Three-dimensional direct numerical simulations are performed of turbulent combustion of initially spherical flame kernels. The chemistry is described by a progress variable which is attached to a flamelet library. The influence of flame stretch and curvature on the local mass burning rate is studied and compared to an analytical model. It is found that there is a good agreement between the simu...

The effects of unsteady strain rate on the burning velocity of hydrogen/air premixed flames have been studied in an opposed nozzle configuration. The numerical method employs adaptive time integration of a system of differential–algebraic equations. Detailed hydrogen/air kinetic mechanism and transport properties are considered. The equivalence ratio is varied from lean to rich premixtures in o...

In the present study, we have formulated the G equation concept for large-eddy simulation (LES) of premixed turbulent combustion. The developed model for the subgrid burning velocity is shown to correctly reflect Damköhler’s limits for largeand small-scale turbulence. From the discussion of the regime diagram for turbulent premixed combustion, it is shown that given a particular configuration o...

Models of infrared spectra of Type Ia supernovae around maximum light are presented. The underlying dynamic models are delayed detonation explosions in Chandrasekhar mass carbon/oxygen white dwarfs. In combination with the radiative transport codes employed here, these models provide plausible fits to the optical spectra of “normal” Type Ia supernova. Two independent radiative transport codes a...

In this work, the effects of the electric fields on the flame propagation and combustion characteristics of lean premixed methane–air mixtures were experimentally investigated in a constant volume chamber. Results show that the flame front is remarkably stretched by the applied electric field, the stretched flame propagation velocity and the average flame propagation velocity are all accelerate...

Spotting ignition by lofted firebrands is a significant mechanism of fire spread, as observed in many largescale fires. The role of firebrands in fire propagation and the important parameters involved in spot fire development are studied. Historical large-scale fires, including wind-driven urban and wildland conflagrations and post-earthquake fires are given as examples. In addition, research o...