An experimental and kinetic modeling study of the auto-ignition delay times of trimethyl phosphate-in-air mixtures

Abstract

Organophosphorus compounds (OPCs) are known to be combustion inhibitors (CI), fire suppressants, or flame retardant molecules (FRMs) for polymers and as surrogates (simulants) for the disposal or thermal degradation of chemical war agents (CWAs). Despite a significant number of studies on the mechanism of their action, OPCs’ combustion chemistry is still insufficiently understood. There is a need for further understanding of their auto-ignition and oxidation characteristics at relevant conditions (high pressures and low temperatures). This study reports on new data on the autoignition delays of Trimethyl Phosphate (TMP)-in-air mixtures obtained from experiments performed on a high-pressure shock tube (HPST) at pressures of 5 and 10 bar in the initial temperature range from 1200 to 2200 K. An updated TMP kinetic model deduced from the Glaude et al. model for the thermal degradation of OPCs is also proposed for the estimation of the autoignition delays of the studied mixtures by incorporating new reaction pathways and corresponding rate constants estimation of some reactions involving TMP and some intermediate products of its degradation. The results indicate that the proposed model is in satisfactory agreement with all the investigated mixtures.

Keywords

• Trimethyl phosphate
• Auto-ignition delay times
• High-pressure shock tube
• Chemical kinetic modeling
• Flame retardants
• Organophosphorus compounds