A numerical study on the response of chemically active flame inhibitors to strain rate variations

Abstract

In the current work, a framework for assessing the effect of strain rate on the effectiveness of chemically active flame inhibitors is presented. The effect of inhibitors added in a counterflow diffusion flame of methane is studied numerically. Four different compounds representing iron, potassium, phosphorus, and bromine-based inhibitors are chosen for a detailed study. The flame variables under the influence of these inhibitors are investigated in terms of peak flame temperature, heat release rate and radical pool concentration. Analysis of the above parameters indicates that while the effectiveness of iron, potassium, and phosphorus-based inhibitors reduce significantly at high strain rates, that of the bromine-based inhibitor remains relatively unaffected throughout the range of strain rates studied. Through quantitative reaction pathway analysis, it is shown for the first time that the composition of the radical pool has a great bearing on the effectiveness of the inhibitor. Differences in the observed behaviour between different inhibitors are also explained based on this analysis.