252
5 Numerical Models for Pebble-Bed Heat Transfer
Fig. 5.9 Comparison of numerical obstructed view factor and Radiation Interaction Function (RIF)
in packed bed of spheres
Fig. 5.10 The bed packed of cubical particles (a) and the view factor as function of distance (b)
numerical computation of the obstructed view factor [30]. Hence, it proves that basic
assumptions in the approximation function model are reasonable.
In addition, the concept of Radiation Interaction Function (RIF) can be extended to
other packed beds, e.g., packed with non-spherical particles. For example, as shown
in Fig. 5.10a the bed is packed with cubical particles [31], which is of the same
particle volume and packing density as packed with spheres in Fig. 5.7a. The length
of the cube edge L c is 48.36 mm and η =
r i j
L c
. The RIF at α f = 0.39 and X m =
1
6
(for
5 Numerical Models for Pebble-Bed Heat Transfer
Fig. 5.9 Comparison of numerical obstructed view factor and Radiation Interaction Function (RIF)
in packed bed of spheres
Fig. 5.10 The bed packed of cubical particles (a) and the view factor as function of distance (b)
numerical computation of the obstructed view factor [30]. Hence, it proves that basic
assumptions in the approximation function model are reasonable.
In addition, the concept of Radiation Interaction Function (RIF) can be extended to
other packed beds, e.g., packed with non-spherical particles. For example, as shown
in Fig. 5.10a the bed is packed with cubical particles [31], which is of the same
particle volume and packing density as packed with spheres in Fig. 5.7a. The length
of the cube edge L c is 48.36 mm and η =
r i j
L c
. The RIF at α f = 0.39 and X m =
1
6
(for