Link on Participation by Lara Leonelli at the 12th International Symposium on Fire Safety Science with a presentation entitled "Characterization of aerosols from the combustion of dead shrub twigs and leaves using a cone calorimeter"
Lara Leonelli, a third-year student involved with the "Fire" project, participated from 12 to 16 June 2017 in the 12th International Symposium on Fire Safety Science in Lund (Sweden).
The title of her presentation was "Characterization of aerosols from the combustion of dead shrub twigs and leaves using a cone calorimeter", a summary of which can be found here:
This research contributes towards improving knowledge on the smoke released by wildland fires. It focuses on the characterisation of aerosols released through the combustion of dead shrub leaves and branches of various diameters (from 1 to 20mm). The experiments were conducted on a small scale by means of a calorimeter cone for the burning of leaves and branches of the Montpellier cistus. The auto-ignition of samples was obtained by exposing their surface area to a 50 kW/m² flow of heat. The smoke and aerosols released before ignition during the preheating phase were analysed separately to the smoke and spray released during the flame phase. The HRR (Heat Release Rate) was also measured, and two different behaviours were observed depending on the diameter of the branches. The samples with branch diameter less than 4mm present a unique peak of HRR while two peaks were observed for branches of higher diameters. The SPR (Smoke Production Rate) was also measured and it demonstrated that the smoke was mainly released during the pre-ignition phase. We also saw a strong correlation between the HRR and the SPR during the flame phase, but we did not observe the release of smoke during the combustion phase of sooty residue. The release factors for the spray were calculated according to the combustion phases (pre-ignition and flame), and for each of the sample diameters. The aerosols were observed by scanning electron microscopy and transmission electron microscopy (SEM and TEM). The chemical composition of OC (organic carbon) aerosols, released during the pre-ignition phase, was analysed by gas chromatography coupled with mass spectrometry (GC / MS). Carcinogenic compounds were identified. The size of the aerosols released was measured for the OCs and BCs (soot) using an optical device. Most of the BCs were PM0.3, which corresponds to the alveolar fraction of the particles. This research makes a contribution to improving knowledge about the smoke released by wildland fires. It focuses on the characterisation of aerosols released through the combustion of dead shrub leaves and branches of various diameters (from 1 to 20mm). The experiments were conducted on a small scale by means of a calorimeter cone for the burning of leaves and branches of the Montpellier cistus. The auto-ignition of samples was obtained by exposing their surface area to a 50 kW/m² flow of heat. The smoke and aerosols released before ignition during the preheating phase were analysed separately to the smoke and spray released during the flame phase. The HRR (Heat Release Rate) was also measured, and two different behaviours were observed depending on the diameter of the branches. The samples with branch diameter less than 4mm present a unique peak of HRR while two peaks were observed for branches of higher diameters. The SPR (Smoke Production Rate) was also measured and it demonstrated that the smoke was mainly released during the pre-ignition phase. We also saw a strong correlation between the HRR and the SPR during the flame phase, but we did not observe the release of smoke during the combustion phase of sooty residue. The release factors for the spray were calculated according to the combustion phases (pre-ignition and flame), and for each of the sample diameters. The aerosols were observed by scanning electron microscopy and transmission electron microscopy (SEM and TEM). The chemical composition of OC (organic carbon) aerosols, released during the pre-ignition phase, was analysed by gas chromatography coupled with mass spectrometry (GC / MS). Carcinogenic compounds were identified. The size of the aerosols released was measured for the OCs and BCs (soot) using an optical device. Most of the BCs were PM0.3, which corresponds to the alveolar fraction of the particles.