Detailed Modeling of Flame-Wall-Interactions under the influence of phosphorous-containing Flame Retardants and development of a reduced kinetic model

Fire safety engineering plays a vital role in safeguarding lives, property, and the environment by preventing and mitigating fire hazards in buildings, materials, and systems. Phosphorus-based flame retardants, such as dimethyl methylphosphonate (DMMP), are studied for their effectiveness in inhibiting combustion processes. This study investigates the impact of flame retardants on Flame-Wall Interactions by adding varying amounts of DMMP to a premixed methane/air Head-On Quenching flame, where the flame propagates towards a cold wall and extinguishes. Reduced kinetic models for these systems with different DMMP concentrations are developed using the Reaction-Diffusion Manifold (REDIM) method. The REDIM is constructed and validated by comparing results of detailed and reduced kinetics. In this way, the quality of the REDIM reduced kinetics can be verified for the different phenomena resulting due to the inhibiting character of flame retardants. It is shown that the reduced kinetics reproduce the results of the Flame-Wall Interactions under the influence of flame retardants very accurately. The inhibiting character of the flame retardants with respect to the chemical kinetics is well captured, even though it challenges the generation of the reduced kinetics as the amount of added DMMP is very low and in the magnitude of minor species. Additionally, the sensitivity of the simulation with reduced kinetics on the gradient estimate is investigated, showing little to no sensitivity. This model offers significant potential for fire safety engineering, as the drastic reduction in the number of equations enables the analysis of realistic scenarios facilitating the design of safer systems.