Development of Ignition Time and Mass Loss Rate Prediction Models for Rigid Polyurethane Foam with Multi-Step Thermal Degradation Under Various External Heat Flux Conditions

To predict the ignition time and mass loss rate of rigid polyurethane foam (RPU) under various radiative conditions, numerical models with a multi-step thermal degradation process have been developed based on thermogravimetric and combustion experiments. Kinetic parameters are computed via Particle Swarm Optimization with a five-step mechanism. Combustion properties of RPU under various external radiative conditions have been analyzed. From both surface absorption and in-depth absorption, one-dimensional ignition models have been established and solved via COMSOL Multiphysics. According to the ignition criterion, ignition temperature, the numerical ignition model has been established and validated by experimental results. The critical mass flux and its relationship with the external heat flux have been discussed. Moreover, the mass loss rate has been predicted by numerical models. The proposed models in this work potentially have the guiding significance for charring property polymer combustion.