Hello Karthik,nnthank you very much for your reply.nSo if I set the Radiation Model to gray P-1 (Number of bands is set to zero) and I choose an arbitrary value for my Internal Emissivity of my Wall (for example =0., then the radiation heat flux is in equilibrium with the heat flux to the wall of my object? (I am simulating hypersonic external flow around an object).nAnd I saw that for the Inlet and Outlet BCs there is added the Radiation Tab in which I can choose the External Black Body Temperature Method and the Internal Emissivity. if I leave the default values for this BC, this doesn't affect the Inlet and Outlet BC? nI just want to get the radiation equilibrium thermal BC for my wall and everything else should remain the same as if the Radiation Model was turned off.nnThank you very much!n