Difference of result betn Fluent & CFX simulation for S2S radiation
 

Hello,

i am simulating two co-axial cylinder having same length and two end with adiabatic condition for surface to surface radiation model. when i done the above case in fluent by considering S2S model im geting radiation heat from outer to inner surface 650 W and for the same case which was done in CFX by using monte carlo S2S model, i got radiative heat as 595 W.
By theoretical calculation i got result of 594.5 W means it is close to CFX result.

So,My query is why fluent result is deviating much from theoretical one?

Thanx in advance

Regards,
Niks@24:)