Conservative Interface flux
 

Should convey heat radiation from the fluid to another fluid through the air, put the 2 interfaces with the regime - Conservative Interface flux. The air begins to heat up to 3000 K (!) for unknown reasons.
Conservative Interface flux takes into account whether the coefficient of absorption / emission given for materials?

Have I asked the type of interface?

http://depositfiles.com/files/c7djkwe0w (Heat transfer.cfx)

http://imagepost.ru/images/139/Clipboard01.jpg

Can you explain what you are trying to model again?

I simulate the heating of the upper domain (1) through the air (2) of the domain (3).
In the upper domain (1) moves the material from the initial temperature 1000 C, the air domain (2) moves with the initial temperature of 450 C.
In the domain (3) flowing the heated gas with a temperature of 2000 C.

Must be correctly configured interefeysy between domains so that the top domain (1) received warmly by heat and radiation and, accordingly, he could transfer heat.

So domain 1 is a solid, domain 2 is a fluid (air), and what is domain 3?

all domen fluid.

in 1 domen - sand (viscous as water)
in 2 domen - air
in 3 domen - hot gaz.

You clearly have not set up the thermal conditions correctly. You must have missed something to take the heat away from the air. I don't have time to do a detailed debug of your simulation, sorry.