Hello CFX-Users,

I am setting up a model where I want to consider radiative heat transfer and CO2 and H2O vapour are definitely present.

I understand from the manuals that knowing the optical thickness is important in selecting the most appropriate Radiation model.

Does anyone know how to calculate the optical thickness?

Thank you, Jonathan

Using Beer's Law and curves from Hottel and Sarofim will do the trick for H2O and CO2. Siegel and Howell's text is very helpful - Thermal Radiation Heat Transfer.