Hi all I am wondering how big is the influence of thermal radiation during combustion in internal combustion engines, for example. If I had a close transparent box full of air at 3000K, and I were close to this box, would I feel hot? I assume the material of the box is perfectly transparent and is thermally insulated from the hot air, in order to have no radiation from the box itself. Any hint is appreciated. Roadracer

If the material of the box is perfectly transperent (ficticious material) for the radiation you may feel intence radiation. But apprntly transperent looking glasses may be opaque to radiation wavelength under consideration. Generally thermal radiation wavelength range is high i.e. 0.1 to 1000 microns. This contains all UV, visible, infrared radiation. So you should specify transperent for which wavelength. Thanks,

Hi Carno I think that my problem is related to infrared radiation. I´d like to know whether or not include radiation with partecipating media during combustion simulation in internal combustion engines, in order to achieve a more realistic in-cylinder temperature calculation. I´m not expert in the field of radiation, but I think that it all depends on air emissivity coefficient. If this coefficient is very low, probably I can neglect the influence of radiation. Am I right? Thanks Roadracer