Near black surfaces
The Gebhart method describes the radiative heat transfer in terms of heat coming from one surface and absorbed by another, including all reflections. The Gebhart matrix traces exactly the radiative transfer contribution of each surface to the others.
For two surfaces with high emissivities (close to 1) the Gebhart factor can be simplified by:
Reflections are then not taken into account, but because of the low reflectivity its fraction is relatively small and therefore also the error you make. In that case the relation becomes:
His Majesty King Willem-Alexander (in the middle) opened the new wing of the Leiden Instrument Makers School, in a ceremony attended by students, teachers and guests. Dick Harms (right), director...Read more
The December issue of Mikroniek, click here for a first impression, features the theme of ‘Precision in Agro’ and includes articles on the research at famous agricultural knowledge institutes such...Read more