Combustion-radiation

Fred

Hi there, I use the DO model for the modelling of radiaition inside a rotary kiln. The solid phase of the rotary kiln is modelled elsewhere. It yields me profiles of volatiles mass flowrate, bed temperature, and kiln temperature. I use this profiles in order to fix Fluent Bondary conditions of the gas pahse. In fluent, I use k-Epsilon, PDF modelling and DO Radiaition. Well, in fact I want to compute the heat transfer to the kiln and to the bed. But in fluent, you have several choice : inciddent-raidiation, surface incident radiaition, radiaition hat-flux, total surface heat flux. No links seem to exist between these fluxes, and they diffr from several order of magnitudes. Does anybody has an explanation about the signifiance of these fluxes, and which one should I use. Thanking you in anticipation