Engineering topics
Publications and source records attributed to Johansson, O..
Several different numerical methods for calculating diffuse radiation viewfactors are described. Each is applied to a range of surface configurations, from almost completely unobstructed to a dense set of intersecting surfaces. The speed, accuracy and unique characteristics are discussed in order to define optimal methods for different surface geometries.
A method is presented for the computation of radiant heat flux between arbitrary surfaces which permits a user defined level of accuracy. The method can be applied to directionally dependent surface properties, specular radiation, or solar illumination, and ensures conservation of energy. The method is compared with others to demonstrate its value.
The computation of radiation heat transfer through absorbing media is commonly done through the zoning method which relies upon values of the geometric mean transmittance and absorptance. The computation of these values is difficult and expensive, particularly if many spectral bands are used. This paper describes the extension of a scan line algorithm, based upon surface-surface radiation, to the computation of surface-gas and gas-gas radiation transmittances.