c_centroid[1],c_centroid[2]);
Message0("temperature = %f,temp_criteria);
}

DEFINE_EXECUTE_AT_END(get_temperature)
{
	temp_criteria = C_T(cell,thread);
	Message0("temperature = %f,temp_criteria);
}

DEFINE_PROFILE(inlet_temperature, t, i)
{
face_t f;
begin_f_loop (f,t)
{
	if (temp_criteria>=500)
		F_PROFILE(f,t,i) = 500;
	else
		F_PROFILE(f,t,i) = 700;
}
end_f_loop(f,t)
}

modified coordinates for monitor point

execute on_demand function after initialization
hook other functions properly

[Martin_Sz]

Thank You very much !!!
I have question Can I define in this macro location as specify finite element (defined by number)?
This macro I need to load as User define Function like?

For these days I only load transiet table to fluent by the following commands
file
read-transient-table
filename.txt
Best regards

[AlexanderZ]

you may use google and youtube to find answer to these questions