Experimental study on polymer pyrolysis in high-temperature air diluted by H₂O and CO₂ using stagnation-point flow

Combustion experiments were performed for polyethylene (PE) in stagnation-point flow to investigate the fundamental characteristics of PE in high-temperature air combustion (HiTAC). Air diluted by nitrogen, water vapor, and carbon dioxide was tested as the oxidizer, and the oxidizer temperature was varied from 300 to 773 K, to investigate the effect of the dilution and temperature on the regression rate, the extinction limit, and the sooting limit of PE. The kinetic parameters of PE pyrolysis under the combustion conditions were estimated from the regression rate experimental data using a new method combining experiments and numerical simulations. It was found that the previously reported kinetic parameters obtained with thermal gravimetric analysis (TGA) were much smaller than those obtained in this study, and that the kinetic parameters of pyrolysis were affected by dilution.