thermal energy storage
 

Hi all! I have a little problem with Fluent.

I draw a cylinder with a ceramic honeycomb in the internal layer. The entire domain is composed by a fluid zone (porous medium), a steel vessel and an external insulation (rockwool). I'd like to study the heat exchange (transient, axisymmetric, non equilibrium model), so I wrote two UDFs: one for the temperature inlet and the second for the temperature outlet. I monitor temperature in different points along the baricentric line, but it doesn't change as I desrcibed in UDFs! In particular the temperature in the inlet is correct, but when simulating the outlet temperature is quite different (higher). Someone could see if my UDF is well written? Sorry for my bad english...

DEFINE_PROFILE(Toutlet, thread, position)

{

face_t f;

begin_f_loop(f, thread)

{

real t = RP_Get_Real("flow-time");

if (t < 24)

{F_PROFILE(f, thread, position) = 298.03;}

else if(t >= 24 && t < 67)

{F_PROFILE(f, thread, position) = -0.0000001*pow(t,3)+0.0019*pow(t,2)-0.2386*t+302.88;}

else if(t >= 67 && t < 122)

{F_PROFILE(f, thread, position) = 0.00002*pow(t,3)-0.0085*pow(t,2)+1.0896*t+253.69;}

else if(t >= 122 && t < 226)

{F_PROFILE(f, thread, position) = -0.0000003*pow(t,4)+0.0002*pow(t,3)-0.0519*pow(t,2)+6.3665*t+10.831;}

else if(t >= 226 && t < 1001)

{F_PROFILE(f, thread, position) = 0.00000002*pow(t,3)-0.00003*pow(t,2)+0.0248*t+299.27;}

else

{F_PROFILE(f, thread, position) = -0.00000000000000000000004*pow(t,6) - 0.00000000000000000005*pow(t,5) + 0.00000000000006*pow(t,4) - 0.000000001*pow(t,3) + 0.00001*pow(t,2) + 0.0011*t + 300.01;}
}

end_f_loop(f, thread)

}