Learning Forum

[dhirajlote]

Hello,

I have written UDF for the breakage rate of Coulaloglou and Tavlarides model and interpreted in fluent 17.2 (for population balance modeling).

However, I would like to store a memory of breakage rate. For the same I have used syntax C_UDMI (cell, thread, 0)=breakage rate. But, I am getting this stored value zero everywhere in the domain. Please suggest me the solution.

Here is my UDF,

************************************************************************

UDF that computes the particle breakage frequency

*************************************************************************/

#include "udf.h"

#include "sg_pb.h"

#include "sg_mphase.h"

 

 

DEFINE_PB_BREAK_UP_RATE_FREQ(break_up_freq_tav, cell, thread, d_1)

{

real epsi, alpha, f1, f2, rho_d=1.225;

real C1 = 0.00481, C2 = 0.08, sigma = 0.072;

Thread *tm = THREAD_SUPER_THREAD(thread);/*passed thread is phase*/

epsi = C_D(cell, tm);

alpha = C_VOF(cell, thread);

rho_d = C_R(cell, thread);

f1 = C1*pow(epsi, 1./3.)/((1.+alpha)*pow(d_1, 2./3.));

f2 = -(C2*sigma*(1.+alpha)*(1.+alpha))/(rho_d*pow(epsi,2./3.)*pow(d_1, 5./3.));

C_UDMI(cell, thread, 0) = C1*f1*exp(f2);

return C1*f1*exp(f2);

}

[Rob]

I'd strongly recommend updating to 2019R2 given the significant improvements in the multiphase models.  

Looking at the code, I'd also check whether f1 and f2 are giving sensible results: is the problem with the code not returning a number or the number returned is actually zero?