about DPM UDF in fluent5.4.8

devydevyhu

Hello,
     Thank you for your help.
     But I have another problem.I used Compiled UDFs.In my DEFINE_DPM_SOURCE,I just use S->mass and S->energy.I activate DEFINE_DPM_LAW in FLUENT in the Custom Laws panel, which is opened from the Set Injection Properties panel.I also activate DEFINE_DPM_SOURCE in FLUENT in the Discrete Phase Model panel.When I perform trajectory calculations,I can get a result if I  select Uncoupled Calculations.But if I select Coupled Calculations,it's divergence detected.  
     But the result isn't correct if I  select Uncoupled Calculations.In my UDF code,myreactionrate=8.3314*0.00001*2.7*pow(C_P(c,t)/101325.0,0.27)_DIAM(p)=pow( ( pow((P_DIAM0(p)*100),1.8)-myreactionrate*P_TIME(p) ),1.0/1.8 )*0.01;
     Particle Traces Colored by Particle Diameter(m) is in the accessory.The left of the picture is the particle inlet. The right of the picture is the particle outlet.From the picture,we can conclude that the partcile diamter is decreasing,then increasing.Why does this happen?
     I activate Inert Heating law,DEFINE_DPM_LAW and DEFINE_DPM_SWITCH in FLUENT in the Custom Laws panel, which is opened from the Set Injection Properties panel.I  select Uncoupled Calculations.I find the two laws isn't activated when I analyse the result.
DEFINE_DPM_SWITCH(dpm_switch,p,coupled)
{
    cell_t c = RP_CELL(&p->cCell);
    Thread *t = RP_THREAD(&p->cCell);
    if(C_T(c,t) > 1000.0)
        P_CURRENT_LAW(p) = DPM_LAW_USER_1;
    else   
        P_CURRENT_LAW(p) = DPM_LAW_INITIAL_INERT_HEATING;
}
regards
Devy