IIE Lunchtime Seminar - Simón Santamaría (University of Edinburgh)

“Investigation on the ignition of solid fuels under transient heating scenarios. Understanding of the gas phase by use of an FTIR gas analysis.”

Abstract: Deeper understanding on the ignition of solid fuels is required to improve our ability to predict flame spread and fire growth.  The following study focuses on investigating the effect of transient thermal boundary conditions on the onset of ignition. These conditions arise during the early stages of fire development.  A novel approach is used where samples of PA6 (nylon polymer) are exposed to transient incident heat fluxes while the mass and energy balances are monitored in real time. The existence of a critical flux of pyrolysis required for ignition is confirmed by a constant mass loss rate at ignition for all heating scenarios of 3.5 ± 1.5 g/(s∗m^2 ) . Using a Fourier Transformed Infrared Spectroscopy (FTIR) gas analysis, a semi-quantitative approach is used to evaluate the differences in the pyrolysis products arising due to the thermal decomposition process undergone by the solid during pyrolysis. By identifying the yields of a broad range of hydrocarbons and evaluating the total mass of carbon and nitrogen produced during pyrolysis (pre-ignition) and comparing that with the mass loss rate, we are able to show that different decomposition mechanisms take place when the sample is exposed to different heating rates. Analysis of the energy balance allows comparison of the effective heat of reaction associated to surface phenomena such as melting or bubbling and their impact on the thermal decomposition processes. These results demonstrate that the heating rate plays a significant role in predicting ignition. This has application to ignition and flame spread criteria widely used in fire safety engineering. 

Bio: Simon Santamaria is a second year PhD student at The University of Edinburgh. He earned his bachelor degree in Mechanical Engineering at Universidad Simón Bolívar in Caracas, Venezuela and later completed the International Master of Science in Fire Safety Engineering (IMFSE). He joined the fire group in October 2015.