Synergism of trimethylphosphate and carbon dioxide in extinguishing premixed flames

Abstract

This paper presents a method for determining the optimal (in terms of fire-suppression effectiveness) composition of synergistic binary fire suppressants consisting of a chemically active inhibitor (e.g., trimethylphosphate) and an inert diluent (CO2). The method is based on the numerical simulation of the speed and structure of one-dimensional premixed CH4/air and methyl methacrylate/air flames with the addition of a binary fire suppressant using reduced multistep chemical kinetic mechanisms. A decrease in the normal flame speed to 4.7–5.5 cm/s by the addition of a binary fire suppressant was used as a flame extinguishment criterion, and the minimum index of interaction of the components of the binary fire suppressant as a criterion for the maximum fire-suppression effectiveness. The proposed simulation method can help reduce the need for laborious experiments to determine effective mixtures of fire suppressants, thereby saving time and resources.The kinetic analysis performed in this study provides an insight into the mechanism of the synergism between trimethylphosphate and carbon dioxide in flame extinguishment. The results show that at the optimal ratio of fire-suppressant agents (for a specific flame and initial conditions), the rate of H atom production in methane combustion reactions is minimal and, at the same time, the H consumption rate in inhibition reactions is maximal.