Surface Emissivity Values etc.

[JamesEtch]

Hi There. I am currently in the process of writing some simple radiation heat transfer analysis software. I was wondering if anyone could reccommend a good source for obtaining values of surface emissivity etc. By searching for emissivity on this site I have found reference to a good link 'optical and electro' or something. Also a book called: The Satellite Thermal Control Handbook was mentioned. Does anyone have any other ideas? Values for polymers such as polypropylene would be really useful?

Regards, James Etchells

 

[corus]

Heat Transmission by McAdams has tables of total emissivity for various surfaces such as metals, bricks, paints, wood etc. Nothing under poly-thingumajigs though.

corus

 

[IRstuff]

http://www.electro-optical.com/bb_rad/emissivity/matlemisivty.htm

TTFN

 

[Tunalover]

Jamesetch-
Be careful about published values!

A. Spatial considerations. Some emittances are hemispherical and some are normal; you need to know which type is published and decide which type you want to use in your software. Most sources don't make the distinction between the two; they simply say "emittance."

B. Spectral bandwidth. Most real-world surfaces are non-gray especially if the spectrum extends beyond infrared e.g. sunlight. Your sources need to be clear about the spectra that were used to determine the emittances (and reflectances).

Of course if you have specific materials in mind you can get an average of three or more measured values for about $50 per emittance. There are labs that do this routinely...

Tunalover