View factors

The heat transfer by radiation is implemented in CrysMAS by view factors. Therefore you must calculate the view factors before computing the temperature.

On the View factors tab you set numerical parameters for the computation of the view factors and the renormation.

The view factors depend on the mesh and some materials properties.

Numerical parameters dialog, View factors tab 

Figure 40. Numerical parameters dialog, View factors tab

Item

Description

Radiation

The Gebhardt matrix will be renormed if the check box is active.

Note

Renormation is not reversible! Once you computed a renormation you cannot deactivate the renormation check box.

Precision

Specifies the desired accuracy of the computation (real number, default 0.005).

threshold for Gebhardt-Matrix

If this factor is > 0, only Gebhardt factors above a certain value are taken into account, see thesis M. Kurz, p. 71.

Ray Tracing Based Model Parameters

Radiation model for semitransparent media, solves the radiation transport equation directly by the backward ray tracing method.

Ray subdivision density factor

Ray subdivision density for integration of the radiation transport equation along the ray. The value 1 is a normal density, higer values enlarge the density linear proportional to the factor.

Space angle discretization

Subdivision of the hemisphere around each node, defines number of particular fixed spatial directions for integration of the radiation transport equation.

Normal density for simple spatial diastributions of the radiative intensity is obtained with the medium button, about 4 times higher density with the high button. The highest spatial density is given by the huge button (about 16 times higher than the medium one).

Related Procedures

Setting view factor parameters