The view factor $FA$ is equal to the outer surface area of the burned gases divided by the total vessel surface area. In the analysis, it is assumed that, if ignition occurs in one end of a cylindrical vessel, the burned gases will fill that end as the combustion front propagates. This implies that the view factor is given by the ratio of the surface area of the vessel filled with burned gases to a certain height, divided by the total surface area. The formula for ratio of these two surface areas reduces to a function of the volume fraction of space occupied by burned gas, $VF$, and the ratio of the gas space height, $hg$, to the vessel diameter, $dt$, given by
Display Formula

(36)$FA=1+2VF(hgdt)1+2(hgdt)$