Fluent UDF difference between C_YI value and monitor results
 

Hi. I am modeling adsorption bed of porous media.
I used mixture of methane and hydrogen.
and I used source term to adsorb hydrogen in the porous media.
but I stored C_YI(mass fraction of h2) value in udsi but
there is a difference between the value of C_YI(udsi) and monitored mass fraction value of h2.
I used pressure-based solver.
I need the mass fraction of h2 to specify the area where the adsorption takes place.
Any ideas?