Species Diffusivity in PEMFC Simulation
 

Hi everyone,

I want to use the udf to set diffusivity of the mixture in MEA to zero, I use the code posted below

DEFINE_DIFFUSIVITY(my_diff,cell,thread,index) {

real diffu;

Domain *domain=Get_Domain(1); if(thread==Lookup_Thread(domain,MEA_ID))

diffu=1e-10;

else

diffu=2.88e-5;

return diffu; }

But it seems that it only changes the diffusivity of H2, I also tried to use if(index==0.1..n-1){if(thread==...)diffu=...;else diffu=...;return diffu;} to set each species's diffusivity, but it still doesn't work, only H2's diffusivity has been changed.

What can I do? Can someone tell me how to use this function well and how to set diffusivity of every species in the mixture?