I am running an FDS file with a fire of several pallets, a great storage of paper. The total RHR available is more than 2000MW. The total surface of the aforementioned storage is more than 500m2 (total number of Grid Cells 1080000, physical dimensions 24x36x10m).
In the FDS file I used a "Simple Pyrolysis Model" (11.4 FDS User's Guide) with a specific HHRPUA [kW/m2], one for surface ("&SURF") named Burner and one for surface ("&SURF") named Paper.
Also, in the FDS file I used a "Single-Step, Mixing-Controlled Combustion", with reaction characteristics as follow:
and "Mass Fraction Transformation Matrix to Convert Species Mixtures (Columns) to Primitive Species (Rows)" extract from "CHID.out" as follow:
Carta 0.000000 1.000000 0.000000
NITROGEN 0.760861 0.000000 0.632995
OXYGEN 0.230510 0.000000 0.000000
CARBON DIOXIDE 0.000590 0.000000 0.263970
CARBON MONOXIDE 0.000000 0.000000 0.000672
WATER VAPOR 0.008039 0.000000 0.099841
SOOT 0.000000 0.000000 0.002521
HYDROGEN 0.000000 0.000000 0.000000
The ventilation consists to window and doors, the former broke up at 300°C before the 10th minute, and the latter open by fire figther at 20th minute.
The model suffers a low availability of Oxigen within the storage area. I suppose that the total of paper material gets to autoignition Temperature, and than all the paper material produce gaseous fuel due to pyrolisys which doesn’t burn due to the absence of Oxigen.
The gaseous fuel products from pyrolysis spread and exit from the internal area (paper storage) and from the computational domain. Is that plausible?
This idea comes from the following considerations: