FISAMA is a joint research project of Aalto University and VTT, funded by the Academy of Finland. It started in 2016/9.
- Paajanen, A. Vaari, J. High-temperature decomposition of the cellulose molecule: a stochastic molecular dynamics study. Cellulose, 2017. 24:2713-2725. doi:10.1007/s10570-017-1325-7
- Baroudi, D., Ferrantelli, A., Li, K., Hostikka, S. A thermomechanical explanation for the topology of crack patterns observed on the surface of charred wood and particle fibreboard. Combustion and Flame, 2017. 182:206-215. doi:10.1016/j.combustﬂame.2017.04.017
- Li, K. Mousavi, M., Hostikka, S. Char cracking of medium density fibreboard due to thermal shock effect induced pyrolysis shrinkage. Fire Safety Journal, 2017. 91:165-173. doi:10.1016/j.firesaf.2017.04.027
- Hostikka, S., Matala, A. Pyrolysis model for predicting the heat release rate of birch wood. Combustion Science and Technology, 2017. 189(8):1373-1393. doi:10.1080/00102202.2017.1295959
- Li, K. Mousavi, M., Hostikka, S. Char cracking of medium density fibreboard due to thermal shock effect induced pyrolysis shrinkage. 12th International Symporium of Fire Safety Science, Lund, Sweden, June 2017.
- Vaari, J. Building a reactive molecular dynamics framework for cellulose pyrolysis
studies. The 4th International Cellulose Conference, October 17-20,2017, Kyushu University School of Medicine, Fukuoka, Japan.
FISAMA -project deals with multiscale modelling of pyrolysis processes within bio-based materials in conditions relevant for fires. We try to tackle challenges related to
- Unresolvable phenomena in continuum scale pyrolysis modelling
- Hierarchical structure of natural materials
- Fundamental mechanisms of fire-retardancy
The overall goal is to improve the fire safety of bio-based materials by detailed analyses of their thermal degradation processes. Reflecting the physical scales of the problem, the project is divided into three work packages having goals of their own:
WP1 will aim at creating detailed understanding of the molecular level processes leading to the formation of either volatile or solid degradation products, in order to explain and optimize the use of chemical fire retardants.
In WP2, we want to reveal the processes that lead to the formation of char fissures, and to propose physical means of avoiding them in order to strengthen the fire resistance function of the char layer.
Finally, in WP3, we will derive continuum-scale model parameters from the lower level models to apply the results in engineering calculations that demonstrate the real-scale impact of the small-scale findings.
- The molecular scale pyrolysis chemistry of cellulose, our primary polymer to be modelled, will be investigated using Reactive Molecular Dynamics (RMD) simulations. We are usnig code ReaxFF. The purpose of the RMD pyrolysis simulations is to investigate the thermal decomposition of cellulose at a molecular level, providing predictions of the reaction paths, as well as the associated chemical kinetics. The simulations can also be used to estimate the basic thermal properties of the system.
- The possibilities to improve the char layer stability will be investigated using Material Point Method (MPM) simulations. One of the codes used will be Uintah.
- As a third physical scale of modelling, we will use the continuum-scale pyrolysis model embedded within the Fire Dynamics Simulator software (FDS).
- Material characterization will take place using thermogravimetric analyses, mass spectrometry, differential scanning calorimetry, micro-scale combustion calorimetry, and SEM.
- For the validation purposes, we will use the experimental data from the University of Science and Technology of China.