Effects of stretch and radiation on the laminar burning velocity of R-32/air flames

Abstract

Experiments are performed for outwardly propagating spherical flames of R-32/air mixtures at constant pressure. A high-speed video camera captures shadowgraph images from which the flame radius as a function of time is extracted. Direct numerical simulations with an optically thin radiation model and detailed kinetics are performed to predict the flame radius and study the effects of stretch and radiation on the inferred laminar burning velocity. The simulations accurately predict the observed flame radius as a function of time. Analyses of the simulation results show that both stretch and radiation effects are important, occur concurrently, and make extraction of the unstretched adiabatic laminar burning velocity from the experimental data difficult.