Study on Effects of Flame Retardants on Chemically-Inhibited Diffusion Flames

Case Western Reserve University, Cleveland OH

Investigators

Abstract

High-performance and low-cost brominated compounds are popular flame retardants but are being phased out due to environmental and health concerns. It is urgently needed to find environmentally friendly alternatives. In this project, research will be conducted to investigate the effects of various compounds on chemical inhibition in diffusion flames that bear resemblance to real fires. Measurements of flame structure, with corresponding numerical simulations, will shed light on the interactions of flames, flows, and inhibitors. This project will provide the basic understanding of the detailed chemical inhibition mechanisms of potential flame retardants, including both halogen-based and halogen-free compounds. The resulting knowledge will help develop proper screening and testing methods for characterizing flame retardants. This project will benefit society by promoting fire safety and reducing fire losses. This project is to study the effects of gas-phase chemical inhibitors on the structure of coflow diffusion flames, generated using a cup burner. The goal is to obtain a better understanding of flame extinguishment and retardation mechanisms. This work will be focused on the gas phase process, thereby excluding condensed phase charring phenomena. The research team will investigate, experimentally and computationally, the structure of methane and propane diffusion flames with halogenated and halogen-free (phosphorus) inhibitors added to the air or fuel. Unlike premixed flames, the transport of inhibitors and active intermediates play an important role. Modern combustion diagnostic tools will be used, including particle imaging velocimetry, thin-filament pyrometry, and planar laser-induced fluorescence of OH and CH radicals. The experimental results, including flame structures and minimum extinguishing concentrations of inhibitors, will be compared with the transient axisymmetric computations using full chemistry and multi-species transport. This work will greatly advance our knowledge of the combustion and inhibition behaviors of the selected halon replacement agents and phosphorus-containing retardants. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.