HEAT TRANSFER CHARACTERIZATION OF A HOT CYLINDER ON AN INERT SUBSTRATE

Wildland firebrands ignite homes through a variety of ignition pathways, including penetration into attic spaces. The ignition of attic insulation materials is dependent on the air flow conditions and the configurations of firebrands deposited. The heat transfer from the firebrand to the substrate is the key factor in substrate ignition. In this study, experimental heat transfer results from surrogate steel firebrands cooling on an inert substrate are presented. We examine the effects of convective and radiative cooling of these surrogate fire-brands (steel cylinders) and the heat transfer from the cylinders to the substrate. In order to explore the effects of cooling on the surrogate firebrand, non-contact temperature measurements were taken via an IR camera. Initial calibration tests show good agreement between the actual cylinder temperature and the IR temperature data. Constant heat flux experiments were performed to validate the substrate material choice and the placement of thermocouples within the substrate.