[Geng Fu]

Hi, I am using DEFINE_MASS_TRANSFER to add a new phase change model into VOF model.

There is a problem in accessing volume fraction gradient with C_VOF_G. The results of mass transfer rate are 0 on the interface.

After I checked the thread storage(thread, SV_VOF_G), I found it always equals null.

Any help would be appreciated. Thanks in advance.

  DEFINE_MASS_TRANSFER(liq_gas_source_Sun, cell, thread, from_index, from_species_index, to_index, to_species_index)
  {
    real m_lg; // mass transfer rate on the interface, kg/s/m3 ;
    real h_lg = 2257600; // evaporation enthalpy, J/kg 
    real vof_cutoff = 0.05;
    real vpVofT; // dot product of temperature gradient and volume fraction gradient
    real v_sx; // volume fraction gradient dx
    real v_sy; // volume fraction gradient dy
    Thread *liq, *gas;    
    liq = THREAD_SUB_THREAD(thread, from_index); 
    gas = THREAD_SUB_THREAD(thread, to_index); //  from_index and to_index are defined in the Mass panel of Phase interaction.
    m_lg = 0.0; // Initial value of m_lg.
 
        if ((C_VOF(cell, liq) > vof_cutoff) && (C_VOF(cell, liq) < (1-vof_cutoff)))
        {                                               
           if (NULL != THREAD_STORAGE(thread,SV_VOF_G))
              {
                v_sx = C_VOF_G(cell, gas)[0];
                v_sy = C_VOF_G(cell, gas)[1];  
                printf("THREAD_STORAGE : %f \n", THREAD_STORAGE(gas,SV_VOF_G));     
              }
          vpVofT = v_sx*C_T_G(cell, thread)[0] + v_sy*C_T_G(cell, thread)[1];
          printf("v_sy: %f \n", v_sy);
          printf("TempGradx: %f \n", C_T_G(cell, thread)[0]);
          printf("dot product of TempGrad and VOFGrad: %f \n", vpVofT);
          m_lg = 2/h_lg*C_K_L(cell, gas)*vpVofT; //mass transfer rate from liquid to gas;
        }
       return (m_lg);
   }