Showing papers by "Raymond Viskanta published in 1965"

Effectiveness of a layer of an absorbing-scattering gas in shielding a surface from incident thermal radiation

Abstract: A layer of radiating gas is analyzed to determine its effectiveness in shielding a surface from incident radiation The radiation falling on the “free boundary” of the layer is made up of a diffuse and a collimated component It is assumed that the gas is gray and capable of absorbing, emitting and isotropically scattering radiation; and the surface is a gray, diffuse emitter and reflector of radiation Heat transfer by conduction and convection is neglected compared to radiation, the problem is formulated exactly in terms of integral equations, and an approximate solution is obtained by the collocation method A comparison of the heat transfer results with those of the unshielded case shows that for a highly absorbing surface there is considerable reduction in heat transfer if the optical thickness of the layer is large enough On the other hand, there is very little reduction in heat transfer for a highly reflecting surface regardless of the magnitude of the optical thickness