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Old   June 18, 2007, 11:53
Default Sieve Tray Hydraulics,..I'm stuck,
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I'm simulating sieve tray hydraulics using Eulerian Dispersed Multiphase model, with additional UDF to change the default Schiller-Naumann drag model. But everytime i started the simulation, the error pressure correction is always displayed only after 2 or 3 iterations. I try to using Mixture model too, but the obtained results was too far from the experiments. Here is my UDF.

#include "udf.h" #include "sg_mphase.h"

#define void_g_ave 0.6068 #define V_g 1.65

DEFINE_EXCHANGE_PROPERTY(custom_drag,cell,mix_thre ad,s_col,f_col) { Thread *thread_l, *thread_g; real x_vel_l, x_vel_g, y_vel_l, y_vel_g, z_vel_l, z_vel_g, absv,slip_x, slip_y, slip_z, rho_l, rho_g, mu_l, taup, void_l, void_g, vslipave, reyp, cd, fdrgs, k_g_l;

/* find the threads for the liquid (primary) */ /* and gases (secondary phases) */

thread_g = THREAD_SUB_THREAD(mix_thread, s_col);/* gas phase */ thread_l = THREAD_SUB_THREAD(mix_thread, f_col);/* liquid phase*/

/* find phase velocities and properties*/

x_vel_l = C_U(cell, thread_l); y_vel_l = C_V(cell, thread_l); z_vel_l = C_W(cell, thread_l);

x_vel_g = C_U(cell, thread_g); y_vel_g = C_V(cell, thread_g); z_vel_g = C_W(cell, thread_g);

slip_x = x_vel_g - x_vel_l; slip_y = y_vel_g - y_vel_l; slip_z = z_vel_g - z_vel_l;

rho_l = C_R(cell, thread_l); rho_g = C_R(cell, thread_g);

void_l = C_VOF(cell, thread_l); void_g = C_VOF(cell, thread_g);

/*compute slip*/ absv = sqrt(slip_x*slip_x + slip_y*slip_y + slip_z*slip_z);

/*compute drag*/ vslipave = V_g / void_g_ave;

/*compute drag and return drag coeff, k_g_l*/

fdrgs = (rho_l -rho_g)*9.81*void_l *void_g *absv / (vslipave*vslipave*(1.-vslipave));

k_g_l = fdrgs;

return k_g_l; }

Now I'm stuck, and the time is tickling continuously. Any help from you the experts about what should i do, including BC settings, changing this UDF and other settings is absolutely appreciated
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Old   June 19, 2007, 07:11
Default Re: Sieve Tray Hydraulics,..I'm stuck,
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Are there somebody that could help me, pleaaaaseeee..!
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